CN210321703U - Device for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition - Google Patents
Device for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition Download PDFInfo
- Publication number
- CN210321703U CN210321703U CN201921609781.9U CN201921609781U CN210321703U CN 210321703 U CN210321703 U CN 210321703U CN 201921609781 U CN201921609781 U CN 201921609781U CN 210321703 U CN210321703 U CN 210321703U
- Authority
- CN
- China
- Prior art keywords
- soil
- soil body
- body sample
- box
- foundation
- 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.)
- Active
Links
Images
Abstract
A foundation soil actual Poisson ratio measuring device under the condition of lateral confinement stress is characterized in that a reaction frame is fixedly arranged on a base, a load applying oil cylinder is vertically hung at the top of the reaction frame, a soil sample lateral confinement box is inserted into a lateral confinement box slot of the base and is positioned under the load applying oil cylinder, a plurality of micro soil pressure gauges are uniformly arranged on the inner surface of the soil sample lateral confinement box along the circumferential direction, and a gasket, a force transmission cushion block and a pressure sensor are sequentially arranged on the upper surface of the soil sample. The measuring method comprises the following steps: obtaining foundation soil, and preparing a soil sample in a soil sample side limit box; inserting the soil body sample side limiting box on the upper surface of the base to finish the installation of the sample; calculating the load force applied by the oil cylinder needing to apply the load; arranging a gasket, a force transmission cushion block and a pressure sensor; applying a load force to the soil sample through a load applying oil cylinder according to the load force calculation value; obtaining a stable lateral soil pressure value and solving an average value; and calculating the actual Poisson ratio of the foundation soil body under the confined stress condition.
Description
Technical Field
The utility model belongs to the technical field of rock mass mechanics is experimental, especially relates to an actual poisson's ratio measuring device of foundation soil body under lateral confinement stress condition.
Background
The soil body Poisson ratio is a parameter reflecting the lateral deformation of a foundation soil body and is also an essential important parameter in the field of geotechnical engineering design and analysis; because the structure and material characteristics of the soil body and other solids have great difference, the Poisson ratio of the soil body no longer has the significance of originally defining physical property parameters, but is a state parameter which changes along with the stress state of the soil body, and most foundation soil bodies in engineering are under the condition of measuring and limiting stress in a semi-infinite space, so that the measurement method considering the actual stress state is the premise of obtaining the Poisson ratio of the soil body.
Chinese patent publication No. CN103983516A discloses a device and method for measuring the poisson ratio of a soil body, in which a flexible thin steel ring, a resistance displacement meter, a reference support and a press are used comprehensively to measure the poisson ratio of the soil body, but the soil body is required to have a certain cohesive force, so that the soil body is not broken after being stressed, and the side force of the soil body needs to deform the flexible thin steel ring for measurement.
The patent publication No. CN106769462A discloses a prediction method for the internal friction angle and deformation modulus of cohesionless foundation soil, which obtains the internal friction angle and deformation modulus of soil body by the shear wave velocity, compression wave velocity and depth of soil layer obtained on site and combining the existing basic principle of soil mechanics and empirical formula, but the patent lacks strict theoretical basis and is greatly influenced by complex geological environment conditions in the measurement process, and the measurement result has larger uncertainty.
According to the existing literature, the poisson ratio measurement adopts a deformation measurement method, namely the deformation of a soil sample with shattering, non-homogeneity and small deformation is directly measured, the deformation measurement method is known to have lower measurement accuracy, and the recent technologies such as local deformation image measurement and the like can reduce the deformation measurement error in the traditional measurement method to a certain extent, but cannot truly reflect the actual characteristics of the soil deformation, which is determined by the properties of the soil such as the shattering, triphasicity, natural variation and the like.
SUMMERY OF THE UTILITY MODEL
The problem that exists to prior art, the utility model provides an actual poisson ratio measuring device of ground soil body under side limit stress condition can simulate the true stress condition of the ground soil body to combine the indirect method of measuring stress and generalized hooke's law to acquire poisson ratio, make measurement and calculation result more accurate and press close to the true value more, and the stickness all is suitable for with the ground soil body that does not have the stickness, has effectively solved among the prior art measure inaccurate or unable measuring drawback.
