Shear creep tester and test method for in-situ slip band soil

Abstract

The invention discloses a shear creep tester for in-situ slip zone soil and a test method, and relates to the technical field of rock-soil in-situ tests.The shear creep tester comprises a shear box, a shear load system, a normal load system and a ball row structure, and the shear box comprises an upper pressure box and a lower pressure box; the shear load system comprises a first spherical base, a shear stiffness self-adaptive loading assembly and a shear displacement sensor, and the shear displacement sensor is used for measuring the shear displacement of the shear box; the normal loading system comprises a second spherical base, a normal stiffness self-adaptive loading assembly and a normal displacement sensor, and the normal displacement sensor is used for measuring the normal compression amount of the soil body sample in the shear box; the ball row structure is suitable for reducing friction force between the normal rigidity self-adaptive loading assembly and the upper pressure box. The problems that the loading direction and the loading stability are controlled in an existing in-situ slip band soil shear creep test, and a slip band soil microstructure evolution detection device is lacked are solved.

Description

Technical Field

[0001] The invention relates to the technical field of rock and soil in-situ testing, and more specifically to a shear creep testing instrument and a testing method for in-situ sliding zone soil. Background Art

[0002] The long-term shear strength index of large-scale accumulation landslide, especially the shear strength index of weak layer sliding zone, plays a vital role in the stability calculation of accumulation layer landslide.

[0003] The on-site in-situ shear creep test has little disturbance to the in-situ sample, and the test state is more consistent with the actual state of the soil. Therefore, the shear strength parameters of the sample obtained are more realistic. It is one of the important means of in-situ landslide testing.

[0004] At present, most of the shear creep tests of sliding zone soil are indoor tests of small-scale remolded soil, which can hardly objectively reflect the mechanical properties of the original sliding zone soil under the real geological environment. The in-situ shear creep test of sliding zone soil is an ideal test method to obtain the in-situ sliding zone parameters, but due to the constraints of the complex field environment of landslides, the loading angle and stability servo control problems in the in-situ sliding zone soil shear creep test have not been effectively solved.

[0005] Moreover, there is a lack of equipment to detect the mesostructural evolution of sliding zone soil during the shear creep test, and it is impossible to establish the relationship between the shear mechanical parameters of sliding zone soil and the mesostructural damage evolution, which greatly limits the in-situ macro- and meso-integrated degradation evolution research of sliding zone soil. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a shear creep tester and test method for in-situ sliding zone soil, so as to solve the technical problems of controlling the loading direction and loading stability of in-situ sliding zone soil shear creep tests in existing in-situ shear tests and the lack of a device for detecting the micro-structural evolution of sliding zone soil.

[0007] To achieve the above object, the first object of the present invention is to provide a shear creep tester for in-situ sliding zone soil, comprising: A shear box, in which a soil sample is placed, the shear box comprises an upper pressure box and a lower pressure box stacked in parallel; A shear load system, comprising a first spherical base and a shear stiffness adaptive loading assembly installed on one side of the shear box, and a shear displacement sensor installed on an adjacent side of the shear box, wherein one end of the shear stiffness adaptive loading assembly is connected to the first spherical base, and the other end is connected to the side wall of the upper pressure box, and the shear displacement sensor is used to measure the shear displacement of the shear box; A normal load system is vertically mounted on the top of the shear box, the normal load system comprises a second spherical base and a normal stiffness adaptive loading assembly connected in sequence, and a normal displacement sensor mounted between the upper pressure box and the side of the normal stiffness adaptive loading assembly, the normal displacement sensor being used to measure the normal compression of the soil sample in the shear box; A ball row structure is installed between the end faces of the normal stiffness adaptive loading assembly and the upper pressure box that contact each other, and the ball row structure is suitable for reducing the friction between the normal stiffness adaptive loading assembly and the upper pressure box when the shear stiffness adaptive loading assembly is loaded on the upper pressure box.

[0008] Preferably, it also includes: A support and fixing system is installed on the side wall of the lower pressure box, and the support and fixing system and the shear load system are respectively located on two sides of the shear box; An ultrasonic probe is installed on the outer surface of the shear box, and is used for emitting ultrasonic waves and connecting to an ultrasonic imager after the ultrasonic waves are transmitted in the upper pressure box and the lower pressure box.

[0009] Preferably, the supporting and fixing system includes a fixedly arranged third pad and a pressure plate connected between the third pad and the lower pressure box.

[0010] Preferably, the shear stiffness adaptive loading assembly includes a first energy storage chamber, a first loading cylinder, a first telescopic adjustable screw, a shear load sensor and a shear pressure plate, one end of the first telescopic adjustable screw is inserted into the first energy storage chamber, and the other end is hinged in the first spherical base through a ball, one end of the first loading cylinder is inserted and connected to a side of the first energy storage chamber away from the first telescopic adjustable screw, and the other end is connected to the shear pressure plate through the shear load sensor, and the end of the shear pressure plate facing away from the shear load sensor is connected to the side wall of the lower pressure box.

