CN107974888A

CN107974888A - Construction method of the strength concrete pile as roadbed filling

Info

Publication number: CN107974888A
Application number: CN201711251129.XA
Authority: CN
Inventors: 朱春明; 郎卫军; 曾庆伟; 王军艳; 冯伟; 原慕兴
Original assignee: Jiangsu Sinoroad Engineering Technology Institute Co Ltd
Current assignee: Jiangsu Sinoroad Engineering Technology Institute Co Ltd
Priority date: 2017-12-01
Filing date: 2017-12-01
Publication date: 2018-05-01

Abstract

The present invention relates to a kind of construction method of strength concrete pile as roadbed filling; construction method of the strength concrete pile of the present invention as roadbed filling; the collapsible loess that can not be utilized in the past is used using specially treated measure; as roadbed filling, the combination of arable land, ecological protection and refuse reclamation sustainable development is realized.With great researching value and dissemination will be put into practice to administering this project Canal in Loess Area subgrade engineering, while preferably utilization can be obtained on Practical Project field for it and provides certain scientific basis and theoretical reference.

Description

Construction method of the strength concrete pile as roadbed filling

Technical field

The present invention relates to construction of the highway field, is specifically a kind of construction method of strength concrete pile as roadbed filling.

Background technology

For loess when not by water-soaked, common intensity is higher, and compression is small, but structure is easily destroyed after chance water and produces aobvious Write.And collapsibility is a kind of special engineering geological property of loess, it is under dead weight or external action, by water logging Notable additional deformation occurs for rapid destroy after wet.Loess is quite extensive in whole world distribution, accounts for the ten of whole land gross areas / mono-.China is that loess area is distributed one of most wide country, loess area about 64 × 104km2, main distribution in the world On the ground such as Shanxi, Shaanxi, Gansu, Qinghai, Ningxia, Henan, i.e. the Yellow River between 34 °~45 ° of north latitude, 101 °~114 ° of east longitude One band of middle reaches, wherein Qinghai Area are mainly distributed on the river valley area such as southeastern Caidamu basin and tree rings, Datonghe River.Hand over In logical engineering construction, particularly in Eastern Region of Qinghai Province, this loess zone with collapsibility feature of route crosses, gives Design and construction bring inconvenience, and builders will be often to solve the problems, such as the costly energy of collapsible loess and cost. Generally the loess that cannot be directly used to roadbed filling is discarded in Collapsible Loess District, engineering construction at present, changes and fills out it The roadbed filling of its better performances, or the area for the difficulty that fetches earth using the method that lime or chemical agent are improved to loess into Row improvement is used for roadbed filling.For directly discarded, although can solve in Canal in Loess Area subgrade construction problems faced, It is also to bring environmental disruption, land resource to waste, a series of excessively high adverse effects of cost.

In view of the defects of above-mentioned, the designer is actively subject to research and innovation, to found a kind of strength concrete pile conduct The construction method of roadbed filling, makes it with more the utility value in industry.

The content of the invention

In order to solve the above technical problems, the object of the present invention is to provide it is a kind of it is more simple, convenient, effectively to loess Improve and using the Loess Filling after improvement as roadbed filling strength concrete pile as roadbed filling construction method.

To achieve the above object of the invention, construction method of the strength concrete pile of the present invention as roadbed filling, including：Loess Middle cement blending rate determines, construction survey setting-out, feeding, first leveling, cement spreading, machine mixing, it is secondary flatten, roll, Compactness detects, wherein, cement blending rate determines to specifically include in loess：Prepare 5 parts of loess and cement of identical weight part Soil is blended, blending soil to each part respectively carries out liquid model limitation test, compaction test, has done shearing strength examination respectively to mechanical characteristic Test, unconfined compression strength test, CBR experiment, collapsibility experiment, cement is determined based on obtained test data analyzer result Volume, wherein the cement blending rate that each part blends soil is respectively：4%th, 5%, 6%, 7%, 8%.

Further, the construction survey setting-out specifically includes：

Former coordinate points, elevational point, encryption traverse point, bench mark are checked by construction requirement, recover route center line, Add temporary bench mark；

Rear ground elevation is rolled before being filled out using spirit level detection, fill toe is determined according to actual measurement absolute altitude and designed elevation Line, roadbed leg wire of slope is released using total powerstation, while width of subgrade is designed width than it and had more 30 ㎝, is drawn using lime Go out roadbed fills sideline, and 30cm sets a skirt piles outside the roadbed both sides sideline of every 20m straightways, and with red paint mark with Determine a cross section, measuring point is laid according to test section floor plan, actual measurement each point rolls rear top surface absolute altitude；

Compacted thickness is calculated according to front and rear depth displacement is filled, calculates coefficient of loose laying, wherein, coefficient of loose laying=(pine paving elevation- Sub-layer elevation)/(elevation-sub-layer elevation after compacting).

Further, the feeding includes：Loess is carried out to pave, after the stacking spacing draw square of cloth, filler By horizontal slice, center carries out discharging behind high, first both sides after first low, and when embankment is complete disconnected using longitudinal direction according to design section Face horizontal slice is filled, from lowest point placement in layers, successively compacting 25cm is not to be exceeded；

Paving using loading machine for filler, uniform filling stall with goods spread out on the ground for sale is layered on predetermined width, by actual measurement filler Moisture content, if the filler moisture content after paving is too small, is sprinkled water compared with optimum moisture content on packing layer, Until reaching the moisture content of requirement, watering amount is computed determining；If moisture content is excessive, it should be tedded, be reached most Good moisture content；

Every layer of roadbed fills strict implement " frame soil loading ", and grid is spread out with lime line before banketing, pine paving when paving Coefficient is using 1.2 controls, and loose laying depth 30cm, definite grid size is 10m × 10m, and dumper preferentially uses when unloading soil The mode of soil loading is fallen back, i.e., after discharging vehicle unloads soil, is immediately pushed open the earthwork newly fallen with loading machine；Next dumper exists Just spread out on soil layer and fallen back, using banket attack and occupy by the way of unload soil；According to the method control of loose laying depth ruler method or heap ash platform Filled height processed.

Further, the specific steps of moisture content detection include：Take cement improvement loess subgrade sample, fine grained soil 15~ 30g, sandy soil, organic soil 50g, sand gravel are 1~2kg, are put into and weigh in box, cover box lid immediately, claim quality；Claim During amount, the counterweight with the quality such as the weighing box is put in balance one end, mobile balance rider, weighing result subtracts title after balance It is wet soil quality to measure box quality；

Box lid is opened, sample and box are put into baking oven, is dried under 105~110 DEG C of constant temperature of temperature；Drying time is to thin Grain soil must not be less than 8h, and 6h must not be less than to sandy soil；To containing native or gypseous soil of the organic matter more than 5%, by temperature control Make the constant temperature F at 60~70 DEG C, dry 12~15h；

Sample after drying and box are taken out, cooling in drier is put into, cools down 0.5~1h, box lid is covered after cooling, claim Quality m_s, accurately to 0.01g；

Moisture content is calculated as follows：

In formula：W-moisture content (%), calculates to 0.1；

M-wet soil quality (g)；

m_s- dry ground quality (g).

Further, the first leveling specifically includes：

After the dosage for calculating loess and cement, height control line is set up to control loose laying depth, filler first passes through loading Machine is slightly put down, then is carried out essence with land leveller and put down, wherein, loose laying depth is no more than 30cm；

Land leveller essence should usually be struck off by a lateral other side, accomplish that aspect is smooth, uniform, if necessary can be again Return is scraped one time, static pressure 1 time after essence is flat；

The secondary leveling specifically includes：Voltage stabilizing one time is carried out after soil cement mixture uniform mixing again, immediately with flat Ground machine is just flat again, and land leveller is struck off by a lateral opposite side, then with road roller immediately on just just flat section it is fast Fast static pressure one time, then it is flat once with land leveller essence.

Further, the cement is dispensed and specifically included：The spreading of cement is carried out using outer doping, sets truck spreader water Mud spreading amount is 23kg/m², before dispensing cement, according to processing width, it is 2.3m to pull width with lime, both sides overlap joint 5cm's Runway guides cement truck spreader to dispense cement, and the artificial draw square of the use less than 2.3m width carries out cloth ash.

Further, the machine mixing specifically includes：

In the case where moisture content is met the requirements, cement, loess soil mix are carried out using road-mixed machine, check that mix is deep in real time Spend and coordinate road-mixed machine operator to adjust mix depth, the surface of l0cm sub-layers is destroyed when mixing and stirring；Road-mixed machine normally mixes and stirs two It is secondary, after mix is uniform, carry out moisture content, the sampling and measuring of grey dosage；If lime dosage is unsatisfactory for requiring, according to testing number The cement consumption for needing to add according to calculating, is mixed and stirred again after uniformly dispensing；

At the end of mix, if the moisture content deficiency of mixture, is supplemented with sprinkling truck and sprinkled water；After watering, carry out again Mix, makes moisture be evenly distributed in blended stock；Mixing machinery should reduce moisture stream immediately sprinkling truck followed by mix Lose；Sprinkle water during mix, check the moisture content of mixture in real time, answer color and luster consistent after mixture uniform mixing, without cement Group and flower face, and uniform moisture is suitable；For cement using in outer doping incorporation loess, admixture volume is 4%, 5% or 6%.

Further, the roller compaction process specifically includes：

When the moisture content of filler is equal to or more than optimum moisture content 1-2% and cement dose EDTA titration qualifications after integer When, rolled immediately according to the compaction procedure drafted, detect compactness in real time so that compactness is more than design and normal value More than；It is whole roll work and to control completed before failing no more than slow setting cement, after the completion of rolling, through after the assay was approved into Row is lower to construct together；Test section is rolled using " 1-1-N-1 " combination, i.e. a static pressure, one time it is weak shake, N is all over by force Shake, a static pressure, it is specific as follows to roll step：

First with road roller static pressure and it is weak shake, when compacting, is first pressed among both sides lean on behind curb part and press, after static pressure Superficial compaction situation, to the artificial feed supplement in low-lying location, makes surface reach the degree of uniform compaction；

Then first pass and second time vibrating compacting are carried out with heavy road roller.When heavy road roller rolls second time completion Afterwards, use Determining Degree of Extrusion by Impregnation Sand respectively near the lime point of mark and use total station survey three-dimensional coordinate.To measure, Testing result is recorded in corresponding record sheet according to numbering and level, vibrating compacting pass；

Compactness detection is carried out, as compactness is met the requirements, then carries out a static pressure；As compactness is unsatisfactory for requiring, then Second step program is repeated, shakes by force a compactness detection is carried out after rolling every time, until stopping after compactness detection is qualified strong Shake；

If vibroroller cmpacting pass cannot still reach design requirement compactness more than 8 times, then require to replace rolling apparatus, This roadbed is set to reach design requirement；

The control of the road roller static pressure speed of travel is left in 3.7km/h in 2.3km/h or so, the control of the vibroroller cmpacting speed of travel It is right；Overlapping widths static pressure is wide for 1/4 wheel when rolling, and pressure of shaking is wide for 1/3 wheel；Road roller is changing travel direction, is slowing down or stop It should first stop vibrating before sailing, smoothly change traffic direction, not allow road roller to change direction in the state of inertia rolling.

