CN202131595U - Field soaking load test device for determining collapsibility coefficients of collapsibility loess - Google Patents
Field soaking load test device for determining collapsibility coefficients of collapsibility loess Download PDFInfo
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- CN202131595U CN202131595U CN201120250663U CN201120250663U CN202131595U CN 202131595 U CN202131595 U CN 202131595U CN 201120250663 U CN201120250663 U CN 201120250663U CN 201120250663 U CN201120250663 U CN 201120250663U CN 202131595 U CN202131595 U CN 202131595U
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- collapsibility
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- base plate
- punctuate
- loess
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Abstract
The utility model relates to a measuring device, in particular to a device for determining collapsibility coefficients of collapsibility loess on site. The device is characterized in that a top plate and a bottom plate are connected as a whole by a ribbed plate and are parallel to each other, and holes for marking are evenly distributed on the bottom board. By utilizing the technical scheme, the device has the advantages of being small in test field, short in test period, convenient to use, and the like when a soaking test is stimulated on the test site, the test result can truly reflect the collapsibility coefficients of the collapsibility loess on the tested site, and the engineering manufacturing cost and test cost can be saved.
Description
Affiliated technical field
The utility model relates to a kind of measurement mechanism, particularly measures the device and the method for testing thereof of collapsible loess coefficient of collapsibility.
Background technology
Along with the Chinese national economy develop rapidly, the Northwest's engineering construction scale, investment are increasing, and safety, technical requirements are increasingly high.In standard GB 50025-2004 " Code for building construction in collapsible loess zone ", two main factor beta
0-receive water-soaked because of the different correction factor of regional soil property and β-consideration ground possibility and substrate down the side direction of soil the correction factor of factor such as extrude, be a value range that provides according to the limited experimental data of zones of different, like area, west of Gansu Province β
0Get 1.50, other areas get 0.50, and 0-5m gets 1.50 under the substrate of β value, and 5-10m gets 1 under the substrate, gets the β of location below the substrate 10m
0Value.Calculating saturated yielding amount through laboratory test multiply by β
0,The β value has just obtained saturated yielding amount evaluation of estimate, and saturated yielding amount that draws like this and actual engineering site ponding loading test measured result there are differences; Sometimes widely different; Instruct engineering design, just might cause engineering construction potential safety hazard or investment waste, even cause the accident; Particularly in deep collapsible loess place, problem is particularly outstanding.
Produce this species diversity main cause, the one, β
0, the β value confirms through limited in-situ data comparative analysis result; Also be a value range, and along with engineering is different, the value range interval is also very big; Nature can create a difference; This is the error that statistical method is brought, in addition laboratory test condition and on-the-spot collapsible loess place under the certain pressure or deadweight the test conditionss such as spatial distribution of immersion, fringe conditions, the soil property of immersion saturated yielding distortion are different down, laboratory test mensuration coefficient of collapsibility can not be represented on-the-spot soil layer settlement by soaking certainly fully; There are differences with field actual measurement results, this is the main immanent cause that makes a difference.
Solving differences method at present is exactly on-the-spot submerging test; Because it is on the self weight collapse loess place, carry out on-the-spot submerging test, long in time limit, cost is big, generally about 2 months; Receive the condition restriction of engineering construction each side again, be difficult to implement submerging test in the actual engineering.In non-deadweight place since on-the-spot submerging test that need be under certain pressure except immersion also needs pressurized conditions and equipment, so in actual engineering, can't implement.Therefore the determinator and the measuring method that design a kind of effective on-the-spot coefficient of collapsibility just become particularly important.
Summary of the invention
The purpose of the utility model is the defective to prior art, and a kind of test period is short, expense is low, accurate test result is measured the collapsible loess coefficient of collapsibility on-the-spot ponding loading test device and method of testing thereof are provided.
The technical scheme of the utility model is: a kind of on-the-spot ponding loading test device of measuring the collapsible loess coefficient of collapsibility; It is characterized in that between top board that is parallel to each other and base plate, connecting as one, on base plate, be evenly equipped with the hole that is used to place punctuate through gusset.
Above-mentioned base plate is circular, and the hole that is used to place punctuate is distributed on the circle concentric with base plate, and the coincidence of the geometric center of top board and base plate.
Be distributed on base plate with one heart in the above-mentioned hole that is used to place punctuate, and radius is on the circle of base plate radius 1/2.
The above-mentioned hole that is used to place punctuate is 4.
Utilize the technical scheme of the utility model to carry out ponding loading test at the scene of needs test; This method has characteristics such as the test site is little, test period short, easy to use; Measure on-the-spot collapsible loess coefficient of collapsibility directly and accurately; Simultaneously the result of the test of indoor collapsible loess coefficient of collapsibility is revised; Proposed a kind of on-the-spot test correction match laboratory test results and estimated the new feasible evaluation method of collapsibility of loess, directly can be used to instruct practical engineering design, this method has broad application prospects and remarkable economic efficiency.
Description of drawings
Accompanying drawing 1 is the utility model plan structure sketch map;
Accompanying drawing 2 is the utility model user mode sketch map.
The specific embodiment
Like Fig. 1, shown in 2, between top board that is parallel to each other 4 and base plate 3, be connected to one through gusset 2.On the circle of 1/2 radius of circular bottom plate, be evenly equipped with the hole 1 that is used to place punctuate.
During use, carry out testing pits and the installed load testing equipment at the scene excavation that needs are tested according to the GB regulation, the diameter of the bottom surface of testing pits should be less than 3 times of base plate diameter, and the bottom surface absolute altitude of testing pits is confirmed according to measuring on-the-spot coefficient of collapsibility soil layer absolute altitude; Before placing this device; Under base plate, lay 10～20mm thickness in, the coarse sand levelling, adopt luoyang spade, with base plate on be used to place punctuate the corresponding position, hole; Get the degree of depth respectively and be each 2 in shallow, the dark punctuate hole of base plate radius and base plate diameter; In the hole, place respectively 2 of shallow, dark punctuates 5 respectively, sleeving plastic pipe 6 on shallow, dark punctuate is native to extruding force shallow, dark punctuate to eliminate in the experimentation simultaneously.By accurate second-class level, precision is measured pressurization front top plate central point respectively, the absolute altitude on base plate point and shallow, dark punctuate summit in 0.15mm then; The fulcrum of load test datum line beam is arranged on 3 times of base plate diameter beyond the scope; After accomplishing above-mentioned work, on top board, load, guarantee during loading that the application point of load overlaps with the geometric center of top board, load grade and be no less than 10 grades, be loaded on 200kPa.Whenever add the forward and backward of one-level load, survey the deflection of No. 1 bearing plate of note respectively, do not have 0.5h to survey note 1 time later on, continuously in the 2h, the deflection of every 1h thinks that pressing plate sinks to having become stable, can add the next stage load during less than 0.10mm.And the blanking time of every grade of load should be less than 2h.Be forced into 200kPa and sink to stablizing back immersion round the clock in testing pits, the progressive flooding time should not be less than 10d, and the underground water head should be less than 200mm, after additional settlement is stable, and the test termination.By accurate second-class level, precision is measured pressurization immersion back this device top board central point respectively, the absolute altitude on base plate point and shallow, dark punctuate summit in 0.15mm.According to on-the-spot sidelights data, get the coefficient of collapsibility design formulas of the corresponding on-the-spot soil thickness of each punctuate buried depth thus:
δ
i＝(S
w－S
i)/h
i
In the following formula: h
iH when-i punctuate buried depth (mm), i=1
1=R, h during i=2
2=2R, R are the radius of bearing plate base plate;
δ
i-h
iThe on-the-spot coefficient of collapsibility that detects soil layer of dark punctuate;
S
w=S
p-S
0, S
pUnder the native state test pressure of bearing plate top behind the settlement stability with total settlement (mm) after stablizing the immersion effect under, S
0Settling amount (mm) after bearing plate top native state test pressure is stable down;
S
w-bearing plate top native state test pressure is stablized the back down under the immersion effect, the settling amount (mm) after additional sinking is stable;
S
i-h
iUnder the dark punctuate native state test pressure behind the settlement stability under the immersion effect, the total settlement (mm) before and after the immersion.
