A rock and soil direct shear test device

Abstract

The present invention discloses a rock and soil direct shear test device, including a foundation pit, displacement grooves are opened at the edge positions of both sides of the foundation pit, a specimen is arranged inside the foundation pit, pressure plates are arranged above and on one side of the specimen, a horizontal hydraulic jack is arranged on the outside of the pressure plate located on one side of the specimen, a reaction plate is arranged on the outside of the horizontal hydraulic jack, steel plates are arranged on both sides above the pressure plate located above the specimen, and a rolling belt is arranged above each side of the steel plate, steel plates are placed on both sides above the rolling belt, and a pressure plate with a vertical hydraulic jack is tightly connected above the steel plate. The device can reduce the eccentricity of the vertical pressure loading system and the vertical reaction force load system and the shear specimen on the one hand, and can ensure the pressure direction of the lateral load system and the vertical pressure loading system during the test, improve the pressure stability, and generally improve the test reliability of the rock and soil direct shear test device.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering test equipment, and more particularly to a rock and soil direct shear test device. Background Art

[0002] Soil slopes are widely found in geotechnical engineering projects such as earth-rock dams, reservoirs, embankments, foundation pit excavations, channels, and dikes. Soil shear strength is an important indicator for determining the stability of earth dams, embankments, slopes, etc. The more common determination methods include indoor direct shear tests (fast shear, consolidation fast shear, slow shear, and drainage repeated shear), indoor triaxial shear tests, and in-situ direct shear tests. Many domestic and foreign engineering designs and constructions use in-situ direct shear tests as one of the main means to determine soil shear strength indicators. Large-scale direct shear tests have been applied in the research of moraine soil, granite residual slope soil, expansive soil, garbage soil, sand and gravel, gravel soil, remolded red clay, remolded silt, etc., because its test conditions are closer to the actual rock and soil. Due to the looseness of the sample soil and other reasons, when the lateral load system causes the shear sample to have a large lateral displacement, the vertical pressure loading system and the vertical reaction load system are prone to eccentricity with the shear sample. In addition, the lateral load system and the vertical pressure loading system cannot guarantee continuous pressure in a straight line during the test, resulting in inaccurate test data or test failure. Summary of the invention

[0003] The purpose of the present invention is to provide a rock and soil direct shear test device, which can, on the one hand, reduce the eccentricity of the vertical pressure loading system and the vertical reaction load system and the shear specimen, and on the other hand, ensure the pressure direction of the lateral load system and the vertical pressure loading system during the test, improve the pressure stability, and generally improve the test reliability of the rock and soil direct shear test device.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A rock and soil direct shear test device comprises a foundation pit, displacement grooves are opened at the edge positions of both sides of the foundation pit, a specimen is arranged inside the foundation pit, pressure plates are arranged above and on one side of the specimen, wherein a horizontal hydraulic jack is arranged on the outer side of the pressure plate located on one side of the specimen, a reaction plate is arranged on the outer side of the horizontal hydraulic jack, steel plates are arranged on both sides above the pressure plate located above the specimen, and a rolling slide is arranged above each side of the steel plate, steel plates are placed on both sides above the rolling slide correspondingly, and a pressure plate with a vertical hydraulic jack is tightly connected above the steel plate, the vertical hydraulic jack is pressed against the center of the top plate through a force transmission steel column, a reaction plate and an I-beam in sequence, a number of sandbags are placed above the top plate, both sides of the top plate are pressed into the displacement groove, and the specimen is above A semicircular groove is provided at the center position of the upper surface of the pressure plate, and a semicircular reset head is connected to the center position of the lower surface of the pressure plate above the corresponding position through a connecting column, and the reset head is sunk into the semicircular groove. A guide device is provided between the horizontal hydraulic jack and the vertical hydraulic jack, and the guide device includes a mounting plate with a plug plate and a mounting head with a slot, the slot is embedded in the plug plate and fixed, and the rear of the mounting plate is pre-buried in the side wall of the foundation pit, the mounting head is in the shape of a cube and rectangular grooves are processed on the bottom and outer sides, a sliding rod is welded inside the rectangular groove, and a guide rod is mounted on the sliding rod, one end of the guide rod is provided with a through hole and is mounted on the sliding rod, and the other end is respectively mounted on the telescopic sections of the horizontal hydraulic jack and the vertical hydraulic jack through a ring.

[0006] Furthermore, a buffer zone is provided on the inner side of the displacement groove.

[0007] Furthermore, an L-shaped slot plate is provided at one end of the outer reaction plate of the horizontal hydraulic jack, the inner side of the L-shaped slot plate is a fill layer and the outer side is clamped with the reaction plate.

[0008] Furthermore, percentage test gauges are provided above the pressure plate of the vertical hydraulic jack and on the other side of the specimen.