Further, using the cement dose of titration determination roadbed, specifically include：

EDTA is prepared：Weigh EDTA37.23 grams；Dissolved with 40~50 distilled water, 1000ml is settled to after cooling；

Ammonium chloride solution is prepared：Claim 500 grams of ammonium chlorides, add distilled water 4500ml to dissolve；

Sodium hydroxide is prepared：Claim 18 grams of sodium hydroxides, be put into the beaker of cleaning, add 1000ml distilled water to make its whole Dissolving, adds 2ml triethanolamines, is stored in after stirring evenly in glass jar after cooling；

Calred indicator is prepared：0.2 gram of Binding Reaction between Calconcarboxylic Sodium and 20 grams are dried in an oven in advance 1 it is small when potassium sulfate Mixing, is put into finely ground in mortar, is stored in stand-by in brown, wide-mouth bottle；

1000 grams of sampling, adds ammonium chloride solution 2000ml, stirs 5 minutes, stands 10 minutes；

Upper clear supernate is transferred in the beaker of 300ml stir evenly capping it is stand-by；

With clear liquid 10ml above pipette, extract, it is put into the triangular flask of 200ml, sodium hydroxide 50ml is drawn with buret, Add in triangular flask, the pH value for surveying solution at this time is 12.5~13；

0.2 gram of calred indicator is added to shake up；

EDTA solution is added in buret and records volume V₁；

Start to titrate, shaken up in titration, examine solution colour, when solution colour is changed into purple, slow down titration speed Spend, shake up, until pure blue is terminal, record the volume V of EDTA₂；

Calculate V₂-V₁, look into standard curve table and determine cement dose.

Further, the measurement of the compactness specifically includes：

S1 selects one piece of flat surfaces in test site, and is cleaned up, its area cannot be less than substrate area；

S2 puts back to substrate on the surface cleaned up, holes along substrate mesoporous, hole hole hole diameter with filling sand cylinder one Cause；Measure layer thickness should be equal to by trying the depth in hole, but must not have subsurface material to be mixed into, finally by whole chisel pine material in hole Take out；To soil matrix or basic unit, divide the quality for weighing material several times；The gross mass for all taking out material is m_w, accurately to 1g；When When needing to detect thickness, the step for carrying out again after thickness should be first measured；

S3 takes out sample from all material dug out, is placed in aluminium box or the enamel tray of cleaning, measures its water content；Sample The quantity of product is as follows：When being measured with small-sized filling sand cylinder, for fine grained soil, no less than 100g；For various middle grain soil, it is no less than 500g；When being measured with large-scale filling sand cylinder, for fine grained soil, no less than 200g；For various middle grain soil, no less than 1000g；It is right In the stabilized with inorganic binder material such as coarse-grained soil or cement, lime, flyash, preferably all material of taking-up is dried, and much In 2000g, claim its quality m_d, accurately to 1g；

Substrate is placed in by S4 test pits on, by fill sand cylinder be placed among substrate, chiltern amount m is piled in cartridge₁, make filling The mesoporous of the lower mouth alignment substrate of sand cylinder and examination hole, open the switch for filling sand cylinder, allow in sand flow enters to test pits；Until in cartridge Sand no longer flow down when, turn off the switch；Take away and fill sand cylinder, and in weighing tank remaining sand quality m₄, it is accurate to 1g；

After being dug in examination hole, the directly alignment of filling sand cylinder is placed on testing pits, centre need not put substrate；Open opening for cylinder Close, allow in sand flow enters to test pits；When the sand in cartridge no longer flows down, turn off the switch, carefully take away and fill sand cylinder, and weigh The quality m ' of remaining sand₄, accurately to 1g；

S5 carefully takes out the amount sand in examination cylinder, in case being used again during experiment next time；If the humidity of amount sand has been changed or measured Impurity is mixed with sand, then should again dry, sieve, and places a period of time, the temperature of itself and air is reached after balance again With；

The quality m for filling up sand used of testing pits is calculated as follows in S6_b(g)：

When filling husky, test pits on be placed with substrate：

m_b=m₁- m₄- (m₅- m₆)

When filling husky, test pits on be not placed with substrate：

m_b=m₁- m₄'-m₂

In formula：m_b- fill up the quality (g) of the sand tested pits；

m₁The quality (g) of sand in-filling sand placket；

m₂The quality (g) of sand in-filling sand cylinder lower cone body；

m₄、m₄After '-fill sand, the quality (g) of remaining sand in cylinder；

(m₅- m₆Total quality (g) of)-fill sand in lower cone body and between substrate and rough surface in sand cylinder；

The wet density ρ for material of testing pits is calculated as follows_w(g/cm³):

ρ_w=m_w/m_b×ρ_s

In formula：m_wThe quality (g) of all material of-middle taking-up of testing pits；

ρ_sLoose measure density (the g/cm of-amount sand³)；

The dry density ρ for material of testing pits is calculated as follows_d(g/cm³)：

ρ_d=ρ_w/(1+0.01w)

In formula：The moisture content (%) of w-material of testing pits；

When for the occasion of the inorganic colloid methoders such as cement, lime, flyash, dry density ρ is calculated as follows_d(g/ cm³)；

ρ_d=m_d/m_b×ρ_s

In formula：m_dThe dries quantity (g) for stablizing soil of-middle taking-up of testing pits；

Construction compaction is calculated as follows；

K=ρ_d/ρ_c×100

In formula：The construction compaction (%) of K-testing location；

ρ_dDry density (the g/cm of-sample³)；

ρ_cMaximum dry density (the g/cm of-the sample obtained by compaction test³)；

m₄、m₄After '-fill sand, the quality (g) of remaining sand in cylinder.

According to the above aspect of the present invention, strength concrete pile of the present invention as roadbed filling construction method at least have it is following excellent Point：

1st, the collapsible loess that can not be utilized in the past is used using specially treated measure, as roadbed filling, Realize the combination of arable land, ecological protection and refuse reclamation sustainable development, while to administering Canal in Loess Area subgrade engineering It is of great significance.

2nd, strength concrete pile mixing proportion design method and the method for inspection, provide guidance for cement improvement mix-design and borrow Mirror.

3rd, the technological process of arrangement and method for construction is mainly：Construction survey setting-out → first leveling → cement spreading → machine mixing → secondary to flatten → to roll → testing inspection, there is presently no corresponding specification, institute's shape for the construction technology of strength concrete pile Into strength concrete pile construction technology can for some reference construct provide refer to and invaluable experience.

Described above is only the general introduction of technical solution of the present invention, in order to better understand the technological means of the present invention, And can be practiced according to the content of specification, below with presently preferred embodiments of the present invention and coordinate attached drawing describe in detail as after.

Brief description of the drawings

Fig. 1 is flow chart of the strength concrete pile of the present invention as the construction method of roadbed filling；

The Atterberg Limit and plasticity index curve map of Fig. 2 difference cement doses；

Fig. 3 difference cement dose tamping curve figures；

Fig. 4 difference cement dose direct shear test results change figures；

Fig. 5 strength concrete pile unconfined compressive strength results contrast figures；

Fig. 6 cement doses different addition quantity improves loess CBR result of the test curve maps；

Fig. 7 loess improves coefficient of collapsibility.

Embodiment

With reference to the accompanying drawings and examples, the embodiment of the present invention is described in further detail.Implement below Example is used to illustrate the present invention, but is not limited to the scope of the present invention.

The mechanism of improvement of strength concrete pile：

Native property can just be changed with a small amount of cement incorporation soil, the reason is that cement, which is distributed in, forms firm core in soil The heart, forms the skeleton of hydrated cement in all gaps, the result so as to constraining grogs.He Zuoge (Herzog) points out, In montmorillonite, stress-strain behavior during low dosage cement shows that cement forms core in soil first, when cement consumption increases Added-time, cement then become skeleton structure, and continuous skeleton structure is just constituted in 2.5% cement consumption.Cement is mixed with soil With it is rear, with the moisture in soil strong hydrolysis and hydration reaction occur for cement minerals, while Ca (OH) is decomposited from solution₂ And other hyrates are formed, their some voluntarily continue hardening and form Behavior of Hardened Cement Paste skeleton, and then with soil interaction, it leads some The action mode wanted is as follows:

1st, ion exchange and pellet effect

In colloid after hydrated cementitious, Ca (OH)₂And Ca²⁺、OH^-Coexist.And clay mineral is with SiO₂Closed for skeleton Into tabular or acicular crystallization be its main composition part, its usual surface can carry Na⁺And K⁺Plasma.The Ca of precipitation²⁺ Ion can be with the Na in soil⁺And K⁺Ion carries out equivalent adsorption exchange, causes electric double layer thickness thinning, soil particle is leaned on tighter It is close.Its result makes substantial amounts of grogs form larger mass of soil.Due to hydrated cementitious product Ca (OH)₂With strong absorption Activity, and make these larger mass of soil grains further combined with, formed cement on chain-like construction, have closing mass of soil between The effect of hole, forms stable connecting structure.

2nd, hard solidifying reaction

With going deep into for hydrated reaction of cement, substantial amounts of Ca is separated out in solution²⁺, work as Ca²⁺Quantity more than above-mentioned ion hand over After the requirement changed, then alkalescence environment in form clay mineral part Ca²⁺And Al₂O₃Chemically react, generate The crystalline mineral of stabilization not soluble in water.

Learnt according to electron microscope, X-ray diffraction and differential thermal analysis, this crystalline compounds are about:

(1)CaO-Al₂O₃-H₂O series hyrates, such as 3CaO-Al₂O₃-16H₂O；

(2)CaO-SiO₂-H₂O series silicic acid limewash compounds, such as 4CaO-5SiO₂-5H₂O；

(3)CaO-Al₂O₃-SiO₂-H₂O series.

It is worth noting that this firmly solidifying reaction of cement need to carry out in strong alkali environment, with cement improvement containing powder or glutinous During the more and larger plasticity index cohesive soil of grain, Ca (OH)₂Cause first with powder or sticking grain effect in this strong alkali environment It cannot be smoothed out, so as to hamper the normal hardening of cement-hydrate, then intensity decreases, this cement are not suitable for improvement modeling The larger cohesive soil of sex index.

3rd, carbonation

Free Ca (OH) in cement-hydrate₂Constantly absorb the CO in air₂Work with vapor one and generate carbonic acid Calcium, this reaction can make mass of soil knot, play coarse, improve the intensity of soil, but more weaker than the effect of hard solidifying reaction.

4th, crystallization

While crystallization is formed, the precipitation end of crystallization, that is, separate out the Al of crystal edge³⁺Ion positive charge will attract to be incorporated into The OH of crystal face is separated out^-Ion negative electrical charge, and then repel between crystal face, so as to form so-called " crystal edge-crystal face combination " Honeycomb structure, and the mineral grain in soil is coated in honeycomb structure, and here it is the structure of Cement Soil.Cement Crystal in soil plays important skeleton function；Hydrated cementitious generation hydrated calcium silicate gel play link crystal, mass of soil, The important cementation of grogs, for this cohesive force from Van der Waals force, hydrogen bond, the synthesis of surface energy, it is main than in weak soil Van der Waals force it is much bigger, soil cement intensity is far above bury intensity.Crystallization process also includes pellet state, no It is same as that cation physical exchange is pellet, crystallization process is the magnetic excitation of zwitterion, it is finally to form continuous crystalline substance Body, equally plays the role of skeleton.

In fact, in Stabilization of Loess, the mass of soil grain of some all sizes not being crushed is always inevitably left. So it will appear from wrapping up soil particle phenomenon by cement mortar in mixing soil cement, the macrovoid between the granule of soil or between sand grains Substantially filled up by cement granules, and there is no cement inside mass of soil.Only under the action of long-time diffusion process, soil Group is internal could to be penetrated into by cement hydrolysate and change its original property.Inevitably result from having in soil cement The cement region of higher-strength and water stability and not completely by the poor region of the intensity of cement stabilization.Both are mutual in space Alternately, so as to form a kind of unique cement soil skeleton.In the more buckshot aggregate region of cement, the hydrolysis and hardening of cement Process is dominant；And in the place that cement is contacted with discrete particle or granule, then physical chemical process is dominant, this effect Produced with the interaction type of physical absorption and chemisorbed, and irreversibly absorb indivedual products of cement hydrolysis.

In conclusion strength concrete pile is Ca (OH) under Behavior of Hardened Cement Paste skeleton function₂The coefficient knot of physical chemistry Fruit, the latter makes the loess particulate crumb structure into stable with micelle particle shape, and cement then coats and connect into heavily fortified point these granules Solid entirety.

