A testing device and testing method for measuring the deformation characteristics of soil mass

Abstract

The present invention provides a test device and a test method for measuring the deformation characteristics of soil masses. The test device includes a consolidation experiment component and a soil mass loading component. The soil mass loading component includes a loading balance beam, a balance beam mounting member, a soil sample loading rod, a pressure weight, and a balance weight. The test method includes: preparing a soil sample to be tested, wrapping an elastic ring cutter of the material to be tested around the soil sample to be tested and assembling it in the consolidation experiment component; installing the soil mass loading component, applying different pressure-level loads required for testing to the soil sample to be tested, and obtaining the height deformation amount and radial radius after lateral deformation of the soil sample to be tested under different pressure-level loads; calculating the void ratio of the soil sample to be tested after lateral deformation and compression under different pressure-level loads; and calculating the settlement amount of the soil mass in a three-dimensional stress state according to the radial radius, the compressed void ratio, and the parameters of the soil sample to be tested under the condition of complete lateral confinement. The present invention has the advantages of truly simulating the stress state of the soil mass and being able to obtain the true compression deformation parameters of the soil mass, etc.

Description

Technical Field

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

[0002] In the field of geotechnical engineering, the study of the consolidation characteristics of soil is of crucial 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 gradually drains out, the excess pore water pressure dissipates over time, and the effective stress in the soil increases correspondingly until the excess pore water pressure completely disappears. During this process, the soil will inevitably undergo compressive deformation, and accurately measuring the compression performance parameters of the soil is of decisive significance for the design, construction, and stability evaluation of construction projects such as building foundation treatment, road embankment filling, and dam projects.

[0003] To measure the compression performance parameters of soil, the existing method is to use a consolidometer 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 gradually increasing the pressure in the loading direction. In the existing experimental mode, the soil is forced to be in a one-dimensional deformation state. Specifically: The design principle of the consolidometer is based on Terzaghi's one-dimensional consolidation theory, and a rigid ring cutter is used to impose lateral restraint on the soil sample. Although its lateral confinement conditions theoretically meet the requirements of the one-dimensional compression hypothesis, the rigid ring cutter completely inhibits the development of the lateral strain of the soil sample during the test, making the soil only able to produce vertical compressive deformation. This idealized boundary condition is fundamentally different from the actual three-dimensional stress state of the soil in the engineering field.

[0004] The soil in actual engineering is in a natural environment, and the stress and deformation of the soil are three-dimensional. There are differences between the existing experimental devices and the actual situation. The excessive restraint of the test conditions leads to the key parameters such as the compression modulus and consolidation coefficient obtained being unable to truly reflect the deformation response of the soil under complex stress paths. This directly results in a significant deviation between the deformation parameters measured by the traditional one-dimensional consolidation compression experiment 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, thereby affecting the settlement calculation accuracy and engineering safety evaluation, and increasing the risks and uncertainties of engineering construction. For example, in the design of building foundations, if the design is based on inaccurate compression parameters, it may lead to uneven settlement of the building during use, affecting the safety and normal use functions 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 provide a test device and a test method for measuring the deformation characteristics of soil, which can apply different levels of loads to the soil sample to be tested, truly simulate the stress state of the soil, and obtain the true compression deformation parameters of the soil.

[0006] To solve the above technical problems, the technical solution proposed by the present invention is as follows:

[0007] A test device for measuring the deformation characteristics of soil includes a consolidation experiment component and a soil loading component. The soil loading component includes a loading balance beam, a balance beam mounting member provided on the loading balance beam, a soil sample loading rod, a pressure weight, and a balance weight. The soil sample loading rod is located between the balance beam mounting member and the pressure weight to form a lever structure with the balance beam mounting member as the fulcrum; the balance weight is provided at one end of the loading balance beam away from the pressure weight; the consolidation experiment component includes a soil sample to be tested and an elastic ring cutter for causing the lateral deformation of the soil sample to be tested during ballasting. The elastic ring cutter is wrapped outside the soil sample to be tested, and the bottom end of the soil sample loading rod presses tightly against the soil sample to be tested.

[0008] As a further improvement of the above technical solution:

[0009] The loading balance beam is uniformly provided with lever ratio adjustment holes along the length direction, and the number of the lever ratio adjustment holes is in a proportional relationship with the lever ratio; the soil sample loading rod is installed in the corresponding lever ratio adjustment hole between the balance beam mounting member and the pressure weight according to the required lever ratio to form the lever structure with different lever ratios and different levels of loading loads.

[0010] The connecting end of the soil sample loading rod is rotatably installed on the loading balance beam, and the loading end of the soil sample loading rod is pre-pressed tightly against the top end of the consolidation experiment component by the pre-pressing force of the pressure weight before the soil sample to be tested is loaded.

[0011] It further includes a displacement detection component for measuring the deformation amounts of the soil sample to be tested in the loading direction and the radial direction after loading. The displacement detection component includes a digital display displacement meter and a vernier caliper. The digital display displacement meter is fixedly arranged, and the detection end is pressed tightly against the top end of the soil sample to be tested; the vernier caliper is used to measure the diameters of the soil sample to be tested at different heights and different circumferential positions.

[0012] The consolidation experiment component further includes a consolidation container, a pressure plate provided on the consolidation container, an upper permeable layer, and a lower permeable layer. The soil sample to be tested is pressed tightly between the upper permeable layer and the lower permeable layer, and the pressure plate is uniformly pressed tightly against the top end of the upper permeable layer through the soil sample loading rod; an anti-blocking filter paper for preventing the soil particles of the soil sample to be tested from blocking the permeable layer during compression is provided between the soil sample to be tested and the upper permeable layer and the lower permeable layer.

