CN215448777U - Plane strain test device for reinforced soil unit body - Google Patents
Plane strain test device for reinforced soil unit body Download PDFInfo
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- CN215448777U CN215448777U CN202121206016.XU CN202121206016U CN215448777U CN 215448777 U CN215448777 U CN 215448777U CN 202121206016 U CN202121206016 U CN 202121206016U CN 215448777 U CN215448777 U CN 215448777U
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Abstract
The utility model discloses a plane strain test device for a reinforced earth unit body, which comprises a test box, wherein the top of the test box is provided with an axial loading device for loading in a matching way; a lateral confining pressure loading device for applying confining pressure is arranged in the test box; the lateral confining pressure loading device and the confining pressure adjusting device are connected with the control device; the test box is provided with a deformation measuring device in a matching way, and the deformation measuring device is connected with the data acquisition system. The device can replace the existing large-scale triaxial test device, obtain the stress-strain characteristic of the reinforced earth unit body under the plane strain condition, and the test result can be directly used for analyzing the mechanical characteristics of the reinforced earth structure without transformation.
Description
Technical Field
The utility model belongs to the technical field of geotechnical engineering, and particularly relates to a soft foundation structure for reinforcing a concrete panel rock-fill dam and a construction method.
Background
When mechanical characteristics of a reinforced earth structure (such as a reinforced earth side slope, a reinforced earth retaining wall, a reinforced earth abutment and the like) made of a geosynthetic material are researched, some unit body tests are often performed to calibrate an established numerical model. At present, a cylindrical reinforced earth unit body with the diameter of 300mm and the height of 600mm is commonly adopted to carry out large-scale triaxial test under different confining pressure conditions so as to obtain information such as stress-strain curves of the reinforced earth unit body. However, in the geosynthetic reinforced soil structure, it is generally considered that the reinforced soil structure is not deformed in the width direction, and the reinforced soil structure is simplified into a plane strain state, and a study is performed on the plane strain state, and the mechanical properties of the reinforced soil unit body are tested in the state, but the mechanical properties of the reinforced soil structure can be more accurately analyzed under a triaxial condition, but a large-scale test device for testing the mechanical properties of the reinforced soil unit body under the plane strain condition is lacked at present.
In the prior art, a triaxial test mode is adopted to test the mechanical properties of the reinforced earth unit bodies, the reinforced earth unit bodies are allowed to deform in the radial direction, but the reinforced earth structure made of the geosynthetic material, such as a reinforced earth side slope, a reinforced earth retaining wall, a reinforced earth abutment and the like, can be considered not to deform in the width direction and meets the assumption of a plane strain state, and when the mechanical properties of the reinforced earth structure made of the geosynthetic material are studied indoors, model tests are often carried out under the plane strain condition according to a scale. The mechanical property test of the reinforced soil unit body is more accurate by adopting a large triaxial test mode than under the plane strain condition, and meanwhile, the test result obtained under the triaxial condition is used for numerical analysis or model test and needs to be correspondingly transformed by a theoretical empirical formula, so that the precision of the test result can be reduced, and the test result obtained under the plane strain condition can be directly used without being transformed additionally.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a plane strain test device for a reinforced earth unit body, which can replace the existing large-scale triaxial test device to obtain the stress-strain characteristic of the reinforced earth unit body under the plane strain condition, and the test result can be directly used for analyzing the mechanical characteristic of the reinforced earth structure without transformation.
In order to achieve the technical features, the utility model is realized as follows: a plane strain test device for a reinforced earth unit body comprises a test box, wherein an axial loading device for loading is installed at the top of the test box in a matched mode; a lateral confining pressure loading device for applying confining pressure is arranged in the test box; the lateral confining pressure loading device and the confining pressure adjusting device are connected with the control device;
the test box is provided with a deformation measuring device in a matching way, and the deformation measuring device is connected with the data acquisition system.
The test box comprises a base, support beams are fixedly arranged at four corners of the top of the base respectively, rigid panels are fixedly arranged between the lower part of each support beam and the base respectively, and the space at the lower part of each support beam is enclosed into a rectangular box body; wherein the rigid panel positioned on the front side adopts a transparent organic glass panel.
Rigid transverse ribs are fixedly mounted on four side faces of the test box, and the rigid panels are mounted in a detachable plug-in mounting mode.
The axial loading device comprises a reaction frame fixed at the top of a supporting beam of the test box, a hydraulic cylinder is arranged at the bottom end of the reaction frame in an inverted mode, the bottom end of the hydraulic cylinder is matched with a rigid bearing plate arranged at the top of the test sample, and the axial loading force is transmitted to the surface of the reinforced soil unit body for loading.
The hydraulic cylinder is connected with a hydraulic oil inlet connecting pipe and a hydraulic oil outlet connecting pipe, and the hydraulic oil inlet connecting pipe and the hydraulic oil outlet connecting pipe are connected with a hydraulic pump station through a reversing valve group; the reversing valve group and the hydraulic pump station are connected with a control device, and the control device realizes the accurate control of loading/unloading through a program.
The lateral confining pressure loading device comprises air bags arranged inside the test box and located on two sides of the test sample, the air bags are connected with a toughened glass tube used for storing high-pressure gas through an air bag connecting tube, and a confining pressure adjusting device is installed on the toughened glass tube.
The confining pressure adjusting device comprises a barometer arranged at the top of a toughened glass pipe, the toughened glass pipe is connected with an air compressor for providing high-pressure gas through an air compressor connecting pipe, and an air pressure adjusting valve is arranged on the air compressor connecting pipe; the pressure in the air bag is controlled through an air pressure regulating valve, the pressure value is displayed through an air pressure meter, the air pressure regulating valve is connected with a control device, and the pressure in the range of 5 kPa-200 kPa can be accurately controlled; the maximum compression deformation of the air bag is 80 mm under the condition of external pressure.
The deformation measuring device comprises a vertical deformation measuring device and a lateral deformation measuring device, wherein the vertical deformation measuring device is used for measuring the vertical settlement of the unit body sample and comprises an LVDT displacement sensor arranged on the top of the rigid bearing plate; lateral deformation measuring device is used for measuring the lateral deformation volume of cell cube sample, including the toughened glass pipe, wireless displacement laser sensor with be used for connecting the gasbag connecting pipe of toughened glass pipe and gasbag, the diameter of toughened glass pipe is 100~200 mm, wireless displacement laser sensor is located the intraductal top of toughened glass, a change for measuring the intraductal liquid level of glass, with this lateral deformation volume that reflects the cell cube sample, the volume deformation of cell cube sample is obtained through the monitoring data of vertical deformation and lateral deformation.
The data acquisition system is used for acquiring vertical settlement, lateral deformation, axial load and bar strain data of the unit body sample in real time, and the data acquisition frequency can be set automatically;
the air bag of the lateral confining pressure loading device is filled with water and is connected with the toughened glass tube through an air bag connecting tube; gas enters the toughened glass tube through a connecting tube at the top of the toughened glass tube, and extrudes a water body to apply confining pressure on the unit body sample;
the top of the rigid bearing plate of the axial loading device is fixedly provided with a force sensor, and the axial load realizes the feedback control of the pressure in the hydraulic cylinder through the force sensor and the control device;
and the LVDT displacement sensors of the deformation measuring device are respectively arranged on the left side and the right side of the rigid bearing plate, and the average value of the LVDT displacement sensors is taken as the vertical sedimentation value of the unit body sample.
The utility model has the following beneficial effects:
1. the utility model researches and develops a device for testing the mechanical characteristics of the reinforced earth unit bodies under the condition of plane strain aiming at the deformation stress characteristics of the reinforced earth structure, and the mechanical parameters obtained by the device can be directly applied to the mechanical characteristic analysis of the reinforced earth structure without conversion of a theoretical empirical formula, so that the accuracy of an analysis result can be improved. Meanwhile, measuring elements such as a soil pressure gauge, a strain gauge and the like can be arranged in the unit body samples and used for analyzing the reinforcement effect of the reinforcement materials on the soil body.
2. The device can directly measure the mechanical properties of the reinforced earth unit bodies under the plane strain condition without using the result of a triaxial test for transformation, and is favorable for enhancing the accuracy of the analysis result of the mechanical properties of the reinforced earth structure. Meanwhile, strain gauges can be pasted on the surfaces of the ribs, the strain of the ribs at different positions in the unit bodies is measured, and the distribution rule of the strain is analyzed.
Drawings
Fig. 1 is a front view of a plane strain test device for a reinforced earth unit body provided by the utility model.
Fig. 2 is a side view of a plane strain test device for a reinforced earth unit body provided by the utility model.
In the figure: 1-a support beam; 2-a rigid panel; 3-rigid cross ribs; 4-a transparent organic glass panel; 5-a hydraulic cylinder; 6-air bag; 7-a force sensor; 8-LVDT displacement sensors; 9-barometer; 10-air pressure regulating valve; 11-air compressor connecting pipe; 12-a rigid bearing plate; 13-a toughened glass tube; 14-wireless displacement laser sensor; 15-air bag connecting pipe; 16-bolt; 17-hydraulic oil inlet connecting pipe; and 18-hydraulic oil outlet connecting pipe.
Detailed Description
Embodiments of the present invention will be further described with reference to the accompanying drawings.
Example 1:
referring to fig. 1-2, a plane strain test device for a reinforced earth unit body comprises a test box, wherein an axial loading device for loading is arranged at the top of the test box in a matching manner; a lateral confining pressure loading device for applying confining pressure is arranged in the test box; the lateral confining pressure loading device and the confining pressure adjusting device are connected with the control device; the test box is provided with a deformation measuring device in a matching way, and the deformation measuring device is connected with the data acquisition system. The test device adopting the structure can replace the existing large triaxial test device, the stress-strain characteristic of the reinforced earth unit body under the plane strain condition is obtained, and the test result can be directly used for analyzing the mechanical characteristic of the reinforced earth structure without conversion.
Further, the test box comprises a base, four corners of the top of the base are respectively and fixedly provided with a support beam 1, rigid panels 2 are respectively and fixedly arranged between the lower part of the support beam 1 and the base, and the space at the lower part of the support beam 1 is enclosed into a rectangular box body; wherein the rigid panel 2 positioned on the front surface adopts a transparent organic glass panel 4. The test box can be used for storing unit body tests, and the machine glass panel 4 is adopted to facilitate observation of the test conditions inside the machine glass panel.
Preferably, the internal dimensions of the test chamber are 760 mm by 300mm by 1050 mm.
Furthermore, four side surfaces of the test box are fixedly provided with rigid transverse ribs 3, and the rigid panel 2 is detachably inserted and mounted. The structural strength of the entire test chamber is enhanced by the rigid cross-ribs 3 described above.
Further, the axial loading device comprises a reaction frame fixed on the top of the supporting beam 1 of the test box, a hydraulic cylinder 5 is arranged at the bottom end of the reaction frame in an inverted mode, the bottom end of the hydraulic cylinder 5 is matched with a rigid bearing plate 12 arranged on the top of the test sample, and the axial loading force is transmitted to the surface of the reinforced soil unit body for loading.
Further, the hydraulic cylinder 5 is connected with a hydraulic oil inlet connecting pipe 17 and a hydraulic oil outlet connecting pipe 18, and the hydraulic oil inlet connecting pipe 17 and the hydraulic oil outlet connecting pipe 18 are connected with a hydraulic pump station through a reversing valve group; the reversing valve group and the hydraulic pump station are connected with a control device, and the control device realizes the accurate control of loading/unloading through a program.
Further, the lateral confining pressure loading device comprises air bags 6 which are arranged inside the test box and located on two sides of the test sample, the air bags 6 are connected with a toughened glass tube 13 used for storing high-pressure gas through an air bag connecting tube 15, and a confining pressure adjusting device is installed on the toughened glass tube 13. The purpose of the flexible boundary can be achieved by using a lateral confining pressure loading device.
Further, the confining pressure adjusting device comprises a barometer 9 mounted at the top of a toughened glass tube 13, the toughened glass tube 13 is connected with an air compressor for providing high-pressure air through an air compressor connecting tube 11, and an air pressure adjusting valve 10 is mounted on the air compressor connecting tube 11; the pressure in the air bag 6 is controlled through an air pressure regulating valve 10, the pressure value is displayed through an air pressure gauge 9, the air pressure regulating valve 10 is connected with a control device, and the pressure in the range of 5 kPa-200 kPa can be accurately controlled; the maximum compression deformation of the air bag 6 under the condition of being subjected to external pressure is 80 mm. The confining pressure adjusting device can be used for providing lateral confining pressure in the test process.