Admixture volume (blending rate) refers to the percentage of admixture quality and soil property amount, i.e., calculates by mass percentage, See below formula：

Embodiment 1

As shown in Figure 1, construction method of the present embodiment strength concrete pile as roadbed filling, including：Cement in loess Blending rate determines, construction survey setting-out, feeding, first leveling, cement spreading, machine mixing, it is secondary flatten, roll, compactness Detection, wherein, cement blending rate determines to specifically include in loess：Prepare the blending of 5 parts of loess and cement of identical weight part Soil, blends soil to each part respectively and carries out liquid model limitation test, compaction test, done shear strength test, nothing respectively to mechanical characteristic Confined compression strength test, CBR experiments, collapsibility experiment, cement mixing content is determined based on obtained test data analyzer result, Wherein each part blends native cement blending rate：4%th, 5%, 6%, 7%, 8%.

This implementation first has to determine cement blending rate in loess, and the preferred plan of cement blending rate passes through experiment in loess Mode determines, liquid model limitation test, compaction test have been done respectively to strength concrete pile physical characteristic, and mechanical characteristic is done respectively Shear strength test, unconfined compression strength test, CBR experiments, collapsibility experiment.By analyzing test data, Show that 4%, 5%, 6% cement mixing content improvement loess effect is preferable and more economical, specific experiment method is：

First, experiment carries out the measure of strength concrete pile Atterberg Limit using liquid plastic combine tester：

The disturbance loess sample for field of fetching earth is air-dried, is sieved by the sieve of 0.5mm, field of fetching earth respectively takes 4 parts of 200g's Representative soil sample, additive ratio are respectively 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% cement, then will not with pure water Loess sample with cement mixing content improvement is modulated into uniform paste.

Liquid model limitation test result and analysis

Tested according to above-mentioned liquid model limitation test scheme, concrete outcome is shown in Table 1.

The liquid model limitation test result of 1 strength concrete pile of table

Liquid limit：The liquid limit of undisturbed soil is significantly lower than the liquid limit for the loess for having mixed cement, for the water of different cement mixed weights The liquid limit change of soil is not very greatly.

Plastic limit：Soil cement is less obvious relative to the plastic limit change of undisturbed soil, and soil cement is with the raising of cement mixing content, Plastic limit also gradually steps up.

Plasticity index：Soil cement has relative to the plasticity index of loess significantly to become larger, and plasticity index is with cement The raising of volume first increases and then reduces, and the plasticity index that loess is improved when cement mixed weight is 4% reaches maximum.

Undisturbed soil, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% cement have been carried out to field of fetching earth as can be seen from Figure 2 The experiment of volume.From liquid model limitation test result, the liquid of strength concrete pile, the plastic limit undisturbed soil that compares are significantly increased, And gradually increase with the increase of cement mixing content, and plasticity index first increases and reduces afterwards.When cement mixing content is 4%~5%, Liquid, plastic limit amplitude of variation are smaller；When cement mixing content is 7%~8%, amplitude of variation accordingly increases.Main reason is that to Huang After adding cement in native filler, certain cement is formed, its specific surface area increase, the moisture of absorption also accordingly increases.Cause This, the property of conditioned soil gradually tends to grittiness, changes Loess Yuan and carrys out farinograph property, while also improves its water repelling property.

2nd, the improvement loess to different cement mixing contents carries out compaction test.

The relation curve of dry density under certain compactive effort with water-cut variation can be measured, tries to achieve and changes under the conditions of different addition quantity The maximum dry density and optimum moisture content of good loess, are rolled to improve the design of the indoor and outdoor of loess subgrade filler and site operation Quality control provides foundation.

The plastic limit moisture content of different cement mixing content improvement loess is surveyed according to liquid model limitation test, to each cement mixing content in field of fetching earth Improvement loess prepare sample, every part of example weight is about 4.5kg.According to《Railway engineering earthwork test rule》 (TB10102-2004) requirement, it is selected to determine the field difference cement mixing content that fetches earth with weight I types compaction test (design parameter is as follows) Improve the optimum moisture content (ω of loess_op) and maximum dry density (ρ d_max)。

Compaction test is carried out according to above-mentioned compaction test scheme, real examination is hit in field difference cement mixing content improvement loess actual measurement of fetching earth Test and show that maximum dry density and optimum moisture content are shown in Table 2, and the result of the test in table, draw out the field difference cement that fetches earth The relation curve that the optimum moisture content and maximum dry density of volume improvement loess change with cement mixing content, such as Fig. 3.

2 strength concrete pile compaction test results of table

Undisturbed soil, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% cement have been carried out to field of fetching earth as can be seen from Figure 3 The compaction test of volume.From result of the test in figure：In modified compaction test, loess is improved compared with intact loess, Maximum dry density varies, and is not much different with undisturbed soil, but optimum moisture content is all higher than intact loess.Mixed in different cement Under the conditions of amount, improvement loess maximum dry density increased with the increase of cement mixing content before this, but carrying with mixed ratio Height, maximum dry density show the trend reduced, and cement mixing content maximum dry density at 5% reaches maximum；Different cement mixing contents Under the conditions of, for improvement loess with the increase of cement mixing content, the trend for first increasing and easing up afterwards is presented in optimum moisture content, but totally most Good moisture content is all higher than undisturbed soil moisture content, main reason is that the fineness that cement is added into loess is small compared with loess, due to water The moisture increase that mud absorbs, the moisture of absorption is of a relatively high, and cement mixing content optimum moisture content at 5% reaches maximum, 4% It is also larger with optimum moisture content under 6% cement mixing content；With the increase of additive ratio, soil cement optimum moisture content eases up substantially, nothing Significant change.It is poor in view of the water stability of loess, therefore, the larger cement mixing content of optimum moisture content is selected, is selected in summary It is both economical reliable that test section construction is carried out with 4%, 5% and 6% cement mixing content.

3rd, shear strength test carries out the measure of strength concrete pile shearing strength using direct shear apparatus.

A certain amount of disturbance loess is taken at random from field of fetching earth, and sample is air-dried to be sieved by the sieve of 0.5mm, is configured to 4%th, the sample of 5%, 6%, 7%, 8% 5 kinds of cement mixing contents, moisture content use compaction test in each cement mixing content it is optimal Moisture content, and require coefficient of compaction K=0.95.Test specimen is put into standard curing box maintenance 7d after the completion of preparing, finally with cutting ring pair The test specimen conserved cuts sample and is tested.Improvement loess to each cement mixing content carries out 1 group of experiment, and every group is 4 examinations Sample, sizeUsing quick shear test method, carried out on strain controlling formula direct shear apparatus, shear rate is 0.8mm/min, loading grade is respectively 100,200,300,400kPa.

To be tested according to above-mentioned direct shear test scheme, the field difference cement mixing content improvement shear strength of loess that fetches earth is shown in Table 3, Shearing strength is made of the cohesive strength and interior frictional resistance two parts of loess on sliding surface.Fig. 4 is shear test scene photo, root The relation curve of fetch earth field difference cement mixing content improvement loess and shearing strength is drawn out according to the direct shear test result in table 3, such as Fig. 4.

3 direct shear test result table of table

Undisturbed soil, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% cement have been carried out to field of fetching earth as can be seen from Figure 4 The shear strength test of volume.It can be seen that by result of the test in figure:

(1) after cement improvement, the intensity of loess increases, and the intensity of strength concrete pile is with cement mixing content Increase and increase.

(2) cohesive strength increases relatively low before 4% during cement mixing content, then quick increase；When cement mixing content 5%~ Cohesive strength slowdown in growth when 8%.Cohesive strength is the characteristic index of cohesive soil, and cohesive strength is formed including molecular attraction between grogs After the curing cohesive strength cement that the cementation of compound is formed in original cohesive strength and soil is fully reacted with loess, soil is formed Body skeleton, strengthens soil structures, while colloid is generated in Cement Soil.Therefore, the cohesive strength c of strength concrete pile Increase larger.

(3) compared with the loess of cement improvement, internal friction angle significantly diminishes undisturbed soil, then with the increasing of cement mixing content Add, internal friction angle change is little.This is because loess, after cement improvement, its mineral composition does not change thoroughly, simply sends out Part has been given birth to change, though therefore the internal friction angle of strength concrete pile change, change is little.

4th, strength concrete pile compression strength research.

Take a certain amount of disturbance loess, sample to be sieved after air-drying by the sieve of 0.5mm at random from field of fetching earth, be configured to 4%th, the sample of 5%, 6%, 7%, 8% 5 kinds of cement mixing contents, the sample of the different cement mixing contents for field of fetching earth make 12, Moisture content uses the optimum moisture content of each cement mixing content in compaction test, and requires coefficient of compaction K=0.95.Specimen size isAfter the completion of sample is prepared, standard curing box maintenance 7d, 14d and 28d are respectively put into.Finally to conserving Sample carry out compressive strength test, sample is placed in strain controlling formula triaxial apparatus and is at the uniform velocity added with the speed of 1.52mm/min Lotus, sample is under conditions of no lateral pressure after experiment mainly test loess improvement, strength concrete pile resistance axial compressive force Ultimate strength, be evaluate soil sample resistance vertical pressure ultimate strength important mechanical index.

7d, 14d and 28d saturation of different cement mixing content improvement loess are carried out without side by above-mentioned testing program and operating procedure Compressive strength test is limited, and the average value of the result of the test of same 4 samples of age of the identical cement mixing content in field of fetching earth is as most Whole result of the test.The field difference cement mixing content improvement loess compression strength that fetches earth is shown in Table 4, the non-confining strength in table Result of the test is spent, draws out the relation curve of fetch earth field difference cement mixing content improvement loess and unconfined compressive strength, such as Fig. 5.

4 strength concrete pile unconfined compressive strength value (MPa) of table

Can be seen that from table 4 and Fig. 5 field of fetching earth has been carried out undisturbed soil, 1%, 2%, 3%, 4%, 5%, 6%, 7%, The unconfined compression strength test of 8% cement mixing content.By result of the test it can be seen that:

(1) unconfined compressive strength intensity in original state earth forming 7d is 0.26Mpa, and then 14d and 28d test specimens are being supported There is different degrees of voluntarily breakage during shield and compressive strength test can not be completed.For strength concrete pile, 7d is without lateral spacing In first growth and then when cement dose reaches 4%, growth trend tends towards stability compression strength, 14d and 28d compression strength is in first The intensity of the trend slowly increased after rapid growth, 14d and 28d are very close, but significantly greater than 7d intensity.

(2) unconfined compressive strength of improvement Loess Filling shows under various criterion curing age, strength concrete pile Intensity linearly increases with the increase of cement mixing content early period, but short term strength rate of rise is smaller, mid-term intensity and long-term strong Degree is larger with the increase rate of rise of cement mixing content, in the trend to ease up after first rapid growth.When cement mixing content is 3%, Its long-term strength is less than mid-term intensity；The long-term strength of other cement mixing contents improvement loess is higher than mid-term to varying degrees Intensity.Showing that it is not particularly stable to be less than 3% cement mixing content intensity, when cement mixing content is more than 6%, gain in strength is relatively slow, therefore really Strength concrete pile test section dose ratio is determined for 4%, 5%, 6%.Consider the loss of the generations such as site operation factor, should be greater than Above-mentioned volume.

5th, CBR is tested in strength concrete pile room.

CBR experiments are carried out to the strength concrete pile that volume is 4%, 5%, 6%, 7%, 8% respectively.Different cement mixing contents The CBR experiments of improvement loess are main to include three parts, i.e. compaction test, immersion expansion test and penetration test, specific experiment In strict accordance with《Standard for test methods of earthworks》(GB/T 50123-1999) is carried out.