In order to achieve the above purpose, the utility model adopts the following technical scheme: a foundation soil body actual Poisson ratio measuring device under the condition of laterally limited stress comprises a base, a reaction frame, a load applying oil cylinder, a soil body sample laterally limited box and a miniature soil pressure gauge, wherein the reaction frame is fixedly arranged on the base, the load applying oil cylinder is vertically hung at the top of the reaction frame, a piston rod of the load applying oil cylinder is arranged downwards, and a pressure sensor is arranged at the end part of the piston rod of the load applying oil cylinder; the soil body sample side limit box is of a cylindrical structure, a side limit box slot is formed in the upper surface of the base, the soil body sample side limit box is vertically inserted into the side limit box slot, the soil body sample side limit box is positioned right below the load applying oil cylinder, and the soil body sample side limit box is coincided with the central axis of the load applying oil cylinder; the miniature soil pressure gauge is a plurality of in quantity, and a plurality of miniature soil pressure gauges are installed at the internal surface of soil body sample limit box along circumference equipartition.
A barrel mouth at one end of the soil body sample side limiting box is provided with a cutting edge chamfering structure, a barrel mouth at the other end of the soil body sample side limiting box is not provided with the cutting edge chamfering structure, the barrel mouth at one side of the soil body sample side limiting box is inserted into a side limiting box slot, and the diameter of the soil body sample side limiting box is equal to the outer diameter of the side limiting box slot.
The soil body sample is used for filling the soil body sample in the soil body sample side limit box, the soil body sample is in direct contact with the miniature soil pressure meter, a gasket and a force transmission cushion block are sequentially arranged on the upper surface of the soil body sample, and the diameter of the gasket is equal to the inner diameter of the soil body sample side limit box.
The pressure sensor is connected with a pressure digital display meter, and axial load data acquired by the pressure sensor is directly read through the pressure digital display meter.
The miniature soil pressure gauge is connected with a strain type stress test analyzer, and soil pressure data collected by the miniature soil pressure gauge is directly read through the strain type stress test analyzer.
A method for measuring the actual Poisson ratio of a foundation soil body under a laterally limited stress condition adopts a device for measuring the actual Poisson ratio of the foundation soil body under the laterally limited stress condition, and comprises the following steps:
the method comprises the following steps: preparation of foundation soil sample
Firstly, acquiring a foundation soil body in a geotechnical engineering investigation mode, and then carrying out alignment connection in a soil body sample side limit box according to geotechnical test regulation standards in the industry to prepare a soil body sample;
step two: inserting the soil mass sample side limit box with the prepared soil mass sample into a side limit box slot on the upper surface of the base to finish the installation of the sample;
step three: according to the size and the characteristics of the actual axial load value of the foundation soil body at the in-situ sampling position point, the self-weight stress of the overlying soil body at the in-situ sampling position point and the additional stress caused by the engineering load are calculated firstly, then the self-weight stress and the additional stress are added and divided by the actual load application area, and the load force applied by the load application oil cylinder can be obtained;
step four: sequentially placing an upper gasket and a force transmission cushion block on the upper surface of a soil body sample, and simultaneously installing a pressure sensor at the end part of a piston rod of a load application oil cylinder;
step five: starting the load applying oil cylinder to enable a piston rod of the load applying oil cylinder to extend downwards until the pressure sensor abuts against the force transmission cushion block, then applying a load force at a constant speed through the load applying oil cylinder, acquiring load force data in real time through the pressure sensor, and monitoring the numerical change of the load force in real time through a pressure digital display meter until the load force numerical value reaches a load force calculation value in the third step;
step six: acquiring lateral soil pressure data of a soil sample in real time through a miniature soil pressure gauge, monitoring the numerical change of the lateral soil pressure in real time through a strain type stress test analyzer until all lateral soil pressure numerical values are stable, recording the stable lateral soil pressure numerical values at the moment, and calculating an average value;
step seven: according to the formula mu-sigmaSide wall/(σSide wall+σLotus leaf) Calculating the actual poisson ratio of the foundation soil body under the lateral limit stress condition, wherein mu is the actual poisson ratio of the foundation soil body under the lateral limit stress condition, and sigma isSide wallIs the average of the lateral soil pressure values, σLotus leafIs a load force value;
step eight: and repeating the first step to the seventh step to obtain the actual Poisson ratio of the foundation soil body of other in-situ sampling position points.