Further, the deformation measuring device comprises a vertical deformation measuring device and a lateral deformation measuring device, wherein the vertical deformation measuring device is used for measuring the vertical settlement of the unit body sample and comprises an LVDT displacement sensor 8 arranged at the top of the rigid bearing plate 12; lateral deformation measuring device is used for measuring the lateral deformation volume of cell cube sample, including toughened glass pipe 13, wireless displacement laser sensor 14 and the gasbag connecting pipe 15 that is used for connecting toughened glass pipe 13 and gasbag 6, the diameter of toughened glass pipe 13 is 100~200 mm, wireless displacement laser sensor 14 is located toughened glass pipe 13 internal top, a change for measuring the intraductal liquid level of glass, with this lateral deformation volume that reflects the cell cube sample, the volume deformation that obtains the cell cube sample through vertical deformation and lateral deformation's monitoring data.
Furthermore, the data acquisition system is used for acquiring vertical settlement, lateral deformation, axial load and bar strain data of the unit body sample in real time, and the data acquisition frequency can be set by self. The air bag 6 of the lateral confining pressure loading device is filled with water and is connected with the toughened glass tube 13 through an air bag connecting tube; gas enters the toughened glass tube 13 through a connecting tube at the top of the toughened glass tube, and extrudes a water body to apply confining pressure on the unit body sample; the top of the rigid bearing plate 12 of the axial loading device is fixedly provided with a force sensor 7, and the axial load realizes the feedback control of the pressure in the hydraulic cylinder 5 through the force sensor 7 and the control device. The data acquisition system can be used for acquiring various data in the test process.
Furthermore, the LVDT displacement sensors 8 of the deformation measuring device are respectively arranged on the left side and the right side of the rigid bearing plate 12, and the average value of the sensors is taken as the vertical settlement value of the unit body sample. Accurate measurement of the amount of deformation can be achieved by using the LVDT displacement sensor 8.
Preferably, the dimensions of rigid pressure bearing plate 12 are 580 mm × 270 mm × 105 mm.
The working process and principle of the utility model are as follows:
before the test, checking whether the instrument can be normally used, calibrating a measuring element, preparing filling soil and reinforcing materials required by the test, when the indoor test is carried out, firstly filling water in the air bag 6, switching on a power supply, starting an air compressor to generate certain pressure in the air bag 6, observing the reading of a barometer 9, and adjusting an air pressure adjusting valve 10 to enable the air pressure to be greatly higher than the set confining pressure so as to achieve the purpose of limiting the displacement generated in the sample filling process; opening the data acquisition device, then filling soil and paving geosynthetic materials in the test box according to test requirements until the sample is manufactured, placing a rigid bearing plate 12 and a force sensor 7 on the top of the sample, fixing LVDT displacement sensors 8 on the left side and the right side of the rigid bearing plate, adjusting an air pressure adjusting valve 10 to enable the reading of a barometer 9 to be equal to a set confining pressure value, starting an axial load loading device, resetting the readings of the LVDT displacement sensors 8 and a wireless displacement laser sensor 14, setting the data acquisition frequency of the data acquisition device, setting a loading scheme in a computer program, controlling a hydraulic cylinder 5 to load through a control end, stopping data acquisition and storing after the test is finished, unloading the axial load, taking out the sample, cleaning the test device, repeating the steps and carrying out the next test.
Claims (9)
1. The utility model provides a reinforced earth unit body plane strain test device which characterized in that: the device comprises a test box, wherein the top of the test box is provided with an axial loading device for loading in a matching way; a lateral confining pressure loading device for applying confining pressure is arranged in the test box; the lateral confining pressure loading device and the confining pressure adjusting device are connected with the control device;
the test box is provided with a deformation measuring device in a matching way, and the deformation measuring device is connected with the data acquisition system.
2. The reinforced earth unit body plane strain test device of claim 1, wherein: the test box comprises a base, wherein supporting beams (1) are fixedly arranged at four corners of the top of the base respectively, rigid panels (2) are fixedly arranged between the lower part of each supporting beam (1) and the base respectively, and the space at the lower part of each supporting beam (1) is enclosed into a rectangular box body; wherein the rigid panel (2) positioned on the front surface adopts a transparent organic glass panel (4).
3. The reinforced earth unit body plane strain test device of claim 2, wherein: four side surfaces of the test box are fixedly provided with rigid transverse ribs (3), and the rigid panel (2) is detachably inserted and mounted.
