CN101280563B - Pretensioned prestressing pipe pile construction method under weak expansion soil condition - Google Patents
Pretensioned prestressing pipe pile construction method under weak expansion soil condition Download PDFInfo
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Abstract
The invention discloses a pretensioning prestressed pipe pile construction method under the condition of weak expansive soil and the characteristics of prestressed pipe pile engineering construction. Considering all processes such as pipe pile design, equipment selection, construction management and quality monitoring, we adopt measures such as canceling pile tip, taking out soil by through holes, dynamic monitoring, holo-authentic pile testing, rain protection and waterlogging drainage, bottom sealing, retapping, separate piling, etc. and carry out two types of work, namely, prevention and correction, so as to reduce the extent of damage of compaction effect to the scope allowable by design and standards during the process of prestressed pipe pile construction under the condition of expansive soil. The construction method is applicable to the industrial and civil architecture prestressed pipe pile foundation treatment and construction which have lower requirements on noise in suburban, villages and towns and suitable for prestressed pipe pile foundation treatment and construction of various engineering, wherein, geological conditions are of cohesive soil, silty soil, sandy soil and gravel types and particularly the bearing stratum is strongly weathered or moderately weathered rock stratum and close-grained sand layer (or cobble layer) with weak expansive soil.
Description
Technical field
The present invention relates to pretensioned prestressing pipe pile construction method under a kind of weak expansion soil condition.
Background technology
The intensity height of pretensioned prestressing pile tube, durable resistance is good, and penetration power is strong, the bearing capacity height, in coastal areas such as Guangdong Province is a kind of application ground processing more widely stake type, also obtains pushing away handful in recent years gradually in central and west regions, especially is subjected to real estate developer's favor.But the pile for prestressed pipe blemish in an otherwise perfect thing is the harmfulness that will overcome soil compaction effect in the work progress.When under weak expansion soil condition, carrying out tube pile construction, since water body in work progress by disturbance or be subjected to underground water and the erosion of rainwater, make soil layer absorb water repeatedly and dehydration generation swell-shrinking deformation, thus the harmfulness of having aggravated the soil compaction effect in the tube pile construction process.
In the pile tube formation of pile, be equivalent to the long-pending soil body of pile body to around squeeze, the soil body of stake point and stake Zhou Yiding scope is subjected to undrained shear and very big level extruding, pile peripheral earth approaches " incompressibility ", produce bigger shear strain, formation has the very disturbance of high-voidage water pressure and reinvents layer, thereby reduced native undrained shear strength, impel and close on the soil body week and can destroy because of undrained shear, near the soil body that is embodied in ground is upwards to swell, and at below ground than the deep layer soil body because the effect of overlying soil pressure can not upwards swell, just push to horizontal direction.Because the superposition effect of a clump of piles, can make that driven pile produces bigger lateral displacement and come-up, according to existing data demonstration, earth heaving can reach 500-600mm, have in addition reach 800-1000mm.
Expansive soil be a kind ofly have significantly to expand in suction back, the remarkable high liquid limit clay of shrinkage character after the dehydration.The mineralogical composition of expansive soil mainly is montmorillonite, and general bearing capacity is higher, but has characteristics such as imbibition, dehydration contraction and repeated expansion and shrinkage distortion, the decay of immersion bearing capacity, desiccation crack growth, and character is extremely unstable.Expansive soil produces the swell-shrinking deformation of uneven vertical or level to pile for prestressed pipe, cause displacement, cracking, inclination even destruction, and often occur in groups, generally in tube pile construction to 1/3-1/2 in addition upper building completion 1-5 occur.In addition when under weak expansion soil condition, carrying out tube pile construction, because the erosion of water body disturbance and underground water and rainwater in work progress, make characteristics such as expansive soil such as suction and dehydration repeated expansion and shrinkage distortion repeatedly, the decay of immersion bearing capacity, desiccation crack growth further aggravate, therefore carrying out the prestressing pipe pile construction difficulty under the expansion soil condition will become bigger.According to existing Engineering Projects analysis, if do not solve soil compaction effect problem under the expansion soil condition effectively, the pile tube that will cause squeezing into large tracts of land protuberance, displacement occur even fractures, thereby great accident resulting from poor quality of projects occurs.
Summary of the invention
Technical problem to be solved by this invention provides pretensioned prestressing pipe pile construction method under a kind of weak expansion soil condition that the extent of injury of the soil compaction effect in the expansion soil condition lower prestress tube pile construction process can be reduced in design and the standard allowed band.