The utility model has the advantages that:
the utility model discloses an actual poisson ratio measuring device of ground soil body under side limit stress condition can simulate the true stress condition of the ground soil body to combine the indirect method of measuring stress and generalized hooke's law to acquire poisson ratio, make measurement and calculation result more accurate and press close to the true value more, and the ground soil body of stickness and no stickness all is suitable for, has effectively solved among the prior art and has measured inaccurate or unable measuring drawback.
Drawings
FIG. 1 is a schematic structural view of a device for measuring the actual Poisson's ratio of a foundation soil body under a confined stress condition of the present invention;
FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;
FIG. 3 is a schematic illustration of in-situ sampling locations of a foundation soil mass in an embodiment;
in the figure, 1-base, 2-reaction frame, 3-load application oil cylinder, 4-soil mass sample side limit box, 5-miniature soil pressure gauge, 6-pressure sensor, 7-side limit box slot, 8-soil mass sample, 9-gasket, 10-force transmission cushion block.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1 and 2, the device for measuring the actual poisson ratio of the foundation soil body under the lateral limit stress condition comprises a base 1, a reaction frame 2, a load applying oil cylinder 3, a soil body sample lateral limit box 4 and a miniature soil pressure gauge 5, wherein the reaction frame 2 is fixedly arranged on the base 1, the load applying oil cylinder 3 is vertically hung at the top of the reaction frame 2, a piston rod of the load applying oil cylinder 3 is arranged downwards, and a pressure sensor 6 is arranged at the end part of the piston rod of the load applying oil cylinder 3; the soil body sample side limit box 4 is of a cylindrical structure, a side limit box slot 7 is formed in the upper surface of the base 1, the soil body sample side limit box 4 is vertically inserted into the side limit box slot 7, the soil body sample side limit box 4 is positioned under the load applying oil cylinder 3, and the soil body sample side limit box 4 is coincided with the central axis of the load applying oil cylinder 3; the miniature soil pressure gauge 5 is a plurality of, and a plurality of miniature soil pressure gauges 5 are installed at the internal surface of soil body sample limit box 4 along circumference equipartition.
A barrel mouth at one end of the soil body sample side limiting box 4 is provided with a cutting edge chamfering structure, a barrel mouth at the other end of the soil body sample side limiting box 4 is not provided with a cutting edge chamfering structure, the barrel mouth at one side of the soil body sample side limiting box 4 without the cutting edge chamfering structure is inserted into the side limiting box slot 7, and the diameter of the soil body sample side limiting box 4 is equal to the outer diameter of the side limiting box slot 7.
The soil body sample side limit box 4 is internally used for filling a soil body sample 8, the soil body sample 8 is in direct contact with the miniature soil pressure gauge 5, a gasket 9 and a force transmission cushion block 10 are sequentially arranged on the upper surface of the soil body sample 8, and the diameter of the gasket 9 is equal to the inner diameter of the soil body sample side limit box 4.
The pressure sensor 6 is connected with a pressure digital display meter, and axial load data acquired by the pressure sensor 6 are directly read through the pressure digital display meter.
The miniature soil pressure gauge 5 is connected with a strain type stress test analyzer, and soil pressure data collected by the miniature soil pressure gauge 5 are directly read through the strain type stress test analyzer.
As shown in fig. 3, under the column for a certain buildingThe method comprises the following steps of forming an independent square foundation, wherein the size of the bottom surface of the foundation is 2.5m multiplied by 2.5m, the burial depth of the foundation is 2m, the axial engineering load acting on the foundation is 1250kN, and according to the investigation result of rock mass engineering, the foundation soil body is filled with viscous elements and the gravity of the foundation soil body is 19kN/m3And the deformation influence depth of the foundation soil body is about 5m, the foundation bottom surface is taken as a starting point, and in-situ sampling position points of the foundation soil body are determined vertically downwards every 1m, so that six in-situ sampling position points are obtained. The device and the method of the utility model are used for measuring the Poisson's ratio of the foundation soil body of the six in-situ sampling position points.
