Testing device and testing method for measuring deformation characteristics of soil body

Abstract

The invention provides a testing device and a testing method for measuring deformation characteristics of a soil body. The testing device comprises a consolidation experiment assembly and a soil body loading assembly, wherein the soil body loading assembly comprises a loading balance beam, a balance beam mounting piece, a soil sample loading rod, a pressurizing weight and a balance weight. The testing method comprises the following steps: preparing a to-be-tested soil sample, wrapping the to-be-tested soil sample with an elastic cutting ring made of a to-be-tested material, and assembling the to-be-tested soil sample in a consolidation experiment assembly; a soil body loading assembly is installed, loads of different pressure levels needing to be tested are loaded to the to-be-tested soil sample, and the height deformation amount and the radial radius of the to-be-tested soil sample after lateral deformation under the loads of the different pressure levels are obtained; calculating the void ratio of the to-be-tested soil sample after lateral deformation compression under different pressure stage loads; according to the radial radius, the compressed void ratio and the parameters of the to-be-tested soil sample under the complete lateral confinement condition, the settlement amount of the soil body in the three-dimensional stress state is calculated. The device has the advantages that the stress state of the soil body is truly simulated, and real compression deformation parameters of the soil body can be obtained.

Description

Technical Field

[0001] The invention relates to the field of geotechnical engineering, and in particular to a testing device and a testing method for measuring soil deformation characteristics. Background Art

[0002] In the field of geotechnical engineering, the study of soil consolidation characteristics is of vital importance. Soil consolidation refers to the process in which excess pore water pressure is generated inside the soil under the action of external loads, and then the pore water is gradually discharged, the excess pore water pressure dissipates over time, and the effective stress in the soil increases accordingly, until the excess pore water pressure completely disappears. In this process, the soil will inevitably undergo compression deformation, and the accurate determination of the compression performance parameters of the soil is of decisive significance for the design, construction and stability assessment of construction projects such as building foundation treatment, road embankment filling, and dam engineering.

[0003] In order to determine the compression performance parameters of the soil, the existing method is to use an oedometer to measure the compression performance of the soil under the load in the loading direction. The existing compression consolidation experiment is carried out under the conditions of complete lateral confinement and step-by-step increase of the pressure in the loading direction. In the existing experimental mode, the soil is forced to be constrained to a one-dimensional deformation state. Specifically: The design principle of the oedometer is based on Terzaghi's one-dimensional consolidation theory, and a rigid ring cutter is used to implement lateral constraints on the soil sample. Although its lateral confinement conditions theoretically meet the assumptions of one-dimensional compression, the rigid ring cutter completely suppresses the lateral strain development of the soil sample during the test, so that the soil can only produce vertical compression deformation. This idealized boundary condition is fundamentally different from the actual three-dimensional stress state of the soil at the engineering site.

[0004] The soil in actual engineering is in a natural environment, and the stress and deformation of the soil are three-dimensional. The existing experimental equipment is different from the actual situation. The excessive constraints of the test conditions lead to the fact that the key parameters such as the compression modulus and consolidation coefficient obtained cannot truly reflect the deformation response of the soil under complex stress paths, which directly leads to a significant deviation between the deformation parameters measured by the traditional one-dimensional consolidation compression test and the deformation parameters of the soil under actual working conditions. This deviation makes the engineering design and analysis based on the experimental parameters unable to accurately reflect the true mechanical behavior of the soil, which in turn affects the settlement calculation accuracy and engineering safety evaluation, and increases the risk and uncertainty of engineering construction. For example, in the design of building foundations, if the design is based on inaccurate compression parameters, it may cause uneven settlement of the building during use, affecting the safety and normal use function of the building. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and to provide a testing device and a testing method for measuring the deformation characteristics of soil, which can load different levels of loads on a soil sample to be tested, truly simulate the stress state of the soil, and obtain the true compression deformation parameters of the soil.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is: A test device for measuring soil deformation characteristics, including a consolidation test component and a soil loading component, the soil loading component including a loading balance beam, a balance beam mounting member arranged on the loading balance beam, a soil sample loading rod, a pressurized weight and a balancing weight, the soil sample loading rod is located between the balance beam mounting member and the pressurized weight to form a lever structure with the balance beam mounting member as a fulcrum; the balancing weight is arranged at one end of the loading balance beam away from the pressurized weight; the consolidation test component includes a soil sample to be tested and an elastic ring knife that causes the soil sample to be tested to deform laterally when pressurized, the elastic ring knife is wrapped around the outside of the soil sample to be tested, and the bottom end of the soil sample loading rod presses the soil sample to be tested.

[0007] As a further improvement of the above technical solution: The loading balance beam is evenly provided with lever ratio adjustment holes along the length direction, and the number of the lever ratio adjustment holes is directly proportional to the lever ratio; the soil sample loading rod is installed in the lever ratio adjustment hole corresponding to the balance beam mounting part and the pressurizing weight according to the required lever ratio to form the lever structure with different lever ratios and different levels of loading loads.

[0008] The connecting end of the soil sample loading rod is rotatably mounted on the loading balance beam, and the loading end of the soil sample loading rod is pre-pressed against the top of the consolidation test assembly by the pre-pressing force of the pressurized weight before the soil sample to be tested is loaded.

[0009] It also includes a displacement detection component for measuring the deformation of the soil sample to be tested in the loading direction and radial direction after loading. The displacement detection component includes a digital displacement meter and a vernier caliper. The digital displacement meter is fixedly arranged, and the detection end is pressed against the top of the soil sample to be tested; the vernier caliper is used to measure the diameter of the soil sample to be tested at different heights and different circumferential positions.

[0010] The consolidation experiment assembly also includes a consolidation container, a pressure plate arranged on the consolidation container, an upper water-permeable layer and a lower water-permeable layer. The soil sample to be tested is pressed between the upper water-permeable layer and the lower water-permeable layer, and the pressure plate is evenly pressed on the top of the upper water-permeable layer through the soil sample loading rod; anti-blocking filter paper is arranged between the soil sample to be tested and the upper water-permeable layer and the lower water-permeable layer to prevent soil particles of the soil sample to be tested from blocking the water-permeable layer when compressed.