[0011] Preferably, the normal stiffness adaptive loading assembly includes a second energy storage chamber, a second loading cylinder, a second telescopic adjustable screw, a normal load sensor and a four-wing force transmission plate, one end of the second telescopic adjustable screw is inserted into the second energy storage chamber, and the other end is hinged in the second spherical base through a ball, one end of the second loading cylinder is inserted into and connected to a side of the second energy storage chamber away from the second telescopic adjustable screw through the normal load sensor, and the other end is connected to the ball row structure through the four-wing force transmission plate, and one end of the ball row structure facing away from the normal stiffness adaptive loading assembly is connected to the top surface of the upper pressure box.

[0012] Preferably, the ball row structure includes a cover plate connected between the upper pressure box and the four-wing force transmission plate, a lower ball row and an upper ball row located on the cover plate, and balls arranged between the lower ball row and the upper ball row, a groove extending along the shear direction is arranged between the lower ball row and the upper ball row, and the balls are suitable for rolling in the groove.

[0013] Preferably, the grooves are evenly arranged in multiple rows, and multiple balls are arranged in each row of the grooves, and the top ends of the balls are in contact with the lower surface of the bottom plate of the four-wing force transmission plate, and the bottom ends of the balls are in contact with the upper surface of the cover plate.

[0014] Preferably, the ultrasonic probe includes a transmitting end and a receiving end; the shear box is evenly provided with a plurality of the receiving ends on the side wall in the shear direction, the shear box is evenly provided with a plurality of the receiving ends on the side wall perpendicular to the shear direction, and the cover plate is evenly provided with a plurality of the transmitting ends on the bottom surface facing the upper pressure box.

[0015] Preferably, the first spherical base comprises a first fixed pad and a first base connected to the first pad, and a side of the first base away from the first pad is hingedly connected to the spherical end of the first telescopic adjustable screw; The second spherical base includes a fixed second pad and a second base connected to the second pad, and a side of the second base away from the second pad is hingedly connected to the ball end of the second telescopic adjustable screw.

[0016] The second object of the present invention is to provide a shear test method for in-situ sliding zone soil, using the above-mentioned shear creep tester for in-situ sliding zone soil, the test method comprises: Step S 100 : At the selected test site of the in-situ sliding zone soil, soil samples are cut and made, and shear boxes are placed; Step S 200 : Flatten the top of the soil sample inside the shear box, then install the ball row structure and the normal load system in sequence, pour concrete between the normal load system and the surrounding rock, start the normal load system to apply pressure, so that the normal load system is tightly combined with the shear box; Step S 300 : Install the shear load system in the shear direction, pour concrete between the shear load system and the surrounding rock, start the shear load system to apply pressure, so that the shear load system is tightly combined with the shear box; Step S 400: After debugging the shear load system and the normal load system, install and turn on the ultrasonic probe, and communicate with the ultrasonic imager to perform real-time scanning and imaging; Step S 500 : The shear displacement sensor is reset to zero, the normal load system is loaded to the set normal pressure, the shear load system is loaded to the set shear force, and the creep test is carried out.

[0017] Compared with the prior art, the present invention has the following advantages and effects: 1. The shear creep tester in the present invention is composed of a shear box, a shear load system, a normal load system and a ball row structure, wherein the shear box is composed of an upper pressure box and a lower pressure box stacked in parallel to each other in order to apply vertical and horizontal loads to the soil sample and simulate the stress state of the actual soil in the stratum; the shear load system is used to apply shear force, and the shear load system is composed of a first spherical base, a shear stiffness adaptive loading component and a shear displacement sensor, the first spherical base can provide a flexible connection point, allowing the shear stiffness adaptive loading component to rotate freely during the shearing process, reducing the additional stress caused by the installation error, and the shear stiffness adaptive loading component can automatically adjust the applied shear force according to the shear stiffness of the soil sample, ensuring the uniformity and continuity of the load during the test. The shear displacement sensor is used to measure the shear displacement of the shear box, providing data support for analyzing the shear deformation characteristics of the soil sample. The normal load system is used to apply vertical pressure. The normal load system is installed vertically on the top of the shear box. The normal load system consists of a second spherical base, a normal stiffness adaptive loading assembly and a normal displacement sensor. The normal stiffness adaptive loading assembly can automatically adjust the applied vertical pressure according to the normal stiffness of the soil sample to ensure the uniformity and continuity of the load during the test. The normal displacement sensor is installed between the upper pressure box and the side of the normal stiffness adaptive loading assembly. The normal displacement sensor is used to measure the normal compression of the soil sample in the shear box. The ball row structure is used to reduce the friction of the shear box when applying the load, ensure the accurate transmission of the load, and reduce the friction between the normal stiffness adaptive loading assembly and the upper pressure box. Through the shear load system and the normal load system, the shear force and vertical pressure applied to the soil sample can be accurately controlled to simulate the stress state of the actual soil in the stratum. Shear displacement sensors and normal displacement sensors can monitor the shear displacement and normal compression of soil samples in real time. Through the data of shear displacement and normal compression, the shear strength, compression characteristics and creep behavior of soil samples can be analyzed, providing a scientific basis for evaluating the stability of soil and designing anti-landslide structures.