[0013] A test method using the above test device includes the following steps:

[0014] Step 1: Prepare the soil sample to be tested. Wrap the elastic ring cutter of the material to be tested around the soil sample to be tested and assemble it into the consolidation test component;

[0015] Step 2: Install the soil loading component. Apply different pressure level loads required for testing to the soil sample to be tested in the consolidation test component, record the deformation data of the soil sample to be tested in the loading direction and the diameter data in the radial direction under different pressure level loads, and obtain the height deformation amount and radial radius of the soil sample to be tested after lateral deformation under different pressure level loads;

[0016] Step 3: Calculate the void ratio of the soil sample to be tested after lateral deformation compression under different pressure level loads according to the height deformation amount and radial radius of the soil sample to be tested under different pressure level loads;

[0017] Step 4: Calculate the compression modulus of the soil sample to be tested during lateral deformation according to the radial radius and the compressed void ratio of the soil sample to be tested under different pressure level loads, and the parameters of the soil sample to be tested under the condition of complete lateral confinement. Select the corresponding compression modulus according to the actual pressure level load of the soil, and calculate the settlement amount of the soil under the three-dimensional stress state. The parameters of the soil sample to be tested under the condition of complete lateral confinement include the compression modulus of the soil sample to be tested under the condition of complete lateral confinement or the height deformation amount of the soil sample to be tested under the condition of complete lateral confinement.

[0018] As a further improvement of the above technical solution:

[0019] In Step 4, calculate the compression modulus of the soil sample to be tested during lateral deformation according to the following formula:

[0020]

[0021] Where, is the compression modulus of the soil sample to be tested during lateral deformation under the current level of load, is the load increment of the soil sample to be tested before and after compression, is the void ratio of the soil sample to be tested after lateral deformation compression under the previous level of load, is the void ratio of the soil sample to be tested after lateral deformation compression under the current load, is the height of the soil sample to be tested under the previous level of load, is the radial radius of the soil sample to be tested after lateral deformation under the previous level of load, is the radial radius of the soil sample to be tested after lateral deformation under the current load.

[0022] In Step 3, calculate the void ratio of the soil sample to be tested after lateral deformation compression according to the following formula:

[0023]

[0024] Among them, is the void ratio after lateral deformation and compression of the soil sample to be tested, is the height of the soil sample to be tested under the previous load, is the height deformation of the soil sample to be tested, is the void ratio after lateral deformation and compression of the soil sample to be tested under the previous load, is the radial radius of the soil sample to be tested under the previous load after lateral deformation, is the radial radius of the soil sample to be tested after lateral deformation under the current load.

[0025] In step 2, installing the soil loading component includes the following steps: determining the loading weight of the soil sample to be tested according to the different pressure-level loads required for testing 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-level loads; determining the installation positions of the balance beam mounting member, 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 member, the soil sample loading rod, and the pressure weight, placing the pressure weight with the initial weight and leveling the loading balance beam by adjusting the balance weight; adjusting the weight of the pressure weight to apply a pre-pressure to the soil sample to be tested so that the adjacent components in the consolidation experiment component are in full contact; sequentially adjusting the pressure weight to the required additional weight to apply the different pressure-level loads required for testing to the soil sample to be tested through the soil sample loading rod.

[0026] In step 2, recording the diameter data of the soil sample to be tested in the radial direction and obtaining the radial radius of the soil sample to be tested after lateral deformation includes: 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 different circumferences, taking the average value of the diameter data of the soil sample to be tested at the same height and different circumferences 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, so as to obtain the radial radius of the soil sample to be tested after lateral deformation.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] 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 member and the pressure weight to form a lever structure with the balance beam mounting member as the fulcrum. At this time, the ratio of the distance from the soil sample loading rod to the balance beam mounting member to the distance from the pressure weight to the balance beam mounting member is the lever ratio of the lever structure, so that by changing the position of the soil sample loading rod between the balance beam mounting member and the pressure weight, the adjustment of different lever ratios can be realized. It has a wide adaptability range, which is convenient for loading different levels of loads on the soil sample to be tested, and its structure is simple and compact, occupying a small space.

[0029] At the same time, the consolidation experiment component wraps an elastic ring cutter around the soil sample to be tested, so that the soil sample to be tested can have lateral deformation when the soil sample loading rod is under pressure, reflecting the lateral deformation characteristics under the true stress state of the soil body, thereby truly simulating the three-dimensional stress state of the soil body during loading, providing a basis for obtaining soil deformation parameters highly consistent with the actual situation.

[0030] The test method of the present invention also has the above advantages of the test device, and the test method of the present invention constructs the compression modulus of the soil sample to be tested under the condition of lateral deformation, so that the compression deformation parameters (compression modulus) of the soil sample to be tested under the condition of lateral deformation can be quickly and accurately calculated to calculate the settlement amount of the soil body under the three-dimensional stress state. The settlement amount obtained by the present invention is closer to the actual value than the settlement amount obtained by the existing settlement calculation method.

[0031] It can be seen that the present invention fills the technical gap that the one-dimensional consolidation experiment results cannot reflect the three-dimensional soil body deformation. It can accurately simulate the actual three-dimensional stress and deformation environment of the soil body, accurately reflect the lateral deformation characteristics of the soil body, and at the same time can obtain soil compression deformation parameters highly consistent with the actual situation, providing accurate values for the subsequent prediction of the settlement amount, so as to ensure that the engineering and design based on the experimental parameters can accurately reflect the true mechanical behavior of the soil body and ensure the certainty and safety of the engineering construction. Description of the Drawings

[0032] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings. Among them:

[0033] Figure 1 is a schematic structural diagram of the test device for measuring the deformation characteristics of the soil body of the present invention;

[0034] Figure 2 is a front view of the test device for measuring the deformation characteristics of the soil body of the present invention;

[0035] Figure 3 is a left view of the test device for measuring the deformation characteristics of the soil body of the present invention;

[0036] Figure 4It is the top view of the test device for measuring the deformation characteristics of soil mass in the present invention;

[0037] Figure 5 It is the structural schematic diagram of the consolidation experiment component of the present invention;

[0038] Figure 6 It is the flow chart of the test method of the present invention.

