CN101482474A - Method for testing elastic modulus of soil body - Google Patents
Method for testing elastic modulus of soil body Download PDFInfo
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- CN101482474A CN101482474A CNA2009100210992A CN200910021099A CN101482474A CN 101482474 A CN101482474 A CN 101482474A CN A2009100210992 A CNA2009100210992 A CN A2009100210992A CN 200910021099 A CN200910021099 A CN 200910021099A CN 101482474 A CN101482474 A CN 101482474A
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Abstract
The invention discloses a soil mass elastic modulus testing method, which comprises: connecting the elastic modulus instrument with the surrounding pressure applying system for controlling the surrounding stress sigma3; filling the pressure measuring chamber with pure water and eliminating the bubbles therein; pasting filter paper on the prepared undisturbed soil sample; placing the upper porous stone and the pressurizing cover on the top of the soil sample; placing on the lower porous stone on base; covering the soil sample with a latex film; coating silicone grease on the external surface of the latex film; fastening the latex film by rubber band and fixing it on the outer side of the pressurizing cover and the base; opening the exhaust valve on the pressurizing cover; applying axial stress and surrounding stress step by step until reaching the needed value; loading and unloading in four steps according to 1/3 of the soil sample breaking strength with time interval of 1 min, and recording the axial deflection of the soil sample when loading or unloading for 1min; repeating the loading and unloading for 5 times; and calculating out the elastic modulus of the soil sample according to the elastic strain and stress of the last hysteresis loop soil sample.
Description
Technical field
The present invention relates to the Geotechnical Engineering field tests, a kind of specifically method of testing that can measure elastic modulus of soil body.
Background technology
The soil body is a kind of elasticoplastic body, and under external force, the soil body deforms, and after external force shed, some distortion was restored, and this part distortion is called elastic deformation, and irreclaimable distortion is called plastic yield.The elastic modulus of the soil body is meant the ratio of the elastic strain that the suffered stress of the soil body and this stress condition produce down.The mechanical property index of essential soil when elastic modulus is employing elasto-plastic Constitutive Model calculating soil body ess-strain.The stress-strain relation of the soil body is rendered as complicated elastic-plastic constitutive relation, the existing plasticity of strain that the soil body produces under load action resilient again, and when load surpassed the yield limit of soil, unstable distortion took place in the soil body, and plastic strain only takes place.It is generally acknowledged and work as load less than 0.7 (σ
1-σ
3)
fDuring stress level, the distortion of the soil body is stable, at this moment, can the elastic strain and the plastic strain of the soil body be separated by repeatedly pressurization and release under certain stress level.In pressurization and stress-relief process, it is fast that rate of loading is wanted, if the loading time is longer, rheology will take place the soil body.Along with the increase of loading and off-load number of times, hysteresis circle area is more and more littler, and the strain of the soil body is near the perfect elasticity strain, thereby can be calculated its value by the definition of elastic modulus.
Summary of the invention
The object of the present invention is to provide a kind of method of measuring elastic modulus of soil body, this method can be carried out loading fast and effeciently and off-load, and is easy and measure the elastic modulus of the soil body fast, and the precision as a result that records is higher.
In order to realize above-mentioned task, the present invention takes following technical solution:
A kind of method of testing elastic modulus of soil body is characterized in that, carries out according to the following steps:
1) at first prepare the elastic modulus instrument, this elastic modulus instrument comprises base, and the bottom of base is provided with the water pressure chamber, and there is the pressurization water inlet this water pressure chamber, and the base top is provided with the ambient water pressure chamber, and this ambient water pressure chamber has the pressurization water inlet equally; The space that base and ambient water pressure chamber are surrounded is used to place soil sample; The upper and lower surface of soil sample is respectively equipped with upper dankness stone and following permeable stone, adds gland and is placed on the upper dankness stone, and pressurization covers and leaves vent valve, following permeable stone, soil sample, upper dankness stone and add being coated by latex film of gland on every side;
2) inlet opening, ambient water pressure chamber of elastic modulus instrument is connected the ambient stress σ when measuring elastic modulus in order to control with on every side pressure application system
3
3) before the test, pure water is filled with in water pressure chamber and ambient water pressure chamber, and get rid of bubble wherein;
4) outside the undisturbed sample for preparing, stick filter paper, the top of soil sample is placed upper dankness stone and is added gland, be placed on the following permeable stone on the base, outside soil sample, put latex film, and smear silicone grease (ambient pressure effectively is applied on the soil sample) at the latex film outside surface, latex film is tightened the outside of being fixed in pressurization lid and bottom seat with rubber band;
5) open the vent valve that covers of pressurization, classification applies axial stress and ambient stress to testing desirable value;
6) when per hour consolidation deformation amount of soil sample is not more than 0.01mm, fixed finishing closed the vent valve that pressurization covers;
7) 1/3rd stress levels by the soil sample breakdown strength divide 4 grades of loadings and off-load, and loading and unloading time are 1min at interval, when each loading, off-load 1min, and the axial deflection of record soil sample; Add repeatedly, off-load carries out 5 times, the elastic modulus that goes out soil sample according to the elastic strain and the Stress calculation of last hysteretic loop soil sample.
The present invention adopts the elastic modulus of soil body instrument to test, and has that instrument is simple, loading speed is fast, an advantage such as highly sensitive, reliable test result; Can simulate the stress state of the soil body more exactly; Adopt lever loading method, loading speed is fast, and the soil body rheology can not take place; Instrumentation is easy, finishes repeatedly rebound test in the short period of time, and the elastic modulus of the soil of mensuration has higher reliability and precision.
Description of drawings
Fig. 1 is a testing elastic modulus of soil body synoptic diagram of the present invention;
The present invention is described in further detail below in conjunction with drawings and Examples.
Embodiment
Referring to Fig. 1, the method of testing elastic modulus of soil body of the present invention, at first prepare the elastic modulus instrument, this elastic modulus instrument comprises base 7, the bottom of base 7 is provided with water pressure chamber 6, there is pressurization water inlet 12 this water pressure chamber 6, and base 7 tops are provided with ambient water pressure chamber 2, and this ambient water pressure chamber 2 has pressurization water inlet 11 equally; The space that base 7 and ambient water pressure chamber 2 are surrounded is used to place soil sample 4;
The upper and lower surface of soil sample 4 is respectively equipped with upper dankness stone 1 and following permeable stone 5, adds gland 9 and is placed on the upper dankness stone 1, add and leave vent valve 8 on the gland 9, following permeable stone 5, soil sample 4, upper dankness stone 1 and add gland 9 around by latex film 13 coatings; Latex film 13 usefulness bungees 10 are fixed in base 7 and add the outside of gland 9.
During test, the inlet opening 11 of the ambient water pressure chamber 2 of elastic modulus instrument is connected the ambient stress σ when measuring elastic modulus in order to control with the ambient pressure application system
3The water pressure of ambient water pressure chamber 2 is applied to the sample outside by latex film 3.The gland 9 that adds at sample top is provided with vent valve 8.The pressure application system adopts the lever compression system to apply axial stress σ
1, according to pressurization rating calculation lever pressurization counterweight.
Before the test, earlier pure water is filled with in water pressure chamber 6 and ambient water pressure chamber 2, and get rid of bubble wherein.Stick filter paper in undisturbed sample 4 peripheries that prepare, soil sample 4 tops are gone up and are placed upper dankness stone 1 and add gland 9, soil sample 4 underneath deposit permeable stone 5, and put latex film 13, and smear silicone grease (ambient pressure effectively is applied on the undisturbed sample) at latex film 13 outside surfaces, latex film 13 usefulness bungees 10 are tightened the outside of being fixed in base 7 and adding gland 9.Soil sample 4 put into permeable stone 5 on the base of elastic modulus instrument above.
Effective unit weight according to the fetch earth degree of depth and the soil layer of soil sample calculates fixed axial stress and ambient stress.Adopt lever loading method, load application speed is fast, load directly acts on and adds on the gland 9, by adding gland 9 required stress is put on the soil sample top, having overcome instrument complexity, piston and pressure chamber's frictional resistance that the stress-type triaxial apparatus exists influences test accuracy and loading and reacts shortcoming such as insensitive.
During measurement, open the vent valve 8 that adds on the gland 9, apply axial stress and ambient stress to desirable value from pressurization water inlet 12 and 11 classifications of pressurization water inlet.When per hour deflection was not more than 0.01mm, fixed finishing closed the vent valve 8 that adds on the gland 9.Character and ambient stress estimation breakdown strength (σ according to soil
1-σ
3)
f, by (σ
1-σ
3)
f/ 3 stress levels divide 4 grades of loadings and off-load.Calculate the loading counterweight according to loading grade and loading lever ratio, and should consider the upper dankness stone at soil sample 4 tops and add the weight of gland 9.Loading and unloading time are 1min at interval, survey the note axial deflection when each loading, off-load 1min.Add repeatedly, off-load carries out 5 times.The elastic modulus that goes out the soil body according to the elastic strain and the Stress calculation of last hysteretic loop soil body.
Claims (5)
1, a kind of method of testing elastic modulus of soil body is characterized in that, carries out according to the following steps:
1) at first prepare the elastic modulus instrument, this survey elastic modulus comprises base, and the bottom of base is provided with the water pressure chamber, and there is the pressurization water inlet this water pressure chamber, and the base top is provided with the ambient water pressure chamber, and this ambient water pressure chamber has the pressurization water inlet equally; The space that base and ambient water pressure chamber are surrounded is used to place soil sample; The upper and lower surface of soil sample is respectively equipped with upper dankness stone and following permeable stone, adds gland and is placed on the upper dankness stone, and pressurization covers and leaves vent valve, following permeable stone, soil sample, upper dankness stone and add being coated by latex film of gland on every side;
2) inlet opening, ambient water pressure chamber of elastic modulus instrument is connected the ambient stress σ when measuring elastic modulus in order to control with on every side pressure application system
3
3) before the test, pure water is filled with in water pressure chamber and ambient water pressure chamber, and get rid of bubble wherein;
4) outside the undisturbed sample for preparing, stick filter paper, the top of soil sample is placed upper dankness stone and is added gland, is placed on the following permeable stone on the base, puts latex film outside soil sample, and smear silicone grease at the latex film outside surface, latex film is tightened the outside of being fixed in pressurization lid and bottom seat with rubber band;
5) open the vent valve that covers of pressurization, classification applies axial stress and ambient stress to testing desirable value;
6) when per hour consolidation deformation amount of soil sample is not more than 0.01mm, fixed finishing closed the vent valve that pressurization covers;
7) 1/3rd stress levels by the soil sample breakdown strength divide 4 grades of loadings and off-load, and loading and unloading time are 1min at interval, when each loading, off-load 1min, and the axial deflection of record soil sample; Add repeatedly, off-load carries out 5 times, the elastic modulus that goes out soil sample according to the elastic strain and the Stress calculation of last hysteretic loop soil sample.
2, the method for claim 1 is characterized in that, described sample top applies different pressure around reaching, and simulates the stress state of the soil body exactly, carries out the fixed of sample and test.
3, the method for claim 1 is characterized in that, described axial stress adopts lever loading method, and load directly acts on pressurization and covers, and by adding gland required stress is put on the soil sample top.
4, the method for claim 1 is characterized in that, described loading grade adopts packed sand grains or the accurate weighing of plumb as counterweight, accomplishes that loading is accurate.