As domestic to being positioned at fort town, Yanchi County Huian, Ningxia; The coefficient of collapsibility of six inter-pile soils that surround is in fact surveyed in the Collapsible Loess District II Long Dong-northern Shensi-regional the northern fringe in west, Shanxi, and specific practice is: in the plain native compaction pile ground that lays out pile by equilateral triangle is handled; Construction is adopted and is broken into pile constructing process 4 times; Beat not pile of emptying at the 4th time, form one with 6 positive 6 limit shapes of surrounding of pile, each pile forms the circle of the ground processing area of bearing; With the hexagon centre of form just the 4th time not the pile stake heart be the center of circle; Draw one and bear the tangent circle of circle of ground processing area with 6 piles, this diameter of a circle is exactly the diameter of this load test device base plate 1.Adopt this load test device to carry out on-the-spot ponding loading test, load test is soaked, and the settling amount of this pressure-bearing device is respectively 4.23 ㎜ and 19.45 ㎜ under the forward and backward 200 kPa pressure, differs from 15.22 ㎜ before and after the immersion.Before and after loading, this load test device and each punctuate total settlement see the following form:
| ? | Bearing plate | 0.5m dark punctuate | 1.0m dark punctuate |
| Total settlement/mm | 22.6 | 5.38 | 0.25 |
| Saturated yielding amount/mm | 15.22 | 9.84 | 5.13 |
| Coefficient of collapsibility | ? | 0.02 | 0.01 |
| Central point σ z/kPa | 200 | 120 | 50 |
The coefficient of collapsibility contrast sees the following form under immersion load and the laboratory test 200kPa pressure:
| ? | 0.5m dark punctuate | The dark 3m of J03 place | J03 average in the 4m | Whole place average in the 4m |
| Coefficient of collapsibility | 0.02 | 0.066 | 0.085 | 0.061 |
| Saturated yielding amount/mm | 9.84 | 49.5 | 63.75 | 45.75 |
Can count through above data, correction factor β=0.3, and β=1.5th that standard GB 50025-2004 " Code for building construction in collapsible loess zone " recommends under native state, do not have STRUCTURES CONSIDERING PILE deeply to the fastening and effect of contraction of inter-pile soil.
Claims (4)
1. an on-the-spot ponding loading test device of measuring the collapsible loess coefficient of collapsibility is characterized in that between top board that is parallel to each other (4) and base plate (3), connecting as one through gusset (2), on base plate, is evenly equipped with the hole (1) that is used to place punctuate.
2. the on-the-spot ponding loading test device of mensuration collapsible loess coefficient of collapsibility according to claim 1; It is characterized in that above-mentioned base plate (3) is for circular; The hole (1) that is used to place punctuate is distributed on the circle concentric with base plate, and the geometric center of top board (4) and base plate (3) overlaps.
3. the on-the-spot ponding loading test device of mensuration collapsible loess coefficient of collapsibility according to claim 2, it is concentric to it is characterized in that the above-mentioned hole (1) that is used to place punctuate is distributed on base plate (3), and radius is on the circle of base plate radius 1/2.
4. the on-the-spot ponding loading test device of mensuration collapsible loess coefficient of collapsibility according to claim 3 is characterized in that the above-mentioned hole (1) that is used to place punctuate is 4.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120250663U CN202131595U (en) | 2011-07-15 | 2011-07-15 | Field soaking load test device for determining collapsibility coefficients of collapsibility loess |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120250663U CN202131595U (en) | 2011-07-15 | 2011-07-15 | Field soaking load test device for determining collapsibility coefficients of collapsibility loess |
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| Publication Number | Publication Date |
|---|---|
| CN202131595U true CN202131595U (en) | 2012-02-01 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102312421A (en) * | 2011-07-15 | 2012-01-11 | 宁夏回族自治区电力设计院 | Field immersion load test device for determining collapsibility coefficient of collapsible loess and test method thereof |
| CN102312422A (en) * | 2011-07-15 | 2012-01-11 | 宁夏回族自治区电力设计院 | Test device for collapsibility coefficient of soil among collapsible loess compaction piles and test method |
| CN108344857A (en) * | 2018-02-09 | 2018-07-31 | 黄河勘测规划设计有限公司 | Native saturated yielding memory characteristic two-wire test method under the conditions of drying and watering cycle |
| CN108344858A (en) * | 2018-02-09 | 2018-07-31 | 黄河勘测规划设计有限公司 | Native saturated yielding memory characteristic single line test method under the conditions of drying and watering cycle |
-
2011
- 2011-07-15 CN CN201120250663U patent/CN202131595U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102312421A (en) * | 2011-07-15 | 2012-01-11 | 宁夏回族自治区电力设计院 | Field immersion load test device for determining collapsibility coefficient of collapsible loess and test method thereof |
| CN102312422A (en) * | 2011-07-15 | 2012-01-11 | 宁夏回族自治区电力设计院 | Test device for collapsibility coefficient of soil among collapsible loess compaction piles and test method |
| CN108344857A (en) * | 2018-02-09 | 2018-07-31 | 黄河勘测规划设计有限公司 | Native saturated yielding memory characteristic two-wire test method under the conditions of drying and watering cycle |
| CN108344858A (en) * | 2018-02-09 | 2018-07-31 | 黄河勘测规划设计有限公司 | Native saturated yielding memory characteristic single line test method under the conditions of drying and watering cycle |
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| GR01 | Patent grant | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120201 Termination date: 20130715 |