[0039] Each label in the figure represents:

[0040] 1. Consolidation experiment component; 11. Soil sample to be measured; 12. Elastic cutting ring; 13. Consolidation container; 14. Pressing plate; 15. Upper permeable layer; 16. Lower permeable layer; 17. Cutting ring positioning groove; 2. Soil mass loading component; 21. Loading balance beam; 211. Lever ratio adjustment hole; 22. Balance beam mounting member; 221. Vertical mounting rod; 222. Mounting cross beam; 23. Soil sample loading rod; 231. Loading rod mounting cross bar; 24. Pressing weight; 25. Balance weight; 3. Displacement detection component; 31. Digital display displacement meter; 4. Mounting base. Specific embodiments

[0041] The present invention will be further described in detail below in conjunction with the specification drawings and specific embodiments, but the protection scope of the present invention is not limited thereby.

[0042] Figures 1 to 5 An embodiment of the test device for measuring the deformation characteristics of soil mass in the present invention is shown. The test device includes a consolidation experiment component 1 and a soil mass loading component 2. Among them, the soil mass loading component 2 includes a loading balance beam 21, a balance beam mounting member 22 provided on the loading balance beam 21, a soil sample loading rod 23, a pressing weight 24 and a balance weight 25. Among them, the soil sample loading rod 23 is located between the balance beam mounting member 22 and the pressing weight 24 to form a lever structure with the balance beam mounting member 22 as the fulcrum. The pressing weight 24 applies pressure to the soil sample 11 to be measured of the consolidation experiment component 1 through the soil sample loading rod 23, and the balance beam mounting member 22 mounts the loading balance beam 21. The balance weight 25 is provided at one end of the loading balance beam 21 far from the pressing weight 24 to level the loading balance beam 21 through the balance 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, ensuring the reliable and safe progress of subsequent loading.

[0043] The test device of the present invention is provided with a consolidation experiment 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 member 22 and the pressure weight 24 to form a lever structure with the balance beam mounting member 22 as the fulcrum. At this time, the ratio of the distance from the pressure weight 24 to the balance beam mounting member 22 and the distance from the soil sample loading rod 23 to the balance beam mounting member 22 is the lever ratio of the lever structure, so that by changing the position of the soil sample loading rod 23 between the balance beam mounting member 22 and the pressure weight 24, the adjustment of different lever ratios can be realized, so as to facilitate the loading of different grades of loads on the soil sample to be tested. It has a wide adaptation range, and its structure is simple and compact, occupying a small space.

[0044] At the same time, the consolidation experiment component 1 includes a soil sample to be tested 11 and an elastic cutter ring 12, and the elastic cutter ring 12 is wrapped outside the soil sample to be tested 11; the bottom end of the soil sample loading rod 23 presses tightly on the soil sample to be tested 11. The elastic cutter ring 12 enables the soil sample to be tested 11 to have lateral deformation when the soil sample loading rod 23 is under pressure, so as to reflect the lateral deformation characteristics of the soil body under the true stress state, and avoid the problem that the diameter of the existing cutter ring is fixed and the soil sample to be tested 11 cannot have lateral deformation, providing a basis for obtaining soil deformation parameters that highly match the actual situation.

[0045] In this embodiment, the elastic cutter ring 12 can be made of materials such as rubber, PVC, aluminum, and steel. Elastic cutter rings 12 of different materials can provide different lateral constraints to the soil sample to be tested 11 during loading, so as to change the lateral constraint conditions of the cutter ring and make the soil sample to be tested 11 have different lateral deformations, reflecting the influence of the lateral deformation of the elastic cutter ring 12 on the deformation parameters of the soil sample to be tested 11. Preferably, the elastic modulus interval between elastic cutter rings of different materials is 1 to 10 GPa to better study the differences in soil settlement values under different elastic cutter rings. In other embodiments, the material of the cutter ring can also be other materials, as long as it can reflect the lateral deformation of the soil sample to be tested 11 under load pressure, it should be within the protection scope of the present invention.

[0046] Furthermore, the loading balance beam 21 is uniformly provided with lever ratio adjustment holes 211 along the length direction. The number of lever ratio adjustment holes 211 provided is in a proportional relationship with the lever ratio. The soil sample loading rod 23 is installed in the corresponding lever ratio adjustment hole 211 between the beam body mounting rod and the pressure weight 2 according to the required lever ratio to form a lever structure with different lever ratios and different grades of loading loads, so as to facilitate the loading of different load grades on the soil sample to be tested 11, and it has a wide range of uses. In this embodiment, the specific selection of the lever ratio is set according to the load grade. For example, when the maximum weight of the required pressure weight 24 does not exceed 100 kg, a small lever ratio (such as 5:1) can be selected; when the maximum weight of the required pressure weight 24 exceeds 100 kg, a large lever ratio (such as 10:1 or 20:1) can be selected.

[0047] In this embodiment, the number of the lever ratio adjustment holes 211 is set according to the required lever ratio. If a small lever ratio is needed, the number of the lever ratio adjustment holes 211 can be correspondingly reduced; if a large lever ratio is needed, the number of the lever ratio adjustment holes 211 can be correspondingly increased. At the same time, the interval between adjacent lever ratio adjustment holes 211 is the length of the loading balance beam 21 divided by the number of the lever ratio adjustment holes 211 minus one.

[0048] Exemplarily, as Figure 1 and Figure 2 shown, the number of the lever ratio adjustment holes 211 of the loading balance beam 21 is 13, and the determination basis for the interval between adjacent lever ratio adjustment holes 211 is the length of the loading balance beam 21 divided by 12. The loading balance beam 21 is numbered from 1 to 13 from left to right. Among them, the No. 3 hole connects the loading balance beam 21 and the balance beam mounting member 22, the No. 4 hole connects the soil sample loading rod 23, and the No. 13 hole connects the pressure weight 24. At this time, the lever ratio is 10:1. When the soil sample loading rod 23 is placed at other hole positions, the change of the lever ratio can be realized. For example, when the soil sample loading rod 23 is at the No. 5 hole and the pressure weight 24 is at the No. 13 hole, the lever ratio is 5:1.

