CN101915698B - Testing method for simulating precipitation earth lateral pressure coefficient change of foundation pit - Google Patents
Testing method for simulating precipitation earth lateral pressure coefficient change of foundation pit Download PDFInfo
- Publication number
- CN101915698B CN101915698B CN2010102217113A CN201010221711A CN101915698B CN 101915698 B CN101915698 B CN 101915698B CN 2010102217113 A CN2010102217113 A CN 2010102217113A CN 201010221711 A CN201010221711 A CN 201010221711A CN 101915698 B CN101915698 B CN 101915698B
- Authority
- CN
- China
- Prior art keywords
- sample
- precipitation
- consolidation
- lateral pressure
- earth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a testing method for simulating precipitation earth lateral pressure coefficient change of a foundation pit, which relates to an indoor geotechnical testing method. In the invention, a cut sample is put on a pre-consolidation instrument for consolidating twice, wherein consolidation for the first time enables the sample to restore to the natural self-weight stress state of earth mass, and consolidation for the second time simulates the stress state of the earth mass after precipitation. The invention considers the effects of reduction of the water content of precipitation earth of the foundation pit, intensification of effective stress and consolidation and compaction of earth on the earth lateral pressure coefficient, and provides reference for the accurate selection of the precipitation earth lateral pressure coefficient of the foundation pit, thereby providing guaranty for safe, economic and reasonable design and construction of a soft earth water-rich deep foundation pit.
Description
Technical field
The present invention relates to a kind of laboratory soil test method, relate in particular to a kind of test method that soft soil layer base pit dewatering earth lateral pressure coefficient changes of simulating.
Background technology
Earth lateral pressure coefficient K0 is meant the soil body under no lateral deformation condition, the ratio of side direction effective stress and vertical effective stress, it be in the reflection foundation soil level to the important mechanical index of STRESS VARIATION.Lateral pressure coefficient is to be used for calculating soil deformation; Confirm underground exterior-protected structure and soil-baffling structure soil pressure and the necessary basic parameter of pile foundation side friction resistance; It is widely used in the practical project design calculating such as base pit engineering, gravity retaining wall, dykes and dams, mine, tunnel, soil deformation, and receives building and Geotechnical Engineering domain experts' great attention.For this reason, Chinese scholars have also been carried out a large amount of shop experiments, site test and theoretical analysis research, propose assay method and the empirical Calculation formula of some K0.Yet the factor that influences earth lateral pressure coefficient is many, comprises particulate component, water cut, packing and the structure etc. of soil, and they all have material impact to lateral pressure coefficient.In the engineering practice, the rationality of lateral pressure coefficient value is directly connected to the accuracy of Model Calculation and the economy and the safe reliability of design and construction.
For the deep basal pit on coastal weak soil Fu Shui stratum, excavation of foundation pit usually will be taked dewatering measure, and base pit dewatering can cause mesoporosity, water-bearing zone water pressure to reduce on the one hand, and effective stress increases, and the water-bearing zone produces densification; On the other hand, base pit dewatering is destroyed original seepage field, produces new seepage flow, is accompanied by seepage effect and puts on the seepage force of soil skeleton, also makes soil body densification.After the soil body densification, its packing, water cut and structure all can change, thereby the earth lateral pressure coefficient also changes thereupon.In the designing and calculating of weak soil Fu Shui stratum deep basal pit; At present lateral pressure coefficient K0's chooses the material parameter before most employing precipitation; Do not consider the influence of base pit dewatering to earth lateral pressure coefficient, and fewer about the research of base pit dewatering earth lateral pressure coefficient aspect, and lateral pressure coefficient K0 value is often only chosen by rule of thumb; Sometimes differ far away with actual, its result is obviously reasonable inadequately.
Summary of the invention
In order to solve the problem that exists in the prior art; The present invention provides a kind of test method that the base pit dewatering earth lateral pressure coefficient changes of simulating; Soil body stress state through under the simulation precipitation condition records earth lateral pressure coefficient, for accurately choosing of base pit dewatering earth lateral pressure coefficient provides foundation.