In order to solve the problems of the technologies described above, pretensioned prestressing pipe pile construction method under the weak expansion soil condition provided by the invention, comprise measurement and positioning, draw to fetch earth in the hole, the engineering piles examination is beaten, engineering piles injection, engineering piles repetition measurement, engineering piles strike-on, engineering pile detect examination, it is characterized in that:
(1), engineering piles measurement and positioning
By the axial line control point, make the stake position one by one before the piling, set the reinforcing bar stake, near the ground stake, draw a center of circle and the circle that stake coincidence, diameter equate with pile tube,, keep the stake position correct to make things convenient for pitching pile centering with lime;
(2), drawing the hole fetches earth
Draw the hole when fetching earth the diameter of prebored hole be preferably 70% of pile tube diameter, the degree of depth is the stake of 1/3-1/2 long (actual value is determined according to structure Design and Calculation), the cross section, hole is no more than 2/3 of a cross section; Draw the hole and fetch earth and carry out stage by stage according to construction speed and weather, the prebored hole injection on the same day on the same day finishes, and must not disposablely get;
(3), the engineering piles examination is beaten
Still be necessary before the engineering piles injection to carry out engineering piles examination manual labour work, choose the intensive cushion cap of a clump of piles and carry out authentic test pile at each construction section or construction piece; After clump of piles examination is beaten and finished, choose stake position representative in the clump of piles and carry out the engineering piles detection in advance, according to on-the-spot pile situation and examining report to construction parameter is revised;
(4), engineering piles injection
A, injection
Adopting weight to hang down hits, between pile cover and the pile crown elastic insert should be set during piling, stop the hammer standard and carry out two controls according to test pile definite pile penetration and structural elevation, will notice that simultaneously the total hammering number of 1 pile generally is not more than 2500 hammers, last 1m hammering number is no more than 300 and hammers into shape; Rationally arrange the pile sinking order, rule be earlier in outside the back, by center outside symmetrical construction then gradually; Dredge earlier close back, beats earlier a closeer clump of piles, and a clump of piles of dredging is beaten in the back; When near existing building or structure, driving piles, should carry out along the direction that deviates from building or structure; Strengthen carrying out drainage works such as underground water and rainwater, strengthen pile is prevented the covering work that rainwater ponding corrodes, carry out the covering at pile pore-forming position, prevent to expose to the sun and rain; Concentrate on the pile sinking on daytime, keep good hours, control pile quantity every day, every stake machine pile every day amount is the 8-12 root;
B, pile extension
Pile extension adopts the welding pile extension; Every pile contrast geological drilling data estimates that total stake is long, and the pile extension number of times is reduced as far as possible, and the joint quantity of arbitrary single pile is no more than 2, and pile extension carries out after the stake point passes boulder bed; When pile tube needs spreading, the stake 0.5-1.0m above ground level of its part pile cutoff that do not bury; The pile crown place of following joint stake should establish the guiding hoop, and to go up the joint stake in place with convenient, saves pile cutoff during pile extension up and down and should keep straight, and the dislocation deviation should not be greater than 2mm, stake bent-segment vector height must not greater than stake long 0.1%;
C, back cover
Owing to cancelled the stake point, softening for preventing bearing course at pile end for soaked by underground water or surface rain or ponding, when last 3 gusts of stake injection, to fill out in the pipe immediately and irritate the microdilatancy concrete, concrete strength grade is C30, influx height is no less than 1m, plays the effect of vibration with shutoff concrete vibration compacting by the pile tube examination.When prebored hole has ponding, ponding should be gone ahead of the rest and carry out the pile tube injection again behind the pump drainage, if rich groundwater is can't pump drainage clean keep the body of groundwater balance again simultaneously the time, can when last 3 gusts of pile tube injection, will mixes the dry microdilatancy concrete that makes immediately and fill out and irritate to the pile tube ponding and be absorbed as and end;
(5), engineering piles repetition measurement
Engineering piles repetition measurement content comprises axis, absolute altitude and verticality when carrying out the single pile pile, axis, absolute altitude and verticality situation of change and construction section or construction piece construction pile tube are finished original records such as posterior axis, absolute altitude and verticality situation of change during clump of piles bore forming, axis, absolute altitude and verticality when when engineering piles needs strike-on, carrying out the stake of single pile strike-on in addition according to the requirement of engineering piles injection, axis, absolute altitude and verticality situation of change and construction section or construction piece construction strike-on are finished original records such as posterior axis, absolute altitude and verticality situation of change during clump of piles strike-on;
(6), engineering piles strike-on
Carry out the work of engineering piles strike-on, every record in the time of strike-on will being carried out in the strike-on process according to engineering piles pile record and engineering piles repetition measurement situation tissue;
(7), engineering piles detects and checks and accepts
Tube pile construction is checked and accepted and should be carried out by the regulation of GB50202-2002; The detection of pile tube should be carried out by the regulation of GB50007-2002.