[0049] 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 measured will be compressed, the height of the soil sample 11 to be measured is gradually decreasing, and the loading balance beam 21 is also descending. The soil sample loading rod 23 is rotationally arranged so that the soil sample 11 to be measured is uniformly stressed. The loading end of the soil sample loading rod 23 is pre-pressed against the top of the consolidation experiment assembly 1 by the pre-pressure force of the pressure weight 24 before the soil sample 11 to be measured is loaded, and the pre-pressure can ensure that all components of the consolidation experiment assembly 1 are in full contact.

[0050] In this embodiment, the testing device further includes a displacement detection assembly 3. The displacement detection assembly 3 includes a digital display displacement meter 31 and a vernier caliper. The digital display displacement meter 31 is fixedly arranged, and the detection end of the digital display displacement meter 31 is pressed against the top of the soil sample 11 to be measured through the pressure plate 14, and is used for measuring the change amount of the soil sample 11 to be measured in the loading direction after loading deformation, so as to obtain the accurate height deformation amount of the soil sample 11 to be measured after lateral deformation under different load levels; the vernier caliper is used for measuring the diameters of the soil sample 11 to be measured at different heights and different circumferential positions after loading deformation, so as to accurately obtain the radial radius of the soil sample 11 to be measured after lateral deformation under different pressure level loads. In other embodiments, the digital display displacement meter 31 and the vernier caliper can also adopt detection components such as displacement sensors to detect displacement changes.

[0051] Preferably, the digital display displacement gauge 31 is fixed to the beam mounting rod using its built-in magnetic universal base. In other embodiments, the fixed position of the digital display displacement gauge 31 can be any position as long as it ensures that the displacement gauge reading is only affected by the compression of the soil sample. For example, the digital display displacement gauge 31 can also be installed on the ground or the mounting base 4 through a magnetic universal base.

[0052] Furthermore, as Figure 5 shown, the consolidation test assembly 1 further includes a consolidation container 13, a pressure plate 14 provided in the consolidation container 13, an upper permeable layer 15, and a lower permeable layer 16. Among them, the soil sample to be tested 11 is pressed tightly between the upper permeable layer 15 and the lower permeable layer 16, and the pressure plate 14 is uniformly pressed against the top of the upper permeable layer 15 through the soil sample loading rod 23, so as to uniformly apply the load to the soil sample to be tested 11, ensuring the safe and reliable progress of the test and improving the accuracy of the test results.

[0053] Even further, an anti-blocking filter paper is provided between the soil sample to be tested 11 and the upper permeable layer 15 and the lower permeable layer 16 to prevent the soil particles of the soil sample to be tested 11 from blocking the permeable layer during compression and ensure the water permeability effect 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 - 2 cm. The thicknesses of the anti-blocking filter paper and the pressure plate 14 can be adjusted according to the actual situation.

[0054] Preferably, a core cutter positioning groove 17 is provided at the bottom of the consolidation container 13, and the radius of the core cutter positioning groove 17 is set according to the size of the required elastic core cutter 12, so as to fix the elastic core cutter 12 and ensure that the elastic core cutter 12 will not move during the experiment, ensuring the smooth and reliable progress of the experiment. For example, if the diameter of the elastic core cutter 12 is 100 mm and the thickness of the elastic core cutter 12 is 2 mm, the diameter of the core cutter positioning groove 17 can be set to 104 mm.

[0055] 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 cross beam 222. The mounting cross beam 222 is fixedly connected between the vertical mounting rods 221, and the U-shaped balance beam is rotatably mounted on the mounting cross beam 222 through the lever ratio adjustment hole 211. A first bearing is provided between the mounting cross beam 222 and the lever ratio adjustment hole 211 to ensure the reliable rotation of the loading balance beam 21 and the effective loading of the soil sample to be tested 11.

[0056] Furthermore, a loading rod mounting cross bar 231 is provided at the position where the U-shaped balance beam places the soil sample loading rod 23, 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 is 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.

[0057] Furthermore, the testing device further includes 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 testing device, provides a reliable and stable experimental environment, and ensures the smooth progress of the loading experiment.

[0058] As Figure 6 shown, the testing method using the above-mentioned testing device in this embodiment includes the following steps:

[0059] Step 1, prepare the soil sample 11 to be tested, wrap the elastic ring cutter 12 of the material to be tested around the soil sample 11 to be tested, and assemble it into the consolidation experiment component 1;

[0060] Step 2, install the soil body loading component 2, apply different pressure level loads required for testing to the soil sample 11 to be tested in the consolidation experiment component 1, and record 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 level loads, so as to obtain the height deformation amount and radial radius of the soil sample 11 to be tested under different pressure level loads;

[0061] Step 3, according to the height deformation amount and radial radius of the soil sample 11 to be tested under different pressure level loads, calculate the void ratio of the soil sample 11 to be tested after lateral deformation compression under different pressure level loads;

[0062] Step 4, according to the radial radius and the compressed void ratio of the soil sample 11 to be tested under different pressure level loads, as well as the parameters of the soil sample 11 to be tested under the condition of complete lateral confinement, calculate the compression modulus of the soil sample 11 to be tested when undergoing lateral deformation 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 amount of the soil body in the three-dimensional stress state. The parameters of the soil sample 11 to be tested under the condition of complete lateral confinement include the compression modulus of the soil sample 11 to be tested under the condition of complete lateral confinement or the height deformation amount of the soil sample 11 to be tested under the condition of complete lateral confinement.

