A Method and Device for Adapting and Adjusting the Shear-Normal Stiffness of Soil Structure Interfaces

Abstract

The present application discloses a method and device for adapting and adjusting the shear normal stiffness of a soil structure interface, relating to the technical field of geotechnical engineering. The method includes: measuring the stiffness of the soil to be tested by using a stiffness adjustment module, and installing a plurality of mutually independent micro-spring unit bodies between the normal loading unit and the upper surface of the soil to be tested according to the measurement result of the stiffness of the soil to be tested; the stiffness of the micro-spring unit body is equal to the measurement result of the stiffness of the soil to be tested, so that the normal stiffness at the boundary of the soil to be tested during the shear test is consistent with the stiffness of the soil to be tested, and the adaptation of the shear normal stiffness of the soil structure interface is completed; meanwhile, the pressure change of the soil at each loading point during the shear test of the soil to be tested is measured in real time to obtain the corresponding soil pressure monitoring result, and whether the adapted constant stiffness boundary meets the preset conditions is verified through the soil pressure monitoring result. The present application can provide more realistic constant stiffness boundary conditions for the soil to be tested during the shear test.

Description

Technical Field

[0001] The present application relates to the technical field of geotechnical engineering, and particularly relates to a method and device for adapting and adjusting the shear normal stiffness of a soil-structure interface. Background Technique

[0002] At present, the bearing capacity and stability of various underground structures are largely controlled by the soil-structure interface. Studying the shear deformation characteristics and ultimate failure performance of the soil-structure interface is of great significance for accurately designing the bearing capacity of underground structures and determining the deformation characteristics of underground structures. The relevant shear test equipment generally provides a constant normal stress boundary condition, that is, the normal stress during the shear process is kept constant. However, the constant normal stress boundary condition is only applicable to the case where the interface deformation is relatively uniform during the shear process. In actual engineering, there are a large number of interfaces with uneven particle dislocation. The rigid loading of the constant normal stress boundary condition will cause serious stress concentration during the loading process and is not applicable. The deformation of the specimen in the constant normal stiffness boundary condition is not restricted by the loading plate, and the simulation of this situation is more accurate, that is, the normal stiffness during the shear process of the soil to be tested is ensured to be constant.

[0003] At present, the normal loading plate of the constant normal stiffness shear test equipment mostly adopts an integrated design. However, the deformation during the shear process of the soil to be tested is not uniform. The relevant technologies can only ensure the constant total stiffness and cannot provide a suitable constant normal stiffness boundary condition at each point. At the same time, the constant normal stiffness provided by the relevant equipment is a preset fixed value and cannot be adapted to the actual stiffness of different soils to be tested, and still cannot reflect the true shear characteristics of the soil-structure interface during the shear process.

[0004] Therefore, it is necessary to provide a method and device for adapting and adjusting the shear normal stiffness of a soil-structure interface to solve the above problems. Summary of the Invention

[0005] The purpose of the present application is to provide a method and device for adapting and adjusting the shear normal stiffness of a soil-structure interface, which can provide a more realistic constant stiffness boundary condition for the soil to be tested during the shear test process.

[0006] To achieve the above object, the present application provides the following solutions:

[0007] In the first aspect, the present application provides a method for adapting and adjusting the shear normal stiffness of a soil-structure interface, and the method for adapting and adjusting the shear normal stiffness of a soil-structure interface includes:

[0008] Before the start of the shear test, use the stiffness adjustment module to measure the stiffness of the soil to be tested to obtain the stiffness measurement result of the soil to be tested;

[0009] According to the stiffness measurement result of the soil to be measured, a plurality of mutually independent micro-spring unit bodies are installed between the normal loading unit and the upper surface of the soil to be measured; the plurality of micro-spring unit bodies form an array structure covering the upper surface of the soil to be measured, and each micro-spring unit body can move independently; the stiffness of the micro-spring unit body is equal to the stiffness measurement result of the soil to be measured, so that the normal stiffness at the boundary of the soil to be measured during the shear test is consistent with the stiffness of the soil to be measured, and the adaptation of the shear normal stiffness of the soil structure interface is completed;

[0010] Meanwhile, the pressure change of the soil at each loading point during the shear test of the soil to be measured is measured in real time, the corresponding soil pressure monitoring result is obtained, and whether the adapted constant stiffness boundary meets the preset conditions is verified through the soil pressure monitoring result.

[0011] In a second aspect, the present application further provides a device for adapting and adjusting the shear normal stiffness of a soil structure interface. The device for adapting and adjusting the shear normal stiffness of a soil structure interface is used to implement the method for adapting and adjusting the shear normal stiffness of a soil structure interface. The device for adapting and adjusting the shear normal stiffness of a soil structure interface includes: a discretized micro-spring stiffness adaptation combination module and a stiffness adjustment module;

[0012] The discretized micro-spring stiffness adaptation combination module includes: a plurality of mutually independent micro-spring unit bodies, each of the micro-spring unit bodies is installed between the normal loading unit and the upper surface of the soil to be measured, and each micro-spring unit body is used to perform stiffness adaptation on the soil to be measured under the corresponding loading point;

[0013] The plurality of micro-spring unit bodies form an array structure covering the upper surface of the soil to be measured, and each micro-spring unit body can move independently;

[0014] The stiffness adjustment module is used for:

[0015] Measuring the stiffness of the soil to be measured before the start of the shear test to obtain the stiffness measurement result of the soil to be measured;

[0016] According to the stiffness measurement result of the soil to be measured, adjusting the stiffness of the micro-spring unit body to be equal to the stiffness measurement result of the soil to be measured, so that the normal stiffness at the boundary of the soil to be measured during the shear test is consistent with the stiffness of the soil to be measured, and the adaptation of the shear normal stiffness of the soil structure interface is completed;

[0017] Measuring the pressure change of the soil at each loading point during the shear test of the soil to be measured in real time, obtaining the corresponding soil pressure monitoring result, and verifying whether the adapted constant stiffness boundary meets the preset conditions through the soil pressure monitoring result.

[0018] Optionally, the micro spring unit body includes: an elastic unit and a micro loading head. The elastic unit is respectively connected to the normal loading unit and the corresponding micro loading head. Each micro loading head is respectively in contact with the soil to be measured. The stiffness of each elastic unit is adapted to the stiffness of the soil to be measured at the corresponding loading point, and each micro loading head moves independently.

[0019] Optionally, the size of each micro spring unit body is less than or equal to 10 times the average particle size of the soil to be measured.

[0020] Optionally, the normal loading unit includes: a normal loading head and a normal loading plate;

[0021] The normal loading plate is located below the normal loading head, and the normal loading plate is connected to each elastic unit;

[0022] The normal loading head is used to apply a preset normal pressure to the elastic unit through the normal loading plate;

[0023] The normal loading plate is used to disperse and apply the corresponding normal pressure to the corresponding elastic unit.

[0024] Optionally, the difference in stiffness value between the normal loading plate and the soil to be measured is greater than a preset threshold.

[0025] Optionally, the elastic unit is a spring.

[0026] Optionally, the stiffness adjustment module includes: a soil stiffness test element and a micro spring unit body stiffness control element;

[0027] The soil stiffness test element is installed on the shear box, and the micro spring unit body stiffness control element is located on the normal loading plate;

[0028] The soil stiffness test element is used to measure the stiffness of the soil to be measured before the shear test starts, and obtain the stiffness measurement result of the soil to be measured;

[0029] The micro spring unit body stiffness control element is used to determine the stiffness of the micro spring unit body to be installed according to the stiffness measurement result of the soil to be measured.

[0030] Optionally, the stiffness adjustment module further includes:

[0031] A plurality of micro pressure test elements, fixed to the lower surface of the corresponding micro spring unit body, are used to measure the pressure change of each point of the soil to be measured in real time during the shear test, and obtain the corresponding soil pressure monitoring result.

[0032] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0033] The present application discloses a method and device for adapting and adjusting the shear normal stiffness of a soil-structure interface. Based on the device for adapting and adjusting the shear normal stiffness of the soil-structure interface, the present application first measures the stiffness of the soil to be tested before the shear test begins, obtaining the stiffness measurement result of the soil to be tested. Secondly, according to the stiffness measurement result of the soil to be tested, a plurality of mutually independent micro-spring unit bodies are installed between the normal loading unit and the upper surface of the soil to be tested, and the stiffness of the micro-spring unit bodies is equal to the stiffness measurement result of the soil to be tested, so that the normal stiffness at the boundary of the soil to be tested during the shear test is consistent with the stiffness of the soil to be tested, completing the adaptation of the shear normal stiffness of the soil-structure interface, enabling the present application to provide more realistic constant stiffness boundary conditions for the soil to be tested during the shear test. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0035] Figure 1 Schematic flow chart of a method for adapting and adjusting the shear normal stiffness of a soil-structure interface provided by an embodiment of the present application;

[0036] Figure 2 Schematic diagram of a device for adapting and adjusting the shear normal stiffness of a soil-structure interface provided by an embodiment of the present application;

[0037] Figure 3 Schematic diagram of the array arrangement of elastic units and micro-loading heads on a loading plate provided by an embodiment of the present application;

[0038] Figure 4 Schematic diagram of a spring structure provided by an embodiment of the present application;

[0039] Figure 5 Schematic diagram of a micro-spring unit body stiffness control element provided by an embodiment of the present application.

[0040] Reference numerals:

[0041] Upper shear box 1, lower shear box 2, soil to be tested 3, structural material 4, normal loading head 5, normal loading plate 6, elastic unit 7, micro-loading head 8, first bending element 9, second bending element 10, tangential loading head 11, micro pressure test element 12. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0043] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0044] In an exemplary embodiment, as Figure 1 shown, a method for adapting and adjusting the shear normal stiffness of a soil-structure interface is provided. The method for adapting and adjusting the shear normal stiffness of a soil-structure interface includes:

[0045] Step S1, before the start of the shear test, use the stiffness adjustment module to measure the stiffness of the soil to be tested, and obtain the stiffness measurement result of the soil to be tested.

[0046] Step S2, according to the stiffness measurement result of the soil to be tested, install a plurality of mutually independent micro-spring unit bodies between the normal loading unit and the upper surface of the soil to be tested; referring to Figure 2 , a plurality of the micro-spring unit bodies form an array structure covering the upper surface of the soil to be tested, and each of the micro-spring unit bodies can move independently; the stiffness of the micro-spring unit body is equal to the stiffness measurement result of the soil to be tested, so that the normal stiffness at the boundary of the soil to be tested during the shear test is consistent with the stiffness of the soil to be tested, and the adaptation of the shear normal stiffness of the soil-structure interface is completed.

[0047] Step S3, at the same time, measure the pressure change of the soil at each loading point during the shear test of the soil to be tested in real time, obtain the corresponding soil pressure monitoring result, and verify whether the adapted constant stiffness boundary meets the preset conditions through the soil pressure monitoring result.

[0048] Further, based on the same inventive concept, as Figure 2 shown, the present application also provides a device for adapting and adjusting the shear normal stiffness of a soil-structure interface. The device for adapting and adjusting the shear normal stiffness of a soil-structure interface is used to implement the method for adapting and adjusting the shear normal stiffness of a soil-structure interface. The device for adapting and adjusting the shear normal stiffness of a soil-structure interface includes: a discretized micro-spring stiffness adaptation combination module and a stiffness adjustment module.

[0049] The discretized micro-spring stiffness adaptation assembly module includes: a plurality of independent micro-spring unit bodies, each of the micro-spring unit bodies is installed between the normal loading unit and the upper surface of the soil to be tested, and the plurality of micro-spring unit bodies form an array structure covering the upper surface of the soil to be tested, and each of the micro-spring unit bodies can move independently. During the interface shear process, it is ensured that the deformation of the soil to be tested under each loading point is only affected by the surrounding soil and not restricted by the normal loading plate.

[0050] Each of the micro-spring unit bodies is used to adapt the stiffness of the soil to be tested under the corresponding loading point.

[0051] The stiffness adjustment module is used for:

[0052] Before the start of the shear test, measure the stiffness of the soil to be tested to obtain the stiffness measurement result of the soil to be tested.

[0053] According to the stiffness measurement result of the soil to be tested, adjust the stiffness of the micro-spring unit body to be equal to the stiffness measurement result of the soil to be tested, so that the normal stiffness at the boundary of the soil to be tested during the shear test is consistent with the stiffness of the soil to be tested, and the adaptation of the normal stiffness of the soil structure interface shear is completed.

[0054] Measure the pressure change of each point of the soil to be tested in real time during the shear test to obtain the corresponding soil pressure monitoring result, and verify whether the adapted constant stiffness boundary meets the preset conditions through the soil pressure monitoring result.

[0055] Optionally, the micro-spring unit body includes: an elastic unit 7 and a micro-loading head 8, the elastic unit 7 is respectively connected to the normal loading unit and the corresponding micro-loading head 8, each of the micro-loading heads 8 is in contact with the soil to be tested respectively, the stiffness of each of the elastic units 7 is adapted to the stiffness of the soil to be tested under the corresponding loading point, and each of the micro-loading heads moves independently. The schematic diagram of the array arrangement of each of the elastic units 7 and the micro-loading heads 8 on the normal loading plate 6 is as Figure 3 shown.

[0056] Among them, the micro-loading head 8 is a metal rigid structure in the shape of a cuboid, the thickness of each of the micro-loading heads 8 is greater than the corresponding preset thickness threshold, and each of the micro-loading heads 8 can slide relative to each other, and the thickness can ensure that each unit does not stagger.

[0057] The elastic unit 7 is used to apply a corresponding normal pressure to the soil to be tested 3 through the micro-loading head 8. Among them, the stiffness of each of the elastic units 7 remains constant during the loading process, and this constant value can be adjusted in advance by replacing the elastic units 7 with different stiffnesses.

[0058] Each of the micro-loading heads is used to apply the received normal pressure to the soil to be tested 3.

[0059] Optionally, the size of each of the micro spring units is less than or equal to 10 times the average particle size of the soil to be measured.

[0060] Optionally, the normal loading unit includes: a normal loading head 5 and a normal loading plate 6; wherein, the normal loading unit is used to disperse and apply a preset normal pressure to each elastic unit 7.

[0061] The normal loading plate 6 is located below the normal loading head 5, and the normal loading plate 6 is connected to each of the elastic units 7.

[0062] The normal loading head 5 is used to apply a preset normal pressure to the elastic unit 7 through the normal loading plate 6.

[0063] The normal loading plate 6 is used to disperse and apply the corresponding normal pressure to the corresponding elastic unit 7. Each of the elastic units 7 is arranged on the lower surface of the normal loading plate 6, and together with the micro loading head 8, forms a loading plane identical to the surface of the soil to be measured 3. Each elastic unit 7 can move independently, and the lower surface area of a single micro loading head 8 is as small as possible, so as to make the plane discretized finer, be able to match the shape of the soil to be measured 3 more accurately, and make the boundary conditions of stiffness adaptation more real (more in line with the natural condition of the soil).

[0064] Optionally, the difference in stiffness values between the normal loading plate 6 and the soil to be measured is greater than a preset threshold.

[0065] Specifically, the stiffness of the normal loading plate 6 is much greater than the stiffness of the soil to be measured 3, and the normal loading plate 6 is an integrated flat plate with a relatively large stiffness.

[0066] Optionally, the elastic unit 7 is a spring.

[0067] Specifically, according to the spring stiffness calculation formula, springs with appropriate morphologies can be designed and replaced to have the same stiffness as the soil to be measured. Specifically as follows:

[0068] By changing indexes such as spring material, helix diameter, wire diameter, pitch, etc., a series of springs with different stiffnesses can be obtained. By replacing the springs and making different series and parallel combinations, the stiffness of the micro spring unit can be changed to achieve adaptation to the stiffness of the soil sample.

[0069] The schematic diagram of the spring structure is as Figure 4 shown, Figure 4 in which D represents the center diameter, D 1 represents the inner diameter, D 2 represents the outer diameter, t represents the pitch, and d represents the wire diameter (d = (D 2 - D 1 ) / 2); The spring stiffness is calculated according to the following spring stiffness formula:

[0070] 。

[0071] Among them, G represents the shear modulus of elasticity, with the unit of MPa; the unit of the wire diameter d is mm; n represents the number of active coils, with the unit of coil; the unit of the mean diameter D is mm; K represents the spring constant, with the unit of kg / mm.

[0072] When springs are in series, K = 1 / (1 / K 1 + 1 / K 2 ), and when springs are in parallel, K = K 1 + K 2 。

[0073] Optionally, the stiffness adjustment module includes: a soil stiffness test element and a micro-spring unit body stiffness regulation element.

[0074] The soil stiffness test element is installed on the shear box, and the micro-spring unit body stiffness regulation element is located on the normal loading plate.

[0075] The soil stiffness test element is used to measure the stiffness of the soil to be tested before the start of the shear test, and obtain the stiffness measurement result of the soil to be tested.

[0076] The micro-spring unit body stiffness regulation element is used to determine the stiffness of the micro-spring unit body to be installed according to the stiffness measurement result of the soil to be tested. The schematic diagram of the micro-spring unit body stiffness regulation element is as Figure 5 shown.

[0077] Optionally, the stiffness adjustment module further includes: a plurality of micro pressure test elements 12, fixed to the lower surface of the corresponding micro-spring unit body. The positions of the micro pressure test elements 12 are as Figure 5 shown, and are used to measure the pressure change of each point of the soil to be tested in real time during the shear test, and obtain the corresponding soil pressure monitoring result. Obtaining the soil pressure monitoring result here is used, on the one hand, to measure the shear band of the soil sample and reflect the evolution and development of the soil shear band, and on the other hand, it is also a verification of the adapted stiffness boundary.

[0078] In an exemplary embodiment, as Figure 2 shown, the soil-structure interface shear normal stiffness adaptation and adjustment device further includes: an upper shear box 1, a lower shear box 2, and a tangential loading unit.

[0079] The lower shear box 2 is used to place the structural material 4.

[0080] The upper shear box 1 is located above the structural material 4, and the upper shear box 1 is used to place the soil to be tested 3. The lower shear box 2 and the upper shear box 1 are made of metal, resin or plastic; the structural material 4 is one or a combination of a soil-structure interface, concrete, soil and wood, and soil and steel.

[0081] The tangential loading unit is arranged on the outer side wall of the lower shear box 2, and the tangential loading unit is used to apply a horizontal pressure to the soil to be tested 3 so that the soil to be tested 3 interacts with the structural material 4 to form a shear force.

[0082] Specifically, a discontinuous plane composed of a plurality of micro loading heads 8 is used to apply a constant normal stiffness boundary condition to the soil to be tested 3. During the shearing process, when the soil to be tested 3 undergoes discontinuous deformation (for example, the soil to be tested 3 corresponding to below some of the micro loading heads 8 bulges or sags due to the shearing process), each micro loading head 8 and the elastic unit 7 cooperate together to ensure that each point in the soil to be tested 3 adapts to the constant stiffness boundary condition. For example, when the soil to be tested 3 corresponding to below the micro loading head 8 bulges, the soil to be tested 3 gives an extrusion force to the elastic unit 7 through the micro loading head 8, and the micro loading head 8 compresses the corresponding elastic unit 7. The elastic unit 7 will contact the upper normal loading plate 6 when receiving the extrusion force, avoiding the situation where the normal pressure is zero; each micro spring unit body corresponding to below each micro loading head 8 can undergo shear deformation according to a situation more conforming to the natural real soil during the shearing process and is not restricted by the micro loading head 8.

[0083] As an optional implementation manner, the total lower surface area of the plurality of micro loading heads 8 is equal to the upper surface area of the soil to be tested 3 contained in the upper shear box 1.

[0084] As an optional implementation manner, the loading surface area of the normal loading plate 6 is equal to the upper surface area of the soil to be tested 3.

[0085] As an optional implementation manner, the soil stiffness test element includes: a first bending element 9 and a second bending element 10.

