Shearing box, measuring device and testing method for measuring sliding friction coefficient of loose soil

Abstract

The invention relates to a shear box for measuring the sliding friction coefficient of loose soil, a measuring device and a test method thereof, the shear box comprises an upper box body and a lower box body which are arranged up and down, and an accommodating cavity for accommodating test soil is defined between the upper box body and the lower box body; wherein the butt joint ends of the upper box body and the lower box body can move relatively, and the two limiting rods penetrate through the upper box body in the first direction and are inserted into the lower box body; the clamping piece comprises a clamping block and a limiting piece connected with the clamping block, the upper box body is provided with an installation cavity for installing the limiting piece, the clamping block is located in the installation cavity, and the limiting rod is provided with a clamping groove corresponding to the clamping block so that locking and releasing of the limiting rod can be achieved. According to the shear box, the clamping blocks are matched with the clamping grooves in the limiting rods, so that the limiting rods are quickly assembled and disassembled between the upper box body and the lower box body, the problem that repeated screwing, disassembling and positioning are needed in a traditional shear box is solved, the operation efficiency is remarkably improved, and a sample is conveniently and quickly replaced or a device is conveniently and quickly adjusted in the experiment process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geotechnical test equipment, in particular to a shear box for measuring sliding friction coefficient of loose soil, a measuring device and a test method thereof. BACKGROUND

[0002] Loose soil widely exists in natural foundation, filling area and slope body and other geological environment, and has significant engineering sensitivity due to loose particle structure and easy disturbance. In the process of foundation engineering design, the mechanical properties of loose soil directly affect the analysis of foundation bearing capacity, the calculation of slope stability and the anti-sliding design of earth retaining wall, tunnel and other geotechnical structures. Among them, the sliding friction coefficient as a key parameter for evaluating the shear strength of soil and the interface friction performance has important engineering significance in geotechnical engineering investigation and design.

[0003] At present, the test of sliding friction coefficient of loose soil is usually carried out by using direct shear apparatus, ring shear apparatus or sliding test device based on special loading structure. The shear force is loaded between the upper and lower shear boxes, and the relationship between the shear force and the normal force is recorded, so as to calculate the friction coefficient. However, in the actual test process, the traditional shear box usually fixes the position of the upper box body and the lower box body by screws or pins. In each time of loading and unloading soil sample or replacing test piece, the screws or pins need to be manually unscrewed, which is time-consuming and laborious, and is not conducive to high-frequency repeated test. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application aims to provide a shear box for measuring sliding friction coefficient of loose soil, a measuring device and a test method thereof, so as to solve the problem that the upper and lower box bodies are not convenient to quickly install and disassemble in the prior art.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A shear box for measuring sliding friction coefficient of loose soil, comprising an upper box body and a lower box body arranged in an upper and lower manner, a containing cavity for containing test soil being formed between the upper box body and the lower box body; wherein the abutting ends of the upper box body and the lower box body are relatively movable, further comprising:

[0007] Two limiting rods penetrating through the upper box body along a first direction and inserted into the lower box body;

[0008] A clamping piece comprising a clamping block and a limiting piece connected with the clamping block, the upper box body being provided with a mounting cavity for mounting the limiting piece, the clamping block being located in the mounting cavity, and the limiting rod being provided with a clamping groove corresponding to the clamping block;

[0009] The limiting member can move along a second direction perpendicular to the first direction, thereby driving the clamping block to engage with or disengage from the clamping slot, so as to achieve locking and releasing of the limiting rod.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The clamping block cooperates with the slot on the limit rod to achieve quick assembly and disassembly of the limit rod between the upper box body and the lower box body, avoiding the problem of repeated unscrewing and positioning in traditional shear boxes, significantly improving operating efficiency and facilitating quick sample replacement or device adjustment during the experiment.

[0012] 2. The shear box structure of the present invention can be combined with different forms of tensile loading systems and normal loading devices, and is suitable for testing the sliding friction performance of soil in various engineering simulation scenarios. It has wide applicability and promotion value.

[0013] Furthermore, the limiting member includes a driving block and a compression spring which are slidably arranged in the installation cavity along the second direction; the clamping block is arranged on the driving block, and both ends of the compression spring are respectively in contact with the driving block and the installation cavity.

[0014] Furthermore, the driving block is provided with a rack, and the mounting cavity is rotatably provided with a gear, and the gear is engaged with the rack.

[0015] Furthermore, a bevel gear is provided at one end of the gear, an adjusting disk is rotatably provided on the upper box body, the adjusting disk is provided with a tooth groove, and the bevel gear is meshed with the tooth groove.