A method for measuring the actual Poisson ratio of a foundation soil body under a laterally limited stress condition adopts a device for measuring the actual Poisson ratio of the foundation soil body under the laterally limited stress condition, and comprises the following steps:
the method comprises the following steps: preparation of foundation soil sample
Firstly, acquiring a foundation soil body in a geotechnical engineering investigation mode, and then directly preparing a soil body sample 8 in a soil body sample side limit box 4 according to geotechnical test regulation standards in the industry; in actual engineering, when the foundation soil body is an original foundation soil body, the foundation soil body at the moment belongs to cohesive soil, and when the foundation soil body is a disturbed foundation soil body, the foundation soil body at the moment belongs to non-cohesive soil; in the embodiment, according to the standard of soil engineering test method (GB/T50123-1999), the foundation soil of six in-situ sampling position points completes sample preparation in the soil sample side limit box 4, the diameters of six soil samples 8 are 61.8mm, and the thicknesses of the six soil samples 8 are 40 mm;
step two: inserting the soil mass sample side limit box 4 with the prepared soil mass sample 8 into a side limit box slot 7 on the upper surface of the base 1 to finish the sample installation;
step three: according to the size and the characteristics of the actual axial load value of the foundation soil body at the in-situ sampling position point, the self-weight stress of the overlying soil body at the in-situ sampling position point and the additional stress caused by the engineering load are calculated firstly, then the self-weight stress and the additional stress are added and divided by the actual load application area, and the load force to be applied by the load application oil cylinder 3 can be obtained; in this embodiment, according to the design specification of foundation of building foundation (GB 50007-2011), the self-weight stress of the overlying soil body of the foundation soil body at the six in-situ sampling position points and the additional stress (corner point method) caused by the engineering load are shown in table 1, and then the load forces that the six soil body samples 8 need to be applied by the load applying cylinder 3 are 717N, 653N, 499N, 440N, 439N and 464N, respectively;
step four: sequentially placing an upper gasket 9 and a force transmission cushion block 10 on the upper surface of a soil body sample 8, and simultaneously installing a pressure sensor 6 at the end part of a piston rod of a load application oil cylinder 3;
step five: starting the load applying oil cylinder 3, enabling a piston rod of the load applying oil cylinder 3 to extend downwards until the pressure sensor 6 abuts against the force transmission cushion block 10, then applying a load force at a constant speed through the load applying oil cylinder 3, acquiring load force data in real time through the pressure sensor 6, and monitoring the numerical change of the load force in real time through a pressure digital display meter until the load force numerical value reaches a load force calculation value in the third step;
step six: the method comprises the steps that lateral soil pressure data of a soil body sample 8 are collected in real time through a miniature soil pressure meter 5, numerical value changes of lateral soil pressure are monitored in real time through a strain type stress test analyzer until all lateral soil pressure numerical values are stable, the stable lateral soil pressure numerical values are recorded at the moment, and an average value is obtained;
step seven: according to the formula mu-sigmaSide wall/(σSide wall+σLotus leaf) Calculating the actual poisson ratio of the foundation soil body under the lateral limit stress condition, wherein mu is the actual poisson ratio of the foundation soil body under the lateral limit stress condition, and sigma isSide wallIs the average of the lateral soil pressure values, σLotus leafIs a load force value; in the embodiment, the lateral soil pressure values (average values) of the six soil mass samples 8 are 353.15N, 351.67N, 318.95N, 269.95N, 280.59N and 322.53N in sequence;
step eight: and repeating the first step to the seventh step to obtain the actual Poisson ratio of the foundation soil body of other in-situ sampling position points.
TABLE 1
In order to further improve the accuracy of measuring the actual Poisson ratio of the foundation soil body, a plurality of parallel tests can be carried out, and the average value of the Poisson ratios obtained in the parallel tests is obtained, so that the measurement result is closer to the true value.
The embodiments are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the scope of the present invention are intended to be included within the scope of the present invention.
Claims (5)
1. The utility model provides an actual poisson ratio measuring device of foundation soil body under side limit stress condition which characterized in that: the soil mass testing device comprises a base, a reaction frame, a load applying oil cylinder, a soil mass sample side limit box and a miniature soil pressure gauge, wherein the reaction frame is fixedly arranged on the base; the soil body sample side limit box is of a cylindrical structure, a side limit box slot is formed in the upper surface of the base, the soil body sample side limit box is vertically inserted into the side limit box slot, the soil body sample side limit box is positioned right below the load applying oil cylinder, and the soil body sample side limit box is coincided with the central axis of the load applying oil cylinder; the miniature soil pressure gauge is a plurality of in quantity, and a plurality of miniature soil pressure gauges are installed at the internal surface of soil body sample limit box along circumference equipartition.