[0086] The first bending element 9 is arranged at the center of the first side wall of the upper shear box 1 along the shearing direction, and the second bending element 10 is arranged at the center of the second side wall of the upper shear box 1 along the shearing direction. The first bending element 9 and the second bending element 10 are fixed on the corresponding side walls by means of drilling or gluing.

[0087] As an optional implementation manner, the interface area of the structural material 4 contained in the lower shear box 2 is larger than the lower surface area of the soil to be tested 3 in the upper shear box 1 to ensure that the area of the shear surface remains constant.

[0088] As an alternative embodiment, the tangential loading unit includes a tangential loading head 11.

[0089] The tangential loading head 11 is disposed on the outer side wall of the lower shear box 2. The tangential loading head 11 is configured to apply a horizontal pressure to the soil sample 3 to be tested, so that the soil sample 3 to be tested interacts with the structural material 4 to generate a shear force. Wherein, the tangential loading head 11 is fixed to the outer side wall of the lower shear box 2 by pins and rings.

[0090] Beneficial effects:

[0091] (1) Before the interface shear test, the stiffness of the soil sample to be tested is measured, and the applied normal stiffness is adjusted to match it, which is more in line with the actual engineering situation, and this stiffness matching method is not available in the related art.

[0092] (2) By applying the constant normal stiffness boundary condition to the soil sample to be tested through the discontinuous plane composed of multiple micro-spring units, when the soil sample to be tested undergoes discontinuous deformation during the shear process, each micro-loading head 8 and the elastic unit 7 cooperate together to ensure that each point in the soil sample to be tested adapts to the constant stiffness boundary condition.

[0093] Based on the same inventive concept, an embodiment of the present application further provides a test method based on the above-mentioned soil-structure interface shear normal stiffness adaptation and adjustment device, including:

[0094] (1) Install the specimen: First, install the prefabricated structural material 4 in the lower shear box 2, and then place the soil sample 3 to be tested in the upper shear box 1.

[0095] (2) Pre-consolidation of the soil sample 3 to be tested: Operate the normal loading head 5 through the control system to gradually apply a normal pressure to the soil sample 3 to be tested until a preset pressure threshold is reached (that is, finally apply a preset normal pressure of a preset magnitude).

[0096] (3) Measure the stiffness of the soil sample 3 to be tested: Start the soil stiffness measurement system to measure the stiffness of the soil sample 3 to be tested under the corresponding normal pressure.

[0097] (4) Loading stiffness adaptation: Select the corresponding elastic unit 7 to make it the same as the measured stiffness of the soil sample 3 to be tested, and then arrange it at the corresponding position.

[0098] (5) Interface shear test: Operate the normal loading head 5 through the control system to apply the corresponding normal pressure to the preset pressure threshold again, keep the position of the normal loading plate 6 fixed, and according to the test plan, operate the tangential loading head 11 to complete the soil-underground structure interface shear test to obtain the corresponding shear test results.

[0099] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0100] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present application.

Claims

1. A method for adapting and adjusting the shear normal stiffness of a soil structure interface, characterized in that: The soil structure interface shear normal stiffness adaptation and adjustment method comprises: Before the shear test begins, the stiffness of the soil to be tested is measured using the stiffness adjustment module to obtain the stiffness measurement result of the soil to be tested; According to the stiffness measurement result of the soil body to be tested, a plurality of mutually independent microspring units are installed between the normal loading unit and the upper surface of the soil body to be tested; the plurality of microspring units form an array structure covering the upper surface of the soil body to be tested, and each of the microspring units can move independently; the stiffness of the microspring unit is equal to the stiffness measurement result of the soil body to be tested, so that the normal stiffness at the boundary of the soil body to be tested during the shear test is consistent with the stiffness of the soil body to be tested, and the adaptation of the shear normal stiffness of the soil structure interface is completed; wherein, the microspring unit comprises: an elastic unit and a microloading head, the elastic unit is respectively connected to the normal loading unit and the corresponding microloading head, each of the microloading heads is respectively in contact with the soil body to be tested, the stiffness of each elastic unit is adapted to the stiffness of the soil body to be tested at the corresponding loading point, and each of the microloading heads moves independently; At the same time, the pressure changes of the soil at each loading point during the shear test are measured in real time to obtain the corresponding soil pressure monitoring results, and the soil pressure monitoring results are used to verify whether the adapted constant stiffness boundary meets the preset conditions.