[0011] A testing method using the above-mentioned testing device comprises the following steps: Step 1, prepare a soil sample to be tested, wrap an elastic ring knife of the material to be tested around the soil sample to be tested, and assemble it in a consolidation test assembly; Step 2, installing the soil loading assembly, loading the different pressure levels required for the test onto the soil sample to be tested in the consolidation test assembly, recording the deformation data of the soil sample to be tested in the loading direction and the diameter data in the radial direction under the different pressure levels, and obtaining the height deformation and radial radius of the soil sample to be tested after lateral deformation under the different pressure levels; Step 3, calculating the porosity of the soil sample to be tested after lateral deformation and compression under different pressure levels of loads according to the height deformation and radial radius of the soil sample to be tested under different pressure levels of loads; Step 4, according to the radial radius and the porosity after compression of the soil sample to be tested under different pressure level loads, and the parameters of the soil sample to be tested under the full lateral confinement condition, calculate the compression modulus of the lateral deformation of the soil sample to be tested under different pressure level loads, select the corresponding compression modulus according to the actual pressure level load of the soil body, and calculate the settlement of the soil body under a three-dimensional stress state. The parameters of the soil sample to be tested under the full lateral confinement condition include the compression modulus of the soil sample to be tested under the full lateral confinement condition or the height deformation of the soil sample to be tested under the full lateral confinement condition.

[0012] As a further improvement of the above technical solution: In step 4, the compression modulus of the soil sample to be tested that undergoes lateral deformation is calculated according to the following formula: in, is the compression modulus of the lateral deformation of the soil sample under the current load level, is the load increment of the soil sample before and after compression, The soil sample to be tested is in the previous level The porosity ratio after lateral deformation and compression under load, The soil sample to be tested is The porosity ratio after lateral deformation and compression under load, The soil sample to be tested is in the previous level Height under load, The soil sample to be tested is in the previous level Radius after lateral deformation under load, The soil sample to be tested is The radial radius after lateral deformation under load.

[0013] In step 3, the porosity ratio of the soil sample to be tested after lateral deformation and compression is calculated according to the following formula: in, is the porosity ratio of the soil sample after lateral deformation and compression. The soil sample to be tested is in the previous level Height under load, is the height deformation of the soil sample to be tested, The soil sample to be tested is in the previous level The porosity ratio after lateral deformation and compression under load, The soil sample to be tested undergoes lateral deformation in the previous stage. Radius under load, The soil sample to be tested is The radial radius after lateral deformation under load.

[0014] In step 2, installing the soil loading assembly includes the following steps: determining the loading weight of the soil sample to be tested according to the different pressure levels of loads required to be tested on the soil sample to be tested, and determining the lever ratio of the lever structure according to the maximum loading weight of the soil sample to be tested under different pressure levels; determining the installation positions of the balance beam mounting, the soil sample loading rod and the pressure weight on the loading balance beam according to the lever ratio; when installing the balance beam mounting, the soil sample loading rod and the pressure weight, placing the pressure weight of the initial weight, and leveling the loading balance beam by the balance weight; adjusting the weight of the pressure weight, applying pre-pressure to the soil sample to be tested, so that adjacent components in the consolidation experiment assembly are in full contact; adjusting the pressure weight to the required weight in sequence, so as to load the different pressure levels required to be tested to the soil sample to be tested through the soil sample loading rod.

[0015] In step 2, the diameter data of the soil sample to be tested in the radial direction is recorded to obtain the radial radius of the soil sample to be tested after lateral deformation, including: measuring the diameter data of the soil sample to be tested at different heights, and measuring the diameter data of the soil sample to be tested at the same height and in different circumferential directions, taking the average value of the diameter data of the soil sample to be tested at the same height and in different circumferential directions as the average diameter of the soil sample to be tested at the same height, and taking the average value of the average diameters of the soil sample to be tested at different heights as the radial diameter of the soil sample to be tested, thereby obtaining the radial radius of the soil sample to be tested after lateral deformation.

[0016] Compared with the prior art, the advantages of the present invention are: The test device of the present invention is provided with a consolidation experiment component and a soil loading component. The soil loading component adopts the lever principle, and the soil sample loading rod is arranged between the balance beam mounting part and the pressurized weight to form a lever structure with the balance beam mounting part as the fulcrum. At this time, the ratio of the distance from the soil sample loading rod to the balance beam mounting part to the distance from the pressurized weight to the balance beam mounting part is the lever ratio of the lever structure, so that different lever ratios can be adjusted by changing the position of the soil sample loading rod between the balance beam mounting part and the pressurized weight. It has a wide range of adaptability, so as to facilitate loading different levels of loads on the soil sample to be tested, and its structure is simple and compact, and occupies little space.

[0017] At the same time, the consolidation test component is wrapped with an elastic ring knife outside the soil sample to be tested, so that the soil sample to be tested can be deformed laterally when the soil sample loading rod is loaded, reflecting the lateral deformation characteristics of the soil under the actual stress state, thereby truly simulating the three-dimensional stress state of the soil during loading, and providing a basis for obtaining soil deformation parameters that are highly consistent with the actual situation.

[0018] The testing method of the present invention also has the above-mentioned advantages of the testing device, and the testing method of the present invention constructs the compression modulus of the soil sample to be tested under lateral deformation conditions, so that the compression deformation parameters (compression modulus) of the soil sample to be tested under lateral deformation conditions can be quickly and accurately calculated to calculate the settlement of the soil under a three-dimensional stress state. The settlement obtained by the present invention is closer to the actual value than the settlement obtained by the existing settlement calculation method.