5, method as claimed in claim 3 is characterized in that, in the described lever loading method, when calculating every grade of loading counterweight according to loading grade and loading lever ratio, should consider the permeable stone at sample top and add the weight of gland.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2009100210992A CN101482474A (en) | 2009-02-11 | 2009-02-11 | Method for testing elastic modulus of soil body |
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|---|---|---|---|
| CNA2009100210992A CN101482474A (en) | 2009-02-11 | 2009-02-11 | Method for testing elastic modulus of soil body |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102359910A (en) * | 2011-07-27 | 2012-02-22 | 绍兴文理学院 | Determination method for critical plastic yield-point and initial elastic modulus of soil stress-strain curve |
| CN103033406A (en) * | 2012-12-26 | 2013-04-10 | 上海交通大学 | Sample preparation device for remoulded soil with different stress ratios |
| CN103076436A (en) * | 2012-12-26 | 2013-05-01 | 上海交通大学 | Device for measuring soil lateral pressure and consolidometer |
| CN107884274A (en) * | 2017-12-13 | 2018-04-06 | 重庆科技学院 | The test device and method of testing of the class lateral pressure value of the soil body three |
| CN109187168A (en) * | 2018-10-25 | 2019-01-11 | 南京工业大学 | A kind of stabilization and accurate temperature controlled anisotropy Resonant Column system and method |
| US10508978B2 (en) | 2017-11-03 | 2019-12-17 | Saudi Arabian Oil Company | Strain energy-based method and apparatus to determine the coefficient of resilience of lost circulation materials |
| CN110907273A (en) * | 2019-11-15 | 2020-03-24 | 河北科技大学 | Elasticity modulus measuring device of biomass granular fuel and using method thereof |
| CN111965060A (en) * | 2020-08-03 | 2020-11-20 | 河海大学 | Press-in type on-site modulus of resilience measuring device |
| CN113138207A (en) * | 2021-04-22 | 2021-07-20 | 安徽理工大学 | System and method for testing thermal diffusion coefficient of orthotropic solid material |
| CN116106122A (en) * | 2023-02-23 | 2023-05-12 | 廊坊市阳光建设工程质量检测有限公司 | Device for detecting compressive strength of concrete by radial annular pressure of concrete core sample with any diameter |
-
2009
- 2009-02-11 CN CNA2009100210992A patent/CN101482474A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102359910A (en) * | 2011-07-27 | 2012-02-22 | 绍兴文理学院 | Determination method for critical plastic yield-point and initial elastic modulus of soil stress-strain curve |
| CN103033406A (en) * | 2012-12-26 | 2013-04-10 | 上海交通大学 | Sample preparation device for remoulded soil with different stress ratios |
| CN103076436A (en) * | 2012-12-26 | 2013-05-01 | 上海交通大学 | Device for measuring soil lateral pressure and consolidometer |
| CN103076436B (en) * | 2012-12-26 | 2015-07-08 | 上海交通大学 | Device for measuring soil lateral pressure and consolidometer |
| US10508978B2 (en) | 2017-11-03 | 2019-12-17 | Saudi Arabian Oil Company | Strain energy-based method and apparatus to determine the coefficient of resilience of lost circulation materials |
| CN107884274A (en) * | 2017-12-13 | 2018-04-06 | 重庆科技学院 | The test device and method of testing of the class lateral pressure value of the soil body three |
| CN107884274B (en) * | 2017-12-13 | 2023-08-01 | 重庆科技学院 | Testing device and testing method for three types of lateral pressure values of soil body |
| CN109187168A (en) * | 2018-10-25 | 2019-01-11 | 南京工业大学 | A kind of stabilization and accurate temperature controlled anisotropy Resonant Column system and method |
| CN110907273A (en) * | 2019-11-15 | 2020-03-24 | 河北科技大学 | Elasticity modulus measuring device of biomass granular fuel and using method thereof |
| CN111965060A (en) * | 2020-08-03 | 2020-11-20 | 河海大学 | Press-in type on-site modulus of resilience measuring device |
| CN113138207A (en) * | 2021-04-22 | 2021-07-20 | 安徽理工大学 | System and method for testing thermal diffusion coefficient of orthotropic solid material |
| CN116106122A (en) * | 2023-02-23 | 2023-05-12 | 廊坊市阳光建设工程质量检测有限公司 | Device for detecting compressive strength of concrete by radial annular pressure of concrete core sample with any diameter |
| CN116106122B (en) * | 2023-02-23 | 2023-06-30 | 廊坊市阳光建设工程质量检测有限公司 | Device for detecting compressive strength of concrete by radial annular pressure of concrete core sample with any diameter |
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Application publication date: 20090715 |