[0063] 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 condition of lateral deformation under the current level of load, so as to quickly and accurately calculate the compression deformation parameter (compression modulus) of the soil sample 11 to be tested under the condition of lateral deformation, in order to calculate the settlement amount of the soil body in the three-dimensional stress state. The settlement amount obtained by the present invention is closer to the actual value than the settlement amount obtained by the existing settlement calculation method.

[0064] The present invention fills the technical gap that the results of one-dimensional consolidation experiments cannot reflect the three-dimensional deformation of soil. It can accurately simulate the actual three-dimensional stress and deformation environment of soil, accurately reflect the lateral deformation characteristics of soil, and at the same time obtain soil compression deformation parameters that highly match the actual situation, providing accurate numerical values for the prediction of subsequent settlement amounts. Thus, it ensures that engineering and design based on experimental parameters can accurately reflect the true mechanical behavior of soil, guaranteeing the certainty and safety of engineering construction.

[0065] The specific steps of the testing method using the above-mentioned testing device in the present invention are as follows:

[0066] In step 1, a soil sample 11 to be tested is prepared, and an elastic cutting ring 12 of the material to be tested is wrapped outside the soil sample 11 to be tested and assembled into the consolidation experiment component 1.

[0067] When the soil sample 11 wrapped with the elastic cutting ring 12 is assembled into the consolidation experiment component 1, the lower permeable layer 16, anti-blocking filter paper, soil sample 11 to be tested, anti-blocking filter paper, upper permeable layer 15, pressure plate 14, and digital display displacement meter 31 in the consolidation experiment component 1 are assembled from bottom to top to complete the installation of the consolidation experiment component 1.

[0068] Furthermore, when it is necessary to test the settlement amount of the soil sample 11 to be tested under elastic cutting rings 12 of different materials, after completing the load experiment of the elastic cutting ring 12 of the same material, the components in the consolidation experiment component 1 can be taken out, the elastic cutting ring 12 outside the soil sample 11 to be tested can be replaced, and steps 1 to 4 can be cycled to obtain the settlement amount of the soil sample 11 under elastic cutting rings 12 of different materials, providing an accurate and reliable analysis basis for subsequent comparative analysis of the compression deformation characteristics of soil samples under elastic cutting rings 12 of multiple materials.

[0069] In step 2, the installation of the soil loading component 2 specifically includes the following steps:

[0070] According to the different pressure-level loads required to be tested for 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:

[0071]

[0072] Wherein, is the loading weight of the soil sample 11 to be tested, is the pressure-level load required to be tested for the soil sample 11 to be tested, is the cross-sectional area of the soil sample 1 to be tested, is the acceleration of gravity.

[0073] Determine the lever ratio of the lever structure based on the maximum loading weight of the soil sample 11 to be measured under different pressure-level loads and the additional weight of the pressure-applying weights 24. Exemplarily, if the maximum loading weight of the soil sample 11 to be measured is 600 kg and the lever ratio is set to 1:10, after conversion, the additional weight of the pressure-applying weights 24 is 60 kg. If this additional weight is too heavy and difficult to achieve, then adjust the lever ratio to 1:30. At this time, the additional weight of the pressure-applying weights 24 is 20 kg, which is easy to achieve. At this time, the lever ratio can be set to 1:30.

[0074] Determine the installation positions of the balance beam mounting member 22, the soil sample loading rod 23, and the pressure-applying weights 24 on the loading balance beam 21 according to the lever ratio. Specifically, the lever ratio adjustment can be achieved by adjusting the distance between the soil sample loading rod 23 between the balance beam mounting member 22 and the pressure-applying weights 24.

[0075] When installing the balance beam mounting member 22, the soil sample loading rod 23, and the pressure-applying weights 24, place the pressure-applying weights 24 with the initial weight, and level the loading balance beam 21 through the balance weights 25 to facilitate the subsequent loading of the pressure-applying weights 24.

[0076] Further, adjust the weight of the pressure-applying weights 24, and apply a pre-pressure to the soil sample 11 to be measured (such as applying a pre-pressure of 1 kPa) to ensure that adjacent components in the consolidation experiment assembly 1 are in full contact, so as to ensure that pressure can be transmitted between components during the experiment and ensure the integrity of the experimental data. After that, zero the digital display displacement gauge 31 to facilitate recording the height deformation of the soil sample 11 to be measured after compression.

[0077] After that, sequentially adjust the pressure-applying weights 24 to the required additional weights to apply different pressure-level loads required for testing to the soil sample 11 to be measured through the soil sample loading rod 23. In this embodiment, the pressure-level loads required for the soil sample 11 to be measured can be adjusted by changing the quantity and weight of the pressure-applying weights 24.

[0078] After the loading of the same pressure-level load is completed, record the deformation data of the soil sample 11 to be measured in the loading direction and the diameter data in the radial direction under different pressure-level loads, so as to obtain the height deformation and radial radius of the soil sample 11 to be measured after lateral deformation under different pressure-level loads. Preferably, read the data once every 24 h after each load is applied, or when the dial gauge reading change within 1 h is not greater than 0.01 mm, it is determined that the loading has reached the stable state, and then the next-level loading can be carried out until the last-level loading is completed.

[0079] Further, record the diameter data of the soil sample 11 to be measured in the radial direction to obtain the radial radius of the soil sample 11 to be measured after lateral deformation, which specifically includes the steps of: measuring the diameter data of the soil sample 11 to be measured at different heights, and measuring the diameter data of the soil sample 11 to be measured at the same height but different circumferential directions. Take the average value of the diameter data of the soil sample 11 to be measured at the same height but different circumferential directions as the average diameter of the soil sample 11 to be measured at the same height, and take the average value of the average diameters of the soil sample 11 to be measured at different heights as the radial average diameter of the soil sample 11 to be measured, so as to obtain the radial radius of the soil sample 11 to be measured after lateral deformation.