[0019] It can be seen that the present invention fills the technical gap that one-dimensional consolidation test results cannot reflect three-dimensional soil deformation. It can accurately simulate the actual three-dimensional stress and deformation environment of the soil, accurately reflect the lateral deformation characteristics of the soil, and at the same time obtain soil compression deformation parameters that are highly consistent with the actual situation, providing accurate numerical values ​​for the prediction of subsequent settlement, thereby ensuring that engineering and design based on experimental parameters can accurately reflect the true mechanical behavior of the soil, and ensure the certainty and safety of engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein: Figure 1 It is a structural schematic diagram of a testing device for measuring soil deformation characteristics of the present invention; Figure 2 It is a front view of the testing device for measuring soil deformation characteristics of the present invention; Figure 3 It is a left side view of the testing device for measuring soil deformation characteristics of the present invention; Figure 4 is a top view of a testing device for measuring soil deformation characteristics according to the present invention; Figure 5 It is a schematic diagram of the structure of the consolidation experiment assembly of the present invention; Figure 6 It is a flow chart of the testing method of the present invention.

[0021] The symbols in the figure represent: 1. Consolidation test assembly; 11. Soil sample to be tested; 12. Elastic ring knife; 13. Consolidation container; 14. Pressure plate; 15. Upper permeable layer; 16. Lower permeable layer; 17. Ring knife positioning groove; 2. Soil loading assembly; 21. Loading balance beam; 211. Lever ratio adjustment hole; 22. Balance beam mounting piece; 221. Vertical mounting rod; 222. Mounting crossbeam; 23. Soil sample loading rod; 231. Loading rod mounting crossbeam; 24. Pressure weight; 25. Balance weight; 3. Displacement detection assembly; 31. Digital displacement meter; 4. Mounting base. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereby.

[0023] Figures 1 to 5 The embodiment of the test device for measuring the deformation characteristics of soil of the present invention is shown, and the test device includes a consolidation test assembly 1 and a soil loading assembly 2. The soil loading assembly 2 includes a loading balance beam 21, a balance beam mounting member 22 arranged on the loading balance beam 21, a soil sample loading rod 23, a pressurized weight 24 and a balancing weight 25. The soil sample loading rod 23 is located between the balance beam mounting member 22 and the pressurized weight 24 to form a lever structure with the balance beam mounting member 22 as a fulcrum. The pressurized weight 24 applies pressure to the soil sample 11 to be tested of the consolidation test assembly 1 through the soil sample loading rod 23, and the balance beam mounting member 22 is installed with the loading balance beam 21. The balancing weight 25 is arranged at one end of the loading balance beam 21 away from the pressurized weight 24, so that the loading balance beam 21 is leveled by the balancing weight 25 before the soil sample loading rod 23 is loaded, so that the loading balance beam 21 is in a balanced state before loading, and the subsequent loading is ensured to be carried out reliably and safely.

[0024] The test device of the present invention is provided with a consolidation test component 1 and a soil loading component 2. The soil loading component 2 adopts the lever principle, and the soil sample loading rod 23 is arranged between the balance beam mounting part 22 and the pressurized weight 24 to form a lever structure with the balance beam mounting part 22 as the fulcrum. At this time, the ratio of the distance from the pressurized weight 24 to the balance beam mounting part 22 and the distance from the soil sample loading rod 23 to the balance beam mounting part 22 is the lever ratio of the lever structure, so that different lever ratios can be adjusted by changing the position of the soil sample loading rod 23 between the balance beam mounting part 22 and the pressurized weight 24, so as to facilitate the loading of different levels of loads on the soil sample 11 to be tested. It has a wide range of adaptability, and its structure is simple and compact, and occupies a small space.

[0025] At the same time, the consolidation test assembly 1 includes a soil sample 11 to be tested and an elastic ring cutter 12, and the elastic ring cutter 12 is wrapped around the soil sample 11 to be tested; the bottom end of the soil sample loading rod 23 presses the soil sample 11 to be tested. The elastic ring cutter 12 allows the soil sample 11 to be tested to deform laterally when the soil sample loading rod 23 is loaded, so as to reflect the lateral deformation characteristics of the soil under the actual stress state, avoid the problem that the existing ring cutter diameter is fixed and the soil sample 11 to be tested cannot be deformed laterally, and provide a basis for obtaining soil deformation parameters that are highly consistent with the actual situation.

[0026] In this embodiment, the elastic ring cutter 12 can be made of rubber, PVC, aluminum, steel and other materials. The elastic ring cutters 12 of different materials can provide different lateral constraints to the soil sample 11 to be tested during loading, so as to change the lateral constraint conditions of the ring cutter, allow the soil sample 11 to be tested to undergo different lateral deformations, and reflect the influence of the lateral deformation of the elastic ring cutter 12 on the deformation parameters of the soil sample 11 to be tested. Preferably, the elastic modulus interval between the ring cutters of different materials is 1 to 10 GPa, so as to better study the differences in soil settlement values ​​under different elastic ring cutters. In other embodiments, the ring cutter material can also be made of other materials, as long as the material can reflect the lateral deformation of the soil sample 11 to be tested under load pressure, it should be within the protection scope of the present invention.

[0027] Furthermore, the load balance beam 21 is evenly provided with lever ratio adjustment holes 211 along the length direction, and the number of the lever ratio adjustment holes 211 is in direct proportion to the lever ratio. The soil sample loading rod 23 is installed in the lever ratio adjustment hole 211 corresponding to the beam body mounting rod and the pressurized weight 24 according to the required lever ratio, so as to form a lever structure with different lever ratios and different levels of loading loads, so as to facilitate loading different load levels on the soil sample 11 to be tested, and its use range is wide. In this embodiment, the specific selection of the lever ratio is set according to the load level. For example, when the maximum weight of the pressurized weight 24 required does not exceed 100kg, a small lever ratio (such as 5:1) can be selected; when the maximum weight of the pressurized weight 24 required exceeds 100kg, a large lever ratio (such as 10:1 or 20:1) can be selected.

[0028] In this embodiment, the number of lever ratio adjustment holes 211 is set according to the required lever ratio. If a smaller lever ratio is required, the number of lever ratio adjustment holes 211 can be reduced accordingly. If a larger lever ratio is required, the number of lever ratio adjustment holes 211 can be increased accordingly. Meanwhile, the interval between adjacent lever ratio adjustment holes 211 is the length of the load balance beam 21 divided by the number of lever ratio adjustment holes 211 minus one.

[0029] For example, Figure 1 and Figure 2As shown, the number of lever ratio adjustment holes 211 of the loading balance beam 21 is 13, and the interval between adjacent lever ratio adjustment holes 211 is determined based on the length of the loading balance beam 21 divided by 12. The loading balance beam 21 is numbered 1 to 13 from left to right, wherein hole No. 3 connects the loading balance beam 21 and the balance beam mounting member 22, hole No. 4 connects the soil sample loading rod 23, and hole No. 13 connects the pressurized weight 24. At this time, the lever ratio is 10:1. When the soil sample loading rod 23 is placed in the remaining hole positions, the lever ratio can be changed. For example, when the soil sample loading rod 23 is in hole No. 5 and the pressurized weight 24 is in hole No. 13, the lever ratio is 5:1.

[0030] In this embodiment, the connecting end of the soil sample loading rod 23 is rotatably mounted on the loading balance beam 21. During the experiment, the soil sample 11 to be tested will be compressed, the height of the soil sample 11 to be tested will gradually decrease, and the loading balance beam 21 will also descend. The soil sample loading rod 23 is rotated to make the soil sample 11 to be tested evenly stressed. Before the soil sample 11 to be tested is loaded, the loading end of the soil sample loading rod 23 is pre-pressed against the top of the consolidation test assembly 1 by the pre-pressing force of the pressure weight 24. The pre-pressing pressure can ensure that the various components of the consolidation test assembly 1 are fully in contact.

[0031] In this embodiment, the test device also includes a displacement detection component 3, which includes a digital displacement meter 31 and a vernier caliper. The digital displacement meter 31 is fixedly arranged, and the detection end of the digital displacement meter 31 is pressed against the top of the soil sample 11 to be tested through the pressure plate 14, and is used to measure the change of the soil sample 11 to be tested in the loading direction after the loading deformation, so as to obtain the accurate height deformation of the soil sample 11 to be tested after lateral deformation under different load levels; the vernier caliper is used to measure the diameter of the soil sample 11 to be tested at different heights and different circumferential positions after the loading deformation, so as to accurately obtain the radial radius of the soil sample 11 to be tested after lateral deformation under different pressure levels. In other embodiments, the digital displacement meter 31 and the vernier caliper can also use displacement sensors and other detection components to detect displacement changes.

[0032] Preferably, the digital displacement meter 31 is fixed to the beam mounting rod using its own magnetic universal meter seat. In other embodiments, the fixing position of the digital displacement meter 31 can be any position as long as the displacement meter reading is only affected by the soil sample compression, such as the digital displacement meter 31 can also be installed on the ground or the mounting base 4 through the magnetic universal meter seat.

[0033] Furthermore, if Figure 5As shown, the consolidation test assembly 1 also includes a consolidation container 13, a pressure plate 14 arranged on the consolidation container 13, an upper water-permeable layer 15 and a lower water-permeable layer 16. The soil sample 11 to be tested is pressed between the upper water-permeable layer 15 and the lower water-permeable layer 16, and the pressure plate 14 is evenly pressed on the top of the upper water-permeable layer 15 through the soil sample loading rod 23, so that the load is evenly pressurized to the soil sample 11 to be tested, ensuring the safe and reliable conduct of the test and improving the accuracy of the experimental results.

[0034] Furthermore, an anti-blocking filter paper is provided between the soil sample 11 to be tested and the upper permeable layer 15 and the lower permeable layer 16 to prevent the soil particles of the soil sample 11 to be tested from blocking the permeable layer during compression, thereby ensuring the water permeability of the permeable layer. In this embodiment, the upper permeable layer 15 and the lower permeable layer 16 are permeable stones. In this embodiment, the thickness of the anti-blocking filter paper is 0.1 mm, and the thickness of the pressure plate 14 is 1 to 2 cm. The thickness of the anti-blocking filter paper and the pressure plate 14 can be adjusted according to actual conditions.

[0035] Preferably, a knife ring positioning groove 17 is provided at the bottom of the consolidation container 13, and the radius of the knife ring positioning groove 17 is set according to the required size of the elastic knife ring 12, so as to fix the elastic knife ring 12 and ensure that the elastic knife ring 12 will not move during the experiment, thereby ensuring the smooth and reliable conduct of the experiment. For example, if the diameter of the elastic knife ring 12 is 100 mm and the thickness of the elastic knife ring 12 is 2 mm, the diameter of the knife ring positioning groove 17 can be set to 104 mm.

[0036] In this embodiment, the loading balance beam 21 is a U-shaped balance beam; the balance beam mounting member 22 includes two vertical mounting rods 221 and a mounting crossbeam 222. The mounting crossbeam 222 is fixedly connected between the vertical mounting rods 221, and the U-shaped balance beam is rotatably mounted on the mounting crossbeam 222 through the lever ratio adjustment hole 211. A first bearing is provided between the mounting crossbeam 222 and the lever ratio adjustment hole 211 to ensure that the loading balance beam 21 can rotate reliably and effectively load the soil sample 11 to be tested.

[0037] Furthermore, a loading rod mounting cross bar 231 is provided at the position where the soil sample loading rod 23 is placed on the U-shaped balance beam, and a second bearing is provided between the soil sample loading rod 23 and the loading rod mounting cross bar 231, so that the soil sample loading rod 23 can be rotatably mounted on the U-shaped balance beam. In this embodiment, the U-shaped balance beam is a U-shaped channel steel, and the vertical mounting rod 221 is an angle steel mounting rod.

[0038] Furthermore, the test device further comprises a mounting base 4, two vertical mounting rods 221 are mounted on the mounting base 4, and the consolidation container 13 is placed on the mounting base 4. This facilitates the overall installation of the test device, provides a reliable and stable experimental environment, and ensures the smooth progress of the loading experiment.