For this reason, the present invention adopts following technical scheme:
A kind of test method of simulating the variation of base pit dewatering earth lateral pressure coefficient is characterized in that comprising the steps:
1) cuts native cutting ring with K0 and cut undisturbed sample, stick filter paper at the sample two ends;
2) with the sample that cuts be placed on carry out on the preconsolidation appearance twice fixed, the for the first time fixed sample that makes recovers the natural gravity stress state of the soil body, simulate precipitation for the second time after soil body stress state carry out fixed;
3) after the fixed completion, open K0 container inlet valve, make the latex film of K0 container recessed to inwall with the negative pressure method;
4) edge of a knife is upwards cut native cutting ring with K0 and is placed in the K0 container steady arm, with the pressure transmission piston soil sample is pushed in the K0 container from cutting ring;
5) injection water gets into container and eliminates negative pressure then, makes latex film be close to soil sample, closes inlet valve;
6) according to a plurality of pressurization grades, load step by step, numerical value when writing down every grade of load and stablizing is drawn vertical effective stress-side direction effective stress curve and is obtained the K0 value.
As to the improving and replenishing of technique scheme, the present invention further takes the following technical measures or the combination in any of these measures:
In described two secondary consolidation, fixed pressure equals native natural gravity stress for the first time, and consolidation time is 24 hours; For the second time consolidation pressure by base pit dewatering after native effective stress increase and apply, consolidation time is 24 hours.
For the second time fixed according to soil body stress state behind a plurality of precipitation depth simulation precipitation, obtain the K0 value under a plurality of precipitation depths.
In the step 3), the latex film that makes the K0 container with the negative pressure method is coated silicone oil on latex film after inwall is recessed, to reduce the friction of sample and latex film.
In the step 6), adopt 50.0kPa, 100.0kPa, 200.0kPa, 300.0kPa, five grades of 400.0kPa to load step by step, be 2 hours the stabilization time of each grade load pressurization.
Beneficial effect: test method of the present invention has considered that the foundation pit precipitation soil water cut reduces, effective stress increases, native fixed densification is to the influence of earth lateral pressure coefficient; For accurately choosing of base pit dewatering earth lateral pressure coefficient provides foundation, thereby guarantee is provided for the rich depth of water foundation ditch of design and construction weak soil safely, economically and reasonably.
Description of drawings
Fig. 1 is the σ ' of the 3. layer mud matter silty clay part sample of the embodiment of the invention one
1-σ '
3Matched curve;
Fig. 2 is the σ ' of the 4. layer grey silt clay part sample of the embodiment of the invention two
1-σ '
3Matched curve;
Fig. 3 is 5.-1 σ ' of layer gray clay part sample of the embodiment of the invention three
1-σ '
3Matched curve;
Fig. 4 is 5.-2 σ ' of layer grey clay silt part sample of the embodiment of the invention four
1-σ '
3Matched curve.
Embodiment
Embodiment one
The test soil sample is to take from the undisturbed soil of urban district, Shanghai deep basal pit, and appearance soil is 3. layer mud matter silty clay, buried depth 3.2～9.5m, and severe is 17.5kN/m
3, average gravity stress is 60.0kPa.Test simulation not precipitation with 2.0m, 4.0m totally 3 kinds of operating modes fall, corresponding consolidation pressure is respectively 60.0kPa, 80.0kPa, 100.0kPa; The precipitation sample does not only carry out a secondary consolidation, and the precipitation sample carries out two secondary consolidation; Do 3 groups of tests altogether.3. layer mud matter silty clay earth lateral pressure coefficient before and after precipitation by above-mentioned test procedure records is as shown in table 1.The σ ' of part sample
1-σ '
3Matched curve is seen shown in Figure 1.
Embodiment two
The test soil sample is to take from the undisturbed soil of urban district, Shanghai deep basal pit, and appearance soil is 4. layer grey silt clay, buried depth 9.5～17.5m, and severe is 16.7kN/m
3, average gravity stress is 100.0kPa.Test simulation not precipitation with 2.0m, 4.0m, 8m totally 4 kinds of operating modes fall, corresponding consolidation pressure is respectively 100.0kPa, 120.0kPa, 140.0kPa, 180.0kPa; The precipitation sample does not only carry out a secondary consolidation, and the precipitation sample carries out two secondary consolidation; Do 3 groups of tests altogether.4. layer grey silt clay earth lateral pressure coefficient before and after precipitation by above-mentioned test procedure records is as shown in table 1.The σ ' of part sample
1-σ '
3Matched curve is seen shown in the accompanying drawing 2.
Embodiment three
The test soil sample is to take from the undisturbed soil of urban district, Shanghai deep basal pit, and appearance soil is 5.-1 layer gray clay, buried depth 17.5～22.0m, and severe is 17.5kN/m
3, average gravity stress is 150.0kPa.Test simulation not precipitation with 2.0m, 4.0m, 8.0m totally 4 kinds of operating modes fall, corresponding consolidation pressure is respectively 150.0kPa, 170.0kPa, 190.0kPa, 230.0kPa; The precipitation sample does not only carry out a secondary consolidation, and the precipitation sample carries out two secondary consolidation; Do 3 groups of tests altogether.5.-1 layer gray clay earth lateral pressure coefficient before and after precipitation by above-mentioned test procedure records is as shown in table 1.The σ ' of part sample
1-σ '
3Matched curve is seen shown in the accompanying drawing 3.
Embodiment four
The test soil sample is to take from the undisturbed soil of urban district, Shanghai deep basal pit, and appearance soil is 5.-2 layer grey clay silt, buried depth 22.0～33.6m, and severe is 18.1kN/m
3, average gravity stress is 200.0kPa.Test simulation not precipitation with 2.0m, 4.0m totally 3 kinds of operating modes fall, corresponding consolidation pressure is respectively 200.0kPa, 220.0kPa, 240.0kPa; The precipitation sample does not only carry out a secondary consolidation, and the precipitation sample carries out two secondary consolidation; Do 3 groups of tests altogether.5.-2 layer grey clay silt earth lateral pressure coefficient before and after precipitation by above-mentioned test procedure records is as shown in table 1.The σ ' of part sample
1-σ '
3Matched curve is seen shown in the accompanying drawing 4.
Table 1
Should be pointed out that present embodiment just lists expressivity principle of the present invention and effect are described, but not be used to limit the present invention.Any personnel that are familiar with this technology all can make amendment to the foregoing description under spirit of the present invention and scope.Therefore, rights protection scope of the present invention should be listed like claims.
Claims (3)
1. simulate the test method that the base pit dewatering earth lateral pressure coefficient changes for one kind, it is characterized in that comprising the steps:
1) cuts native cutting ring with K0 and cut undisturbed sample, stick filter paper at the sample two ends;
2) with the sample that cuts be placed on carry out on the preconsolidation appearance twice fixed, the for the first time fixed sample that makes recovers the natural gravity stress state of the soil body, simulate precipitation for the second time after soil body stress state carry out fixed;
3) after the fixed completion, open K0 container inlet valve, make the latex film of K0 container recessed to inwall with the negative pressure method;
4) edge of a knife is upwards cut native cutting ring with K0 and is placed in the K0 container steady arm, with the pressure transmission piston soil sample is pushed in the K0 container from cutting ring;
5) injection water gets into container and eliminates negative pressure then, makes latex film be close to soil sample, closes inlet valve;
6) according to a plurality of pressurization grades, load step by step, numerical value when writing down every grade of load and stablizing is drawn vertical effective stress-side direction effective stress curve and is obtained the K0 value;
In described two secondary consolidation, fixed pressure equals native natural gravity stress for the first time, and consolidation time is 24 hours; For the second time consolidation pressure by base pit dewatering after native effective stress increase and apply, consolidation time is 24 hours; For the second time fixed according to soil body stress state behind a plurality of precipitation depth simulation precipitation, obtain the K0 value under a plurality of precipitation depths.
2. the test method that simulation base pit dewatering earth lateral pressure coefficient according to claim 1 changes; It is characterized in that in the step 3); The latex film that makes the K0 container with the negative pressure method is coated silicone oil on latex film after inwall is recessed, to reduce the friction of sample and latex film.
3. the test method that simulation base pit dewatering earth lateral pressure coefficient according to claim 1 changes; It is characterized in that in the step 6); Adopt 50.0kPa, 100.0kPa, 200.0kPa, 300.0kPa, five grades of 400.0kPa to load step by step, be 2 hours the stabilization time of each grade load pressurization.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102217113A CN101915698B (en) | 2010-07-08 | 2010-07-08 | Testing method for simulating precipitation earth lateral pressure coefficient change of foundation pit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102217113A CN101915698B (en) | 2010-07-08 | 2010-07-08 | Testing method for simulating precipitation earth lateral pressure coefficient change of foundation pit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101915698A CN101915698A (en) | 2010-12-15 |
| CN101915698B true CN101915698B (en) | 2012-08-22 |
Family
ID=43323260
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010102217113A Expired - Fee Related CN101915698B (en) | 2010-07-08 | 2010-07-08 | Testing method for simulating precipitation earth lateral pressure coefficient change of foundation pit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101915698B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107229811A (en) * | 2017-07-25 | 2017-10-03 | 华中科技大学 | A kind of Forecasting Methodology of saturated soft soil deadweight consolidation process |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102262022B (en) * | 2011-07-14 | 2013-02-13 | 同济大学 | Test method for simulating shear resistant strength change of foundation pit precipitation soil |
| CN103076436B (en) * | 2012-12-26 | 2015-07-08 | 上海交通大学 | Device for measuring soil lateral pressure and consolidometer |
| CN107271278B (en) * | 2017-06-13 | 2019-07-05 | 上海交通大学 | The model assay systems and method of Circular Pit stage excavation supporting lateral pressure test |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1851443A (en) * | 2006-04-28 | 2006-10-25 | 中国科学院力学研究所 | Method for preparing soil for analogue test |
| CN101041960A (en) * | 2006-03-23 | 2007-09-26 | 周健 | Soft soil foundation high side pressure quick-discharging consolidation method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004339931A (en) * | 2000-07-18 | 2004-12-02 | Ochiken Kk | Analysis on the degree of allowable ground stress using subsurface sounding test |
-
2010
- 2010-07-08 CN CN2010102217113A patent/CN101915698B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101041960A (en) * | 2006-03-23 | 2007-09-26 | 周健 | Soft soil foundation high side pressure quick-discharging consolidation method |
| CN1851443A (en) * | 2006-04-28 | 2006-10-25 | 中国科学院力学研究所 | Method for preparing soil for analogue test |
Non-Patent Citations (3)
| Title |
|---|
| JP特开2004-339931A 2004.12.02 |
| 李晓萍等.静止侧压力系数及其试验方法的探讨.《铁道工程学报》.2007,(第8期), * |
| 赵玉花等.软黏土侧压力系数K0阶段性特征研究.《岩土力学》.2008,第29卷(第5期), * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107229811A (en) * | 2017-07-25 | 2017-10-03 | 华中科技大学 | A kind of Forecasting Methodology of saturated soft soil deadweight consolidation process |
| CN107229811B (en) * | 2017-07-25 | 2019-05-31 | 华中科技大学 | A kind of prediction technique of saturated soft soil self weight consolidation process |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101915698A (en) | 2010-12-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102262022B (en) | Test method for simulating shear resistant strength change of foundation pit precipitation soil | |
| Jardine | Geotechnics, energy and climate change: the 56th Rankine Lecture | |
| CN101915721B (en) | Test method for simulating variation of permeability coefficient of foundation pit precipitation | |
| Chang et al. | Analysis of soil movement around a deep excavation | |
| CN108647473A (en) | A kind of shield method builds seabed tunnel Rational Depth computational methods | |
| CN101915698B (en) | Testing method for simulating precipitation earth lateral pressure coefficient change of foundation pit | |
| CN103614984A (en) | Ecological treatment method oriented to geological environment disasters caused by riverway goafs | |
| Najma et al. | Experimental study on the seismic behavior of composite breakwaters located on liquefiable seabed | |
| Falls et al. | Slope stability | |
| Zhang et al. | Failure mechanism of submarine slopes based on the wave flume test | |
| Ali et al. | Field behavior and numerical simulation of coastal bund on soft marine clay loaded to failure | |
| Li et al. | Geotechnical investigations at the Dalian offshore airport, China | |
| Iqbal et al. | The impact of reservoir fluctuations on reactivated large landslides: a case study | |
| Balasubramaniam | Contributions in geotechnical engineering: Soil mechanics and foundation engineering | |
| Lee et al. | Seismic stability analysis of Hawkins hydraulic fill dam | |
| Hammer et al. | Design and construction of retaining dikes for containment of dredged material | |
| Jørgensen | Secondary Settlements of 4 Danish Road Embankments on Soft Soil | |
| Hou et al. | Analysis of the effect of dam impoundment at the Baihetan site using coupled fluid-mechanical elasto-plastic simulations | |
| Zhao et al. | Deformation mechanism and settlement forecast of soft clay embankment in coastal region | |
| Qiu et al. | Effects of overconsolidation ratio on undrained shear strength of clay considering pressuremeter of limited length: cases study | |
| Jia et al. | Theoretical Prediction of Wave-Induced Sediment Resuspension | |
| Hooper | Crustal layers in Mississippi Delta mudflows | |
| Wang et al. | Case Study on Softening Effect of Coastal Soft Soil Foundation under Cyclic Loading | |
| Wu et al. | Study on bearing capacity of bucket foundation subjected to horizontal loading | |
| ROSSI | Numerical modelling of CPTu in chalk |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120822 Termination date: 20180708 |