Adopt pretensioned prestressing pipe pile construction method under the weak expansion soil condition of technique scheme, cancelled b type open-type piling bar pointed stake point in the tube pile construction, taked to draw hole form of construction work such as fetch earth, carry out exploratory construction in the construction forbidden zone and obtained success.Adopt total powerstation that pile tube is navigated to clump of piles pile overall process from single pile in the tube pile construction and carry out axis and absolute altitude control measurement, to pile tube from the single pile pile to clump of piles pile overall process verticality control measurement.Utilize advanced survey tool that engineering is carried out dynamic monitoring management, and utilize the achievement of dynamic monitoring that follow-up tube pile construction is instructed, these in the past engineering ignore easily.Before carrying out the engineering piles injection, choose the intensive cushion cap of a clump of piles and carry out authentic test pile, single pile did not have representational shortcoming when authentic test pile can solve the test pile construction.The soil compaction effect problem that has solved a clump of piles is also with regard to the soil compaction effect problem of the engineering piles that solved whole engineering, also is easy to remedy even temporarily go wrong during clump of piles test pile.Authentic test pile also is the characteristic of this worker method exploration construction.
In sum, the present invention is a pretensioned prestressing pipe pile construction method under a kind of weak expansion soil condition that the extent of injury of the soil compaction effect in the expansion soil condition lower prestress tube pile construction process can be reduced in design and the standard allowed band.
The specific embodiment
The invention will be further described below in conjunction with the specific embodiment.
Be made up of 6 high-rise residential buildings with Chengdu Zhuo Jincheng R2C2 project, ground is strengthened Design Treatment and is adopted PHC-AB500 (125)-15b pretensioned prestressing high-strength concrete tubular pile, amounts to 1026.The designing requirement stake is about about 22m, and effective length is greater than 15m, and the weathering mud stone was not less than 1.5 times of pile body during the stake end entered, and the bearing capacity of single pile characteristic value is 2200KN.At expansive soil soil property and pile for prestressed pipe engineering construction characteristics, my department starts with from pile tube design, lectotype selection, execution control, each link of quality-monitoring, measures such as having taked cancellation stake point, draw to fetch earth in the hole, process check, dynamic monitoring, authentic test pile, rainproof row's stain and back cover, strike-on, jumping are beaten, carried out prevention and corrected the work of two aspects, the extent of injury of the soil compaction effect in the expansion soil condition lower prestress tube pile construction process has been reduced in design and the standard allowed band.
1, material requirements
Pile tube is manufactured the regulation that quality should meet GB13476-1999; Pile tube punching block material and installation quality should meet the regulation of JC/T605-1995; Concrete strength must reach the regulation of GB13476-1999 during the pile tube demoulding, and pile tube lifting and transportation must be satisfied the regulation of GB13476-1999; The presentation quality of pile tube, permissible variation in dimension and inspection rule etc. are all carried out by GB13476-1999.
Strength grade of concrete is C80, meets the regulation of GB50164-1992, GB13476-1999.
Cement: adopt strength grade to be not less than 42.5 portland cement, Portland cement, portland slag cement, Portland fly ash cement, cement select the regulation that should meet GB175-1999, GB1344-1999 for use.Aggregate: coarse aggregate is selected rubble for use, and maximum particle diameter should not be greater than 25mm, and should not surpass 3/4 of distance of reinforcing bar, meet the regulation of GB/T14685-2001.Fines is selected natural or artificial hard medium coarse sand for use, and fineness modulus meets the regulation of GB/T14684-2001 at 2.3-3.4.Mixing water: the regulation that meets JDJ63-1989.Admixture: meet the regulation of GB8076-1997, forbid to use the chloride salt Admixture.Admixture Admixture: must carry out verification experimental verification before using, must not produce illeffects to pile tube.Steel: prestressed reinforcement should adopt steel bar for prestressed concrete, and its quality meets the regulation of YB/T111-1997.Spiral bar should adopt cold-drawn low-carbon wire, mild steel hot rolling wire rod, and its quality should meet the regulation of GB50204-2002, GB/T701-1997 respectively.The material capability of end plate, pile protection hoop should meet the regulation of Q235 among the GB/T701-1988.
Structure requires: the single-unit maximum length: should adopt the pile tube of external diameter 500mm, the long 8-12m that is preferably of single-unit stake is no longer than 15m.Pile tube is preferably AB type or Type B stake.
Common pile tube structure selects for use table as follows:
The tube pile structure designing and calculating is carried out according to the GB50010-2002 pertinent regulations.
2, prepare
2.1, measure to prepare
2.1.1, measurement and positioning
Survey the bidding knowledge according to engineering drawing at the construction field (site) with each bit number and with each position.
21.2, the setting of internal
Set up semipermanent control point inside, be used for the rough repetition measurement stake of on-the-spot hanging wire position; Set up permanent control point outside the venue, be used for the interior semipermanent point in accurate repetition measurement of on-the-spot total powerstation or measurement stake position and field and check.
2.1.3, coordinate transformation
According to permanent control point outside the venue, the coordinate transformation of each position is come out, be convenient to accurate repetition measurement or location.
2.2, the place prepares
2.2.1, the place tentatively opens and digs with smooth.
According to the characteristics of structure design and initial land form landforms, the soil excavation of the place of being about to earlier to construct carries out levelling of the land then to designing 300-500mm or position, the most shallow cushion cap middle and upper part on the base plate.
2.2.2, the formation of drainage system.
In conjunction with the semipermanent drainage system of foundation ditch, temporary drainage groove in the tube pile construction process is set, the place of guaranteeing to construct is not subjected to the dipping of rainwater, underground water and construction water.
2.2.3, a machinery turnover road forms.
Guarantee that pile tube delivery tube pile material machinery, pile tube injection machinery and pile tube detect the turnover field of machinery
2.2.4, construction equipment track route, material stockyard determine and the formation of work plane along the line.
Require to determine construction equipment track route, material stockyard according to structure design lineament and pile tube injection, and note guaranteeing the minimum work plane (especially noting the minimum work plane of foundation ditch retaining wall or bank protection edge) of tube pile construction machinery along the line.
2.2.5, foundation ditch retaining wall or bank protection and face the limit security protection.
2.3, test pile construction
According to GB13476-1999 and Structural Design Requirement and geological mapping report confirmed test stake quantity and position, a test pile part can adopt the stake of engineering original position, and a part can adopt the stake of non-engineering original position, only the stake of non-engineering original position is used to do Ultimate load test.When carrying out the checking of structure design and geological mapping report and the construction of definite engineering tubular pile according to test pile report such as hammer is heavy, every construction parameters such as distance, hammering number, pile penetration fall.
The cylindrical diesel pile driver pile monkey selects for use reference table as follows:
2.4, the joining stake and produce of pile tube
Determine that according to structure design, test pile report and geological mapping report are preliminary total stake of each position is long, and then the long situation of comprehensive overall stake carries out the stake of joining of economical rationality to every pile, and doubly stake is directly for 3-5 also will to consider clump of piles pile extension point to stagger at same horizontal plane at interval when joining.。Organize the plant produced of pile tube (can join stake according to the practice of construction situation during Construction of Engineering Pile and produce fine setting) according to joining a situation.
3, tube pile construction
3.1, construction technology process
---drawing the hole fetches earth, and---the engineering piles examination is beaten, and------engineering piles repetition measurement---engineering piles strike-on---engineering pile detects to be checked and accepted measurement and positioning in the engineering piles injection
3.2, the engineering piles measurement and positioning
By the axial line control point, make the stake position one by one before the piling, set the reinforcing bar stake, near the ground stake, draw a center of circle and the circle that stake coincidence, diameter equate with pile tube,, keep the stake position correct to make things convenient for pitching pile centering with lime.Before end stake is in place, on pile body, mark the unit length mark, so that observe the embedded depth of stake and write down every meter pile sinking and hit number.Stake is in place wants the centering straightening, makes pile body, pile cover and pile monkey three's central lines, and the assurance pile body is vertical, and its perpendicularity deviation must not be greater than 0.5%.Because vibration is not easy to set up instrument more greatly during site operation, on the verticality observation employing orthogonal direction two plumb-bob verticals is set and observes correction.Because the generation of grand soil and soil compaction phenomenon is still inevitably arranged in the tube pile construction process, therefore should pay much attention to the location and the repetition measurement work of drawing the hole, to constantly carry out repetition measurement to the stake hole by semipermanent some hanging wire in the field, utilize in case of necessity and set up permanent control point outside the venue, check by a semipermanent point in the accurate repetition measurement of total powerstation or measurement stake position, hole and the field.
3.3, draw the hole and fetch earth
Draw the hole when fetching earth the diameter of prebored hole be preferably about 70% of pile tube diameter, the degree of depth is preferably the stake long (actual value is determined according to structure Design and Calculation) of 1/3-1/2, the cross section, hole is no more than 2/3 of a cross section.Draw the hole and fetch earth and carry out stage by stage according to construction speed and weather, preferably the prebored hole injection on the same day on the same day finishes, and must not disposablely get.Should strengthen repetition measurement and protection work to drawing the hole.
3.4, engineering piles examination beats
Although test pile work is finished,, still be necessary before the engineering piles injection to carry out engineering piles examination manual labour work at each construction section or construction piece in order further to improve every construction parameter.Because the strongest position of soil compaction effect occurs in clump of piles dense part, therefore before carrying out the engineering piles injection, should choose the intensive cushion cap of a clump of piles and carry out authentic test pile.Single pile did not have representational shortcoming when authentic test pile can solve the test pile construction.The soil compaction effect problem that has solved a clump of piles is also with regard to the soil compaction effect problem of the engineering piles that solved whole engineering, also is easy to remedy even temporarily go wrong during clump of piles test pile.After clump of piles examination is beaten and finished, choose stake position representative in the clump of piles and carry out the engineering piles detection in advance, according to on-the-spot pile situation and examining report to construction parameter is revised.
3.5, the engineering piles injection
3.5.1, injection
Adopt weight to hang down and hit, with effective reduction hammering stress, it is vertical to note keeping end stake simultaneously, makes the central lines of pile monkey, pile cover and pile body in the overall process of hammer piling, prevents that stake is subjected to eccentric hammering, in order to avoid stake is subjected to curved being turned round.Between pile cover and the pile crown elastic insert should be set during piling, stop the hammer standard and carry out two controls according to test pile definite pile penetration and structural elevation, will notice that simultaneously the total hammering number of 1 pile generally should not be greater than 2500 hammers, last 1m hammering number should not be above 300 hammers.Engineering piles examination is beaten and is wanted strict and carry out according to structure design and geological mapping report, carry out pile driving record, when actual injection situation and structure design and geological mapping report have bigger discrepancy, must research and solve together with relevant unit.
Rationally arrange the pile sinking order, rule be earlier in outside the back, by center outside symmetrical construction then gradually; Dredge earlier close back, beats earlier a closeer clump of piles, and a clump of piles of dredging is beaten in the back; When near existing building or structure, driving piles, should carry out along the direction that deviates from building or structure.
Collect the construction of weather condition rationalization, strengthen carrying out drainage works such as underground water and rainwater, strengthen pile is prevented the covering work that rainwater ponding corrodes, can adopt colour bar cloth to carry out the covering at pile pore-forming position, prevent to expose to the sun and rain; Concentrate on the pile sinking on daytime, keep good hours, control pile quantity every day, every stake machine pile every day amount is preferably the 8-12 root, can effectively reduce the superposition of underground interstitial hydraulic pressure, also be the requirement of carrying out site safety management, quality managemant and the work that do not disturb residents simultaneously.
3.5.2, pile extension
It is most important that can the pile extension quality resist soil compaction effect to the extension spray lance stake at the pile extension position, so pile extension should adopt the welding pile extension.Every pile contrast geological drilling data estimates that total stake is long, and selects the combination of rational stake joint for use, so that the pile extension number of times reduces as far as possible, the joint quantity of arbitrary single pile should not surpass 2, and pile extension should carry out after the stake point passes boulder bed.When pile tube needs spreading, the suitable 0.5-1.0m above ground level of the stake of its part pile cutoff that do not bury; The pile crown place of following joint stake should establish the guiding hoop, and to go up the joint stake in place with convenient, saves pile cutoff during pile extension up and down and should keep straight, and the dislocation deviation should not be greater than 2mm, stake bent-segment vector height must not greater than stake long 0.1%.
Before the pile tube butt joint, end plate surface applications iron brush is cleaned with water clean and is kept dry up and down, and the groove place should brush to exposing metallic luster.Weld appropriate to the occasion elder generation around the groove on balanced welding 4-6 point, treat that guiding is removed in the fixing back of stake joint up and down to bind round the welding of layering again that welding should be undertaken by two welder's symmetries.The welding number of plies must not be less than three layers, can weld outer one deck after the internal layer weld seam must be cleaned out, and ectonexine weld seam interface position should stagger, and weld seam should be full continuous, and every layer of throat thickness should be even, defectives such as the unsuitable slag inclusion of weld seam, pore.The necessary full weld of the electric welding of groove groove, weldering thickness should exceed groove 1mm.Weld seam need satisfy the requirement of " structural steelwork construction and standards of acceptance " GB50205-92 second-order weld.Welding finishes and can continue pile sinking after should cooling off naturally, and nature cool time should not be less than 8 minutes, forbids with water cooling or pile sinking immediately after welding, in order to avoid the embrittlement of weld seam interface.After finishing, pile extension should carry out crank detection test according to the regulation of GB13476-1999.
3.5.3, back cover
Owing to cancelled the stake point, softening for preventing bearing course at pile end for soaked by underground water or surface rain or ponding, when last 3 gusts of stake injection, to fill out in the pipe immediately and irritate the microdilatancy concrete, concrete strength grade is C30, influx height is no less than 1m, plays the effect of vibration with shutoff concrete vibration compacting by the pile tube examination.When prebored hole has ponding, ponding should be gone ahead of the rest and carry out the pile tube injection again behind the pump drainage, if rich groundwater is can't pump drainage clean keep the body of groundwater balance again simultaneously the time, can when last 3 gusts of pile tube injection, will mixes the dry microdilatancy concrete that makes immediately and fill out and irritate to the pile tube ponding and be absorbed as and end.
3.6, the engineering piles repetition measurement
The engineering piles repetition measurement is dynamically to grasp the engineering tubular pile pile to be subjected to soil compaction effect to influence the capsule information of situation.Engineering piles repetition measurement content comprises axis when carrying out the single pile pile, absolute altitude and verticality, axis during clump of piles bore forming, absolute altitude and verticality situation of change and construction section or construction piece construction pile tube are finished posterior axis, original records such as absolute altitude and verticality situation of change, axis when when engineering piles needs strike-on, carrying out the stake of single pile strike-on in addition according to the requirement of engineering piles injection, absolute altitude and verticality, axis during clump of piles strike-on, absolute altitude and verticality situation of change and construction section or construction piece construction strike-on are finished posterior axis, original records such as absolute altitude and verticality situation of change must be researched and solved together with relevant unit in case have greatly changed.
3.7, the engineering piles strike-on
Carry out the work of engineering piles strike-on according to engineering piles pile record and engineering piles repetition measurement situation tissue, every record in the time of will carrying out strike-on in the strike-on process must be researched and solved together with relevant unit in case have greatly changed.
3.8, engineering piles detect to check and accept
Tube pile construction is checked and accepted and should be carried out by the regulation of GB50202-2002; The detection of pile tube should be carried out by the regulation of GB50007-2002.Should be noted that the time want stop time of time effect and bearing capacity check, finish again at the soil body and carry out after fixed.When carrying out tube pile construction under general weak expansion soil condition, its stop time is delayed 5-10 days again on following form value basis.
Stop time selects for use table as follows:
Social benefit
" pile for prestressed pipe is because first of its overall merit score, and its technical factor and economic factor score all locate first, therefore is the stake type that override is promoted ".Pile for prestressed pipe has not only been widened the field of its application in the successful Application of weak expansion soil property, and a series of technical measures of taking at weak expansion soil property have reasonable reference function to the construction of pile tube engineering under the unexpansive soil condition simultaneously.
Economic benefit
Because cancellation stake point, draw to fetch earth in the hole, the application of measure such as process check, dynamic monitoring, authentic test pile, rainproof row's stain and back cover, strike-on, jumping are beaten, significantly reduce or stopped that stake biasedly moves, pile body inclining, broken pile, floating stake even leak common quality defects encountered such as stake, shortened the duration in tube pile construction later stage greatly, compared cocondensation short tubular piles construction period 1-3 month with similar engineering, direct economic benefit reaches 59.8 ten thousand yuan.The construction quality of pile tube reaches the expection requirement, has obtained leader such as owner, design, management, Quality Supervision Station, company and expert's consistent favorable comment.
4, this worker method has also been carried out exploratory construction in the following aspects, and obtains effect preferably, finds out some construction points:
---should adopt the roller type diesel hammer in the tube pile construction, because the roller type diesel hammer can satisfy and carry out according to certain sequence of construction that pile tube is squeezed into construction and strike-on is constructed, and obviously can not finish above-mentioned work well such as diesel pile hammer with crawler carrier.
---cancel the stake point down and prevent the shutoff measure that problems such as underground water, rainwater or other ponding are taked at the expansion soil condition.
---the strike-on taked at soil compaction effect under the expansion soil condition, jump measure such as beat.
---strengthen the quality managemant of pile tube production link, the strict semiproduct system of check and acceptance of marching into the arena; Take to weld the single pile spreading mode of pile extension, strengthen the visual inspection of welding quality and inner flaw detection etc., these concern single pile under weak expansion soil condition, resist the soil compaction effect fundamental management also engineering construction in the past ignore easily.
2.5, construction technology is simple, do not take special technique measure, constructional materials and plant, do not improve construction cost.Take all factors into consideration many-sided influence factors such as design, material, construction, environment simultaneously, carry out the control of pile tube pile quality targetedly.
This worker method be applicable to suburban area or small towns etc. to sound make an uproar require lower industry and civilian construction pile for prestressed pipe Foundation Treatment, suitable geological conditions be cohesive soil, silt, sand, rubble class especially bearing stratum be severely-weathered or middle weathered rock formation, closely knit layer of sand (or boulder bed) and pile for prestressed pipe Foundation Treatment with all kinds of engineerings of weak expansion soil property.
Claims (1)
1. pretensioned prestressing pipe pile construction method under the expansion soil condition a little less than a kind comprises measurement and positioning, draws that fetch earth in the hole, the engineering piles examination is beaten, engineering piles injection, engineering piles repetition measurement, engineering piles strike-on, engineering pile detect examination, it is characterized in that:
(1), engineering piles measurement and positioning
By the axial line control point, make the stake position one by one before the piling, set the reinforcing bar stake, near the ground stake, draw a center of circle and the circle that stake coincidence, diameter equate with pile tube,, keep the stake position correct to make things convenient for pitching pile centering with lime;
(2), drawing the hole fetches earth
Draw the hole when fetching earth the diameter of prebored hole be preferably 70% of pile tube diameter, the degree of depth is that the stake of 1/3-1/2 is long, actual value determines that according to structure Design and Calculation the cross section, hole is no more than 2/3 of a cross section; Draw the hole and fetch earth and carry out stage by stage according to construction speed and weather, the prebored hole injection on the same day on the same day finishes, and must not disposablely get;
(3), the engineering piles examination is beaten
Still be necessary before the engineering piles injection to carry out engineering piles examination manual labour work, choose the intensive cushion cap of a clump of piles and carry out authentic test pile at each construction section or construction piece; After clump of piles examination is beaten and finished, choose stake position representative in the clump of piles and carry out the engineering piles detection in advance, construction parameter is revised according to on-the-spot pile situation and examining report;
(4), engineering piles injection
A, injection
The employing weight is low to be hit, and between pile cover and the pile crown elastic insert should be set during piling, stops the hammer standard and carries out two controls according to test pile definite pile penetration and structural elevation, will notice that simultaneously the total hammering number of 1 pile is not more than 2500 and hammers into shape, and last 1m hammering number is no more than 300 and hammers into shape; Rationally arrange the pile sinking order, earlier in outside the back, by center symmetrical construction laterally gradually; Dredge earlier close back, beats earlier a closeer clump of piles, and a clump of piles of dredging is beaten in the back; When near existing building or structure, driving piles, should carry out along the direction that deviates from building or structure; Strengthen carrying out underground water and rain-water drainage work, strengthen pile is prevented the covering work that rainwater ponding corrodes, carry out the covering at pile pore-forming position, prevent to expose to the sun and rain; Concentrate on the pile sinking on daytime, keep good hours, control pile quantity every day, every stake machine pile every day amount is the 8-12 root;