(1) standard compaction test has been carried out to different cement mixing contents improvement loess first before testing.According to compaction test As a result, preparing sample according to optimum moisture content to different cement mixing contents improvement loess, heavy compaction is then carried out, every group is hit reality Number be respectively 30,50,98 times, every kind of striking times respectively produce 3 test specimens, and one group of CBR experiment needs 9 test specimens, product altogether Finish and measure its water content, and obtain corresponding dry density.

(2) it is simulation material worst state in engineering use, different cement mixing content improvement loess are hit after the completion of reality Soak test is carried out, it is immersion standard round the clock to take four.To simulate roadbed situation, in immersion process, placed on soil body top certain Bearing plate, the porous plate adjusting rod with adjusting rod is placed under bearing plate, is placed the dial gauge of detection swell increment thereon, is measured The final reading of dial gauge is read after immersion after test specimen change in elevation, that is, improves the final swell increment of loess immersion.

(3) after the completion of soaking, take out test specimen and stand 15min, carry out CBR penetration tests.Before experiment first on injection bar Apply 45N power to return to zero again, axial compressive force then is applied to test specimen, while measure dynamometer and specify corresponding injection amount on reading.Examination Carry out drawing unit pressure and injection magnitude relation curve after the completion of testing, finally calculate the CBR of different cement mixing content improvement loess Value, specific calculate see equation below, strength concrete pile CBR result of the tests such as table 5.

CBR=P/7000*100

In formula：CBR is the carrying ratio of injection amount 2.5mm；

P is soil matrix unit pressure, unit K Pa.

5 strength concrete pile CBR result of the tests of table

It can be seen that from table 5 and Fig. 6 and undisturbed soil, 2%, 3%, 4%, 5%, 6%, 7%, 8% water carried out to field of fetching earth The CBR experiments of mud volume.By result of the test it can be seen that：Carry ratio after cement improvement to significantly improve, with cement mixing content Improve, carry than in rising trend, and as the increase of striking times, carrying ratio are also in rising trend；Hit and 50 for 30 Hit cement mixing content CBR at 2% to 5% to rise steadily, be then increased sharply with the raising CBR of cement mixing content, hit for 98 It is more uniform with the raising increase of cement mixing content.In addition, it can be seen that strength concrete pile carrying ratio is satisfied by by data in table Demand of technical standard.

6th, strength concrete pile collapsibility experimental study.

A certain amount of disturbance loess is taken at random from field of fetching earth, and sample is air-dried to be sieved by the sieve of 0.5mm, is configured to 4%th, the sample of 5%, 6%, 7%, 8% 5 kinds of cement mixing contents, moisture content use the optimum moisture content of each cement mixing content, and will Seek K=0.95.Test specimen is put into standard curing box maintenance 7d after the completion of preparing, finally the test specimen conserved is cut using cutting ring Sample is tested, and specimen size isThe strength concrete pile of the every kind of cement mixing content in field of fetching earth respectively carries out The experiment of 1 group of 4 sample.

Collapsibility experiment is carried out according to above-mentioned testing program, field difference cement mixing content improvement Loess Collapsibility property coefficient examination of fetching earth Test and the results are shown in Table 6.Fig. 7 is collapsibility testing ground figure, the collapsibility result of the test in table 6,

6 strength concrete pile coefficient of collapsibility of table

Can be seen that from table 6 and Fig. 7 undisturbed soil has been carried out to field of fetching earth respectively, 4%, 5%, 6%, 7%, 8% cement is mixed The collapsibility experiment of amount.By result of the test it can be seen that：Collapsible loess can effectively improve its saturated yielding by cement improvement Property, it can be seen that improvement Loess Collapsibility property coefficient is respectively less than 0.015, shows do not have collapsibility by data in table.Can from figure To find out, with the increase of cement mixing content, coefficient of collapsibility is also gradually reduced, and shows that strength concrete pile can be removed preferably Collapsibility of loess.

Embodiment 2

Construction method of the present embodiment strength concrete pile as roadbed filling, the concrete construction method of roadbed filling：Apply Work surveying and locating, feeding, first leveling, cement spreadings, machine mixing, it is secondary flatten, roll, compactness is detected and specifically wrapped Include：

Construction survey setting-out:

1st, according to design document and《Highway Survey specification》Required precision, by construction requirement to former coordinate points, elevation Point, encryption traverse point, bench mark are checked.Recover route center line, temporary bench mark is added, in order to right in work progress Elevation is controlled at any time, and reinforcement protection is carried out to important control stake.

2nd, rear ground elevation is rolled before being filled out using spirit level detection, fill toe is determined according to actual measurement absolute altitude and designed elevation Line.Roadbed leg wire of slope is released using total powerstation, while width of subgrade is designed width than it and has more 30 ㎝.Drawn using lime Go out roadbed fills sideline, and 30cm sets a skirt piles outside the roadbed both sides sideline of every 20m straightways, and with red paint mark with Determine a cross section.Measuring point is laid according to test section floor plan, actual measurement each point rolls rear top surface absolute altitude, to carry out pine Spread the calculating of thickness.

3rd, according to front and rear depth displacement calculating compacted thickness is filled, coefficient of loose laying is calculated.Coefficient of loose laying=(pine paving elevation-under Hold floor height journey)/(elevation-sub-layer elevation after compacting).

Stock:

1st, soil cement (exemplified by 6%)：The soil test of laboratory's reply is done as a result, being calculated according to outer doping according to chief inspector The cement consumption mixed is needed, is stored on demand into purchase cement and according to standardized construction requirement with reference to construction speed.

2nd, cement consumption presses outer doping, is often compacted 1m3 soil cements and is about with cement amount：M=(1.87 × 1000/1.06) × 0.06=105.85kg；Test section compacting 22cm is thick per square meter cement consumption be about 105.85/ (1/0.22)= 23.287kg；Thick about (1870/1.06)/(the 1/0.22)=388.113kg per square meter soil dosage of test section compacting 22cm.

3rd, the roadway diagraph result of the test of laboratory's reply is done according to chief inspector and difference is measured by the design side of each area's roadbed filling The dosage of each area's soil cement and loess is calculated, soil is transported to by construction site using transport vehicle.

Feeding (cloth, pave):

Loess is carried out first to pave, after the stacking spacing draw square of cloth, is commanded by special messenger, and filler is by horizontal point Layer, center carries out discharging behind high, first both sides after first low.Must be horizontal using longitudinal tunneling boring according to design section during embankment Placement in layers, from lowest point placement in layers, successively compacting 25cm is not to be exceeded.

Paving using loading machine for filler, uniform filling stall with goods spread out on the ground for sale is layered on predetermined width, and surface makes every effort to smooth, paves When soil block, oversize grain and other debris are picked and removed, when soil block is more, should be crushed.By containing to actual measurement filler Water rate, if the filler moisture content after paving is too small, is sprinkled water on packing layer, is spilt compared with optimum moisture content Water is computed determining.It should be noted that during watering and forbid sprinkling truck to stop and reverse end for end in watering section, watering is uniform, prevents out Current situation portion overly moist phenomenon, until reaching the moisture content of requirement.It if moisture content is excessive, should be tedded, be reached optimal Moisture content.

Every layer of roadbed fills strict implement " frame soil loading ", and grid, muck haulage automobile side are spread out with lime line before banketing Measure as 10T, coefficient of loose laying is intended using 1.2 controls when test section paves, and loose laying depth 30cm, definite grid size is 10m × 10m, calculates car number needed for per lattice, and sends special messenger to command.It is preferential using soil loading is fallen back by the way of when dumper unloads soil, i.e., oneself After unloading unloading for vehicle soil, the earthwork newly fallen is pushed open with loading machine immediately；Next dumper is fallen back on soil layer just having spread out, and is adopted The mode attacked and occupied with banketing unloads soil, to reduce the damage to underlying surfaces.To ensure the uniformity of soil loading, according to loose laying depth In test section ruler method or the method for heap ash platform control filled height.

First leveling:

After the dosage for calculating loess and cement, height control line is set up to control loose laying depth (being no more than 30cm), is filled out Material first passes through loading machine and is slightly put down, then carries out essence with land leveller and put down.

Land leveller essence should usually be struck off by a lateral other side, accomplish that aspect is smooth, uniform, if necessary can be again Return is scraped one time, static pressure 1 time after essence is flat, to facilitate cement spreader to travel.

Cement dispenses:

Cement consumption should be selected outer doping, set truck spreader cement spreading amount as 23kg/m2 according to result of the test, dispense Before cement, according to processing width, pull the runway that width is 2.3m (both sides overlap 5cm) with lime and guide cement truck spreader to spread Cloth cement, the artificial draw square of use less than 2.3m width carry out cloth ash.

Mix dirt:

In the case where moisture content is met the requirements, soil cement mix is carried out using road-mixed machine in time, if special messenger follows road mix Machine, checks mix depth and coordinates road-mixed machine operator to adjust mix depth, forbid to leave " loess " mixing and stirring a layer bottom at any time Interlayer.The surface of l0cm sub-layers should be slightly destroyed when mixing and stirring, so that levels are pasted；Road-mixed machine normally mixes and stirs twice, mix After uniformly, the sampling and measuring of moisture content, grey dosage is synchronously carried out by testing crew and supervisor.(grey dosage is unsatisfactory for requiring When, the cement consumption for needing to add is calculated according to detection data, is mixed and stirred again after uniformly dispensing.)

At the end of mix, if the moisture content deficiency of mixture, is supplemented with sprinkling truck sprinkle water in time.After watering, again Mix is carried out, moisture is evenly distributed in blended stock.Mixing machinery should reduce water immediately sprinkling truck followed by mix Shunting is lost.Sprinkle water during mix, should check the moisture content of mixture in time, answer color and luster consistent after mixture uniform mixing, do not have There is cement to roll into a ball and spend face, and uniform moisture is suitable.

Secondary leveling:

Voltage stabilizing one time is carried out after soil cement mixture uniform mixing again, it is just flat again with land leveller immediately.

Land leveller is struck off by a lateral opposite side, then with road roller immediately in just quick static pressure on first flat section One time, then it is flat once with land leveller essence.Pay special attention to the leveling of seam crossing, make seam pleasantly smooth.

Roll：

When the moisture content of filler is equal or slightly larger than optimum moisture content (1-2%) and cement dose EDTA titration is closed after integer During lattice, rolled immediately according to the compaction procedure drafted.Testing crew detects compactness at any time, and final compactness need to be more than It is more than design and normal value.Completion (the cement initial set) before failing no more than slow setting cement will be controlled by entirely rolling work, be rolled After the completion of, through that can carry out down constructing together after the assay was approved.Test section is rolled using " 1-1-N-1 " combination, i.e., A time static pressure (Luoyang 20T), one time it is weak shake (Luoyang 20T), N all over shaking by force (Xu work 22T), a static pressure (Luoyang 20T), roll Step is specific as follows：

The first step：

First with road roller static pressure and it is weak shake, when compacting, is first pressed among both sides (i.e. by curb part) press afterwards, after static pressure Superficial compaction situation, to the artificial feed supplement in low-lying location, surface is reached the degree of uniform compaction.

Second step：

Then first pass and second time vibrating compacting are carried out with heavy road roller.When heavy road roller rolls second time completion Afterwards, use Determining Degree of Extrusion by Impregnation Sand respectively near the lime point of mark and use total station survey three-dimensional coordinate.To measure, Testing result is recorded in corresponding record sheet (book) according to numbering and level, vibrating compacting pass.

3rd step：

Compactness detection is carried out, as compactness is met the requirements, then carries out a static pressure；As compactness is unsatisfactory for requiring, then Second step program is repeated, shakes by force a compactness detection is carried out after rolling every time, until stopping after compactness detection is qualified strong Shake.

If vibroroller cmpacting pass cannot still reach design requirement compactness more than 8 times, then require to replace rolling apparatus, This roadbed is reached design requirement, and re-start the construction of this project test section and coherent detection work.

The control of the road roller static pressure speed of travel is left in 3.7km/h in 2.3km/h or so, the control of the vibroroller cmpacting speed of travel It is right.Overlapping widths static pressure is wide for 1/4 wheel when rolling, and pressure of shaking is wide for 1/3 wheel.Road roller is changing travel direction, is slowing down or stop It should first stop vibrating before sailing, smoothly change traffic direction, not allow road roller to change direction in the state of inertia rolling.

Health：

After the completion of conditioned soil rolls, such as cannot continuously construct should carry out health, using the method for watering health, surface health Moisturizing is generally no less than 7 days.Close traffic is answered during health in addition to sprinkling truck, must not allow conditioned soil overly moist, dry neglect can not be neglected It is wet.Conditioned soil uses construction in layer, can be without special health when upper strata, which is banketed, continuously to construct, but requires lower floor to examine Test such as compactness, flatness qualified to meet the requirements, in addition, the roadbed top surface of winter construction needs covering insulation material Carry out health.

The present embodiment, 1, according to the characteristics of Cement Soil and applicable elements, test section is carried out using low-grade cement and is applied Work, it is ensured that improved packing has preferable elastoplasticity feature, avoids filler from producing multiple cracking, influences the stability of roadbed.

3rd, the technological process of arrangement and method for construction is mainly：Construction survey setting-out → first leveling → cement spreading → machine mixing → essence put down → rolls → testing inspection, and there is presently no corresponding specification, this problem institute for the construction technology of strength concrete pile The strength concrete pile construction technology of formation can construct for some reference and provide reference and invaluable experience.

In the various embodiments described above,

Moisture content detects：

1st, detection method

1) purpose and the scope of application：Suitable for measure clayey soil, slity soil, yellow soil's water content.

2) instrument and equipment

Baking oven：105-110 DEG C other energy baking ovens can be kept using Electric heat oven or temperature.

Balance：Weigh 200g, sensibility reciprocal 0.01g；Weigh 1000g, sensibility reciprocal 0.1g.

Other：Drier, weigh box etc..

3) step

(1) cement improvement loess subgrade sample, 15~30g of fine grained soil, sandy soil, organic soil 50g, sand gravel are taken For 1~2kg, it is put into and weighs in box, cover box lid immediately, claims quality.During weighing, it can be put in balance one end and the weighing box Etc. the counterweight of quality, mobile balance rider, it is wet soil quality that weighing result, which subtracts and weighs box quality, after balance.

(2) box lid is opened, sample and box are put into baking oven, is dried under 105~110 DEG C of constant temperature of temperature.Drying time 8h must not be less than to fine grained soil, 6h must not be less than to sandy soil.To containing native or gypseous soil of the organic matter more than 5%, Ying Jiang Constant temperature F of the temperature control at 60~70 DEG C, dry 12~15h is preferably.

(3) sample after drying and box are taken out, is put into cooling in drier (general only to need 0.5~1h) cooling After cover box lid, claim quality m_s, accurately to 0.01g.

4) calculate

Moisture content is calculated as follows：

In formula：W-moisture content (%), calculates to 0.1；

M-wet soil quality (g)；

Ms-dry ground quality (g).

2nd, result and analysis

One key property of loess is exactly water sensitivity, i.e., water disintegration, intensity substantially reduce, and construct in test section Cheng Zhong, the undisturbed soil sample to test section and strength concrete pile soil sample have carried out water ratio test detection, specific pile No. respectively With testing result as shown in table 7 to table 8.

7 test section Water Content Tests in Soil Samples testing result summary sheet of table

8 test section Water Content Tests in Soil Samples testing result summary sheet of table

9 test section Water Content Tests in Soil Samples testing result summary sheet of table

From table 7 into table 9 data：It is yellow to undisturbed soil sample and the cement improvement of combination soil cement, 5% and 6% respectively Soil sample has randomly selected 10 pile No. in test section region and has carried out moisture content detection, is tried in K173+290-K173+550 Section is tested, is up to 19.1%, minimum 17.2% for undisturbed soil sample moisture content, average out to 18.05%；For combination water Mud improvement loess Water Content Tests in Soil Samples is up to 17%, minimum 15.7%, average out to 16.39%；Being satisfied by Construction control will Ask.In K168+966-K169+220 test sections, it is up to 19.3%, minimum 17.2% for undisturbed soil sample moisture content, Average out to 18.2%；It is up to 17.2%, minimum 14.8% for 5% strength concrete pile Water Content Tests in Soil Samples, average out to 16.23%；It is satisfied by Construction control requirement.In K170+320-K170+607 test sections, for undisturbed soil sample moisture content most Greatly 19.4%, minimum 17.3%, average out to 18.4%；It is up to for 6% strength concrete pile Water Content Tests in Soil Samples 16.9%, minimum 14.4%, average out to 15.9%；And the difference of optimum moisture content is controlled in the range of 2%, meet construction control System requires.

Cement dose：

1st, detection method

1) purpose and the scope of application

Our law regulation is in the highway engineering scene cement dose of cement dose titration determination roadbed.

2) method and step

(1) EDTA is prepared：Weigh EDTA37.23 grams.Dissolved with 40~50 distilled water, 1000ml is settled to after cooling.

(2) ammonium chloride solution is prepared：Claim 500 grams of ammonium chlorides, add distilled water 4500ml to dissolve.

(3) sodium hydroxide is prepared：Claim 18 grams of sodium hydroxides, be put into the beaker of cleaning, add 1000ml distilled water to make its complete Portion is dissolved, and is added 2ml triethanolamines after cooling, is stored in after stirring evenly in glass jar.

(4) calred indicator is prepared：0.2 gram of Binding Reaction between Calconcarboxylic Sodium and 20 grams are dried in an oven in advance 1 it is small when sulfuric acid Potassium mixes, and is put into finely ground in mortar, is stored in stand-by in brown, wide-mouth bottle.

(5) 1000 grams are sampled, adds ammonium chloride solution 2000ml, is stirred 5 minutes, stands 10 minutes.

(6) upper clear supernate is transferred in the beaker of 300ml stir evenly capping it is stand-by.

(7) with clear liquid 10ml above pipette, extract, it is put into the triangular flask of 200ml, sodium hydroxide is drawn with buret 50ml, adds in triangular flask, and the pH value for surveying solution at this time is 12.5~13.

(8) add about 0.2 gram of calred indicator to shake up, solution is in rose.

(9) EDTA solution is added in buret and records volume V₁。

(10) start to titrate, shaken up in titration, examine solution colour, when solution colour is changed into purple, slow down drop Constant speed degree, shake up, and until pure blue is terminal, records the volume V of EDTA₂。

(11) V is calculated₂-V₁, look into standard curve table and determine cement dose.

2nd, testing result and analysis

In test section work progress, the detection of cement dose has been carried out to different tests section strength concrete pile respectively, 10 pile No. are randomly selected in each test section region, concrete outcome is as shown in table 10 to table 12.From data in table： K173+290-K173+550 test sections, cement dose maximum are 5.2%, are 4.6% at minimum, average value 4.84%, Meet Construction control requirement.In K168+966-K169+220 test sections, cement dose maximum is 5.6%, and minimum place is 4.9%, average value 5.2%, meets Construction control requirement.It is maximum in K170+320-K170+607 test sections, cement dose Locate as 6.6%, minimum place is 5.2%, average value 6.1%, meets that Construction control requires.

10 test section of table combines cement dose measurement result summary sheet

11 test section of table, 5% cement dose testing result summary sheet

12 test section of table, 6% cement dose testing result summary sheet

Compactness：

1st, detection method

1) purpose and the scope of application

This method is suitable for measuring a variety of materials compacted lift of basic unit's (or underlayment), sand-gravel surface and subgrade soils at the scene Density and compactness detection.

2) instrument tool and material

This experiment needs following instrument tool and material：

Fill sand cylinder：There is two kinds of size, use as needed.There is a circular hole at cartridge cylinder bottom center, and lower part fills one and falls The conical funnel put, funnel upper end opening, diameter is identical with the circular hole of cartridge, and funnel is welded on one piece of iron plate, iron plate Center has a circular hole to connect with funnel upper shed, is not switched between cartridge cylinder bottom and funnel.Switch as a sheet iron, one End is hinged with cylinder bottom and funnel iron plate, and the other end is stretched out outside stack shell, switchs the circle for also having a same diameter on iron plate Hole.

Metal tank prover：The metal can made of sheet iron, has a tank edge around upper end.

Substrate：The metal square plate made of sheet iron, there is a circular hole at the center of disk.

Glass plate：The square plate of the length of side about 500~600mm.

Tray sample：The sample that small cylinder is dug out can use aluminium box to store, and the sample that big cylinder is dug out can use 300mm*500mm*40mm Enamel tray storage.

Balance or table scale：10~15kg is weighed, sensibility reciprocal is not more than 1g.For the accuracy of balance of measurement of water-content coefficient, to particulate Native, middle grain soil, coarse grain local product are respectively 0.01g, 0.1g, 1.0g.

Moisture determination utensil：Such as aluminium box, baking oven.

Measure sand：The dry sand of 0.3~0.6mm of particle diameter cleanings, about 20~40kg, is cleaned, drying using preceding palpus, and is placed The sufficiently long time, makes the humidity of itself and air reach balance.

Contain the container of sand：Plastic barrel etc..

Other：Chisel, screwdriver, iron hammer, length are spoon, length small dustpan, hairbrush etc..

3) method and step

(1) quality of sand in cylinder lower cone body is demarcated

1. on sand cylinder nozzle height is filled, into filling sand cylinder, sand loading is untill away from cylinder top 15mm or so.Weigh and load in cylinder The quality m of sand₁, accurately to 1g.Calibration and experiment should all maintain sand loading height and mass conservation every time later.

2. switch is opened, allow sand freely to flow out, and make the volume of outflow sand and to dig interior volume of testing pits suitable in building site (volume that can be equal to tank prover), then shuts switch.

3. not rocking the sand of cartridge, it will lightly fill sand cylinder and move on glass plate, switch is opened, allows sand flow to go out, directly When sand no longer flows down in cylinder, switch is shut, and carefully takes away and fills sand cylinder.

4. the sand in the sand or graduated cylinder stayed onboard is collected and weighs, accurately to 1g.Sand on glass plate is just to fill up The sand m of cone₂。

5. repeating above-mentioned measurement three times, its average value is taken.

(2) the loose measure density p of scalar quantity sand_s(g/cm³)

1. the volume V of tank prover is determined with water, accurately to 1mL.

2. it is m to load quality in cartridge₁Sand, and be placed on sand cylinder is filled on tank prover, switch opened, allows sand flow Go out, during whole quicksand, keep off dynamic filling sand cylinder, when sand no longer flows down, switch is closed, removes and fills sand cylinder, title The quality for taking remaining sand in cylinder is m₃, accurately to 1g.

3. the quality m for filling up sand needed for calibration filling is calculated as formula 5-2_a(g)：

m_a=m₁- m₂- m₃ (5-2)

In formula：m_aThe quality (g) of sand during-calibration fills；

m₁- load the gross mass (g) for filling sand in sand cylinder；

m₂The quality (g) of sand in-filling sand cylinder lower cone body；

m₃After-filling sand enters tank prover, the quality (g) of remaining sand in cylinder；

4. repeating above-mentioned measurement three times, its average value is taken.

5. the loose measure density p of calculation amount sand_s：

Ρ_s=m_a/V (5-3)

In formula：ρ_sLoose measure density (the g/cm of-amount sand³)；

Volume (the cm that V-calibration fills³)。

4) test procedure

(1) in test site, one piece of flat surfaces is selected, and is cleaned up, its area cannot be less than substrate area.