[0039] like Figure 6As shown, the testing method using the above-mentioned testing device in this embodiment includes the following steps: Step 1, prepare a soil sample 11 to be tested, wrap an elastic ring knife 12 of the material to be tested around the soil sample 11 to be tested, and assemble it in a consolidation test assembly 1; Step 2, installing the soil loading component 2, loading the different pressure level loads required for the test to the soil sample 11 in the consolidation test component 1, and recording the deformation data of the soil sample 11 in the loading direction and the diameter data in the radial direction under the different pressure level loads, to obtain the height deformation and radial radius of the soil sample 11 under the different pressure level loads; Step 3, calculating the porosity of the soil sample 11 to be tested after lateral deformation and compression under different pressure levels of loads according to the height deformation and radial radius of the soil sample 11 to be tested under different pressure levels of loads; Step 4, according to the radial radius and the porosity after compression of the soil sample 11 to be tested under different pressure level loads, and the parameters of the soil sample 11 to be tested under the full lateral confinement condition, calculate the compression modulus of the lateral deformation of the soil sample 11 to be tested under different pressure level loads, select the corresponding compression modulus according to the actual pressure level load of the soil body, and calculate the settlement of the soil body under a three-dimensional stress state. The parameters of the soil sample 11 to be tested under the full lateral confinement condition include the compression modulus of the soil sample 11 to be tested under the full lateral confinement condition or the height deformation of the soil sample 11 to be tested under the full lateral confinement condition.

[0040] The testing method of the present invention also has the above-mentioned advantages of the testing device, and the testing method of the present invention constructs the compression modulus of the soil sample 11 to be tested under the lateral deformation condition under the current level load, so that the compression deformation parameter (compression modulus) of the soil sample 11 to be tested under the lateral deformation condition can be quickly and accurately calculated to calculate the settlement of the soil under a three-dimensional stress state. The settlement obtained by the present invention is closer to the actual value than the settlement obtained by the existing settlement calculation method.

[0041] The present invention fills the technical gap that one-dimensional consolidation test results cannot reflect three-dimensional soil deformation. It can accurately simulate the actual three-dimensional stress and deformation environment of the soil, accurately reflect the lateral deformation characteristics of the soil, and obtain soil compression deformation parameters that are highly consistent with the actual situation, providing accurate numerical values ​​for the prediction of subsequent settlement, thereby ensuring that engineering and design based on experimental parameters can accurately reflect the true mechanical behavior of the soil, and ensure the certainty and safety of engineering construction.

[0042] The specific steps of the testing method using the above-mentioned testing device of the present invention are as follows: In step 1, a soil sample 11 to be tested is prepared, an elastic ring cutter 12 of the material to be tested is wrapped around the soil sample 11 to be tested, and the elastic ring cutter 12 is assembled into a consolidation test assembly 1.

[0043] Among them, when the soil sample 11 to be tested wrapped with the elastic ring knife 12 is assembled in the consolidation experiment component 1, the lower permeable layer 16, anti-blocking filter paper, the soil sample 11 to be tested, the anti-blocking filter paper, the upper permeable layer 15, the pressure plate 14 and the digital displacement meter 31 in the consolidation experiment component 1 are assembled in sequence from bottom to top to complete the installation of the consolidation experiment component 1.

[0044] Furthermore, when it is necessary to test the settlement of the soil sample 11 to be tested under the elastic ring cutters 12 of different materials, after completing the load test of the elastic ring cutter 12 of the same material, the components in the consolidation test assembly 1 can be taken out, the elastic ring cutter 12 outside the soil sample 11 to be tested can be replaced, and steps 1 to 4 can be repeated to obtain the settlement of the soil sample 11 to be tested under the elastic ring cutters 12 of different materials, so as to provide an accurate and reliable analysis basis for the subsequent comparative analysis of the compression deformation characteristics of the soil samples under the elastic ring cutters 12 of various materials.

[0045] In step 2, installing the soil loading component 2 specifically includes the following steps: According to the different pressure levels of the soil sample 11 to be tested, the loading weight of the soil sample 11 to be tested is determined according to the following formula: in, is the loading weight of the soil sample 11 to be tested, is the pressure level load required for the soil sample 11 to be tested, is the cross-sectional area of ​​the soil sample 1 to be tested, is the acceleration due to gravity.

[0046] The lever ratio of the lever structure is determined according to the maximum loading weight of the soil sample 11 to be tested under different pressure levels and the weight added to the pressurized weight 24. For example, if the maximum loading weight of the soil sample 11 to be tested is 600 kg, the lever ratio is set to 1:10, and the weight added to the pressurized weight 24 after conversion is 60 kg. If the weight added is too heavy and difficult to achieve, the lever ratio is adjusted to 1:30. At this time, the weight added to the pressurized weight 24 is 20 kg, which is easy to achieve. At this time, the lever ratio can be set to 1:30.

[0047] The installation positions of the balance beam mounting member 22, the soil sample loading rod 23 and the pressurized weight 24 on the load balance beam 21 are determined according to the lever ratio. Specifically, the lever ratio can be adjusted by adjusting the distance between the soil sample loading rod 23 and the balance beam mounting member 22 and the pressurized weight 24.

[0048] When installing the balance beam mounting member 22 , the soil sample loading rod 23 and the pressurized weight 24 , place the pressurized weight 24 of the initial weight, and level the loaded balance beam 21 through the balance weight 25 to facilitate the subsequent loading of the pressurized weight 24 .

[0049] Furthermore, the weight of the pressure weight 24 is adjusted to apply a pre-pressure (e.g., a pre-pressure of 1 kPa) to the soil sample 11 to be tested, so that adjacent components in the consolidation test assembly 1 are in full contact, thereby ensuring that pressure can be transmitted between components during the test and ensuring the integrity of the experimental data. Afterwards, the digital displacement meter 31 is adjusted to zero to facilitate recording the height deformation of the soil sample 11 to be tested after compression.

[0050] Afterwards, the pressurizing weights 24 are adjusted to the required weights in sequence, so as to load the required pressure levels to the soil sample 11 through the soil sample loading rod 23. In this embodiment, the pressure level load required for the soil sample 11 to be tested can be adjusted by changing the number and weight of the pressurizing weights 24.