[0080] Assume that the soil sample 11 to be measured is uniform and isotropic during the compression process, and its deformation is also uniform under the action of the upper load. Therefore, the average diameter at the same height is obtained through the average value of the diameter data of the soil sample 11 to be measured at the same height but different circumferential directions, and the radial radius of the soil sample 11 to be measured after lateral deformation is obtained according to the average value of the average diameters at different heights, so as to reflect the true radial deformation of the soil sample 11 during lateral deformation, thereby providing true and accurate data for subsequent parameter calculation.

[0081] Preferably, use a vernier caliper to measure the diameter data three times at the same height but different circumferential positions of the soil sample 11 to be measured. The purpose of measuring three times at the same height is to obtain the average diameter of the soil sample 11 to be measured at this height to reduce errors. The time interval between the three tests can be considered to be completed within one minute. Then, change the height and repeat the operation to measure the diameter. For example, if the height of the elastic cutting ring 12 is 100 mm, the diameter data can be measured at intervals of 10 mm along the height direction, that is, the average diameters of 10 heights are measured. The average diameters at each height are different. Take the average value of the 10 different average diameters as the radial average diameter of the soil sample 11 to be measured at this load level. During the experiment, the soil sample 11 to be measured in the present invention deforms into a "drum shape". The present invention divides it into several regular objects to take the average value, which can more truly reflect the true radial deformation of the soil sample 11.

[0082] Step 3, according to the height deformation and radial radius of the soil sample 11 to be measured under different pressure level loads, calculating the void ratio of the soil sample 11 to be measured after lateral deformation compression includes: constructing a calculation model for the void ratio of the soil sample 11 to be measured after lateral deformation compression, and its basic principle is:

[0083] Derived from the volume change of the soil sample 11 to be measured in the elastic cutting ring 12. First, before loading, the soil sample 11 to be measured occupies the entire internal volume of the elastic cutting ring 12. At this time, according to the parameters of the soil sample 11, assume that the volume of soil particles is , since the soil particles cannot be compressed after loading, the volume of the soil particles remains unchanged after the lateral deformation of the elastic cutting ring 12. According to the assumption that the total volume of the soil particles in the soil sample 11 to be measured remains unchanged during the compression process, the void ratio of the soil sample 11 to be measured under the condition of lateral deformation can be derived. That is, the formulas for calculating the volume of the soil particles before and after loading change, but the two are equal. After that, by changing the equal formulas obtained above, the height of the soil sample 11 to be measured after compression can be obtained. The height deformation of the soil sample 11 to be measured can be directly measured through step 2, as shown in Equation (6). At this time, the unknown in the formula (the void ratio after compression) can be calculated. The specific process is as follows:

[0084] First, assume that the total volume of the soil particles in the soil sample 11 to be measured is 1. The total volume of the soil particles in the soil sample 11 to be measured before compression is:

[0085] (1)

[0086] Where, is the total volume of the soil particles in the soil sample 11 to be measured before compression, is the height of the soil sample 11 to be measured before compression, is the void ratio of the soil sample 11 to be measured after lateral deformation and compression under the previous load, is the radial radius of the soil sample 11 to be measured after lateral deformation under the previous load.

[0087] At the same time, the total volume of the soil particles in the soil sample 11 to be measured after compression is:

[0088] (2)

[0089] Where, is the total volume of the soil particles in the soil sample 11 to be measured after compression, is the height of the soil sample 11 to be measured after compression, is the void ratio of the soil sample 11 to be measured after lateral deformation and compression under the current load, is the radial radius of the soil sample 11 to be measured after lateral deformation under the current load.

[0090] In this embodiment, according to the assumption that the total volume of the soil particles in the soil sample 11 to be measured remains unchanged during the compression process, we have:

[0091] (3)

[0092] From the above formula (3), the formula for the height of the soil sample 11 to be measured after compression can be obtained:

[0093] (4)

[0094] Meanwhile, since the height deformation of the soil sample to be tested 11 after lateral deformation can be directly measured during the loading process of Step 2 , the radial radius of the soil sample to be tested 11 after lateral deformation under the previous load , and the radial radius of the soil sample to be tested 11 after lateral deformation under the current load , it can be obtained that:

[0095] (5)

[0096] After transforming the above formula (5), the void ratio of the soil sample to be tested 11 after lateral deformation compression under the current load can be obtained:

[0097] (6)

[0098] Through the above formula (6), the void ratio of the soil sample to be tested 11 after lateral deformation compression can be quickly and accurately calculated, that is, according to the height deformation and radial radius of the soil sample to be tested 11 after lateral deformation, the void ratio of the soil sample to be tested 11 after lateral deformation compression can be quickly and accurately calculated. By applying the void ratio of the soil sample to be tested 11, the deformation parameters (compression modulus of the soil sample to be tested 11 during lateral deformation) of the soil under different pressure-level loads can be calculated, thereby providing a basis for obtaining the settlement of the soil under three-dimensional stress conditions closer to the actual situation. At the same time, when elastic cutting rings 12 made of different materials are used, the void ratios of the soil sample to be tested 11 after lateral deformation compression under different constraint conditions can be measured, thereby providing a basis for accurately comparing the settlement amounts of elastic cutting rings 12 made of different materials.

[0099] In Step 4, according to the radial radius and the compressed void ratio of the soil sample to be tested 11 under different pressure-level loads, and the parameters of the soil sample to be tested 11 under the condition of complete lateral confinement, calculate the compression modulus of the soil sample to be tested 11 during lateral deformation under different pressure-level loads; select the corresponding compression modulus according to the actual pressure-level load of the soil, and calculate the settlement of the soil under three-dimensional stress conditions; the parameters of the soil sample to be tested 11 under the condition of complete lateral confinement include the compression modulus of the soil sample to be tested 11 under the condition of complete lateral confinement or the height deformation of the soil sample to be tested 11 under the condition of complete lateral confinement. Specifically:

[0100] By constructing the compression modulus of the soil sample to be tested 11 under the condition of lateral deformation at the current load level, the compression modulus of the soil sample to be tested 11 under the condition of lateral deformation at the current load level can be quickly and accurately calculated, so that the settlement of the soil under three-dimensional stress conditions can be calculated. In this embodiment, first, the construction principle of the compression modulus of the soil sample to be tested 11 during lateral deformation is analyzed:

[0101] It can be seen from the above formula (5) that the height deformation of the soil sample 11 to be measured after lateral deformation is:

[0102] (7)

[0103] In the case of lateral deformation of the soil mass, after the total volume of soil particles in the soil sample 11 to be measured deforms, the deformed volume of soil particles in the loading direction is:

[0104] (8)

[0105] Among them, is the deformed volume of soil particles in the loading direction, is the height deformation of soil particles, is the radial radius after lateral deformation of the soil sample 11 to be measured under the previous load.

[0106] The lateral deformation volume of soil particles is:

[0107] (9)

[0108] Among them, is the lateral deformation volume of soil particles, is the radial radius after lateral deformation of the soil sample 11 to be measured under the current ... load.

[0109] Based on 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 deformed volume of soil particles in the loading direction:

[0110] (10)

[0111] Derived from formula (10) and combined with formula (4), we can get:

[0112] (11)

[0113] After deforming formula (7), a formula containing formula (11) can be constructed to conveniently and intuitively show the composition of the height deformation of the soil sample 11 to be measured after lateral deformation. Specifically:

[0114] (12)

[0115] Substituting formula (11) into formula (l2), we can obtain the relationship between the height deformation of the soil sample 11 to be measured after lateral deformation and the height deformation of soil particles:

[0116] (13)

[0117] It can be seen from Equation (13) that the height deformation of the soil sample 11 to be measured after lateral deformation includes the deformation caused by the discharge of water and air from the soil sample 11 to be measured ( ), the height deformation caused by the lateral movement of soil particles in the soil sample 11 to be measured ( ), and the deformation caused by the change in void ratio during the lateral deformation of soil particles in the soil sample 11 to be measured ( ). Thus, it can be conveniently and intuitively seen the composition of the height deformation of the soil sample 11 to be measured after lateral deformation .

[0118] Under the condition of complete lateral confinement, the soil sample 11 to be measured will not undergo lateral deformation. The calculation formula for the height deformation of the soil sample 11 to be measured under the condition of complete lateral confinement is:

[0119] (14)

[0120] is the height deformation of the soil sample 11 to be measured under the condition of complete lateral confinement, is the void ratio of the soil sample 11 to be measured under the condition of complete lateral confinement at the previous load, is the void ratio of the soil sample 11 to be measured under the condition of complete lateral confinement at the current load.

[0121] By comparing Equation (14) and Equation (13), it can be found that the height deformation of the soil sample 11 to be measured after lateral deformation and the height deformation of the soil sample 11 to be measured under the condition of complete lateral confinement , the difference between the two lies in the height deformation caused by the lateral movement of soil particles in the soil sample 11 to be measured and the deformation caused by the change in void ratio during the lateral deformation of soil particles in the soil sample 11 to be measured.

[0122] The calculation formula for the compression modulus of the soil sample 11 to be measured under the condition of complete lateral confinement is:

[0123] (15)

[0124] Among them, is the compression modulus of the soil sample 11 to be measured under the condition of complete lateral confinement, is the change in void ratio of the soil sample 11 to be measured under the condition of complete lateral confinement, is the load increment of the soil sample 11 to be measured before and after compression.

[0125] Referring to Equation (15), the compression modulus of the soil sample 11 to be measured during lateral deformation The calculation formula is as follows:

[0126] (16)

[0127] Substituting Equation (13) into Equation (16), we can obtain:

[0128] (17)

[0129] According to the above Equation (17), the compression modulus of the soil sample 11 to be measured under different pressure-level loads can be quickly and accurately calculated for the lateral deformation.

[0130] After that, according to the actual pressure-level load of the soil mass, the corresponding compression modulus is selected. According to the compression modulus, the settlement amount of the soil mass under the three-dimensional stress state can be accurately calculated by using the layered summation method relationship of the following Equation (18). Specifically:

[0131] (18)

[0132] Among them, is the settlement value of the soil mass under the three-dimensional stress state, is the load increment of the soil mass on the th layer of the soil sample 11 to be measured, is the compression modulus of the th layer of the soil sample 11 to be measured, is the thickness of the th layer of the soil sample 11 to be measured, is the number of vertical layers of the soil mass, is the th layer in the vertical direction of the soil mass.

[0133] In Equation (18), the compression modulus of the th layer of the soil sample 11 to be measured corresponds to the compression modulus of the th layer of the soil sample 11 to be measured for the lateral deformation in the above Equation (17). In this embodiment, the soil mass is divided into layers of the soil sample 11 to be measured. The compression modulus of each layer of the soil sample 11 to be measured for the lateral deformation is obtained by using Equation (17). Substituting the compression modulus of the soil sample 11 to be measured for the lateral deformation into Equation (18) to obtain the settlement amount of the soil mass under the three-dimensional stress state. The obtained settlement amount is closer to the actual value than the settlement amount obtained by the existing settlement calculation method, thus ensuring that the engineering and design based on the experimental parameters can accurately reflect the true mechanical behavior of the soil mass and ensuring the certainty and safety of the engineering construction.