4. The reinforced earth unit body plane strain test device of claim 1, wherein: the axial loading device comprises a reaction frame fixed at the top of a supporting beam (1) of the test box, a hydraulic cylinder (5) is inversely installed at the bottom end of the reaction frame, the bottom end of the hydraulic cylinder (5) is matched with a rigid bearing plate (12) arranged at the top of the test sample, and the axial loading force is transmitted to the surface of the reinforced soil unit body for loading.
5. The reinforced earth unit body plane strain test device of claim 4, wherein: the hydraulic cylinder (5) is connected with a hydraulic oil inlet connecting pipe (17) and a hydraulic oil outlet connecting pipe (18), and the hydraulic oil inlet connecting pipe (17) and the hydraulic oil outlet connecting pipe (18) are connected with a hydraulic pump station through a reversing valve group; the reversing valve group and the hydraulic pump station are connected with a control device, and the control device realizes the accurate control of loading/unloading through a program.
6. The reinforced earth unit body plane strain test device of claim 1, wherein: the lateral confining pressure loading device comprises air bags (6) arranged inside the test box and located on two sides of the test sample, the air bags (6) are connected with a toughened glass tube (13) used for storing high-pressure gas through air bag connecting tubes (15), and a confining pressure adjusting device is installed on the toughened glass tube (13).
7. The reinforced earth unit body plane strain test device of claim 6, wherein: the confining pressure adjusting device comprises a barometer (9) arranged at the top of a toughened glass pipe (13), the toughened glass pipe (13) is connected with an air compressor for providing high-pressure air through an air compressor connecting pipe (11), and an air pressure adjusting valve (10) is arranged on the air compressor connecting pipe (11); the pressure in the air bag (6) is controlled through an air pressure regulating valve (10), the pressure value is displayed through an air pressure meter (9), and the air pressure regulating valve (10) is connected with a control device and can accurately control the pressure within the range of 5 kPa-200 kPa; the maximum compression deformation amount of the air bag (6) is 80 mm under the condition of receiving external pressure.
8. The reinforced earth unit body plane strain test device of claim 1, wherein: the deformation measuring device comprises a vertical deformation measuring device and a lateral deformation measuring device, wherein the vertical deformation measuring device is used for measuring the vertical settlement of the unit body sample and comprises an LVDT displacement sensor (8) arranged at the top of a rigid bearing plate (12); lateral deformation measuring device is used for measuring the lateral deformation volume of unit body sample, including toughened glass pipe (13), wireless displacement laser sensor (14) and be used for connecting gasbag connecting pipe (15) of toughened glass pipe (13) and gasbag (6), the diameter of toughened glass pipe (13) is 100~200 mm, wireless displacement laser sensor (14) are located toughened glass pipe (13) inside top, a change for measuring the intraductal liquid level of glass, with this lateral deformation volume that reflects the unit body sample, the volume deformation of unit body sample is obtained through the monitoring data of vertical deformation and lateral deformation.
9. The reinforced earth unit body plane strain test device of claim 1, wherein: the data acquisition system is used for acquiring vertical settlement, lateral deformation, axial load and bar strain data of the unit body sample in real time, and the data acquisition frequency can be set automatically;
the air bag (6) of the lateral confining pressure loading device is filled with water and is connected with the toughened glass tube (13) through an air bag connecting tube; gas enters the toughened glass tube (13) through a connecting tube at the top of the toughened glass tube, and extrudes a water body to apply confining pressure on the unit body sample;
the top of a rigid bearing plate (12) of the axial loading device is fixedly provided with a force sensor (7), and the axial load realizes feedback control on the pressure in the hydraulic cylinder (5) through the force sensor (7) and a control device;
the LVDT displacement sensors (8) of the deformation measuring device are respectively arranged on the left side and the right side of the rigid bearing plate (12), and the average value of the LVDT displacement sensors is taken as the vertical sedimentation value of the unit body sample.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113295539A (en) * | 2021-06-01 | 2021-08-24 | 中国长江三峡集团有限公司 | Plane strain test device and method for reinforced soil unit body |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113295539A (en) * | 2021-06-01 | 2021-08-24 | 中国长江三峡集团有限公司 | Plane strain test device and method for reinforced soil unit body |
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