[0051] After the same pressure level load is loaded, the deformation data of the soil sample 11 to be tested in the loading direction and the diameter data in the radial direction under different pressure levels are recorded, so as to obtain the height deformation and radial radius of the soil sample 11 to be tested after lateral deformation under different pressure levels. Preferably, the data is read once every 24 hours after each level of load is loaded, or when the change of the dial indicator reading is not greater than 0.01mm within 1 hour, it is determined that the loading has reached a stable state, and the next level of loading can be carried out until the last level of loading is completed.

[0052] Furthermore, the radial diameter data of the soil sample 11 to be tested is recorded to obtain the radial radius of the soil sample 11 to be tested after lateral deformation, which specifically includes the steps of: measuring the diameter data of the soil sample 11 to be tested at different heights, and measuring the diameter data of the soil sample 11 to be tested at the same height and in different circumferential directions, taking the average value of the diameter data of the soil sample 11 to be tested at the same height and in different circumferential directions as the average diameter of the soil sample 11 to be tested at the same height, and taking the average value of the average diameters of the soil sample 11 to be tested at different heights as the radial average diameter of the soil sample 11 to be tested, thereby obtaining the radial radius of the soil sample 11 to be tested after lateral deformation.

[0053] Assuming that the soil sample 11 to be tested is uniform and isotropic during the compression process, and the deformation of the soil sample 11 to be tested is also uniform under the upper load, the average diameter at the same height and in different circumferential directions of the soil sample 11 to be tested is obtained, and the radial radius of the soil sample 11 to be tested after lateral deformation is obtained according to the average value of the average diameters at different heights, so as to reflect the actual radial deformation of the soil sample 11 to be tested during lateral deformation, thereby providing real and accurate data for subsequent parameter calculations.

[0054] Preferably, a vernier caliper is used to measure the diameter data three times at the same height and different circumferential positions of the soil sample 11 to be tested. The purpose of measuring three times at the same height is to obtain the average diameter of the soil sample 11 to be tested at this height to reduce errors. The time interval between the three tests can be considered to be completed within one minute. Afterwards, the height is changed and the operation and diameter measurement are repeated. If the height of the elastic ring knife 12 is 100mm, the diameter data can be measured at intervals of 10mm in the height direction, that is, the average diameter of 10 heights is measured, and the average diameter at each height is different. The average of the average diameters at 10 different heights is calculated as the radial average diameter of the soil sample 11 to be tested at this load level. The soil sample 11 to be tested of the present invention is deformed into a "drum shape" during the experiment. The present invention divides it into several regular objects to calculate the average value, which more truly reflects the radial deformation of the soil sample 11 to be tested.

[0055] Step 3, according to the height deformation and radial radius of the soil sample 11 under different pressure levels, calculate the porosity of the soil sample 11 under different pressure levels, including: constructing a porosity calculation model for the soil sample 11 under different pressure levels, wherein the porosity calculation model is: The volume change of the soil sample 11 to be tested in the elastic ring cutter 12 is deduced. First, the soil sample 11 to be tested occupies the entire internal volume of the elastic ring cutter 12 before loading. At this time, according to the parameters of the soil sample 11 to be tested, it is assumed that the volume of the soil particles is , since soil particles cannot be compressed after loading, the volume of soil particles remains unchanged after the elastic ring cutter 12 undergoes lateral deformation. Based on the assumption that the total volume of soil particles of the soil sample 11 to be tested remains unchanged during compression, the porosity of the soil sample 11 to be tested under lateral deformation conditions can be derived. That is, the formula for calculating the volume of soil particles changes before and after loading, but the two are equal. After that, the above-mentioned equal formula is changed to obtain the height of the soil sample 11 to be tested after compression. The height deformation of the soil sample 11 to be tested can be directly measured through step 2, as shown in formula (6). At this time, the unknown number in the formula (porosity ratio after compression) can be calculated. The specific process is as follows: First, assuming that the total volume of soil particles in the soil sample 11 to be tested is 1, the total volume of soil particles in the soil sample 11 to be tested before compression is: (1) in, is the total volume of soil particles of the soil sample 11 before compression, is the height of the soil sample 11 before compression, The soil sample 11 to be tested is in the previous level The porosity ratio after lateral deformation and compression under load, The soil sample 11 to be tested is in the previous level The radial radius after lateral deformation under load.

[0056] At the same time, the total volume of soil particles of the soil sample 11 to be tested after compression is: (2) in, is the total volume of soil particles of the soil sample 11 to be tested after compression, is the height of the soil sample 11 after compression, The soil sample 11 to be tested is The porosity ratio after lateral deformation and compression under load, The soil sample 11 to be tested is The radial radius after lateral deformation under load.

[0057] In this embodiment, based on the assumption that the total volume of soil particles of the soil sample 11 to be tested remains unchanged during the compression process, the following is true: (3) From the above formula (3), the height formula of the soil sample 11 after compression can be obtained: (4) At the same time, since the loading process in step 2 can directly measure the height deformation of the soil sample 11 after lateral deformation, , the soil sample 11 to be tested is in the previous level Radius after lateral deformation under load , and the soil sample 11 to be tested is currently Radius after lateral deformation under load , therefore, we can get: (5) After changing the above formula (5), we can get the current The void ratio after lateral deformation and compression under load: (6) The porosity ratio of the soil sample 11 to be tested after lateral deformation and compression can be quickly and accurately calculated by the above formula (6), that is, the porosity ratio of the soil sample 11 to be tested after lateral deformation and compression can be quickly and accurately calculated according to the height deformation and radial radius of the soil sample 11 to be tested after lateral deformation and compression. The porosity ratio of the soil sample 11 to be tested can be used to calculate the deformation parameters of the soil under different pressure level loads (the compression modulus of the soil sample 11 to be tested after lateral deformation), thereby providing a basis for obtaining the settlement of the soil under a three-dimensional stress state close to the actual situation. At the same time, when elastic ring cutters 12 of different materials are used, the porosity ratio of the soil sample 11 to be tested after lateral deformation and compression under different constraint conditions can be measured, thereby providing a basis for accurately comparing the settlement of elastic ring cutters 12 of different materials.

[0058] In step 4, the compression modulus of lateral deformation of the soil sample 11 under different pressure levels is calculated according to the radial radius and the porosity after compression of the soil sample 11 under different pressure levels, and the parameters of the soil sample 11 under full confinement. The corresponding compression modulus is selected according to the actual pressure level load of the soil body, and the settlement of the soil body under a three-dimensional stress state is calculated. The parameters of the soil sample 11 under full confinement include the compression modulus of the soil sample 11 under full confinement or the height deformation of the soil sample 11 under full confinement. Specifically: By constructing the compression modulus of the soil sample 11 to be tested under the lateral deformation condition under the current level load, the compression modulus of the soil sample 11 to be tested under the lateral deformation condition under the current level load can be quickly and accurately calculated, thereby calculating the settlement of the soil body under the three-dimensional stress state. This embodiment first analyzes the construction principle of the compression modulus of the soil sample 11 to be tested under lateral deformation: From the above formula (5), it can be known that the height deformation of the soil sample 11 to be tested after lateral deformation is: (7) When the soil body is lateral deformed, after the total volume of soil particles in the soil sample 11 to be tested is deformed, the deformation volume of the soil particles in the loading direction is: (8) in, is the deformation volume of soil particles in the loading direction, is the height deformation of soil particles, The soil sample to be tested is in the previous level The radial radius after lateral deformation under load.

[0059] The lateral deformation volume of soil particles is: (9) in, is the lateral deformation volume of soil particles, The soil sample to be tested is The radial radius after lateral deformation under load.

[0060] According to the principle that the total volume of soil particles remains unchanged, the lateral deformation volume of soil particles due to movement is equal to the deformation volume of soil particles in the loading direction: (10) Derived from formula (10) and combined with formula (4), we can get: (11) After transforming equation (7), it can be constructed into a formula containing equation (11), so as to conveniently and intuitively see the height deformation of the soil sample 11 after lateral deformation. Specifically: (12) Substituting equation (11) into equation (12), we can obtain the height deformation of the soil sample 11 after lateral deformation: Deformation of soil particles Relationship: (13) From formula (13), it can be seen that the height deformation of the soil sample 11 after lateral deformation is The deformation caused by the exhaust of water and air from the soil sample 11 to be tested ( ), the height deformation caused by the lateral movement of soil particles in the soil sample 11 to be tested ( ), and the deformation caused by the change in porosity during the lateral deformation of soil particles in the soil sample 11 to be tested ( ), so that the height deformation of the soil sample 11 to be tested after lateral deformation can be easily and intuitively seen composition.

[0061] The soil sample 11 to be tested will not undergo lateral deformation under the condition of complete lateral confinement. The calculation formula for the height deformation of the soil sample 11 to be tested under the condition of complete lateral confinement is: (14) is the height deformation of the soil sample 11 under full confinement conditions, The soil sample 11 to be tested is in the previous level under the fully confined condition. The void ratio under load, The soil sample 11 to be tested is under full confinement conditions at the current Void ratio under load.

[0062] By comparing equation (14) and equation (13), it can be found that the height deformation of the soil sample 11 after lateral deformation is The height deformation of the soil sample 11 under full confinement condition The difference between the two lies in the height deformation caused by the lateral movement deformation of the soil particles in the soil sample 11 to be tested and the deformation caused by the change of the porosity ratio during the lateral deformation of the soil particles in the soil sample 11 to be tested.

[0063] The calculation formula of the compression modulus of the soil sample 11 under full confinement conditions is: (15) in, is the compression modulus of the soil sample 11 under full confinement conditions, is the change in porosity of the soil sample 11 under full confinement conditions, is the load increment of the soil sample 11 before and after compression.

[0064] Referring to formula (15), the compression modulus of the lateral deformation of the soil sample 11 can be obtained: The calculation formula is: (16) Substituting formula (13) into formula (16), we can obtain: (17) According to the above formula (17), the compression modulus of lateral deformation of the soil sample 11 under different pressure levels can be quickly and accurately calculated.

[0065] Afterwards, the corresponding compression modulus is selected according to the actual pressure level load of the soil. The settlement of the soil under three-dimensional stress state can be accurately calculated using the layered summation method relationship of the following formula (18) based on the compression modulus. Specifically: (18) in, is the settlement value of soil under three-dimensional stress state, For the soil The load increment of the soil sample 11 to be tested, For soil The compression modulus of the soil sample 11 to be tested, For soil The thickness of the soil sample 11 to be tested, is the number of vertical layers of soil, The vertical direction of soil layer.

[0066] In formula (18), the soil Compression modulus of soil sample 11 Corresponding to the above formula (17) The compression modulus of the lateral deformation of the soil sample 11 to be tested In this embodiment, the soil is divided into The compression modulus of each layer of soil sample 11 to be tested when the lateral deformation occurs Formula (17) is used to obtain the compression modulus of the lateral deformation of the soil sample 11 to be tested: Substituting formula (18) into formula (18) to obtain the settlement of soil under three-dimensional stress state, the obtained settlement is closer to the actual value than the settlement obtained by the existing settlement calculation method, thereby ensuring that the engineering and design based on experimental parameters can accurately reflect the real mechanical behavior of the soil and ensure the certainty and safety of engineering construction.

[0067] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A testing device for measuring soil deformation characteristics, characterized in that: It includes a consolidation experiment component and a soil loading component, the soil loading component includes a loading balance beam, a balance beam mounting member arranged on the loading balance beam, a soil sample loading rod, a pressurized weight and a balancing weight, the soil sample loading rod is located between the balance beam mounting member and the pressurized weight to form a lever structure with the balance beam mounting member as a fulcrum; the balancing weight is arranged at one end of the loading balance beam away from the pressurized weight; the consolidation experiment component includes a soil sample to be tested and an elastic ring knife that causes the soil sample to be tested to deform laterally when pressurized, the elastic ring knife is wrapped around the outside of the soil sample to be tested, and the bottom end of the soil sample loading rod presses the soil sample to be tested.

2. The testing device for measuring soil deformation characteristics according to claim 1, characterized in that: The loading balance beam is evenly provided with lever ratio adjustment holes along the length direction, and the number of the lever ratio adjustment holes is directly proportional to the lever ratio; the soil sample loading rod is installed in the lever ratio adjustment hole corresponding to the balance beam mounting part and the pressurizing weight according to the required lever ratio to form the lever structure with different lever ratios and different levels of loading loads.

3. The testing device for measuring soil deformation characteristics according to claim 1, characterized in that: The connecting end of the soil sample loading rod is rotatably mounted on the loading balance beam, and the loading end of the soil sample loading rod is pre-pressed against the top of the consolidation test assembly by the pre-pressing force of the pressurized weight before the soil sample to be tested is loaded.

4. The testing device for measuring soil deformation characteristics according to any one of claims 1 to 3, characterized in that: It also includes a displacement detection component for measuring the deformation of the soil sample to be tested in the loading direction and radial direction after loading. The displacement detection component includes a digital displacement meter and a vernier caliper. The digital displacement meter is fixedly arranged, and the detection end is pressed against the top of the soil sample to be tested; the vernier caliper is used to measure the diameter of the soil sample to be tested at different heights and different circumferential positions.

5. The testing device for measuring soil deformation characteristics according to any one of claims 1 to 3, characterized in that: The consolidation experiment assembly also includes a consolidation container, a pressure plate arranged on the consolidation container, an upper water-permeable layer and a lower water-permeable layer. The soil sample to be tested is pressed between the upper water-permeable layer and the lower water-permeable layer, and the pressure plate is evenly pressed on the top of the upper water-permeable layer through the soil sample loading rod; anti-blocking filter paper is arranged between the soil sample to be tested and the upper water-permeable layer and the lower water-permeable layer to prevent soil particles of the soil sample to be tested from blocking the water-permeable layer when compressed.

6. A testing method using the testing device according to any one of claims 1 to 5, characterized in that: The steps include: Step 1, prepare a soil sample to be tested, wrap an elastic ring knife of the material to be tested around the soil sample to be tested, and assemble it in a consolidation test assembly; Step 2, installing the soil loading assembly, loading the different pressure levels required for the test onto the soil sample to be tested in the consolidation test assembly, recording the deformation data of the soil sample to be tested in the loading direction and the diameter data in the radial direction under the different pressure levels, and obtaining the height deformation and radial radius of the soil sample to be tested after lateral deformation under the different pressure levels; Step 3, calculating the porosity of the soil sample to be tested after lateral deformation and compression under different pressure levels of loads according to the height deformation and radial radius of the soil sample to be tested under different pressure levels of loads; Step 4, according to the radial radius and the porosity after compression of the soil sample to be tested under different pressure level loads, and the parameters of the soil sample to be tested under the full lateral confinement condition, calculate the compression modulus of the lateral deformation of the soil sample to be tested under different pressure level loads, select the corresponding compression modulus according to the actual pressure level load of the soil body, and calculate the settlement of the soil body under a three-dimensional stress state. The parameters of the soil sample to be tested under the full lateral confinement condition include the compression modulus of the soil sample to be tested under the full lateral confinement condition or the height deformation of the soil sample to be tested under the full lateral confinement condition.

7. The testing method according to claim 6, characterized in that: In step 4, the compression modulus of the soil sample to be tested that undergoes lateral deformation is calculated according to the following formula: in, is the compression modulus of the lateral deformation of the soil sample under the current load level, is the load increment of the soil sample before and after compression, The soil sample to be tested is in the previous level The porosity ratio after lateral deformation and compression under load, The soil sample to be tested is The porosity ratio after lateral deformation and compression under load, The soil sample to be tested is in the previous level Height under load, The soil sample to be tested is in the previous level Radius after lateral deformation under load, The soil sample to be tested is The radial radius after lateral deformation under load.

8. The testing method according to claim 6, characterized in that: In step 3, the porosity ratio of the soil sample to be tested after lateral deformation and compression is calculated according to the following formula: in, is the porosity ratio of the soil sample after lateral deformation and compression. The soil sample to be tested is in the previous level Height under load, is the height deformation of the soil sample to be tested, The soil sample to be tested is in the previous level The porosity ratio after lateral deformation and compression under load, The soil sample to be tested undergoes lateral deformation in the previous stage. Radius under load, The soil sample to be tested is The radial radius after lateral deformation under load.

9. The testing method according to claim 6, characterized in that: In step 2, installing the soil loading assembly includes the following steps: determining the loading weight of the soil sample to be tested according to the different pressure levels of loads required to be tested on the soil sample to be tested, and determining the lever ratio of the lever structure according to the maximum loading weight of the soil sample to be tested under different pressure levels; determining the installation positions of the balance beam mounting, the soil sample loading rod and the pressure weight on the loading balance beam according to the lever ratio; when installing the balance beam mounting, the soil sample loading rod and the pressure weight, placing the pressure weight of the initial weight, and leveling the loading balance beam by the balance weight; adjusting the weight of the pressure weight, applying pre-pressure to the soil sample to be tested, so that adjacent components in the consolidation experiment assembly are in full contact; adjusting the pressure weight to the required weight in sequence, so as to load the different pressure levels required to be tested to the soil sample to be tested through the soil sample loading rod.

10. The testing method according to claim 9, characterized in that: In step 2, the diameter data of the soil sample to be tested in the radial direction is recorded to obtain the radial radius of the soil sample to be tested after lateral deformation, including: measuring the diameter data of the soil sample to be tested at different heights, and measuring the diameter data of the soil sample to be tested at the same height and in different circumferential directions, taking the average value of the diameter data of the soil sample to be tested at the same height and in different circumferential directions as the average diameter of the soil sample to be tested at the same height, and taking the average value of the average diameters of the soil sample to be tested at different heights as the radial diameter of the soil sample to be tested, thereby obtaining the radial radius of the soil sample to be tested after lateral deformation.

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