[0134] Although the present invention has been described with reference to the preferred embodiments, various modifications thereof can be made and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. 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 test method for measuring the deformation characteristics of soil mass, characterized in that, It includes the following steps: Step 1): Prepare the soil sample to be tested, wrap the elastic ring cutter of the material to be tested outside the soil sample to be tested, and assemble it into the consolidation test component; Step 2): Install the soil loading component, apply different pressure level loads required for testing to the soil sample to be tested in the consolidation test component, record the deformation data of the soil sample to be tested in the loading direction and the diameter data in the radial direction under different pressure level loads, and obtain the height deformation amount and radial radius of the soil sample to be tested after lateral deformation under different pressure level loads; Step 3): Calculate the void ratio of the soil sample to be tested after lateral deformation compression under different pressure level loads according to the height deformation amount and radial radius of the soil sample to be tested under different pressure level loads; Step 4): Calculate the compression modulus of the soil sample to be tested during lateral deformation according to the radial radius and the compressed void ratio of the soil sample to be tested under different pressure level loads, and the parameters of the soil sample to be tested under the condition of complete lateral confinement. Select the corresponding compression modulus according to the actual pressure level load of the soil body, and calculate the settlement amount of the soil body under the three-dimensional stress state. The parameters of the soil sample to be tested under the condition of complete lateral confinement include the compression modulus of the soil sample to be tested under the condition of complete lateral confinement or the height deformation amount of the soil sample to be tested under the condition of complete lateral confinement; In step 4), calculate the compression modulus of the soil sample to be tested during lateral deformation according to the following formula: Among them, is the compression modulus of the soil sample to be tested for lateral deformation under the current stage of load, is the load increment of the soil sample to be tested before and after compression, is the void ratio of the soil sample to be tested after lateral deformation compression under the previous stage of load, is the void ratio of the soil sample to be tested after lateral deformation compression under the current load, is the height of the soil sample to be tested under the previous stage of load, is the radial radius of the soil sample to be tested after lateral deformation under the previous stage of load, is the radial radius of the soil sample to be tested after lateral deformation under the current load.

2. The test method according to claim 1, wherein In step 3), calculate the void ratio of the soil sample to be tested after lateral deformation compression according to the following formula: Among them, is the void ratio after lateral deformation and compression of the soil sample to be tested, is the height of the soil sample to be tested under the previous level of load, is the height deformation of the soil sample to be tested, is the void ratio after lateral deformation and compression of the soil sample to be tested under the previous level of load, is the radial radius of the soil sample to be tested under the previous level of load after lateral deformation, is the current radial radius of the soil sample to be tested after lateral deformation under load.

3. The test method according to claim 1, characterized in that, In step 2), installing the soil loading component includes the following steps: Determine the loading weight of the soil sample to be tested according to the different pressure level loads required for testing of the soil sample to be tested, and determine the lever ratio of the lever structure according to the maximum loading weight of the soil sample to be tested under different pressure level loads; Determine the installation positions of the balance beam mounting piece, soil sample loading rod and pressure weight on the loading balance beam according to the lever ratio; When installing the balance beam mounting piece, soil sample loading rod and pressure weight, place the pressure weight with the initial weight and level the loading balance beam by adjusting the balance weight; Adjust the weight of the pressure weight, apply a pre-pressure to the soil sample to be tested to make the adjacent components in the consolidation test component in full contact; Adjust the pressure weight to the required additional weight in sequence to apply different pressure level loads required for testing to the soil sample to be tested through the soil sample loading rod.

4. The test method according to claim 3, characterized in that, In step 2), recording the diameter data of the soil sample to be tested in the radial direction and obtaining the radial radius of the soil sample to be tested after lateral deformation includes: Measuring the diameter data of the soil sample to be tested at different heights and the diameter data of the soil sample to be tested at the same height and different circumferences. Take the average value of the diameter data of the soil sample to be tested at the same height and different circumferences as the average diameter of the soil sample to be tested at the same height, and take 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, so as to obtain the radial radius of the soil sample to be tested after lateral deformation.

5. The test method according to any one of claims 1 to 4, characterized in that The described testing method uses a testing device for measuring the deformation characteristics of soil. It is characterized in that the testing device includes a consolidation experiment component and a soil loading component. The soil loading component includes a loading balance beam, a balance beam mounting member provided on the loading balance beam, a soil sample loading rod, a pressure weight, and a balance weight. The soil sample loading rod is located between the balance beam mounting member and the pressure weight to form a lever structure with the balance beam mounting member as the fulcrum. The balance weight is provided at one end of the loading balance beam away from the pressure weight. The consolidation experiment component includes a soil sample to be tested and an elastic cutting ring that enables the lateral deformation of the soil sample to be tested during ballasting. The elastic cutting ring is wrapped outside the soil sample to be tested, and the bottom end of the soil sample loading rod presses tightly against the soil sample to be tested.

6. The test method according to claim 5, characterized in that, The loading balance beam is uniformly provided with lever ratio adjustment holes along its length direction. The number of the lever ratio adjustment holes provided is in a direct proportion relationship with the lever ratio. The soil sample loading rod is installed in the corresponding lever ratio adjustment hole between the balance beam mounting member and the pressure weight according to the required lever ratio to form the lever structure with different lever ratios and different levels of loading loads.

7. The test method according to claim 5, characterized in that The connecting end of the soil sample loading rod is rotatably installed on the loading balance beam. The loading end of the soil sample loading rod is pre-pressed tightly against the top end of the consolidation experiment component by the pre-pressure force of the pressure weight before the soil sample to be tested is loaded.

8. The testing method according to claim 5, characterized in that It further includes a displacement detection component for measuring the deformation amounts of the soil sample to be tested in the loading direction and the radial direction after loading. The displacement detection component includes a digital display displacement meter and a vernier caliper. The digital display displacement meter is fixedly arranged, and its detection end presses tightly against the top end of the soil sample to be tested. The vernier caliper is used to measure the diameters of the soil sample to be tested at different heights and different circumferential positions.

9. The test method according to claim 5, wherein The consolidation experiment component further includes a consolidation container, a pressure plate provided on the consolidation container, an upper permeable layer, and a lower permeable layer. The soil sample to be tested is pressed tightly between the upper permeable layer and the lower permeable layer. The pressure plate is uniformly pressed tightly against the top end of the upper permeable layer through the soil sample loading rod. An anti-blocking filter paper for preventing the soil particles of the soil sample to be tested from blocking the permeable layer during compression is provided between the soil sample to be tested and the upper permeable layer and the lower permeable layer.

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