(2) substrate is put on flat surfaces., then will the amount of filling sand (m when the roughness on surface is larger₅) filling sand Cylinder is placed on the circular hole among substrate, and the switch for filling sand cylinder is opened, allows sand flow to enter in the mesoporous of substrate, until in cartridge Sand no longer flow down when turn off the switch.Remove fill sand cylinder, and in weighing tank sand quality m₆, accurately to 1g.

(3) substrate is taken away, and the amount sand that will be left in test site is withdrawn, and again cleans up surface.

(4) substrate is put back on the surface cleaned up and (is placed on original place as far as possible), hole (the diameter in hole along substrate mesoporous It is consistent with filling sand cylinder).During holing, it should be noted that the material for not making to dig out is lost, and takes out the material dug out fill at any time Enter in polybag, do not make moisture evaporation, can also be placed in bulk specimen box.Measure layer thickness should be equal to by trying the depth in hole, but must not There is subsurface material to be mixed into, finally take out whole chisel pine material in hole.To soil matrix or basic unit, to prevent material in tray sample Moisture evaporation, the quality for weighing material several times can be divided.The gross mass for all taking out material is m_w, accurately to 1g.When needing to examine During Thickness Measurement by Microwave, the step for carrying out again after thickness should be first measured.

(5) representational sample is taken out from all material dug out, is placed in aluminium box or the enamel tray of cleaning, surveys Its fixed water content (w, in terms of %).The quantity of sample is as follows：When being measured with small-sized filling sand cylinder, for fine grained soil, it is no less than 100g；For various middle grain soil, no less than 500g.When being measured with large-scale filling sand cylinder, for fine grained soil, no less than 200g；For Various middle grain soil, no less than 1000g；For the stabilized with inorganic binder material such as coarse-grained soil or cement, lime, flyash, preferably incite somebody to action The all material drying of taking-up, and 2000g is no less than, claim its quality m_d, accurately to 1g.

(6) substrate is placed on testing pits, filling sand cylinder is placed among substrate and (chiltern amount m is piled in cartridge₁), The lower mouth of filling sand cylinder is directed at mesoporous and the examination hole of substrate, open the switch for filling sand cylinder, allow in sand flow enters to test pits.During this period, Sand cylinder is filled it should be noted that not touching, when the sand in cartridge no longer flows down, is turned off the switch.Careful take away fills sand cylinder, and weighs The quality m of remaining sand in cylinder₄, it is accurate to 1g.

(7) roughness of the flat surfaces such as cleaned up is little, can also save the operation of above-mentioned (2) and (3).Trying After hole is dug, the directly alignment of filling sand cylinder is placed on testing pits, centre need not put substrate.The switch of cylinder is opened, allows sand flow to enter examination In hole.During this period, it should be noted that do not touch and fill sand cylinder.When the sand in cartridge no longer flows down, turn off the switch, carefully take Walk to fill sand cylinder, and weigh the quality m ' of remaining sand₄, accurately to 1g.

(8) the amount sand in examination cylinder is carefully taken out, in case being used again during experiment next time.If the humidity of amount sand has been changed or measured Impurity is mixed with sand, then should again dry, sieve, and places a period of time, the temperature of itself and air is reached after balance again With.

5) calculate

The quality m for filling up sand used of testing pits is calculated by formula 5-4 or 5-5_b(g)：

When filling husky, test pits on be placed with substrate：

m_b=m₁- m₄- (m₅- m₆) (5-4)

When filling husky, test pits on be not placed with substrate：

m_b=m₁- m '₄- m₂ (5-5)

In formula：m_b- fill up the quality (g) of the sand tested pits；

m₁The quality (g) of sand in-filling sand placket；

m₂The quality (g) of sand in-filling sand cylinder lower cone body；

m₄、m’₄After-filling sand, the quality (g) of remaining sand in cylinder；

The wet density ρ for material of testing pits is calculated by formula 5-6_w(g/cm³):

ρ_w=m_w/m_b×ρ_s (5-6)

ρ_sLoose measure density (the g/cm of-amount sand³)；

The dry density ρ for material of testing pits is calculated by formula 5-7_d(g/cm³)：

ρ_d=ρ_w/(1+0.01w) (5-7)

In formula：The moisture content (%) of w-material of testing pits；

When for the occasion of the inorganic colloid methoders such as cement, lime, flyash, dry density ρ can be calculated by formula 5-8_d (g/cm³)。

ρ_d=m_d/m_b×ρ_s (5-8)

Construction compaction is calculated by formula 5-9.

K=ρ_d/ρ_c×100 (5-9)

In formula：The construction compaction (%) of K-testing location；

ρ_dDry density (the g/cm of-sample³)；

m₄、m’₄After-filling sand, the quality (g) of remaining sand in cylinder.

2nd, test results and analysis

To determine compacting counting, in test section work progress, scene has carried out compactness tracing detection, specific testing inspection As a result it is as shown in table 13.

13 vibroroller cmpacting pass of table and compactness relation table

From table 13 it was found from compactness testing result：Test section construction vibroroller cmpacting 6 times altogether, it is every all over 12 measuring points of selection It is detected, takes its average value as final compactness.In vibrating compacting 5 times, compactness meets 92nd area up to more than 93% Compacting requirement；In vibrating compacting 6 times, compactness meets the compacting requirement in 94th area up to more than 95%.Compactness is with stone roller Press the increase of pass and become larger.

Coefficient of loose laying：

1st, detection method

1) purpose and the scope of application

Coefficient of loose laying of the our law regulation in highway engineering on-site measurement roadbed.

2) assay method

To ensure the accuracy of measurement data, measurement error is reduced, we are fixed using spirit level, and parallel observation is same The original ground reading of one position, pine spread reading after reading, compacting.Bout length general control is measured in the range of 50m.

3) measurement frequency

Generally per mono- section of 10m, mono- section of 5m can be encrypted as if necessary, the measuring point on both sides will be away from datum mark 1m More than, to avoid caused by the factor such as not in place is rolled in datum turned-down edge and side measurement error it is bigger than normal.Survey on per section Point should be uniformly distributed, and the general 2m of spacing determines each point position with steel tape, and each section both ends are intended to carry out mark, with Each measuring point for ensureing to measure after original ground, pine paving and compacting is in same position.

4) erection of spirit level

Spirit level will be erected at intervisibility, the place away from vibroseis.Vibration is opened when steel roller is rolling, such as Fruit spirit level is set up nearer from the road surface to pave, then spirit level is unstable caused by vibration, reading is produced error, is influenced The measure of coefficient of loose laying, even results in the failure of measurement.

5) observed direction

The starting point section observed during measurement should be carried out since the section parallel with spirit level decorating position along spreading direction Observation.

6) other points for attention

During measurement, each compaction assembly sets up a spirit level, because spirit level cannot move in whole paving process It is dynamic, therefore to there is special messenger to keep an eye on, spirit level is prevented by accidental movement, and cause measurement data to fail.

2nd, test results and analysis

Coefficient of loose laying refers to the ratio of the loose laying depth of paver and compacted thickness in construction, to determine pine paving system Number, has carried out coefficient of loose laying tracking measurement, specific testing result is detailed in K173+290-K173+550 test section work progress As shown in table 14, it was found from measurement result：Final coefficient of loose laying measured value is 1.24.

Table 14 combines cement dosetest section coefficient of loose laying testing result list

Coefficient of loose laying tracking measurement is carried out in K168+966-K169+220 test section work progress, specific detection knot Fruit is as shown in Table 15 in detail, it was found from measurement result：Final coefficient of loose laying measured value is 1.23.

15 5% cement dose test section coefficient of loose laying testing result list of table

Coefficient of loose laying tracking measurement is carried out in K170+320-K170+607 test section work progress, specific detection knot Fruit is as shown in table 16 in detail, it was found from measurement result：Final coefficient of loose laying measured value is 1.22.

16 6% cement dose test section coefficient of loose laying testing result list of table

Settlement observation：

The anti-25cm that excavates buries settlement observation plate after second layer strength concrete pile is completed in construction, and settlement observation plate is set It is symmetrical 1 pair embedded every 20m at away from route center line 6m, it is anti-after the completion of every layer of construction to excavate installation settlement observation Pipe.1 sedimentation situation of observation in every 7 days after the completion of subgrade construction.After on March 7th, 2016 has surveyed sedimentation, to coordinate detection examination A section flexure is tested, the loess for being used for covering health after the completion of construction is disposed, eliminates a section settlement observation pipe.Subgrade settlement 17 are shown in Table in " on November 13rd, 2015 " to the settling amount during " on March 7th, 2016 "；Subgrade settlement is in " March 7 in 2016 Day " to the settling amount during " on March 14th, 2016 " is shown in Table 18；Subgrade settlement is in " on March 14th, 2016 " to " in March, 2016 28 days " during settling amount be shown in Table 19.

17 settling amount statistical form (2015.11.13-2016.3.7) of table

Pile No.	Left side settling amount (m)	Right side settling amount (m)	Remarks
				170+380	-0.006	-0.004
170+400	-0.016	-0.008
				170+420	-0.018	-0.014
170+440	-0.016	-0.016
				170+460	-0.011	-0.009
170+480	-0.005	-0.012
				170+500	-0.008	-0.011

Data above subgrade settlement maximum is 18mm, minimum value 4mm, and analysis reason maximum position occurs and is There is step for subgrade cross section in K170+400-K170+440 regions, original place looks, and step handles relatively poor when being compacted；It is minimum Be worth at the position original place table occurred originally for local Irrigation Ditch, there is spring disease in when processing, after take to change and fill out 1m sand The processing method of gravel material, adds foundation bearing capacity.

18 settling amount statistical form (2016.3.7-3.14) of table

Pile No.	Left side settling amount (m)	Right side settling amount (m)	Remarks
				170+380	-0.003	0.001
170+400	0.001	-0.001
				170+420	-0.001	0.003
170+440	-0.002	-0.003
				170+460	-0.002	-0.001
170+480	0.001	-0.002
				170+500	0.002	0.000

19 settling amount statistical form (2016.3.14-3.28) of table

Pile No.	Left side settling amount (m)	Right side settling amount (m)	Remarks
				170+380	-0.003	0.001
170+400	0	-0.002
				170+420	0	-0.001
170+440	-0.002	-0.002
				170+460	0.001	0

There is positive number and change not without sedimentation phenomenon, settling amount in settling data data it can be seen from table 18 and table 19 Greatly, analysis main cause is to settle basicly stable, and along with reading, there are caused by error.

According to design document, the settlement amount after construction that roadbed allows is up to 30cm, and to sum up observed result is analyzed, subgrade construction To 122 days, average settling amount was 11.0mm, and tended towards stability state at present, due to hardened property after cement improvement collapsible loess By force, water proofing property is preferable, and settling amount shows preferably in common subgrade settlement, but observe during occur rainfall, precipitation number compared with It is few, and the no-load activity of roadbed top, it is contemplated that roadbed also may proceed to settle after constructing in 95th area.

Deflection test：

1st, test objective

The rebound deflection of roadbed is measured, to evaluate its integrated carrying ability, is used for Pavement Structure Design.

2nd, test principle

Utilize lever benkelman beams deflectometer measure wheel gap flexure made of lever principle.

3rd, instrument tool and material

1) standard vehicle：The bogie that twin shaft, rear axle bilateral 4 are taken turns, its standard axle load, tire size, wheel clearance and wheel The major parameters such as air pressure should meet the requirements.Test carriage can be selected by road quality classification as needed, highway, level-one and two Level highway should use the BZZ-100 standard vehicles of rear axle 100kN；Other standard highways can use the BZZ-60 standards of rear axle 60kN Car.

2) pavement benkelman beams deflectometer：It is made of backman beam, dial gauge and dial framework.Backman beam is made of alloy aluminum, above there is water Quasi- bubble, its forearm (contact road surface) are 2 with postbrachium (dress dial gauge) length ratio：1.Benkelman beams deflectometer length has two kinds：One kind is long 3.6m, arm before and after are respectively 2.4m and 1.2m；The long 5.4m of benkelman beams deflectometer that another kind lengthens, arm before and after is respectively 3.6m and 1.8m. When being measured on semi-rigid asphalt pavement or cement concrete pavement, preferably use length curved for the backman beam of 5.4m Heavy instrument, and use BZZ-100 standard vehicles.Flexure is measured using dial gauge, it is also possible to which self-recording unit measures.

3) contact road table thermometer：End is tack, and indexing is not more than 1 DEG C.

4) other：Tape measure, whistle, white oil paint or chalk, control flag etc..

4th, test methods and procedures

1) depending on test segment arranges that measuring point, its distance are needed with test.Measuring point should be in the wheelmark in road surface running vehicle track Take, and upper mark is drawn with white oil paint or chalk.

2) instruction carriage rear wheel rotation gap is aligned on the position after measuring point about at 3-5cm.

3) benkelman beams deflectometer is inserted at the gap between automobile back wheel, consistent with automobile steering, beam arm must not encounter tire, Benkelman beams deflectometer gauge head is placed on measuring point (in front of wheel gap center at 3-5cm), and installs dial gauge on the analyzing rod of benkelman beams deflectometer, and hundred Divide table zeroing, gently whether percussion benkelman beams deflectometer, inspection dial gauge stablize back to zero with finger.Benkelman beams deflectometer can be unilateral measure, Can be that bilateral measures at the same time.

4) measure person, which blows a whistle to issue an order, commands automobile slowly to advance, and dial gauge continues to forward with the increase of surface deformation It is dynamic.It is rapid to read initial reading L when indicator turns to maximum₁Automobile is still moving on, and indicator reversed turning, treats automobile After rolling the flexure radius of influence (about more than 3m) away from, commander's red flag is whistled or brandishes, automobile stops.After indicator gyrostabilized platform, Again read off end readout L₂The speed that automobile advances is preferably 5km/h or so.

5th, test results and analysis

Tested by above-mentioned test methods and procedures, test section K173+290-K173+550, result of the test such as table 20 It is shown, understand that flexure result meets design requirement by deflection test result, while roadbed flexure is obtained greatly by filling cement The raising of amplitude.

20 deflection test result of table

Test section K168+966-K169+220, result of the test is as shown in table 21, while makes roadbed flexure by filling cement It is greatly enhanced.

21 deflection test result of table

Test section K170+320-K170+607, result of the test is as shown in table 22, and flexure result is understood by deflection test result Meet design requirement, while roadbed flexure is greatly enhanced by filling cement.

22 deflection test result of table

Loading plate Rebound Modulus of Subgrade is tested：

1st, purpose and the scope of application

1) this method is suitable for soil matrix surface at the scene, and the method by loading plate to soil matrix multistage loadings, unloading, is surveyed Go out corresponding soil matrix resilience value under every grade of load.

2) Rebound Modulus of Subgrade of this method measure can be used as Pavement Design parameter.

2nd, instrument tool and material

This experiment needs following instrument tool and material：

1) facility is loaded：It is loaded with iron block or weight, the rear axle such as gather materials is not less than one, the truck of 60kN again, as Loading equipemtn.After the rear axle of automotive frame about at 80cm, set up girder one of putting more energy into and make reaction frame.Automobile tyre inflation Pressure 0.50Mpa.

2) on-site testing device, is made of jack, dynamometer (proving ring or pressure gauge) and ball seat.

3) one piece of rigid bearing plate, thickness of slab 20mm, diameter 30cm, diameter both ends are equipped with column and can adjust height Bearing is placed on soil matrix surface for placing benkelman beams deflectometer gauge head, loading plate.

4) pavement benkelman beams deflectometer two, are made of backman beam, dial gauge and stent.

5) hydraulic jack one, 80~100kN, equipped with the pressure gauge or proving ring by calibration, its capacity is not less than Soil matrix intensity, 1/100 of measurement accuracy not less than metering journey.

6) stopwatch.

7) horizon rule.

8) it is other：Fine sand, hairbrush, plumb bob, pick, spade, shovel etc..

3rd, method and step

1) preparation

(1) representational measuring point is selected as needed, and measuring point should be located on horizontal roadbed, uniform soil quality, without miscellaneous Thing；

(2) carefully smooth soil matrix surface, the fine sand for spreading dried and clean fill and lead up soil matrix recess, and sand can not cover whole soil Primary surface, avoids the formation of one layer.

(3) loading plate is disposed, and is corrected with horizon rule, loading plate is placed in horizontality.

(4) instruction carriage is placed on measuring point, plumb bob test is hung in the middle part of girder of putting more energy into, is allowed to be narrowly focused towards in loading plate The heart, then packs up plumb bob.

(5) jack is placed on loading plate, pads steel cylinder, steel plate above, and ball seat is placed in top and horizontal stroke of putting more energy into Beam contacts.When such as using proving ring, proving ring should be placed among jack and crossbeam, jack and sark must keep vertical Directly, in order to avoid jack topples over the accuracy that accident occurs and influences test data when pressurizeing.

(6) benkelman beams deflectometer is placed, the gauge head of two benkelman beams deflectometers is respectively placed on the bearing of loading plate column, dial gauge pair Zero or other suitable initial positions on.

2) testing procedure

(1) start to load with jack, watch proving ring or pressure gauge attentively, to precompressed 0.05Mpa, voltage stabilizing 1min, makes carrying Plate is in close contact with soil matrix, while checks whether the working condition of dial gauge is normal, then loosens the unloading of jack throttle, surely After pressing 1min, it will refer to for zero or record initial reading.

(2) pressure-deformation curve of soil matrix is measured.Loaded with jack, using stepwise loading method, with pressure gauge or survey Power ring controls loading capacity, and when load is less than 0.1Mpa, every grade of increase 0.02Mpa, increases 0.04Mpa or so for every grade later.In order to Make loading and convenience of calculation, loading numerical value can suitably be adjusted to integer.After being loaded onto pre- constant load every time, stablize 1min, immediately Two benkelman beams deflectometer dial gauge numerical values of note are read, jack throttle is then gently decontroled and is offloaded to 0, after stable 1min to be unloaded, again Reading, dial gauge is no longer to zero after unloading every time.When the difference of two benkelman beams deflectometer percentage meter readings is less than the 30% of average value, It is averaged.Such as more than 30%, then should resurvey.When resilience value is more than 1mm, you can stop loading.

(3) resilience of loads at different levels and total deformation, calculate by the following method：

Be resiliently deformed (L)=(reading average value after reading average value-unloading after loading)

× benkelman beams deflectometer lever ratio

Total deformation (L ˊ)=(after loading reading average value-loading initially preceding reading average value)

× benkelman beams deflectometer lever ratio

(4) the total influence amount a of automobile is measured.Last time loading and unloading after circulation terminates, takes jack away, re-reads Dial gauge initial reading, then outputs automobile beyond 10m, reads end readout, and two the first, end readout differences of dial gauge are averaged It is the total influence amount a of automobile that value, which is multiplied by benkelman beams deflectometer lever ratio,.

(5) sampled under testing site, measure material moisture content.Quantity of sampling quantity is as follows：

1. maximum particle diameter is not more than 5mm, sample quantities about 120g；

2. maximum particle diameter is not more than 25mm, sample quantities about 250g；

3. maximum particle diameter is not more than 40mm, sample quantities about 500g.

(6) appropriate location beside testing site, with the density of the measure soil matrix such as sand replacement method or core cutter method.

4th, calculate

1) then it is calculating resilience value after the resilience value of each stage pressure is plus the influence amount of this grade.It is with rear axle The standard vehicle of weight 60kN is the calculated value of the load influence amounts at different levels of test carriage.When using other type test carriages, pressures at different levels Influence amount a under power_i：

In formula：T₁--- test carriage wheel base (m)；

T₂--- girder of putting more energy into is away from rear axle distance (m)；

D --- carrying board diameter (m)；

Q --- test carriage rear axle weight (N)；

P₁--- the loading plate pressure (Pa)；

A --- total influence amount (0.01mm)；

a_i--- the classification influence amount (0.01mm) of the stage pressure.

2) calculating resilience value points at different levels are plotted on criterion calculation paper, exclude the abnormal point that deviates significantly from and draw suitable Sliding P~L-curve.

3) the Rebound Modulus of Subgrade E corresponded under loads at different levels is calculated_iValue：

In formula：E_i--- corresponding to the Rebound Modulus of Subgrade (Mpa) under loads at different levels；

μ₀--- native Poisson's ratio, issues Pavement Design specification regulation according to portion and selects；

D --- carrying board diameter 750px；

p_i--- loading plate pressure (Mpa)；

L_i--- relative to load p_iWhen resilience (cm).

4) take and terminate each resilience value before testing by linear regression method calculating Rebound Modulus of Subgrade E0 values：

In formula：E₀--- Rebound Modulus of Subgrade (Mpa)；

L_i--- terminate the actual measurement resilience values at different levels before experiment；

p_i--- corresponding to L_iPressure values at different levels.

Understand that loading plate Rebound Modulus of Subgrade test result meets design by curved loading plate Rebound Modulus of Subgrade test result It is required that while it is remarkably enhanced loading plate Rebound Modulus of Subgrade by filling cement.

The above is only the preferred embodiment of the present invention, is not intended to limit the invention, it is noted that for this For the those of ordinary skill of technical field, without departing from the technical principles of the invention, some improvement can also be made And modification, these improvements and modifications also should be regarded as protection scope of the present invention.

Claims

A kind of 1. construction method of strength concrete pile as roadbed filling, it is characterised in that including：Cement blending rate in loess Determine, construction survey setting-out, feeding, first leveling, cement spreading, machine mixing, it is secondary flatten, roll, compactness detects, its In, cement blending rate determines to specifically include in loess：Prepare 5 parts of loess of identical weight part and the blending soil of cement, it is right respectively Each part blends soil and carries out liquid model limitation test, compaction test, has done shear strength test, non-confining strength respectively to mechanical characteristic Degree experiment, CBR experiments, collapsibility experiment, cement mixing content is determined based on obtained test data analyzer result, wherein each part blends Soil cement blending rate be respectively：4%th, 5%, 6%, 7%, 8%.
2. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described Construction survey setting-out specifically includes：

Former coordinate points, elevational point, encryption traverse point, bench mark are checked by construction requirement, recovers route center line, adds and face When bench mark；

Rear ground elevation is rolled before being filled out using spirit level detection, fill toe line is determined according to actual measurement absolute altitude and designed elevation, is made Roadbed leg wire of slope is released with total powerstation, while width of subgrade is designed width than it and has more 30 ㎝, roadbed is marked using lime Fill sideline, 30cm sets a skirt piles outside the roadbed both sides sideline of every 20m straightways, and with red paint mark to determine that one is horizontal Section, lays measuring point, actual measurement each point rolls rear top surface absolute altitude according to test section floor plan；

Calculate compacted thickness according to front and rear depth displacement is filled, calculate coefficient of loose laying, wherein, coefficient of loose laying=(pine paving elevation-under hold Floor height journey)/(elevation-sub-layer elevation after compacting).
3. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described Feeding includes：

Carry out loess to pave, after the stacking spacing draw square of cloth, filler presses horizontal slice, after first low behind high, first both sides Center carries out discharging, is filled using longitudinal tunneling boring horizontal slice according to design section during embankment, is layered from lowest point Fill, successively 25cm is not to be exceeded in compacting；

Paving using loading machine for filler, uniform filling stall with goods spread out on the ground for sale is layered on predetermined width, by the aqueous of actual measurement filler Rate, if the filler moisture content after paving is too small, is sprinkled water compared with optimum moisture content on packing layer, until reaching To desired moisture content, watering amount is computed determining；It if moisture content is excessive, should be tedded, be reached optimal aqueous Rate；