[0018] 2. The shear creep tester for in-situ sliding zone soil in the embodiment of the present invention has a simple structure and is easy to operate. It can not only measure the cohesion c and internal friction angle φ of the sliding zone, but also be applicable to the in-situ sliding zone soil shear creep test requirements with different sliding zone inclination angles, improve the normal load stability of the in-situ sliding zone soil shear creep test, and is suitable for in-situ shear creep tests and structural scanning of sliding zone soil in cavern environmental conditions, soil or soft rock landslides. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the three-dimensional structure of a shear creep tester for in-situ sliding zone soil in an embodiment of the present invention; Figure 2 It is a schematic diagram of the main structure of a shear creep tester for in-situ sliding zone soil in an embodiment of the present invention; Figure 3 It is a schematic diagram of the exploded structure of the shear box and the ultrasonic probe in an embodiment of the present invention; Figure 4 Schematic diagram of the decomposed structure of the shear load system in an embodiment of the present invention; Figure 5 This is a schematic diagram of the test installation structure of the in-situ sliding zone soil shear creep tester according to an embodiment of the present invention; Figure 6 It is a schematic flow chart of the shear test method for in-situ sliding zone soil in an embodiment of the present invention.

[0020] Description of reference numerals: 10- shear box; 11-upper pressure box; 12-lower pressure box; 20-Shear load system; 21-first spherical base; 211-first pad; 212-first base; 22-shear stiffness adaptive loading assembly; 221-first energy storage chamber; 222-first loading cylinder; 223-first telescopic adjustable screw; 224-shear load sensor; 225-shear bearing plate; 23- shear displacement sensor; 30-Normal load system; 31-second spherical base; 311-second pad; 312-second base; 32-normal stiffness adaptive loading assembly; 321-second energy storage chamber; 322-second loading cylinder; 323-second telescopic adjustable screw; 324-normal load sensor; 325-four-wing force transmission plate; 33-Normal displacement sensor; 40-ball row structure; 41-cover plate; 42-lower ball row; 43-ball; 44-upper ball row; Ultrasonic probe; 51-transmitting end; 52-receiving end; 60-supporting and fixing system; 61 - the third pad; 62 - the pressure plate. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] See also Figure 1-5 As shown, an embodiment of the present invention provides a shear creep tester for in-situ sliding zone soil, the shear creep tester comprising a shear box 10, a shear load system 20, a normal load system 30 and a ball row structure 40, wherein: In order to apply vertical and horizontal loads to the soil sample and simulate the stress state of the actual soil in the stratum, the shear box 10 in this embodiment includes an upper pressure box 11 and a lower pressure box 12 stacked in parallel. The shear box 10 is used to accommodate soil samples and apply vertical and horizontal loads to simulate the stress state of the soil in the stratum.

[0024] The shear load system 20 is used to apply shear force. The shear load system 20 in this embodiment includes a first spherical base 21, a shear stiffness adaptive loading component 22 and a shear displacement sensor 23. The first spherical base 21 and the shear stiffness adaptive loading component 22 are installed on one side of the shear box 10, and the shear displacement sensor 23 is installed on the adjacent side of the shear box 10. One end of the shear stiffness adaptive loading component 22 is connected to the first spherical base 21, and the other end is connected to the side wall of the upper pressure box 11. In this way, the first spherical base 21 can provide a flexible connection point, allowing the shear stiffness adaptive loading component 22 to rotate freely during the shearing process, reducing the additional stress caused by installation errors. The shear stiffness adaptive loading component 22 can automatically adjust the applied shear force according to the shear stiffness of the soil sample to ensure the uniformity and continuity of the load during the test. The shear displacement sensor 23 is used to measure the shear displacement of the shear box 10 to provide data support for analyzing the shear deformation characteristics of the soil sample.

[0025] The normal load system 30 is used to apply vertical pressure. The normal load system 30 in this embodiment is vertically installed on the top of the shear box 10. The normal load system 30 includes a second spherical base 31, a normal stiffness adaptive loading assembly 32 and a normal displacement sensor 33. Similar to the first spherical base 21, the second spherical base 31 in this embodiment is used to provide a flexible connection point in the normal direction. For this purpose, the second spherical base 31 and the normal stiffness adaptive loading assembly 32 are connected in sequence. The normal stiffness adaptive loading assembly 32 can automatically adjust the applied vertical pressure according to the normal stiffness of the soil sample to ensure the uniformity and continuity of the load during the test. The normal displacement sensor 33 is installed between the upper pressure box 11 and the side of the normal stiffness adaptive loading assembly 32. The normal displacement sensor 33 is used to measure the normal compression of the soil sample in the shear box 10.

[0026] The ball row structure 40 is used to reduce the friction of the shear box 10 when the load is applied to ensure the accurate transfer of the load. The ball row structure 40 in this embodiment is installed between the end faces of the normal stiffness adaptive loading assembly 32 and the upper pressure box 11 that contact each other, and the ball row structure 40 is suitable for reducing the friction between the normal stiffness adaptive loading assembly 32 and the upper pressure box 11 when the shear stiffness adaptive loading assembly 22 is loaded on the upper pressure box 11.

[0027] Specifically in the present embodiment, the shear force and vertical pressure applied to the soil sample can be accurately controlled by the shear load system 20 and the normal load system 30 to simulate the stress state of the actual soil in the stratum. For example, during the test, the soil sample is first compressed to a certain stress level, and then the shear force is applied to observe the deformation and failure process of the soil sample. By analyzing these data, the behavior of the soil sample under different stress states can be understood. The shear displacement sensor 23 and the normal displacement sensor 33 can monitor the shear displacement and normal compression of the soil sample in real time. Through the data of the shear displacement and normal compression, the shear strength, compression characteristics and creep behavior of the soil sample can be analyzed, providing a scientific basis for evaluating the stability of the soil and designing anti-landslide structures.

[0028] Therefore, the shear creep tester for in-situ sliding zone soil in the embodiment of the present invention has a simple structure and is easy to operate. It can not only measure the cohesion c and internal friction angle φ of the sliding zone, but also is applicable to the in-situ sliding zone soil shear creep test requirements with different sliding zone inclination angles, improves the normal load stability of the in-situ sliding zone soil shear creep test, and is applicable to in-situ shear creep tests and structural scanning of sliding zone soil in cavern environmental conditions, soil or soft rock landslides.

[0029] It is necessary to further explain that the so-called shear box refers to a device used in the on-site shear test of the landslide body or landslide zone, and its purpose is to obtain the shear strength value of the weak interlayer or rock mass section of the landslide. The shear box is used to conduct shear tests on soil samples directly in the landslide body or landslide zone to simulate the shearing effect of the soil in the actual environment, so as to obtain shear strength parameters that are closer to the actual ones.

[0030] Creep refers to the deformation of a material over time under constant stress. In the shear creep test of sliding zone soil, the following stages can be observed: decay creep (creep rate decreases), steady-state creep (creep rate is roughly constant), metastable creep (creep rate is constant but greater than 0), and accelerated creep (creep rate increases rapidly).

[0031] The shear deformation law of soil can be analyzed through the relationship curve between shear stress and shear displacement. During the shear process, the soil first reaches the peak strength, then transitions to the softening stage, and continues to load, the soil particles are rearranged, and the strength is reduced to the residual strength.

[0032] In-situ shear tests can obtain the regeneration strength and residual strength values ​​of sliding zone soil. These parameters are of great significance for analyzing shear strength and determining the shear strength index of landslides.

[0033] For further information, see Figure 1 , 2 As shown, the shear creep tester further includes an ultrasonic probe 50 and a support and fixing system 60, wherein: The support and fixing system 60 is installed on the side wall of the lower pressure box 12 , and the support and fixing system 60 and the shear load system 20 are respectively located on two sides of the shear box 10 .

[0034] The ultrasonic probe 50 is mounted on the outer surface of the shear box 10 . The ultrasonic probe 50 is used to emit ultrasonic waves and transmit them in the upper pressure box 11 and the lower pressure box 12 before being connected to an ultrasonic imager.

[0035] Specifically in this embodiment, the ultrasonic probe 50 is installed in an array form on the outer walls of the upper pressure box 11 and the lower pressure box 12 and the lower surface of the ball row structure 40, and then the lower surface of the ball row structure 40 is in direct contact with the sample to detect the microstructure of the sample during the shear creep test.

[0036] For further information, see Figure 1 , 2 As shown in FIG. 3 , the supporting and fixing system 60 includes a third pad 61 and a pressure plate 62 , wherein the third pad 61 is fixedly arranged, and the pressure plate 62 is connected between the third pad 61 and the lower pressure box 12 .

[0037] For further information, see Figure 1 , 2 As shown, the shear stiffness adaptive loading assembly 22 includes a first energy storage chamber 221, a first loading cylinder 222, a first telescopic adjustable screw 223, a shear load sensor 224 and a shear pressure plate 225, wherein one end of the first telescopic adjustable screw 223 is inserted into the first energy storage chamber 221, and the other end is hinged in the first spherical base 21 through a ball, one end of the first loading cylinder 222 is inserted and connected to the side of the first energy storage chamber 221 away from the first telescopic adjustable screw 223, and the other end is connected to the shear pressure plate 225 through the shear load sensor 224, and the end of the shear pressure plate 225 facing away from the shear load sensor 224 is connected to the side wall of the lower pressure box 12.

[0038] Specifically in this embodiment, one end of the first telescopic adjustable screw 223 is spherical and fits with the first base 212, and the other end is inserted into the first energy storage chamber 221. The end of the first energy storage chamber 221 away from the first telescopic adjustable screw 223 is connected to the first loading cylinder 222. When the first loading cylinder 222 is charged, the pressure in the first energy storage chamber 221 increases, and the first telescopic adjustable screw 223 extends outward; when the first loading cylinder 222 is unloaded, the pressure in the first energy storage chamber 221 decreases, and the first telescopic adjustable screw 223 retracts inward. The end of the shear pressure plate 225 away from the shear load sensor 224 is welded to the upper pressure box 11, and the end of the shear pressure plate 225 close to the shear load sensor 224 is in contact with the shear load sensor 224. The shear load sensor 224 is used to measure the shear load loaded on the sample. It should be noted that the servo valve on the first energy storage chamber 221 is controlled by the controller software in the computer, and can accurately adjust the hydraulic pressure in the chamber, thereby controlling the size of the normal and shear loads.

[0039] For further information, see Figure 1 , 2 As shown, the normal stiffness adaptive loading assembly 32 includes a second energy storage chamber 321, a second loading cylinder 322, a second telescopic adjustable screw 323, a normal load sensor 324 and a four-wing force transmission plate 325, one end of the second telescopic adjustable screw 323 is inserted into the second energy storage chamber 321, and the other end is hinged in the second spherical base 31 through a ball, one end of the second loading cylinder 322 is inserted and connected to the side of the second energy storage chamber 321 away from the second telescopic adjustable screw 323 through the normal load sensor 324, and the other end is connected to the ball row structure 40 through the four-wing force transmission plate 325, and the end of the ball row structure 40 away from the normal stiffness adaptive loading assembly 32 is connected to the top surface of the upper pressure box 11.

[0040] Specifically in this embodiment, the normal stiffness adaptive loading assembly 32 is composed of a second energy storage chamber 321, a second loading cylinder 322, a second telescopic adjustable screw 323, a normal load sensor 324 and a four-wing force transmission plate 325. The normal stiffness adaptive loading assembly 32 can be used for adaptive adjustment of the normal loading stiffness during in-situ shear creep tests of sliding belts with different inclination angles. One end of the second loading cylinder 322 is connected to the upper pressure box 11 through a four-wing force transmission plate 325, and the other end of the second loading cylinder 322 is connected to the second energy storage chamber 321 through a normal load sensor 324. The second loading cylinder 322 is also connected to the servo control system. When the normal load sensor 324 below the second loading cylinder 322 senses that the load amount becomes smaller due to the deformation of the cave soil, the servo control system begins to control the second loading cylinder 322 to increase the corresponding normal load, so as to realize the stiffness adaptive adjustment of the normal stiffness adaptive loading component 32; the normal load sensor 324 is located above the second loading cylinder 322, and one end of the second energy storage chamber 321 is connected to the normal load sensor 324 for measuring the normal load loaded on the sample.

[0041] Compared with the direct shear test conducted by the traditional in-situ shear instrument, when facing the soft sliding belt soil, the normal loading will not be in an unstable state due to the deformation of the soft sliding belt soil. The normal load system 30 and the shear load system 20 in the shear creep tester in the embodiment of the present invention can transmit the normal and shear load size changes to the controller software in the computer in real time, and then the software controls the servo valves on the first energy storage cavity 221 and the second energy storage cavity 321 to change the hydraulic size in the energy storage cavity, thereby offsetting the unloading force after the deformation of the soft sliding belt soil and maintaining the stability of the normal loading.

[0042] For further information, see Figure 1 , 2 As shown, in order to minimize friction, the ball row structure 40 in this embodiment includes a cover plate 41, a lower ball row 42, balls 43 and an upper ball row 44, wherein: The cover plate 41 is connected between the upper pressure box 11 and the four-wing force transmission plate 325, the lower ball row 42 and the upper ball row 44 are located on the cover plate 41, the ball 43 is arranged between the lower ball row 42 and the upper ball row 44, a groove extending along the shear direction is arranged between the lower ball row 42 and the upper ball row 44, and the ball 43 is suitable for rolling in the groove.

[0043] Specifically in this embodiment, the ball 43 is placed in the groove formed between the upper ball row 44 and the lower ball row 42, and the ball 43 rolls along the shear direction. Metal blocks are welded on both sides of the groove for limiting to prevent the ball 43 from falling out along the groove.

[0044] For further information, see Figure 1 ,2 As shown, the grooves are evenly arranged in multiple rows, and multiple balls 43 are arranged in each row of grooves, and the top ends of the balls 43 contact the lower surface of the bottom plate of the four-wing force transmission plate 325, and the bottom ends of the balls 43 contact the upper surface of the cover plate 41.

[0045] Specifically in this embodiment, seven rows of grooves are preferably set between the lower ball row 42 and the upper ball row 44, each row of grooves includes 11 balls 43, the top end of each ball 43 contacts the bottom plate of the four-wing force transmission plate 325, and the bottom end of each ball 43 contacts the upper surface of the cover plate 41.

[0046] For further information, see Figure 1-4 As shown, the ultrasonic probe 50 includes a transmitting end 51 and a receiving end 52, the shear box 10 has 40 receiving ends 52 evenly arranged on the side wall in the shear direction, the shear box 10 has 30 receiving ends 52 evenly arranged on the side wall perpendicular to the shear direction, and the cover plate 41 has 6 transmitting ends 51 evenly arranged on the bottom surface of the upper pressure box 11.

[0047] As a preferred embodiment of this embodiment, a plurality of ultrasonic probes 50 are evenly arranged in an array and connected to the ultrasonic imager via wireless communication.

[0048] The ultrasonic probe 50 in this embodiment is composed of 76 individual probes. The ultrasonic probe 50 is composed of a transmitting end 51 and a receiving end 52, which together form a transmitting source and a receiving system, both of which are wireless transmitting or receiving ultrasonic waves. The specific arrangement of the ultrasonic probe 50 is as follows: the left and right sides of the upper pressure box 11 and the lower pressure box 12 (i.e., the attached Figure 1 A total of 40 receiving ends 52 are evenly arranged on the front and back surfaces of the upper pressure box 11 and the lower pressure box 12, and a total of 30 receiving ends 52 are evenly arranged on the front and back surfaces of the upper pressure box 11 and the lower pressure box 12 to form a receiving interface. A total of 6 transmitting ends 51 are evenly arranged on the bottom surface of the cover plate 41 facing the upper pressure box 11, and these 6 transmitting ends 51 form a transmitting interface.

[0049] During operation, each transmitting end 51 transmits ultrasonic waves to propagate in the sample of the shear box 10, and each receiving end 52 receives and records the received ultrasonic waves. By analyzing and processing the ultrasonic waves, the wave velocity of the sample and the structural characteristics inside the sample can be determined.

[0050] In addition, the transmitting end 51 transmits ultrasonic waves to propagate in the sample. When encountering different media and structures, these media and structures will affect the propagation speed, amplitude, spectrum and other parameters of the ultrasonic waves. The receiving end 52 receives and records the propagated ultrasonic waves, and analyzes and studies them to determine the physical and mechanical properties of rock and soil media and structures and understand their internal structural evolution.

[0051] For example, changes in wave velocity can reflect the integrity and loosening range of the sample; the attenuation of the amplitude can reveal the physical properties of the sample; and spectrum analysis can provide information about the dynamic characteristics of the sample. Therefore, it is possible to detect the macroscopic stress-strain response and microscopic structural evolution process of sliding zone soil during the shear process, and reveal the shear creep behavior and structural change law of sliding zone soil.

[0052] For further information, see Figure 1 As shown, the first spherical base 21 includes a first pad 211 and a first base 212. The first pad 211 is fixedly arranged, and the first base 212 is connected to the first pad 211. The side of the first base 212 away from the first pad 211 is hingedly connected to the ball end of the first telescopic adjustable screw 223.

[0053] The second spherical base 31 includes a second pad 311 and a second base 312 . The second pad 311 is fixedly arranged. The second base 312 is connected to the second pad 311 . The side of the second base 312 away from the second pad 311 is hingedly connected to the spherical end of the second telescopic adjustable screw 323 .

[0054] Specifically, the spherical base in this embodiment is in contact with the pad, and the spherical end of the spherical base is connected to the adaptive compensation energy storage cavity through a telescopic adjustable threaded rod. According to the on-site environmental conditions, the spherical base can be adjusted within the angle range of 0-45 degrees, that is, it is not necessary to make the entire normal load system 30 perpendicular to the ground during loading. It is only necessary for all components in the entire normal load system 30 to remain on the same axis and perpendicular to the predetermined shear plane. This device greatly facilitates the application of normal loading and simplifies the data processing process.

[0055] See also Figure 6 As shown, an embodiment of the present invention further provides a test method for in-situ sliding zone soil, using the above-mentioned shear creep tester for in-situ sliding zone soil, the test method comprises: Step S 100 : A shear box 10 is cut and made at the selected test site of the in-situ sliding zone soil.

[0056] In this step, the specific requirements for making the shear box 10 are as follows: Cut out square columnar specimens. The geological conditions of the same group of specimens should be basically the same and as free from disturbance as possible. Each group of specimens should be no less than 5 pieces. The area of ​​each specimen should be no less than 2500cm 2 , the minimum side length shall not be less than 50cm, the height shall be 1 / 2 of the minimum side length, and the distance between specimens shall be greater than 1.5 times the minimum side length.

[0057] Step S 200: Flatten the top of the shear box 10, then install the ball row structure 40 and the normal load system 30 in sequence, pour concrete between the normal load system 30 and the surrounding rock, start the normal load system 30 to apply pressure, so that the normal load system 30 and the shear box 10 are tightly combined.

[0058] In this step, by flattening the top of the shear box 10, it is ensured that there is a good contact surface between the shear box 10 and the subsequently installed ball row structure 40 and the normal load system 30, which helps to improve the stability of the structure and the efficiency of load transfer; the installation of the ball row structure 40 can effectively reduce the friction of the shear box 10 when the load is applied, ensure the accurate transfer of the load, and reduce the additional stress caused by installation errors; the fixation between the normal load system 30 and the surrounding rock is achieved by pouring concrete, which can significantly enhance the fixing effect of the normal load system 30 and ensure the stability and reliability of the system when pressure is applied.

[0059] Step S 300 : Install the shear load system 20 in the shear direction, pour concrete between the shear load system 20 and the surrounding rock, start the shear load system 20 to apply pressure, so that the shear load system 20 and the shear box 10 are tightly combined.

[0060] In this step, the structural stability of the entire shear load system 20 can be significantly improved. The pouring of concrete helps to fix the shear load system 20 and reduce the displacement or deformation that may occur under the load, thereby improving the efficiency of load transfer.

[0061] Step S 400 After debugging the shear load system 20 and the normal load system 30, the ultrasonic probe 50 is installed and turned on, and is connected to the ultrasonic imager for real-time scanning and imaging.

[0062] In this step, the ultrasonic probe 50 is a non-destructive detection method that can image and analyze the internal structure of the soil without destroying the soil structure. Through the ultrasonic imager, detailed information inside the soil, such as the development of cracks, the distribution of deformation, etc., can be collected, providing an effective monitoring and analysis method for shear creep tests.

[0063] Step S 500 : The shear displacement sensor 23 is reset to zero, the normal load system 30 is loaded to the set normal pressure, the shear load system 20 is loaded to the set shear force, and the creep test is carried out.

[0064] In this step, after the normal load is stabilized, the shear load can be applied in stages to carry out the creep test.

[0065] For example, 3 to 5 normal loads can be taken, and 3 to 4 stress levels can be taken under each normal load.

[0066] Then, record the time and shear displacement at regular intervals. The time can be selected as: 0.2min, 0.5min, 1min, 2min, 3min, 5min, 10min, 30min, 60min... In the middle and late stages of the creep test, the readings can be taken every few hours or dozens of hours.

[0067] The creep stability standard can be taken as the change in shear strain within every 24 hours being less than 0.05‰, or the shear strain within 24 hours being less than 1‰ to 5‰ of the cumulative creep shear strain. The test can be terminated after the stability standard is reached.

[0068] Finally, the relationship curve between creep deformation and time is plotted with time as the horizontal axis and strain as the vertical axis.

[0069] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A shear creep tester for in-situ sliding zone soil, characterized in that: include: A shear box, in which a soil sample is placed, the shear box comprises an upper pressure box and a lower pressure box stacked in parallel; A shear load system, comprising a first spherical base and a shear stiffness adaptive loading assembly installed on one side of the shear box, and a shear displacement sensor installed on an adjacent side of the shear box, wherein one end of the shear stiffness adaptive loading assembly is connected to the first spherical base, and the other end is connected to the side wall of the upper pressure box, and the shear displacement sensor is used to measure the shear displacement of the shear box; A normal load system is vertically mounted on the top of the shear box, the normal load system comprises a second spherical base and a normal stiffness adaptive loading assembly connected in sequence, and a normal displacement sensor mounted between the upper pressure box and the side of the normal stiffness adaptive loading assembly, the normal displacement sensor being used to measure the normal compression of the soil sample in the shear box; A ball row structure is installed between the end faces of the normal stiffness adaptive loading assembly and the upper pressure box that contact each other, and the ball row structure is suitable for reducing the friction between the normal stiffness adaptive loading assembly and the upper pressure box when the shear stiffness adaptive loading assembly is loaded on the upper pressure box.

2. The shear creep tester for in-situ sliding zone soil according to claim 1, characterized in that: Also includes: A support and fixing system is installed on the side wall of the lower pressure box, and the support and fixing system and the shear load system are respectively located on two sides of the shear box; An ultrasonic probe is installed on the outer surface of the shear box, and is used for emitting ultrasonic waves and connecting to an ultrasonic imager after the ultrasonic waves are transmitted in the upper pressure box and the lower pressure box.

3. The shear creep tester for in-situ sliding zone soil according to claim 2, characterized in that: The supporting and fixing system comprises a fixedly arranged third pad and a pressure-bearing plate connected between the third pad and the lower pressure box.

4. The shear creep tester for in-situ sliding zone soil according to claim 2, characterized in that: The shear stiffness adaptive loading assembly includes a first energy storage chamber, a first loading cylinder, a first telescopic adjustable screw, a shear load sensor and a shear pressure plate, one end of the first telescopic adjustable screw is inserted into the first energy storage chamber, and the other end is hinged in the first spherical base through a ball, one end of the first loading cylinder is inserted and connected to the side of the first energy storage chamber away from the first telescopic adjustable screw, and the other end is connected to the shear pressure plate through the shear load sensor, and the end of the shear pressure plate facing away from the shear load sensor is connected to the side wall of the lower pressure box.

5. The shear creep tester for in-situ sliding zone soil according to claim 4, characterized in that: The normal stiffness adaptive loading assembly includes a second energy storage chamber, a second loading cylinder, a second telescopic adjustable screw, a normal load sensor and a four-wing force transmission plate, one end of the second telescopic adjustable screw is inserted into the second energy storage chamber, and the other end is hinged in the second spherical base through a ball, one end of the second loading cylinder is inserted into and connected to a side of the second energy storage chamber away from the second telescopic adjustable screw through the normal load sensor, and the other end is connected to the ball row structure through the four-wing force transmission plate, and one end of the ball row structure facing away from the normal stiffness adaptive loading assembly is connected to the top surface of the upper pressure box.

6. The shear creep tester for in-situ sliding zone soil according to claim 5, characterized in that: The ball row structure includes a cover plate connected between the upper pressure box and the four-wing force transmission plate, a lower ball row and an upper ball row located on the cover plate, and balls arranged between the lower ball row and the upper ball row, a groove extending along the shear direction is arranged between the lower ball row and the upper ball row, and the balls are suitable for rolling in the groove.

7. The shear creep tester for in-situ sliding zone soil according to claim 6, characterized in that: The grooves are evenly arranged in multiple rows, and multiple balls are arranged in each row of the grooves, and the top ends of the balls are in contact with the lower surface of the bottom plate of the four-wing force transmission plate, and the bottom ends of the balls are in contact with the upper surface of the cover plate.

8. The shear creep tester for in-situ sliding zone soil according to claim 6, characterized in that: The ultrasonic probe includes a transmitting end and a receiving end; the shear box is evenly provided with a plurality of receiving ends on the side wall in the shear direction, the shear box is evenly provided with a plurality of receiving ends on the side wall perpendicular to the shear direction, and the cover plate is evenly provided with a plurality of transmitting ends on the bottom surface facing the upper pressure box.

9. The shear creep tester for in-situ sliding zone soil according to claim 5, characterized in that: The first spherical base comprises a first fixed pad and a first base connected to the first pad, and a side of the first base away from the first pad is hingedly connected to the spherical end of the first telescopic adjustable screw; The second spherical base includes a fixed second pad and a second base connected to the second pad, and a side of the second base away from the second pad is hingedly connected to the ball end of the second telescopic adjustable screw.

10. A test method for in-situ sliding zone soil, using the shear creep tester for in-situ sliding zone soil according to any one of claims 1 to 9, characterized in that: The test method includes: Step S 100 : At the selected test site of the in-situ sliding zone soil, soil samples are cut and made, and shear boxes are placed; Step S 200 : Flatten the top of the soil sample inside the shear box, then install the ball row structure and the normal load system in sequence, pour concrete between the normal load system and the surrounding rock, start the normal load system to apply pressure, so that the normal load system is tightly combined with the shear box; Step S 300 : Install the shear load system in the shear direction, pour concrete between the shear load system and the surrounding rock, start the shear load system to apply pressure, so that the shear load system is tightly combined with the shear box; Step S 400 : After debugging the shear load system and the normal load system, install and turn on the ultrasonic probe, and communicate with the ultrasonic imager to perform real-time scanning and imaging; Step S 500 : The shear displacement sensor is reset to zero, the normal load system is loaded to the set normal pressure, the shear load system is loaded to the set shear force, and the creep test is carried out.

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