2. A soil structure interface shear normal stiffness adaptation and adjustment device, characterized in that: The soil structure interface shear normal stiffness adaptation and adjustment device is used to implement the soil structure interface shear normal stiffness adaptation and adjustment method described in claim 1, and the soil structure interface shear normal stiffness adaptation and adjustment device includes: a discretized microspring stiffness adaptation assembly module and a stiffness adjustment module; The discrete microspring stiffness adaptation assembly module comprises: a plurality of mutually independent microspring units, each of which is installed between a normal loading unit and an upper surface of a soil body to be tested, and each of which is used to perform stiffness adaptation on the soil body to be tested at a corresponding loading point; A plurality of microspring units form an array structure covering the upper surface of the soil body to be tested, and each of the microspring units can move independently; the microspring unit comprises an elastic unit and a microloading head, the elastic unit is respectively connected to the normal loading unit and the corresponding microloading head, each of the microloading heads is respectively in contact with the soil body to be tested, the stiffness of each of the elastic units is adapted to the stiffness of the soil body to be tested at the corresponding loading point, and each of the microloading heads moves independently; The stiffness adjustment module is used for: Before the shear test begins, the stiffness of the soil to be tested is measured to obtain the stiffness measurement result of the soil to be tested; According to the stiffness measurement result of the soil body to be tested, the stiffness of the microspring unit is adjusted to be equal to the stiffness measurement result of the soil body to be tested, so that the normal stiffness at the boundary of the soil body to be tested during the shear test is consistent with the stiffness of the soil body to be tested, and the adaptation of the shear normal stiffness of the soil structure interface is completed; The pressure changes of each loading point of the soil to be tested during the shear test are measured in real time to obtain the corresponding soil pressure monitoring results, and the soil pressure monitoring results are used to verify whether the adapted constant stiffness boundary meets the preset conditions.

3. The soil structure interface shear normal stiffness adaptation and adjustment device according to claim 2 is characterized in that: The size of each microspring unit body is less than or equal to 10 times the average particle size of the soil to be tested.

4. The soil structure interface shear normal stiffness adaptation and adjustment device according to claim 2 is characterized in that: The normal loading unit comprises: a normal loading head and a normal loading plate; The normal loading plate is located below the normal loading head, and the normal loading plate is connected to each of the elastic units; The normal loading head is used to apply a normal pressure of a preset magnitude to the elastic unit through the normal loading plate; The normal loading plate is used to disperse and apply the corresponding normal pressure to the corresponding elastic unit.

5. The soil structure interface shear normal stiffness adaptation and adjustment device according to claim 4, characterized in that: The difference in stiffness between the normal loading plate and the soil to be tested is greater than a preset threshold.

6. The soil structure interface shear normal stiffness adaptation and adjustment device according to claim 2, characterized in that: The elastic unit is a spring.

7. The soil structure interface shear normal stiffness adaptation and adjustment device according to claim 4, characterized in that: The stiffness adjustment module includes: a soil stiffness test element and a micro-spring unit stiffness control element; The soil stiffness testing element is installed on the shear box, and the microspring unit stiffness regulating element is located on the normal loading plate; The soil stiffness testing element is used to measure the stiffness of the soil to be tested before the shear test begins, and obtain the stiffness measurement result of the soil to be tested; The microspring unit stiffness regulating element is used to determine the stiffness of the microspring unit to be installed according to the stiffness measurement result of the soil body to be measured.

8. The soil structure interface shear normal stiffness adaptation and adjustment device according to claim 7, characterized in that: The stiffness adjustment module also includes: A plurality of micro pressure test elements are fixed on the lower surface of the corresponding micro spring unit body, and are used to measure the pressure change of each point of the soil to be tested during the shear test in real time to obtain the corresponding soil pressure monitoring results.

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