[0016] Furthermore, the adjusting disk is provided with a plurality of anti-slip grooves.

[0017] Furthermore, the clamping block is a wedge-shaped block, and its wedge-shaped surface matches the inner wall of the clamping groove on the limiting rod.

[0018] Furthermore, the driving block is provided with a slider, the mounting cavity is provided with a slide groove, and the slider is slidably connected to the slide groove.

[0019] Furthermore, the lower box body is provided with a mounting groove for accommodating the limit rod, and a pushing member is provided in the mounting groove, and the pushing member includes a mounting rod slidably arranged at the bottom of the mounting groove, a compression spring sleeved on the mounting rod, and a pushing block, the pushing block is slidably arranged in the mounting groove and abuts against the limit rod, one end of the compression spring abuts against the bottom of the mounting groove, and the other end abuts against the pushing block, so as to push the limit rod out of the lower box body under the action of elastic force.

[0020] Furthermore, a limiting block is provided on the limiting rod, a limiting slot is provided in the installation slot, and the limiting block is slidably engaged in the limiting slot.

[0021] A device for measuring the sliding friction coefficient of loose soil includes a tension mechanism and a measuring mechanism, and also includes the shear box for measuring the sliding friction coefficient of loose soil. The tension mechanism is connected to the lower box body, and the measuring mechanism is connected to the upper box body.

[0022] A test method for a loose soil sliding friction coefficient measuring device, using the shear cell for measuring the loose soil sliding friction coefficient, the test method comprising:

[0023] Fill the loose soil sample to be tested evenly into the shear box, make sure that the upper and lower boxes are filled with loose soil, and then lightly compact and level it according to the standard density;

[0024] Install the filled shear box onto the measuring device, connect the tension mechanism to the lower box body, and the measuring mechanism to the upper box body, ensuring that the connection is firm, the initial position is aligned, and there is no prestressed state;

[0025] Apply vertical pressure to the upper box through a loading device (such as weights, oil cylinders, etc.) to simulate the stress state of the soil under actual working conditions, and record the corresponding normal force value;

[0026] Start the tension mechanism to drive the lower box body to shear relative to the upper box body at a constant rate or constant speed loading mode, and gradually apply horizontal shear force;

[0027] The horizontal tension changes generated during the shearing process are recorded by a measuring mechanism, while the displacement changes are monitored until the shear force reaches a peak or obvious relative sliding occurs. The sliding friction coefficient is calculated as:

[0028] According to the normal force N and the maximum shear force T recorded in the test max , according to the formula:

[0029]

[0030] Calculate the coefficient of sliding friction of loose soil;

[0031] To ensure the accuracy of the results, the test can be repeated under different normal loads or different moisture contents, and the data can be compared and analyzed to obtain a stable and effective friction coefficient range. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Attachment Figure 1 : Schematic diagram of the structure of the shear box used for measuring the sliding friction coefficient of loose soil in this embodiment;

[0033] Attachment Figure 2 : Schematic diagram of the exploded structure of the shear box used for measuring the sliding friction coefficient of loose soil in this embodiment;

[0034] Attachment Figure 3: A schematic diagram of a portion of the structure of the shear box used for measuring the sliding friction coefficient of loose soil in this embodiment, mainly showing the limiter;

[0035] Attachment Figure 4 : Attached Figure 3 A local enlarged schematic diagram in FIG.

[0036] Attachment Figure 5 : Schematic diagram of the structure of the pusher in the shear box used for measuring the sliding friction coefficient of loose soil in this embodiment;

[0037] Description of Figure Numbers:

[0038] 1. Upper box body; 11. Accommodation cavity;

[0039] 2. Lower box body;

[0040] 3. Limit rod; 31. Slot; 32. Limit block;

[0041] 4. Card block;

[0042] 5. Limiting member; 51. Driving block; 52. Extrusion spring; 53. Rack; 54. Gear; 55. Bevel gear; 56. Adjusting plate; 561. Tooth groove; 562. Anti-skid groove;

[0043] 6. Pushing member; 61. Mounting rod; 62. Compression spring; 63. Pushing block.

[0044] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and beneficial effects of the present invention more clearly understood, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0046] In the description of the present invention, it should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions for the implementation of the present invention and therefore have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0047] Example 1

[0048] like Figure 1-5 As shown, an embodiment of the present invention proposes a shear box for measuring the sliding friction coefficient of loose soil, comprising an upper box body 1 and a lower box body 2 arranged upper and lower, wherein a accommodating cavity 11 for accommodating test soil is formed between the upper box body 1 and the lower box body 2; wherein the butt ends of the upper box body 1 and the lower box body 2 can move relative to each other, and further comprising: two limit rods 3, which pass through the upper box body 1 along a first direction and are inserted into the lower box body 2; a clamping member, comprising a clamping block 4 and a limit member 5 connected to the clamping block 4, the upper box body 1 is provided with a mounting cavity for installing the limit member 5, the clamping block 4 is located in the mounting cavity, and the limit rod 3 is provided with a clamping groove 31 corresponding to the clamping block 4; wherein the limit member 5 can move along a second direction perpendicular to the first direction, thereby driving the clamping block 4 to engage or disengage with the clamping groove 31, so as to realize the locking and release of the limit rod 3.

[0049] When the shear box of the present invention is used, the upper box body 1 and the lower box body 2 are first docked and assembled to form a complete soil sample accommodating chamber 11; then, the two limiting rods 3 are inserted into the upper box body 1 along the first direction (horizontal direction) and inserted into the corresponding positions in the lower box body 2; then, the clamping block 4 is moved along the second direction (vertical direction) by the limiting member 5, and is engaged with the clamping groove 31 on the limiting rod 3 to complete the locking and fixing of the limiting rod 3, so that the upper box body 1 and the lower box body 2 are stably connected; then, the assembled shear box is installed on the sliding friction coefficient test device, that is, the upper box body 1 is connected to the measuring mechanism, and the lower box body 2 is connected to the tension loading mechanism;

[0050] Then fill the loose soil sample to be tested into the accommodating cavity 11 and lightly compact and level it according to the test requirements to ensure that the density of the sample meets the standard test conditions; then, the block 4 is disengaged from the slot 31 of the limit rod 3 through the limit piece 5, and the limit rod 3 can be pulled out freely to separate the upper box body 1 from the lower box body 2; then the tension mechanism can be started to drive the lower box body 2 to slide horizontally relative to the upper box body 1 at a constant or controlled rate, and apply the corresponding normal load according to the test requirements; during the entire shearing process, the measuring mechanism records the changes in shear force and the corresponding displacement data for the subsequent calculation of the sliding friction coefficient of the loose soil.

[0051] Specifically, such as Figure 2-4As shown, in the embodiment of the present invention, the limiting member 5 includes a driving block 51 and a squeezing spring 52 that are slidably arranged in the installation cavity along the second direction; the clamping block 4 is arranged on the driving block 51, and the two ends of the squeezing spring 52 are respectively abutted against the driving block 51 and the installation cavity. By inserting the limiting rod 3 into the upper box body 1 and the lower box body 2 in sequence, it will push the clamping block 4 to drive the driving block 51 to compress the squeezing spring 52 until the slot 31 on the limiting rod 3 corresponds to the clamping block 4. At this time, the clamping block 4 is clamped to the slot 31 under the action of the squeezing spring 52 to achieve locking. , thereby achieving relative fixation of the upper box body 1 and the lower box body 2; and when the limit rod 3 needs to be released, the driving block 51 is pushed in the opposite direction to disengage the card block 4 from the card slot 31, and the limit rod 3 can be pulled out, thereby achieving quick separation; and, in order to facilitate the operation of the driving block 51, the driving block 51 is provided with a rack 53, and the mounting cavity is rotatably provided with a gear 54, and the gear 54 is engaged with the rack 53. By rotating the gear 54, the rack 53 can be driven to drive the driving block 51 to slide along the second direction, thereby achieving the release between the card block 4 and the card slot 31 of the limit rod 3.

[0052] When the locking rod 3 is in the first position, the locking rod 3 is locked and the locking rod 31 is locked.

[0053] Based on the above scheme, if Figure 3-4As shown, in order to conveniently adjust the two limiting rods 3 synchronously, in the embodiment of the present application, one end of the gear 54 is provided with a bevel gear 55, the upper box body 1 is rotationally provided with an adjusting disc 56, the adjusting disc 56 is provided with a gear slot 561, the bevel gear 55 is engaged with the gear slot 561, by rotating the adjusting disc 56, the two bevel gears 55 can be driven to rotate, thereby synchronously driving the corresponding engaged gears 54 to rotate, and then driving the rack 53 and the driving block 51 to slide in the second direction synchronously, so as to realize the simultaneous locking or releasing operation of the two limiting rods 3, wherein, in order to ensure that the two limiting rods 3 can be synchronously driven to correspond to the clamping block 4 and the driving block 51, and realize the synchronous rotation of the adjusting disc 56, the gear 54 and the bevel gear 55, the two limiting rods 3 should be inserted into the corresponding installation slot at the same time, so as to ensure that the driving mechanism is closed and complete, thereby avoiding the out-of-sync or jamming phenomenon caused by unilateral driving; at the same time, in order to conveniently adjust the adjusting disc 56 and avoid slipping, a plurality of anti-skid grooves 562 are arranged on the adjusting disc 56, and specifically, the plurality of anti-skid grooves 562 are arranged in the circumferential direction of the adjusting disc 56.