B, pile extension
Pile extension adopts the welding pile extension; Every pile contrast geological drilling data estimates that total stake is long, and the pile extension number of times is reduced as far as possible, and the joint quantity of arbitrary single pile is no more than 2, and pile extension carries out after the stake point passes boulder bed; When pile tube needs spreading, the stake 0.5-1.0m above ground level of its part pile cutoff that do not bury; The pile crown place of following joint stake should establish the guiding hoop, and to go up the joint stake in place with convenient, saves pile cutoff during pile extension up and down and should keep straight, and the dislocation deviation should not be greater than 2mm, stake bent-segment vector height must not greater than stake long 0.1%;
C, back cover
Owing to cancelled the stake point, softening for preventing that bearing course at pile end is soaked by underground water or surface rain or ponding, when last 3 gusts of stake injection, fill out in the pipe immediately and irritate the microdilatancy concrete, concrete strength grade is C30, influx height is no less than 1m, play the effect of vibration with shutoff concrete vibration compacting by the pile tube examination, when prebored hole has ponding, ponding should be gone ahead of the rest and carry out the pile tube injection again behind the pump drainage, if rich groundwater is can't pump drainage clean keep the body of groundwater balance again simultaneously the time, when last 3 gusts of pile tube injection, will mixes the dry microdilatancy concrete that makes immediately and fill out and irritate to the pile tube ponding and be absorbed as and end;
(5), engineering piles repetition measurement
Axis, absolute altitude and verticality situation of change and construction section or construction piece construction pile tube were finished posterior axis, absolute altitude and verticality situation of change original record when engineering piles repetition measurement content comprised axis, absolute altitude and verticality when carrying out the single pile pile, clump of piles bore forming, when when engineering piles needs strike-on, carrying out the stake of single pile strike-on in addition according to the requirement of engineering piles injection when axis, absolute altitude and verticality, a clump of piles strike-on axis, absolute altitude and verticality situation of change and construction section or the construction piece strike-on of constructing finish posterior axis, absolute altitude and verticality situation of change original record;
(6), engineering piles strike-on
Carry out the work of engineering piles strike-on, every record in the time of strike-on will being carried out in the strike-on process according to engineering piles pile record and engineering piles repetition measurement situation tissue;
(7), engineering piles detects and checks and accepts
Tube pile construction is checked and accepted the regulation of pressing GB50202-2002 and is carried out; The detection of pile tube is pressed the regulation of GB50007-2002 and is carried out.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101666090B (en) * | 2009-09-29 | 2010-12-08 | 东莞市桦业土木基础工程有限公司 | Typical geology PHC pipe pile construction method |
| CN101851920B (en) * | 2010-06-01 | 2011-07-27 | 中国一冶集团有限公司 | Treatment method of elevation-exceeding part of concrete pouring pile head |
| CN102011401B (en) * | 2010-09-09 | 2012-06-06 | 平煤建工集团有限公司 | High-intensity prestressed concrete tubular pile lead hole hammering construction method for soft soil layer |
| CN103397632B (en) * | 2013-08-06 | 2016-01-13 | 中国电力工程顾问集团华东电力设计院有限公司 | PHC pile tube and pile-sinking method thereof |
| CN104005400B (en) * | 2014-06-06 | 2016-03-09 | 中交上海三航科学研究院有限公司 | The compacted expanding process of underwater sand compaction pile stops hammer standard determination methods |
| CN104452754B (en) * | 2014-11-28 | 2016-05-11 | 中铁二十三局集团有限公司 | Prestressed concrete pipe pile construction method |
| CN104594328B (en) * | 2014-12-04 | 2016-04-13 | 中北大学 | Define and calculate drop inspection dynamic consolidation construction to fall apart from whether reaching calibration method |
| CN106677181A (en) * | 2016-12-30 | 2017-05-17 | 中国十七冶集团有限公司 | Construction method solving pipe pile deviation of pile foundation in pressing process |
| CN112553991A (en) * | 2020-11-30 | 2021-03-26 | 中交路桥建设有限公司 | Weak expansive soil old roadbed reinforcing method and widening method |
| CN112632657B (en) * | 2020-11-30 | 2023-04-21 | 四川建筑职业技术学院 | BIM technology-based prestressed pipe pile matching system and pile matching method |
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Effective date of registration: 20090109 Address after: 20, Jing Wan Road, Yuhua District, Hunan, Changsha: 410004 Applicant after: China Construction five Bureau Third Construction Co., Ltd. Co-applicant after: China Construction Fifth Engineering Division Co., Ltd. Address before: 20, Jing Wan Road, Yuhua District, Hunan, Changsha: 410004 Applicant before: The Third Construction Co., Ltd. of China Construction Fifth Engineering Bureau |
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