Every layer of roadbed fills strict implement " frame soil loading ", spreads out grid with lime line before banketing, coefficient of loose laying when paving Using 1.2 controls, loose laying depth 30cm, definite grid size is 10m × 10m, and dumper unloads preferential using retroversion during soil The mode of soil loading, i.e., after discharging vehicle unloads soil, immediately pushed open the earthwork newly fallen with loading machine；Next dumper is spread out just Fallen back on soil layer, using banket attack and occupy by the way of unload soil；Filled according to loose laying depth ruler method or the control of the method for heap ash platform Highly.
4. construction method of the strength concrete pile according to claim 3 as roadbed filling, it is characterised in that moisture content The specific steps of detection include：Take cement improvement loess subgrade sample, 15~30g of fine grained soil, sandy soil, organic soil 50g, Sand gravel is 1~2kg, is put into and weighs in box, covers box lid immediately, claims quality；During weighing, put and the weighing in balance one end The counterweight of the quality such as box, mobile balance rider, it is wet soil quality that weighing result, which subtracts and weighs box quality, after balance；

Box lid is opened, sample and box are put into baking oven, is dried under 105~110 DEG C of constant temperature of temperature；Drying time is to fine grained soil 8h must not be less than, 6h must not be less than to sandy soil；To containing native or gypseous soil of the organic matter more than 5%, temperature control is existed 60~70 DEG C of constant temperature F, dry 12~15h；

Sample after drying and box are taken out, cooling in drier is put into, cools down 0.5~1h, box lid is covered after cooling, claim quality m_s, accurately to 0.01g；

Moisture content is calculated as follows：

<mrow> <mi>w</mi> <mo>=</mo> <mfrac> <mrow> <mi>m</mi> <mo>-</mo> <msub> <mi>m</mi> <mi>s</mi> </msub> </mrow> <msub> <mi>m</mi> <mi>s</mi> </msub> </mfrac> <mo>&times;</mo> <mn>100</mn> <mi>%</mi> </mrow>

In formula：W-moisture content (%), calculates to 0.1；

M-wet soil quality (g)；

m_s- dry ground quality (g).
5. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described First leveling specifically includes：

After the dosage for calculating loess and cement, set up height control line to control loose laying depth, filler first pass through loading machine into Row is thick flat, then carries out essence with land leveller and put down, wherein, loose laying depth is no more than 30cm；

Land leveller essence should usually be struck off by a lateral other side, to be accomplished that aspect is smooth, uniform, can be returned again to if necessary Scrape one time, static pressure 1 time after essence is flat；

The secondary leveling specifically includes：Voltage stabilizing one time is carried out after soil cement mixture uniform mixing again, uses land leveller immediately Just flat again, land leveller is struck off by a lateral opposite side, then with road roller immediately on just just flat section it is quick quiet Pressure one time, then it is flat once with land leveller essence.
6. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described Cement is dispensed and specifically included：The spreading of cement is carried out using outer doping, sets truck spreader cement spreading amount as 23kg/m², dispense Before cement, according to processing width, it is 2.3m to pull width with lime, and the runway of both sides overlap joint 5cm guides cement truck spreader to dispense Cement, the artificial draw square of use less than 2.3m width carry out cloth ash.
7. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described Machine mixing specifically includes：

In the case where moisture content is met the requirements, cement, loess soil mix are carried out using road-mixed machine, check mix depth simultaneously in real time Coordinate road-mixed machine operator to adjust mix depth, the surface of l0cm sub-layers is destroyed when mixing and stirring；Road-mixed machine normally mixes and stirs twice, mixes After closing uniformly, moisture content, the sampling and measuring of grey dosage are carried out；If lime dosage is unsatisfactory for requiring, calculated according to detection data Go out to need the cement consumption added, mixed and stirred again after uniformly dispensing；

At the end of mix, if the moisture content deficiency of mixture, is supplemented with sprinkling truck and sprinkled water；After watering, mix is carried out again, Moisture is set to be evenly distributed in blended stock；Mixing machinery should reduce water loss immediately sprinkling truck followed by mix；Watering During mix, the moisture content of mixture is checked in real time, answers color and luster consistent after mixture uniform mixing, roll into a ball and spend without cement Face, and uniform moisture is suitable；For cement using in outer doping incorporation loess, admixture volume is 4%, 5% or 6%.
8. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described Roller compaction process specifically includes：

After integer when the moisture content of filler is equal to or more than optimum moisture content 1-2% and cement dose EDTA titration qualifications, stand Rolled according to the compaction procedure drafted, detect compactness in real time so that compactness is more than more than design and normal value；It is whole It is a roll work and to control completed before failing no more than slow setting cement, after the completion of rolling, through carrying out down one after the assay was approved Construction；Test section is rolled using " 1-1-N-1 " combination, i.e. a static pressure, one time it is weak shake, shake by force for N times, one time it is quiet Pressure, it is specific as follows to roll step：

First with road roller static pressure and it is weak shake, when compacting, is first pressed among both sides lean on behind curb part and press, according to the surface after static pressure Compacting situation, to the artificial feed supplement in low-lying location, makes surface reach the degree of uniform compaction；

Then first pass and second time vibrating compacting are carried out with heavy road roller.After the completion of heavy road roller rolls second time, Use Determining Degree of Extrusion by Impregnation Sand respectively near the lime point of mark and use total station survey three-dimensional coordinate.Will measurement, detection As a result it is recorded according to numbering and level, vibrating compacting pass in corresponding record sheet；

Compactness detection is carried out, as compactness is met the requirements, then carries out a static pressure；As compactness is unsatisfactory for requiring, then repeat Second step program, shakes by force a compactness detection is carried out after rolling every time, until stopping shaking by force after compactness detection is qualified；

If vibroroller cmpacting pass cannot still reach design requirement compactness more than 8 times, then require to replace rolling apparatus, make this Roadbed reaches design requirement；

The control of the road roller static pressure speed of travel is controlled in 3.7km/h or so in 2.3km/h or so, the vibroroller cmpacting speed of travel；Grind Overlapping widths static pressure is wide for 1/4 wheel during pressure, and pressure of shaking is wide for 1/3 wheel；Road roller should be first before travel direction, deceleration or stagnation of movement is changed Stop vibration, smoothly change traffic direction, do not allow road roller to change direction in the state of inertia rolling.
9. construction method of the strength concrete pile according to claim 8 as roadbed filling, it is characterised in that using drop Location survey determines the cement dose of roadbed, specifically includes：

EDTA is prepared：Weigh EDTA37.23 grams；Dissolved with 40~50 distilled water, 1000ml is settled to after cooling；

Ammonium chloride solution is prepared：Claim 500 grams of ammonium chlorides, add distilled water 4500ml to dissolve；

Sodium hydroxide is prepared：Claim 18 grams of sodium hydroxides, be put into the beaker of cleaning, add 1000ml distilled water it is all dissolved, 2ml triethanolamines are added after cooling, are stored in after stirring evenly in glass jar；

Calred indicator is prepared：By 0.2 gram of Binding Reaction between Calconcarboxylic Sodium with 20 grams in advance in an oven dry 1 it is small when potassium sulfate mix, It is put into finely ground in mortar, is stored in stand-by in brown, wide-mouth bottle；

1000 grams of sampling, adds ammonium chloride solution 2000ml, stirs 5 minutes, stands 10 minutes；

Upper clear supernate is transferred in the beaker of 300ml stir evenly capping it is stand-by；

With clear liquid 10ml above pipette, extract, it is put into the triangular flask of 200ml, draws sodium hydroxide 50ml with buret, add In triangular flask, the pH value for surveying solution at this time is 12.5~13；

0.2 gram of calred indicator is added to shake up；

EDTA solution is added in buret and records volume V₁；

Start to titrate, shaken up in titration, examine solution colour, when solution colour is changed into purple, slows down rate of titration, shake It is even, until pure blue is terminal, record the volume V of EDTA₂；

Calculate V₂-V₁, look into standard curve table and determine cement dose.
10. construction method of the strength concrete pile according to claim 1 as roadbed filling, it is characterised in that described The measurement of compactness specifically include：

S1 selects one piece of flat surfaces in test site, and is cleaned up, its area cannot be less than substrate area；

S2 puts back to substrate on the surface cleaned up, holes along substrate mesoporous, hole hole hole diameter with fill sand cylinder it is consistent；Examination The depth in hole should be equal to measure layer thickness, but must not have subsurface material to be mixed into, and finally take out whole chisel pine material in hole；It is right Soil matrix or basic unit, divide the quality for weighing material several times；The gross mass for all taking out material is m_w, accurately to 1g；When needing to detect During thickness, the step for carrying out again after thickness should be first measured；

S3 takes out sample from all material dug out, is placed in aluminium box or the enamel tray of cleaning, measures its water content；Sample Quantity is as follows：When being measured with small-sized filling sand cylinder, for fine grained soil, no less than 100g；For various middle grain soil, no less than 500g； When being measured with large-scale filling sand cylinder, for fine grained soil, no less than 200g；For various middle grain soil, no less than 1000g；For coarse grain The stabilized with inorganic binder material such as soil or cement, lime, flyash, preferably dries all material of taking-up, and be no less than 2000g, claims its quality m_d, accurately to 1g；

Substrate is placed in by S4 test pits on, by fill sand cylinder be placed among substrate, chiltern amount m is piled in cartridge₁, make filling sand cylinder Lower mouth alignment substrate mesoporous and examination hole, open the switch for filling sand cylinder, allow in sand flow enters to test pits；Until the sand in cartridge not When flowing down again, turn off the switch；Take away and fill sand cylinder, and in weighing tank remaining sand quality m₄, it is accurate to 1g；

After being dug in examination hole, the directly alignment of filling sand cylinder is placed on testing pits, centre need not put substrate；The switch of cylinder is opened, is allowed In sand flow enters to test pits；When the sand in cartridge no longer flows down, turn off the switch, carefully take away and fill sand cylinder, and weigh remaining sand Quality m₄', accurately to 1g；

S5 carefully takes out the amount sand in examination cylinder, in case being used again during experiment next time；If the humidity of amount sand has changed or has measured in sand Impurity is mixed with, then should again dry, sieve, and places a period of time, the temperature of itself and air is used again after reaching balance；

The quality m for filling up sand used of testing pits is calculated as follows in S6_b(g)：

When filling husky, test pits on be placed with substrate：

m_b=m₁- m₄- (m₅- m₆)

When filling husky, test pits on be not placed with substrate：

m_b=m₁- m₄'-m₂

In formula：m_b- fill up the quality (g) of the sand tested pits；

m₁The quality (g) of sand in-filling sand placket；

m₂The quality (g) of sand in-filling sand cylinder lower cone body；

m₄、m₄After '-fill sand, the quality (g) of remaining sand in cylinder；

(m₅- m₆Total quality (g) of)-fill sand in lower cone body and between substrate and rough surface in sand cylinder；

The wet density ρ for material of testing pits is calculated as follows_w(g/cm³):

ρ_w=m_w/m_b×ρ_s

In formula：m_wThe quality (g) of all material of-middle taking-up of testing pits；

ρ_sLoose measure density (the g/cm of-amount sand³)；

The dry density ρ for material of testing pits is calculated as follows_d(g/cm³)：

ρ_d=ρ_w/(1+0.01w)

In formula：The moisture content (%) of w-material of testing pits；

When for the occasion of the inorganic colloid methoders such as cement, lime, flyash, dry density ρ is calculated as follows_d(g/cm³)；

ρ_d=m_d/m_b×ρ_s

In formula：m_dThe dries quantity (g) for stablizing soil of-middle taking-up of testing pits；

Construction compaction is calculated as follows；

K=ρ_d/ρ_c×100

In formula：The construction compaction (%) of K-testing location；

ρ_dDry density (the g/cm of-sample³)；

ρ_cMaximum dry density (the g/cm of-the sample obtained by compaction test³)；

m₄、m₄After '-fill sand, the quality (g) of remaining sand in cylinder.