A soil-rock mixture indoor direct shear test device

Abstract

An indoor direct shear test device for soil-rock mixture comprises: a frame, with installation areas respectively provided on the top and the side; a horizontal bearing mechanism, arranged at the bottom of the frame, comprising a shear box and a bearing component, wherein the shear box comprises a fixed part and a movable part arranged above the fixed part, wherein the bottom of the fixed part is installed at the bottom of the frame, and the movable part is stacked on the top of the fixed part; the bearing component is arranged at the top of the shear box; a force applying unit, comprising a vertical force applying part and a horizontal force applying part, wherein the vertical force applying part is suspended from the top installation area of ​​the frame, and the force applying end of the vertical force applying part is in contact with the bearing component; the horizontal force applying part is suspended from the side installation area of ​​the frame, and the force applying end of the horizontal force applying part is kept in contact with the movable part; and a detection unit, arranged in the frame, comprising a plurality of displacement meters and a pressure sensor. The beneficial effects of the present invention are: indoor direct shear test and indoor consolidation test can be carried out on soil-rock mixture, and the structure is simple and the operation is convenient.

Description

Technical Field

[0001] The invention relates to an indoor direct shear test device for a soil-rock mixture. Background Art

[0002] In the engineering geological survey of deep foundation pit projects, we often encounter a mixture of fine-grained soil and coarse-grained soil, which is called soil-rock mixture. Since the coarse particle size of soil-rock mixture is large, the existing conventional small triaxial apparatus or direct shear test instrument cannot accurately measure the shear strength parameters of soil-rock mixture. Therefore, it is more important to design a set of indoor direct shear test instruments that can measure the shear strength parameters of soil-rock mixture.

[0003] In the shear test of a general direct shear tester, the shear area of ​​the sample will decrease as the deformation increases during the test, which will affect the test results. In addition, the static side pressure coefficient k0 of the soil-rock mixture cannot be measured on a conventional direct shear tester.

[0004] The patent with invention publication number CN107860647A discloses a shear box device for constant cross-section direct shear test. The structure consists of an upper shear box and a lower shear box. The inner diameter of the lower shear box is larger than that of the upper shear box, and the inner diameters of the two differ by 1.2 times the maximum shear distance of the direct shear apparatus. However, the patent cannot ensure that the pressure of the upper and lower shear boxes is the same during the shearing process.

[0005] The patent with publication number CN207123458U discloses a fully automatic direct shear apparatus. The structure includes a pressure frame, a water tank base, an upper shear box and a lower shear box, and a drainage groove and a drainage hole are provided on the water tank base. However, the patent cannot measure the static side pressure coefficient k0. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes an indoor direct shear test device which can perform indoor direct shear test on soil-rock mixture and measure the static side pressure coefficient k0 of the soil-rock mixture.

[0007] The soil-rock mixture indoor direct shear test device of the present invention is characterized by comprising:

[0008] The frame has mounting areas on the top and sides;

[0009] The horizontal bearing mechanism is arranged at the bottom of the frame, and includes a shear box and a bearing component, wherein the shear box includes a fixed part and a movable part arranged above the fixed part, wherein the bottom of the fixed part is installed at the bottom of the frame, and the movable part is stacked on the top of the fixed part; the bearing component is arranged at the top of the shear box, and is used to transmit longitudinal pressure to the movable part of the horizontal bearing mechanism;

[0010] The force applying unit comprises a vertical force applying part and a horizontal force applying part, wherein the vertical force applying part is suspended on the top mounting area of ​​the frame, the force applying end of the vertical force applying part is in contact with the bearing component, and is used to provide longitudinal pressure to the horizontal bearing mechanism; the horizontal force applying part is suspended on the side mounting area of ​​the frame, and the force applying end of the horizontal force applying part is kept in contact with the moving part, and is used to push the moving part so that the moving part and the fixed part generate horizontal relative movement;

[0011] And a detection unit is arranged in the frame, including multiple displacement meters and pressure sensors, wherein the displacement meter is arranged on the moving part and / or the force unit of the horizontal bearing mechanism, and is used to detect the lateral displacement and / or longitudinal displacement of the horizontal bearing mechanism; the pressure sensor is arranged at the test holes of the upper shear box and the lower shear box, and is used to measure the pressure of the soil sample at the test hole.

[0012] The shear box is composed of an upper shear box and a lower shear box stacked up and down, wherein the lower shear box is installed at the bottom of the frame as a fixed part, and the side wall is embedded with permeable stone; the upper shear box is placed on the top of the lower shear box as a movable part, and the two form a cavity.

[0013] The side walls of the upper shear box and the lower shear box are respectively provided with a testing hole.

[0014] The box cavity of the upper shear box is a vertical through-cavity structure, and the box cavity of the lower shear box is an upper opening structure.

[0015] A ball bearing is arranged at the bottom of the lower shear box or the top of the upper shear box.

[0016] There is a small shear box attached to the right side of the lower shear box.

[0017] The bearing component comprises a pressure plate and a ball bearing, wherein the pressure plate is laid on the top surface of the upper shear box; and the ball bearing is arranged between the pressure plate and the top surface of the upper shear box.

[0018] The displacement meter comprises a vertical displacement meter and an upper shear box displacement meter, wherein the vertical displacement meter is arranged on the force-applying end of the vertical force-applying part or on the pressure-bearing plate; and the upper shear box displacement meter is arranged on the upper shear box.

[0019] The pressure sensor is a soil pressure sensor, which is arranged at the measuring holes of the upper shear box and the lower shear box.

[0020] The frame is a reaction frame, wherein a bracket is provided in a side mounting area on one side of the reaction steel frame, and the bracket is composed of a vertical steel plate and a horizontal steel plate arranged on the vertical steel plate.

[0021] The vertical force applying part is a vertical jack, and the lateral force applying part is a horizontal hydraulic jack.

[0022] During the consolidation stage, the horizontal jack stops running and the pressure of the vertical jack is controlled until the consolidation is complete. At the same time, the soil pressure can be measured. In the shear stage, when the pressure of the vertical jack reaches the designed consolidation pressure and the soil sample is consolidated, the thrust of the horizontal jack begins to be applied until the soil sample is destroyed. There is a ball between the upper bearing plate and the upper shear box.

[0023] The beneficial effects of the present invention are: indoor direct shear test and indoor consolidation test can be carried out on soil-rock mixture, while keeping the shear surface constant during the shearing process, eliminating the test error caused by the change of the shear surface in general tests, and the structure is simple and the operation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the present invention.

[0025] Figure 2 It is a top view of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings.

[0027] Refer to the attached figure:

[0028] Embodiment 1 A soil-rock mixture indoor direct shear test device according to the present invention comprises:

[0029] The frame 1 has mounting areas on the top and sides;

[0030] The horizontal bearing mechanism is arranged at the bottom of the frame 1, and includes a shear box and a bearing component, wherein the shear box includes a fixed part and a movable part arranged above the fixed part, wherein the bottom of the fixed part is installed at the bottom of the frame 1, and the movable part is stacked on the top of the fixed part; the bearing component is arranged at the top of the shear box;

[0031] The force applying unit comprises a vertical force applying part 4 and a horizontal force applying part 2, wherein the vertical force applying part 4 is suspended on the top installation area of ​​the frame 1, and the force applying end of the vertical force applying part 4 is connected to the bearing component; the horizontal force applying part is suspended on the side installation area of ​​the frame, and the force applying end of the horizontal force applying part is kept in contact with the moving part;

[0032] And a detection unit is arranged in the frame, including multiple displacement meters and pressure sensors, wherein the displacement meters are arranged on the moving part and / or the force-applying unit of the horizontal bearing mechanism; the pressure sensors are arranged at the test holes of the upper shear box and the lower shear box.

[0033] The shear box is composed of two upper shear boxes 11 and a lower shear box 7 stacked up one on top of the other, wherein the lower shear box 7 is installed at the bottom of the frame 1 as a fixed part, and the side wall is embedded with permeable stone 8; the upper shear box 11 is placed on the top of the lower shear box 7 as a movable part, and the two form a cavity.

[0034] The side wall of the upper shear box 11 is provided with a test hole for installing a pressure sensor.

[0035] The side wall of the lower shear box 7 is provided with a test hole for installing a pressure sensor.

[0036] The box cavity of the upper shear box 11 is a vertical through-cavity structure, the box cavity of the lower shear box 7 is an upper open structure, and a small shear box is connected to the right side of the lower shear box.

[0037] A ball bearing is arranged at the bottom of the lower shear box or the top of the upper shear box.

[0038] The bearing component includes a pressure plate 12 and a ball 13. The pressure plate 12 is laid on the top surface of the upper shear box; the ball 13 is arranged between the pressure plate and the top surface of the upper shear box.

[0039] The displacement meter comprises a vertical displacement meter 3 and an upper shear box displacement meter 5, wherein the vertical displacement meter 3 is arranged on the force-applying end or the pressure-bearing plate of the vertical force-applying part 4; and the upper shear box displacement meter is arranged on the upper shear box.

[0040] The pressure sensor 6 is a pressure sensor, which is respectively arranged at the measuring holes of the upper shear box and the lower shear box.

[0041] The frame 1 is a reaction frame, including a top beam, a force transmission column and a bottom plate. The top beam and the bottom plate are arranged in parallel and are connected by a force transmission column. A bracket is provided in the side mounting area on one side of the reaction steel frame, and the bracket is composed of a vertical steel plate 9 and a horizontal steel plate 10 arranged on the vertical steel plate.

[0042] The vertical force applying part 4 is a vertical jack, and the lateral force applying part 2 is a horizontal hydraulic jack.

[0043] The implementation steps of the present invention are as follows:

[0044] The first step: determining the size of the invention according to the largest crushed stone particle size in the actual soil-rock mixture;

[0045] Step 2: During the consolidation stage, the horizontal jack stops running, the pressure of the vertical jack is controlled, and the deformation of the vertical displacement meter is recorded until it is stable. The soil sample consolidation is considered complete; the static soil pressure coefficient k0 is calculated by reading the readings of the two pressure sensors of the upper shear box and the lower shear box, taking the average value, and combining it with the pressure value of the vertical jack;

[0046] Step 3: During the shearing stage, the pressure of the vertical jack is maintained at the predetermined design value, and the thrust of the horizontal jack is applied until the soil sample is damaged or deformed to the maximum value. There is a ball between the upper bearing plate and the upper shear box. When the upper shear box moves to the right, the soil in the box contacts the soil in the small shear box on the right side of the lower shear box, keeping the soil contact area constant during the entire shearing process.

[0047] Embodiment 2 In this embodiment: a force transmission column and a vertical jack are arranged downward on the top beam of the reaction frame, a horizontally arranged pressure plate is arranged at the end of the piston rod of the vertical jack, and an upper shear box and a lower shear box are arranged from top to bottom directly below the horizontal pressure plate; the box cavity of the upper shear box is a through-cavity structure, and the box cavity of the lower shear box is an upper opening structure, and a small shear box is connected to the right side of the lower shear box; a ball bearing is arranged at the bottom of the lower shear box or the top of the upper shear box; the piston rod of the horizontal hydraulic jack contacts the corresponding side wall of the lower shear box or the upper shear box; the horizontal bearing mechanism contacts the corresponding side wall of the upper shear box or the lower shear box. There is a vertical steel plate on the side of one side of the reaction steel frame, and there is a horizontal steel plate in the middle of the vertical steel plate. The piston rod of the horizontal hydraulic jack retracts and contracts in the horizontal direction, and the piston rod of the vertical jack retracts and contracts in the vertical direction.

[0048] The contents described in the embodiments of this specification are merely an enumeration of implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the inventive concept.

Claims

1. A soil-rock mixture indoor direct shear test device, characterized in that: include: The frame has mounting areas on the top and sides; The horizontal bearing mechanism is arranged at the bottom of the frame, and comprises a shear box and a bearing component, wherein the shear box comprises a fixed part and a movable part arranged above the fixed part, wherein the bottom of the fixed part is installed at the bottom of the frame, and the movable part is stacked on the top of the fixed part; The bearing member is arranged at the top of the shear box and is used to transmit longitudinal pressure to the moving part of the horizontal bearing mechanism; The force applying unit comprises a vertical force applying part and a horizontal force applying part, wherein the vertical force applying part is suspended on the top mounting area of ​​the frame, the force applying end of the vertical force applying part is connected to the bearing component, and is used to provide longitudinal pressure to the horizontal bearing mechanism; the horizontal force applying part is suspended on the side mounting area of ​​the frame, and the force applying end of the horizontal force applying part is kept in contact with the moving part, and is used to push the moving part so that the moving part and the fixed part generate horizontal relative movement; and a detection unit, which is arranged in the frame and includes a plurality of displacement meters and pressure sensors, wherein the displacement meters are arranged on the moving part and / or the force-applying unit of the horizontal bearing mechanism, and are used to detect the lateral displacement and / or longitudinal displacement of the horizontal bearing mechanism; and the pressure sensors are arranged at the test holes of the upper shear box and the lower shear box, and are used to measure the pressure of the soil sample at the test holes; The shear box is composed of an upper shear box and a lower shear box which are stacked up and down, and a small shear box is connected to the right side of the lower shear box to keep the shear surface constant during the shearing process.

2. The soil-rock mixture indoor direct shear test device according to claim 1, characterized in that: The lower shear box is installed at the bottom of the frame as a fixed part, and the side wall is embedded with permeable stones to allow moisture in the soil sample in the cavity to seep out; the upper shear box is placed on the top of the lower shear box as a movable part, and the two form a cavity for accommodating the soil sample.

3. The soil-rock mixture indoor direct shear test device according to claim 2, characterized in that: The side walls of the upper shear box and the lower shear box are provided with test holes for installing pressure sensors.

4. The soil-rock mixture indoor direct shear test device according to claim 3, characterized in that: The box cavity of the upper shear box is a vertical through-cavity structure, and the box cavity of the lower shear box is an upper opening structure.

5. The soil-rock mixture indoor direct shear test device according to claim 4, characterized in that: A ball bearing is arranged at the bottom of the lower shear box or the top of the upper shear box.

6. The soil-rock mixture indoor direct shear test device according to claim 1, characterized in that: The bearing component includes a pressure plate and a ball bearing, wherein the pressure plate is laid on the top surface of the upper shear box and is used to evenly transfer the pressure of the vertical force application part to the top surface of the upper shear force; The ball bearing is arranged between the pressure plate and the top surface of the upper shear box, and is used to reduce the friction between the upper shear box and the upper pressure plate when horizontal shearing is performed.

7. The soil-rock mixture indoor direct shear test device according to claim 1, characterized in that: The displacement meter includes a vertical displacement meter and an upper shear box displacement meter, wherein the vertical displacement meter is arranged on the force end of the vertical force applying part or the pressure plate, and is used to detect the longitudinal displacement of the force end of the vertical force applying part; the upper shear box displacement meter is arranged on the upper shear box, and is used to detect the lateral displacement of the upper shear box.

8. The soil-rock mixture indoor direct shear test device according to claim 1, characterized in that: The pressure sensor is a pore pressure sensor, which is arranged at the measuring holes of the upper shear box and the lower shear box and is used to detect the soil sample pressure at the measuring holes. There are two of them.

9. The soil-rock mixture indoor direct shear test device according to claim 1, characterized in that: The frame is a reaction frame, including a top beam, a force transmission column and a bottom plate. The top beam and the bottom plate are arranged in parallel and are connected by a force transmission column. A bracket for placing a horizontal force-applying part is provided in the side mounting area on one side of the reaction steel frame. The bracket is composed of a vertical steel plate and a horizontal steel plate arranged on the vertical steel plate.

10. The soil-rock mixture indoor direct shear test device according to claim 1, characterized in that: The vertical force applying part is a vertical jack, and the lateral force applying part is a horizontal hydraulic jack.

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