[0054] Based on the above scheme, as Figure 5 As shown, in the embodiment of the present application, the lower box body 2 is provided with an installation slot for accommodating the limiting rod 3, the installation slot is provided with a pushing piece 6, the pushing piece 6 includes an installation rod 61 slidingly arranged at the bottom of the installation slot, a compression spring 62 sleeved on the installation rod 61, and a pushing block 63, the pushing block 63 is slidingly arranged in the installation slot and abuts against the limiting rod 3, one end of the compression spring 62 abuts against the bottom of the installation slot, and the other end abuts against the pushing block 63, so as to push the limiting rod 3 to separate from the lower box body 2 under the action of the elastic force, in the disassembly or separation stage of the shearing box, after the user releases the locking of the limiting rod 3 by the clamping block 4 in the upper box body 1, since the compression spring 62 in the pushing piece 6 is in a compressed state, the pushing block 63 will slide along the installation slot under the action of the elastic force of the compression spring 62, thereby pushing the limiting rod 3 to move outward, so that the limiting rod 3 rapidly separates from the lower box body 2 without manual pulling out, thereby simplifying the operation steps.

[0055] Moreover, the limiting rod 3 is provided with a limiting block 32, a limiting slot is formed in the installation slot, and the limiting block 32 is slidingly connected to the limiting slot, through the cooperation of the limiting block 32 and the limiting slot, the limiting rod 3 is fixed and orderly arranged along the inside of the installation slot, so as to ensure that the clamping groove 31 of the clamping block 4 and the limiting rod 3 can be stably engaged.

[0056] Embodiment 2

[0057] A device for measuring the sliding friction coefficient of loose soil includes a tension mechanism and a measuring mechanism, and also includes the shear box for measuring the sliding friction coefficient of loose soil described in the above-mentioned embodiment 1, wherein the tension mechanism is connected to the lower box body 2, and the measuring mechanism is connected to the upper box body 1. Since this measuring device adopts all the technical solutions of the above-mentioned embodiment 1, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiment 1, and therefore will not be described one by one here.

[0058] Example 3

[0059] A test method for measuring a loose soil sliding friction coefficient device, using the shear cell for measuring the loose soil sliding friction coefficient described in Embodiment 1 or 2 above, the test method comprising:

[0060] The loose soil sample to be tested is evenly filled in the shear box, so that the upper box body 1 and the lower box body 2 are filled with loose soil, and lightly compacted and leveled according to the standard density;

[0061] Install the filled shear box onto the measuring device, connect the tension mechanism to the lower box body 2, and the measuring mechanism to the upper box body 1, ensuring that the connection is firm, the initial position is aligned, and there is no prestressed state;

[0062] Apply vertical pressure to the upper box body 1 through a loading device (such as weights, oil cylinders, etc.) to simulate the stress state of the soil under actual working conditions, and record the corresponding normal force value;

[0063] Start the tension mechanism and drive the lower box body 2 to move relative to the upper box body 1 at a constant rate (such as 1mm / min) or a constant speed loading method to gradually apply horizontal shear force;

[0064] The horizontal tension changes generated during the shearing process are recorded by a measuring mechanism, while the displacement changes are monitored until the shear force reaches a peak or obvious relative sliding occurs. The sliding friction coefficient is calculated as:

[0065] According to the normal force N and the maximum shear force T recorded in the test max , according to the formula:

[0066]

[0067] Calculate the coefficient of sliding friction of loose soil;

[0068] To ensure the accuracy of the results, the test can be repeated under different normal loads or different moisture contents. For example, each set of tests should be repeated at least three times, and the data can be compared and analyzed to obtain a stable and effective range of friction coefficient.

[0069] Finally, it is to be explained that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the purpose and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A shear box for measuring the sliding friction coefficient of loose soil, comprising an upper box body (1) and a lower box body (2) arranged vertically, wherein a receiving cavity (11) for accommodating test soil is formed between the upper box body (1) and the lower box body (2); wherein: The butt ends of the upper box body (1) and the lower box body (2) are capable of relative movement, and are characterized in that they further comprise: Two limiting rods (3) pass through the upper box body (1) along a first direction and are inserted into the lower box body (2); The clamping member comprises a clamping block (4) and a limiting member (5) connected to the clamping block (4); the upper box body (1) is provided with an installation cavity for installing the limiting member (5); the clamping block (4) is located in the installation cavity; and the limiting rod (3) is provided with a clamping groove (31) corresponding to the clamping block (4); The limiting member (5) can move in a second direction perpendicular to the first direction, thereby driving the clamping block (4) to engage with or disengage from the clamping slot (31), thereby achieving locking and releasing of the limiting rod (3).

2. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 1, characterized in that: The limiting member (5) comprises a driving block (51) and a pressing spring (52) which are arranged in the installation cavity and slide along the second direction; the clamping block (4) is arranged on the driving block (51), and the two ends of the pressing spring (52) are respectively in contact with the driving block (51) and the installation cavity.

3. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 2, characterized in that: The driving block (51) is provided with a rack (53), and the mounting cavity is rotatably provided with a gear (54), and the gear (54) is engaged with the rack (53).

4. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 3, characterized in that: One end of the gear (54) is provided with a bevel gear (55), the upper box body (1) is rotatably provided with an adjustment disk (56), the adjustment disk (56) is provided with a tooth groove (561), and the bevel gear (55) is meshed with the tooth groove (561).

5. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 4, characterized in that: The regulating disk (56) is provided with a plurality of anti-slip grooves (562).

6. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 1, characterized in that: The clamping block (4) is a wedge-shaped block, and its wedge-shaped surface matches the inner wall of the clamping groove (31) on the limiting rod (3).

7. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 1, characterized in that: The lower box body (2) is provided with a mounting groove for accommodating the limiting rod (3), and a pushing member (6) is provided in the mounting groove. The pushing member (6) includes a mounting rod (61) slidingly arranged at the bottom of the mounting groove, a compression spring (62) sleeved on the mounting rod (61), and a pushing block (63). The pushing block (63) is slidably arranged in the mounting groove and abuts against the limiting rod (3). One end of the compression spring (62) abuts against the bottom of the mounting groove, and the other end abuts against the pushing block (63), so as to push the limiting rod (3) out of the lower box body (2) under the action of elastic force.

8. A shear cell for measuring the sliding friction coefficient of loose soil according to claim 7, characterized in that: A limiting block (32) is provided on the limiting rod (3), a limiting slot is provided in the installation slot, and the limiting block (32) is slidably engaged in the limiting slot.

9. A device for measuring the sliding friction coefficient of loose soil, comprising a tension mechanism and a measuring mechanism, characterized in that: It also comprises a shear box for measuring the sliding friction coefficient of loose soil according to any one of claims 1 to 8, wherein the tension mechanism is connected to the lower box body (2), and the measuring mechanism is connected to the upper box body (1).

10. A test method for measuring a device for measuring the sliding friction coefficient of loose soil, characterized in that: Using the shear cell for measuring the sliding friction coefficient of loose soil as claimed in claim 9, the test method includes: The loose soil sample to be tested is evenly filled in the shear box, so that the upper box body (1) and the lower box body (2) are both filled with loose soil, and lightly compacted and leveled according to the standard density; Install the filled shear box onto the measuring device, connect the tension mechanism to the lower box body (2), and connect the measuring mechanism to the upper box body (1), ensuring that the connection is firm, the initial position is aligned, and there is no prestressed state; Applying vertical pressure on the upper box body (1) through a loading device (such as a weight, a cylinder, etc.) to simulate the stress state of the soil under actual working conditions, and recording the corresponding normal force value; The tension mechanism is activated to drive the lower box body (2) to move relative to the upper box body (1) in a shearing manner at a constant rate or in a constant speed loading manner, and a horizontal shear force is gradually applied; The horizontal tension changes generated during the shearing process are recorded by a measuring mechanism, while the displacement changes are monitored until the shear force reaches a peak or obvious relative sliding occurs. The sliding friction coefficient is calculated as: According to the normal force N and the maximum shear force T recorded in the test max , according to the formula: Calculate the coefficient of sliding friction of loose soil; To ensure the accuracy of the results, the test can be repeated under different normal loads or different moisture contents, and the data can be compared and analyzed to obtain a stable and effective range of friction coefficient.

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