2. The device for measuring the actual Poisson's ratio of the foundation soil under the confined stress condition as claimed in claim 1, wherein: a barrel mouth at one end of the soil body sample side limiting box is provided with a cutting edge chamfering structure, a barrel mouth at the other end of the soil body sample side limiting box is not provided with the cutting edge chamfering structure, the barrel mouth at one side of the soil body sample side limiting box is inserted into a side limiting box slot, and the diameter of the soil body sample side limiting box is equal to the outer diameter of the side limiting box slot.
3. The device for measuring the actual Poisson's ratio of the foundation soil under the confined stress condition as claimed in claim 1, wherein: the soil body sample is used for filling the soil body sample in the soil body sample side limit box, the soil body sample is in direct contact with the miniature soil pressure meter, a gasket and a force transmission cushion block are sequentially arranged on the upper surface of the soil body sample, and the diameter of the gasket is equal to the inner diameter of the soil body sample side limit box.
4. The device for measuring the actual Poisson's ratio of the foundation soil under the confined stress condition as claimed in claim 1, wherein: the pressure sensor is connected with a pressure digital display meter, and axial load data acquired by the pressure sensor is directly read through the pressure digital display meter.
5. The device for measuring the actual Poisson's ratio of the foundation soil under the confined stress condition as claimed in claim 1, wherein: the miniature soil pressure gauge is connected with a strain type stress test analyzer, and soil pressure data collected by the miniature soil pressure gauge is directly read through the strain type stress test analyzer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921609781.9U CN210321703U (en) | 2019-09-25 | 2019-09-25 | Device for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921609781.9U CN210321703U (en) | 2019-09-25 | 2019-09-25 | Device for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210321703U true CN210321703U (en) | 2020-04-14 |
Family
ID=70133272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921609781.9U Active CN210321703U (en) | 2019-09-25 | 2019-09-25 | Device for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210321703U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110567429A (en) * | 2019-09-25 | 2019-12-13 | 辽宁工程技术大学 | Device and method for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition |
-
2019
- 2019-09-25 CN CN201921609781.9U patent/CN210321703U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110567429A (en) * | 2019-09-25 | 2019-12-13 | 辽宁工程技术大学 | Device and method for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103344705B (en) | Method of measuring rock brittleness index through applying acoustic emission energy values | |
| CN103174122B (en) | Lateral stress pore pressure probe used for testing soil static lateral pressure coefficient | |
| CN102011389B (en) | Soil body in situ test device and test method applying same | |
| CN110208114B (en) | Interface vibration single shear test device and method for simulating power contact problem | |
| CN113605887B (en) | Deep drilling complex environment local wall stress relief test method and system | |
| CN110082214B (en) | Sandstone oil and gas well casing string simulation test device and evaluation method thereof | |
| CN102221501A (en) | Device and method for measuring mechanical properties of rocks | |
| CN107449678A (en) | Large-scale triaxial shear test devices and methods therefor in situ | |
| CN110567429A (en) | Device and method for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition | |
| CN104034608A (en) | Vertical pull-type bidirectional contact surface shearing strength parameter testing device and testing method | |
| CN107991186A (en) | The tensile strength test experimental rig of rocks containing crack and method | |
| CN210321703U (en) | Device for measuring actual Poisson ratio of foundation soil body under lateral limit stress condition | |
| CN106124123B (en) | A kind of torque sensor spends experimental provision surely | |
| AU2017425530B2 (en) | Free fall ball penetrometer with a booster | |
| CN211927256U (en) | Enlarged footing stock crowd anchor test device | |
| CN109556563B (en) | Radial displacement measuring device for small-aperture tunnel model test | |
| Voyiadjis et al. | Preparation of large-size cohesive specimens for calibration chamber testing | |
| CN209446398U (en) | A kind of multiple dimensioned in situ strength test device of coarse-grained soil | |
| CN207300760U (en) | A kind of large-scale triaxial shear test device in situ | |
| CN210263181U (en) | Pile side frictional resistance test device for indoor simulation of stress state of soil around pile | |
| CN112284899B (en) | Device and method for measuring Poisson ratio of bulk materials in refuse dump | |
| RU2510440C2 (en) | Device for complex determination of physical and mechanical properties of soils under field conditions | |
| CN212180603U (en) | Inversion method sample preparation device for measuring adhesion force between curved surface and soil interface under constant pressure | |
| Chow et al. | Laboratory free falling penetrometer test into clay | |
| CN205015334U (en) | A device that is arranged in layering of laboratory model testing survey soil body to subside |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |