Device and method for testing unconfined compressive strength and direct shear strength of solidified soil

Abstract

The invention provides a solidified soil unconfined compressive strength and direct shear strength testing device and method.The device comprises a bottom plate, a lower shear box capable of horizontally moving is arranged on the upper side of the bottom plate, an upper shear box is arranged on the upper side of the lower shear box, and aligned through grooves are formed in the middle of the upper shear box and the middle of the lower shear box; a lantern ring matched with the corresponding through groove is inserted into each through groove, a transverse pressurizing plate capable of pushing the lower shear box to move horizontally is arranged on the side of the lower shear box, and a longitudinal pressurizing plate capable of moving longitudinally is arranged above the upper shear box. The device has the beneficial effects that the structures required for testing the unconfined compressive strength and the direct shear strength are integrated; the use is convenient and efficient, and the major problems that the sample specification of a traditional direct shear strength test device is fixed, and time and labor are consumed due to complex secondary processing of a solidified soil sample collected on site are solved; the device is convenient to use, and the test efficiency is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical testing, and in particular relates to a device and a method for testing the unconfined compressive strength and direct shear strength of solidified soil. Background Art

[0002] Solidified soil technology is a method of improving building materials by adding specific chemicals or other auxiliary materials to improve the physical and mechanical properties of natural soil, thereby transforming it into a material with higher strength and durability.

[0003] In the road and infrastructure sector, stabilized soil can be used for road bases, shoulder reinforcement, and airport runway paving, improving pavement bearing capacity and reducing maintenance costs. In environmental management, stabilized soil technology can be used to stabilize contaminated land, fixing harmful heavy metals and organic pollutants within the soil to prevent their spread while also providing a stable foundation for subsequent landscaping. The unconfined compressive strength and direct shear strength of stabilized soil are important indicators for calculating the bearing capacity of stabilized soil foundations, evaluating the effectiveness of the stabilized soil, controlling construction quality, and analyzing destructive forces.

[0004] At present, in the field of consolidated soil, the tests on the unconfined compressive strength and direct shear strength of consolidated soil have the following deficiencies: the unconfined compressive strength of consolidated soil is mainly tested using a universal testing machine, but the fixture of the universal testing machine limits the size of the specimen, and the universal testing machine is often bulky and has a relatively single function, making it difficult to adapt to on-site testing; the direct shear strength of consolidated soil is mainly tested using a soil strain-type direct shear instrument, but the strength of consolidated soil is often much higher than that of soil, and the range of the soil strain-type direct shear instrument is difficult to meet the testing requirements, and its function is single, so it can only produce a single strength and cannot perform comprehensive testing. In addition, its specimen specifications are inconsistent with the specimen size obtained on-site, requiring secondary processing, which is time-consuming and labor-intensive. Summary of the Invention

[0005] In view of this, the present invention aims to overcome the deficiencies of the above-mentioned problems in the prior art and proposes a device and a method for testing the unconfined compressive strength and direct shear strength of solidified soil.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] The unconfined compressive strength and direct shear strength testing device of solidified soil includes a base plate, a lower shear box capable of moving horizontally is provided on the upper side of the base plate, an upper shear box is provided on the upper side of the lower shear box, and aligned through grooves are provided between the upper and lower shear boxes, a sleeve matching the corresponding through groove is inserted in each through groove, a transverse pressure plate capable of pushing the lower shear box to move horizontally is provided on the side of the lower shear box, and a longitudinal pressure plate capable of moving longitudinally is provided above the upper shear box.

[0008] Furthermore, the upper shear box and the lower shear box are both rectangular structures, and multiple slide rails are fixed side by side on the upper side of the bottom plate along the horizontal movement direction of the pressure plate, and slide grooves are opened at the bottom of the lower shear box corresponding to the slide rails, and the lower shear box is slidably connected to the slide rails through the slide grooves.

[0009] Furthermore, a limit block is fixedly connected to the front end opening of the slide rail.

[0010] Furthermore, a connecting plate is vertically fixed on the rear side of the upper surface of the base plate, a transverse pressure plate is located in front of the connecting plate, and a transverse screw is horizontally fixed at the middle of the rear side of the transverse pressure plate and is arranged through the connecting plate, a first slave bevel gear is screwed on the transverse screw, a first motor is fixed on the rear side of the connecting plate, a first main bevel gear is fixed on the output shaft of the first motor, and the first main bevel gear and the first slave bevel gear are meshed.

[0011] Furthermore, support rods are vertically fixed at the four corners of the upper side of the bottom plate, and the top ends of the four support rods are commonly fixed to the top plate. A longitudinal screw rod passing through the top plate is fixed at the middle of the upper side of the longitudinal pressure plate, and a second slave bevel gear is screwed on the longitudinal screw rod. A second motor is fixed on the upper side of the top plate, and a second main bevel gear is fixed on the output shaft of the second motor, and the second main bevel gear and the second slave bevel gear are meshed.

[0012] Furthermore, a longitudinal pressure sensor is provided on the longitudinal pressure plate, a transverse pressure sensor is provided on the transverse pressure plate, and a controller is provided on the upper side of the top plate. The longitudinal pressure sensor, transverse pressure sensor, first motor and second motor are all connected to the controller.

[0013] Furthermore, the cross section of the through groove is a circular structure, the outer surface of the collar is a cylindrical structure, and the cross section of the through hole inside the collar is a circular structure, a square structure, a triangular structure or a rectangular structure.

[0014] Furthermore, handles are fixedly connected to the front sides of the upper shear box and the lower shear box.

[0015] The present application also discloses a test method based on the above-mentioned solidified soil unconfined compressive strength and direct shear strength test device, including an unconfined compressive strength test method and a direct shear strength test method, wherein the unconfined compressive strength test method includes the following steps:

[0016] A. Prepare the first specimen, which is cylindrical and has a height-to-diameter ratio of 1:1;

[0017] B. Place a pad covering the through slot on the upper side of the upper shear box. Place the first specimen on the pad, aligning the center of the first specimen with the center of the longitudinal pressure plate.

[0018] C. Set the longitudinal load rate and test end conditions through the controller;

[0019] D. Start the test, pressing the longitudinal compression plate downward on the specimen under the conditions of step C, and record the changes in the longitudinal stress, longitudinal displacement, and strain of the first specimen during the test until the set test end conditions are met;

[0020] The direct shear strength test method includes the following steps:

[0021] a. Prepare the second sample;

[0022] b. Align the upper and lower shear boxes, select an appropriate collar based on the diameter of the second specimen, fill both collars with the second specimen, and then place the collar and the second specimen into the central slots of the upper and lower shear boxes, ensuring that the collars are installed in the corresponding slots.

[0023] c. Set the longitudinal load rate, longitudinal load holding time, shear rate, and shear end conditions through the controller;

[0024] d. Start the test, causing the longitudinal compression plate to apply longitudinal stress to the second specimen and the upper and lower shear boxes at the set longitudinal load rate and longitudinal load holding time. After the longitudinal stress remains stable, cause the transverse compression plate to apply shear force to the lower shear box at the set shear rate to shear the second specimen. Record changes in longitudinal stress, transverse stress, and transverse displacement during the test until the set shear end condition is met.

[0025] Furthermore, in step b, the collar and the sample, the collar and the upper shear box and the lower shear box are tightly fitted, and when there are gaps between the collar and the sample, the collar and the upper shear box and the lower shear box, the gaps are filled with fine sand.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The device for testing the unconfined compressive strength and direct shear strength of consolidated soil described in the present invention integrates the structures required for unconfined compressive strength and direct shear strength tests, and the two can work simultaneously or independently without the need to replace equipment. Moreover, when conducting direct shear strength tests, samples of different specifications can be used for direct shear tests by cooperating with the sleeve, which is convenient and efficient, and solves the major problems of traditional direct shear strength testing devices in which sample specifications are fixed and consolidated soil samples taken on site need to undergo complex secondary processing that is time-consuming and labor-intensive. The device is easy to use and greatly improves test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0029] Figure 1This is a schematic structural diagram of a device for testing the unconfined compressive strength and direct shear strength of solidified soil according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic structural diagram of the unconfined compressive strength and direct shear strength testing device for solidified soil according to an embodiment of the present invention, with the upper shear box and the lower shear box removed;

[0031] Figure 3 This is a structural schematic diagram of the unconfined compressive strength and direct shear strength testing device for solidified soil according to an embodiment of the present invention, viewed from the rear side after removing the upper shear box and the lower shear box.

[0032] Description of reference numerals:

[0033] 1. Bottom plate; 2. Lower shear box; 201. Slide groove; 3. Horizontal pressure plate; 4. Longitudinal pressure plate; 5. Upper shear box; 6. Ring; 7. Slide rail; 701. Limit block; 8. Through groove; 9. Connecting plate; 10. Horizontal screw; 11. Horizontal pressure sensor; 12. Longitudinal screw; 13. Longitudinal pressure sensor; 14. Top plate; 15. Second motor; 16. Controller; 17. First motor; 18. Support rod; 19. Reinforcement rib; 20. Handle. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0038] As shown in the figure, the unconfined compressive strength and direct shear strength testing device of solidified soil includes a base plate 1, a lower shear box 2 which can move horizontally is provided on the upper side of the base plate 1, an upper shear box 5 is provided on the upper side of the lower shear box 2, and aligned through grooves 8 are provided between the upper shear box 5 and the lower shear box 2, and a ring 6 which is adapted to the corresponding through groove 8 is inserted in each through groove 8, a transverse pressure plate 3 which can push the lower shear box 2 to move horizontally is provided on the side of the lower shear box 2, and a longitudinal pressure plate 4 which can move longitudinally is provided above the upper shear box 5.

[0039] The upper shear box 5 and the lower shear box 2 are both rectangular structures. In order to save materials, the rectangular structure can be set as a shell structure with a hollow interior. A plurality of slide rails 7 are fixedly connected side by side on the upper side of the bottom plate 1 along the moving direction of the transverse pressure plate 3, and a slide groove 201 is provided at the bottom of the lower shear box 2 corresponding to the slide rail 7, and the lower shear box 2 is slidably connected to the slide rail 7 through the slide groove 201. In this embodiment, the transverse pressure plate 3 corresponds to the middle of the rear side of the lower shear box 2, so that the lower shear box 2 can move smoothly when the lower shear box 2 is pushed. Of course, a slider that cooperates with the slide rail 7 can also be fixed at the bottom of the lower shear box 2 corresponding to the slide rail 7, and the lower shear box 2 is slidably connected to the slide rail 7 through the slider.

[0040] A limiting block 701 is fixedly connected to the front end opening of the slide rail 7 to limit the lower shear box 2 and prevent the lower shear box 2 from separating from the slide rail 7.

[0041] A connecting plate 9 is vertically fixed to the rear side of the upper surface of the base plate 1. The transverse pressure plate 3 is located in front of the connecting plate 9. A transverse screw 10 is horizontally fixed to the middle of the rear side of the transverse pressure plate 3, which passes through the connecting plate 9. A first slave bevel gear is screwed onto the transverse screw 10. A first motor 17 is fixed to the rear side of the connecting plate 9. A first master bevel gear is fixed to the output shaft of the first motor 17, and the first master bevel gear and the first slave bevel gear are meshed. In this embodiment, a sleeve with an internal thread is screwed onto the transverse screw 10, and the first slave bevel gear is sleeved and fixed on the outside of the sleeve. When the first motor 17 drives the first master bevel gear to rotate, it drives the first slave bevel gear to rotate, thereby achieving horizontal movement of the transverse screw 10. In this embodiment, reinforcing ribs 19 are fixed between the two ends of the front side of the connecting plate 9 and the base plate 1 to enhance the connection strength of the connecting plate 9.

[0042] Support rods 18 are vertically fixed at the four corners of the upper side of the bottom plate 1, and the top ends of the four support rods 18 are commonly fixed to the top plate 14. A longitudinal screw rod 12 is fixed to the middle of the upper side of the longitudinal pressure plate 4 and is arranged through the top plate 14. A second slave bevel gear is screwed on the longitudinal screw 12. A second motor 15 is fixed to the upper side of the top plate 14. A second main bevel gear is fixed to the output shaft of the second motor 15, and the second main bevel gear and the second slave bevel gear are meshed. In this embodiment, a sleeve with an internal thread is also threaded onto the longitudinal screw rod 12, and a second slave bevel gear is sleeved and fixed on the outside of the sleeve. When the second motor 15 drives the second main bevel gear to rotate, it drives the second slave bevel gear to rotate, thereby achieving horizontal movement of the longitudinal screw rod 12. Of course, in this embodiment, the first slave bevel gear is limited in the horizontal direction and only performs circumferential rotation within the vertical plane, and the second slave bevel gear is limited in the vertical direction and only performs circumferential rotation within the horizontal plane. The installation of the bevel gear pair is a conventional technical means mastered by those skilled in the art, such as a screw elevator. Therefore, the specific connection structure of the bevel gear pair is not further described here. In this embodiment, the two rear support rods 18 lean against the front side of the connecting plate 9 to further strengthen the connection strength of the connecting plate 9.

[0043] A longitudinal pressure sensor 13 is provided on the longitudinal pressure plate 4, a transverse pressure sensor 11 is provided on the transverse pressure plate 3, and a controller 16 is provided on the upper side of the top plate 14. The longitudinal pressure sensor 13, the transverse pressure sensor 11, the first motor 17, and the second motor 15 are all connected to the controller 16. The longitudinal pressure sensor 13 and the transverse pressure sensor 11 detect the corresponding pressure conditions and feed them back to the controller 16, which controls the operation of the first motor 17 and the second motor 15. In this embodiment, the controller 16 is a PLC controller.

[0044] The cross section of the through groove 8 is a circular structure, the outer surface of the collar 6 is a cylindrical structure, and the cross section of the through hole inside the collar 6 is a circular structure, a square structure, a triangular structure or a rectangular structure. When selecting, it can be selected according to the sampling structure of the solidified soil.

[0045] A handle 20 is fixedly connected to the front side of the upper shear box 5 and the lower shear box 2.

[0046] In this embodiment, the first motor 17 and the second motor 15 are both servo motors.

[0047] In this embodiment, the controller 16 is also connected to a power supply, which supplies power to the entire electric control system, that is, to the motor and the controller 16 .

[0048] The present application also discloses a test method based on the above-mentioned solidified soil unconfined compressive strength and direct shear strength test device, including an unconfined compressive strength test method and a direct shear strength test method, wherein the unconfined compressive strength test method includes the following steps:

[0049] A. Prepare the first specimen, which is cylindrical and has a height-to-diameter ratio of 1:1;

[0050] B. Place a pad covering the through slot 8 on the upper side of the upper shear box 5, and place the first specimen on the pad, with the center of the first specimen aligned with the center of the longitudinal pressure plate 4;

[0051] C. The controller 16 sets the longitudinal load rate (i.e., the movement rate of the longitudinal pressure plate 4) and the test termination condition. The test termination condition is that when the longitudinal stress reading reaches a peak or stabilizes, the test should be terminated after a further 3%-5% strain. If the reading does not stabilize, the test should be continued until the strain reaches 20%.

[0052] D. Start the test. Controller 16 controls second motor 15 to start, driving longitudinal screw 12 downward, thereby causing longitudinal pressure plate 4 to press down on the specimen under the conditions of step C. Controller 16 records changes in longitudinal stress, longitudinal displacement, and strain of the first specimen during the test until the set test termination condition is met. The force applied by longitudinal pressure plate 4 during downward pressure, as detected by longitudinal pressure sensor 13, is considered the longitudinal stress value. The longitudinal displacement is the longitudinal displacement of longitudinal pressure plate 4 after contact with the first specimen and continued downward pressure. Strain refers to the ratio of the longitudinal displacement to the original height of the first specimen.

[0053] The direct shear strength test method includes the following steps:

[0054] a. Prepare the second sample;

[0055] b. Align the upper shear box 5 and the lower shear box 2, select the appropriate collar 6 according to the diameter of the second specimen, fill both collars 6 with the second specimen, then place the collar 6 and the second specimen into the central slots 8 of the upper shear box 5 and the lower shear box 2, with the collar 6 installed in the corresponding slots 8;

[0056] c. Use the controller 16 to set the longitudinal load rate (i.e., the movement rate of the longitudinal pressure plate 4), the longitudinal load holding time, the shear rate (i.e., the movement rate of the transverse pressure plate 3), and the shear termination condition. The shear termination condition is that the second specimen has been sheared when the transverse stress reading stabilizes or significantly decreases. The shear deformation (i.e., the relative displacement of the shear cross-section of the second specimen) reaches 4 mm. If the transverse stress reading continues to increase, the shear deformation should reach 6 mm.

[0057] d. Start the test. The controller 16 controls the second motor 15 to start, driving the longitudinal screw 12 downward, so that the longitudinal pressure plate 4 applies longitudinal stress to the second sample and the upper shear box 5 and the lower shear box 2 at the set longitudinal load loading rate and longitudinal load holding time. After the longitudinal stress remains stable, the controller 16 controls the first motor 17 to start, driving the transverse screw 10 forward, so that the transverse pressure plate 3 applies shear force to the lower shear box 2 at the set shear rate to shear the second sample. The controller 16 records the changes in longitudinal stress, transverse stress, and transverse displacement during the test until the set shear end condition is reached. Here, the force applied by the transverse pressure sensor 11 when the transverse pressure plate 3 presses the shear box 2 laterally is regarded as the transverse stress value; the shear strength of the second sample is reflected by the changes in longitudinal stress, transverse stress, and transverse displacement.

[0058] In the above direct shear test process, the direct shear test is only performed on one second specimen. In actual operation, according to the requirements of the direct shear test standard, the direct shear test can be repeated on multiple second specimens. The specific operation process is as follows:

[0059] e. After performing step d on the first and second specimens, clean the upper and lower shear boxes 5 and 2;

[0060] f. Repeat steps b to e for the second to fifth second specimens to determine the longitudinal stress, transverse stress, and transverse displacement changes of the second specimens under different longitudinal stresses;

[0061] g. Process the data, plotting the curves of transverse stress, transverse displacement change and longitudinal stress for each second specimen, with transverse stress and transverse displacement change as the ordinate and longitudinal stress as the abscissa. Draw a visual straight line (i.e., a straight line passing through each point) based on each point on the graph. The inclination of the straight line is the internal friction angle of the soil, and the intercept of the straight line on the ordinate axis is the cohesion of the soil.

[0062] In step b, the ring 6 and the sample, the ring 6 and the upper shear box 5 and the lower shear box 2 are tightly fitted, and when there are gaps between the ring 6 and the sample, the ring 6 and the upper shear box 5 and the lower shear box 2, fine sand is filled in the gaps to achieve a tight fit, ensuring that the cross section of the sample is a shear cross section, not a broken cross section.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Unconfined compressive strength and direct shear strength testing device for solidified soil, characterized by: It includes a bottom plate, a lower shear box that can move horizontally is provided on the upper side of the bottom plate, an upper shear box is provided on the upper side of the lower shear box, and aligned through grooves are provided in the middle of the upper shear box and a sleeve that matches the corresponding through groove is inserted in each through groove. A horizontal pressure plate that can push the lower shear box to move horizontally is provided on the side of the lower shear box, and a longitudinal pressure plate that can move longitudinally is provided above the upper shear box.

2. The unconfined compressive strength and direct shear strength testing device for solidified soil according to claim 1, characterized in that: The upper shear box and the lower shear box are both rectangular structures. Multiple slide rails are fixed side by side on the upper side of the bottom plate along the horizontal movement direction of the pressure plate, and slide grooves are opened at the bottom of the lower shear box corresponding to the slide rails. The lower shear box is slidably connected to the slide rails through the slide grooves.

3. The unconfined compressive strength and direct shear strength testing device for solidified soil according to claim 2, characterized in that: A limiting block is fixedly connected to the front end opening of the slide rail.

4. The unconfined compressive strength and direct shear strength testing device for solidified soil according to claim 1, characterized in that: A connecting plate is vertically fixed on the rear side of the upper surface of the base plate, a transverse pressure plate is located in front of the connecting plate, and a transverse screw is horizontally fixed at the middle of the rear side of the transverse pressure plate and passes through the connecting plate, a first slave bevel gear is screwed on the transverse screw, a first motor is fixed on the rear side of the connecting plate, a first main bevel gear is fixed on the output shaft of the first motor, and the first main bevel gear and the first slave bevel gear are meshed.

5. The device for testing the unconfined compressive strength and direct shear strength of solidified soil according to claim 4, characterized in that: Support rods are vertically fixed at the four corners of the upper side of the bottom plate, and the top ends of the four support rods are commonly fixed to the top plate. A longitudinal screw rod passing through the top plate is fixed to the middle of the upper side of the longitudinal pressure plate, and a second slave bevel gear is screwed on the longitudinal screw. A second motor is fixed to the upper side of the top plate, and a second main bevel gear is fixed to the output shaft of the second motor, and the second main bevel gear and the second slave bevel gear are meshed.

6. The device for testing the unconfined compressive strength and direct shear strength of solidified soil according to claim 5, characterized in that: A longitudinal pressure sensor is provided on the longitudinal pressure plate, a transverse pressure sensor is provided on the transverse pressure plate, and a controller is provided on the upper side of the top plate. The longitudinal pressure sensor, the transverse pressure sensor, the first motor and the second motor are all connected to the controller.

7. The device for testing the unconfined compressive strength and direct shear strength of solidified soil according to claim 1, characterized in that: The cross section of the through groove is a circular structure, the outer surface of the collar is a cylindrical structure, and the cross section of the through hole inside the collar is a circular structure, a square structure, a triangular structure or a rectangular structure.

8. The device for testing the unconfined compressive strength and direct shear strength of solidified soil according to claim 1, characterized in that: Handles are fixedly connected to the front sides of the upper shear box and the lower shear box.

9. A method for testing the unconfined compressive strength and direct shear strength of solidified soil, based on the device for testing the unconfined compressive strength and direct shear strength of solidified soil according to any one of claims 1 to 8, characterized in that: Including unconfined compressive strength test method and direct shear strength test method, The unconfined compressive strength test method includes the following steps: A. Prepare the first specimen, which is cylindrical and has a height-to-diameter ratio of 1:1; B. Place a pad covering the through slot on the upper side of the upper shear box. Place the first specimen on the pad, aligning the center of the first specimen with the center of the longitudinal pressure plate. C. Set the longitudinal load rate and test end conditions through the controller; D. Start the test, pressing the longitudinal compression plate downward on the specimen under the conditions of step C, and record the changes in the longitudinal stress, longitudinal displacement, and strain of the first specimen during the test until the set test end conditions are met; The direct shear strength test method includes the following steps: a. Prepare the second sample; b. Align the upper and lower shear boxes, select an appropriate collar based on the diameter of the second specimen, fill both collars with the second specimen, and then place the collar and the second specimen into the central slots of the upper and lower shear boxes, ensuring that the collars are installed in the corresponding slots. c. Set the longitudinal load rate, longitudinal load holding time, shear rate, and shear end conditions through the controller; d. Start the test, causing the longitudinal compression plate to apply longitudinal stress to the second specimen and the upper and lower shear boxes at the set longitudinal load rate and longitudinal load holding time. After the longitudinal stress remains stable, cause the transverse compression plate to apply shear force to the lower shear box at the set shear rate to shear the second specimen. Record changes in longitudinal stress, transverse stress, and transverse displacement during the test until the set shear end condition is met.

10. The method for testing the unconfined compressive strength and direct shear strength of solidified soil according to claim 9, characterized in that: In step b, the collar and the sample, the collar and the upper shear box and the lower shear box are tightly fitted, and when there are gaps between the collar and the sample, the collar and the upper shear box and the lower shear box, the gaps are filled with fine sand.

Images