[0009] Furthermore, an anti-slip ring is provided inside the ferrule.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The present invention provides a reset head, a semicircular groove and rolling slide structures on both sides. When an eccentric displacement occurs between the vertical hydraulic jack and the specimen, the arc-shaped reset head and the groove cooperate with the rolling slides on both sides to perform a return operation, so that the vertical hydraulic jack returns to the initial pressure position of the specimen. By providing a guide device, the telescopic sections of the horizontal hydraulic jack and the vertical hydraulic jack can be limited on all sides, while the stability of the force applied by the contraction section can be improved, thereby improving the test reliability of the rock and soil direct shear test device as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0013] Figure 2 It is a schematic diagram of the structure of the sample of the present invention;

[0014] Figure 3 This is a schematic diagram of the structure below the pressure plate of the present invention;

[0015] Figure 4 It is a schematic diagram of the structure of the guide device of the present invention;

[0016] In the figure: 1. foundation pit; 2. test piece; 3. percentage test gauge; 4. pressure plate; 5. horizontal hydraulic jack; 6. vertical hydraulic jack; 7. guide device (71. mounting plate; 72. mounting head; 73. slide rod; 74. guide rod; 75. through hole; 76. anti-slip ring); 8. displacement groove; 9. buffer belt; 10. top plate; 11. sandbag; 12. fill layer; 13. reaction plate; 14. L-shaped slot plate; 15. semicircular groove; 16. steel plate; 17. I-beam; 18. reset head; 19. roller slide belt. DETAILED DESCRIPTION

[0017] In order to make the technical means, creative features, objectives and effects of the invention easy to understand, the present invention is further explained below with reference to specific diagrams.

[0018] like Figures 1 to 4As shown, a rock and soil direct shear test device comprises a foundation pit 1, displacement grooves 8 are opened at the edges of both sides of the foundation pit 1, a specimen 2 is arranged inside the foundation pit 1, and pressure plates 4 are arranged above and on one side of the specimen 2, wherein a horizontal hydraulic jack 5 is arranged on the outside of the pressure plate 4 on one side of the specimen 2, and a reaction plate 13 is arranged on the outside of the horizontal hydraulic jack 5, steel plates 16 are arranged on both sides above the pressure plate 4 above the specimen 2, and a roller slide 19 is arranged above each side of the steel plate 16, and both sides above the roller slide 19 A steel plate 16 is placed correspondingly, and the pressure plate 4 with a vertical hydraulic jack 6 is tightly connected to the top of the steel plate 16. The top of the vertical hydraulic jack 6 is pressed tightly at the center of the top plate 10 through a force transmission steel column, a reaction plate 13 and an I-beam 17 in sequence. A number of sandbags 11 are placed above the top plate 10. Both sides of the top plate 10 are pressed into the displacement groove 8. A semicircular groove 15 is opened at the center of the upper surface of the pressure plate 4 above the specimen 2, and a semicircular groove 15 is connected to the center of the lower surface of the pressure plate 4 above the corresponding position through a connecting column. A circular reset head 18 is sunk into the semicircular groove 15. A guide device 7 is provided between the horizontal hydraulic jack 5 and the vertical hydraulic jack 6. The guide device 7 includes a mounting plate 71 with a plug plate and a mounting head 72 with a slot. The slot is embedded in the plug plate and fixed. The rear of the mounting plate 71 is pre-buried in the side wall of the foundation pit 1. The mounting head 72 is a cube and has rectangular grooves processed on the bottom and outer sides. A slide bar 73 is welded inside the rectangular groove. A guide rod 74 is mounted on the slide bar 73. The guide A through hole 75 is provided at one end of the rod 74 and is sleeved on the slide rod 73, and the other end is respectively sleeved on the telescopic sections of the horizontal hydraulic jack 5 and the vertical hydraulic jack 6 through rings. A buffer belt 9 is provided on the inner side of the displacement groove 8, and an L-shaped slot plate 14 is provided at one end of the outer reaction plate 13 of the horizontal hydraulic jack 5. The inner side of the L-shaped slot plate 14 is a fill layer 12 and the outer side is clamped with the reaction plate 13. A percentage detection gauge 3 is provided above the pressure plate 4 of the vertical hydraulic jack 6 and on the other side of the specimen 2, and an anti-slip ring 76 is provided inside the ring.

[0019] In the actual test, a 100t hydraulic jack is used. The positions of the horizontal hydraulic jack 5 and the vertical hydraulic jack 6 should be aligned with the horizontal line of the center of gravity and the vertical normal of the specimen 2 respectively. The jack and the oil tank are connected through the oil pipe and the assembled direct shear test device is debugged. The test adopts the slow shear method. The vertical load is applied in 4 levels according to the design standard. The dial indicator value is read immediately after each level of loading. The vertical deformation is observed every 5 minutes. If the vertical deformation does not exceed 0.05mm within 5 minutes, the next level of load can be applied. After all the predetermined design loads are applied, the lateral thrust can be applied. When applying the lateral thrust, it should be continuous and uniform, and the maximum thrust should be estimated by referring to the c and φ values ​​of the same rock type. At the same time, the thrust is divided into 4 levels. It is required to accurately record the dial indicator reading of each level, and observe whether the horizontal displacement exceeds 0.05mm every 5 minutes. If it does not exceed, the next level of loading can be carried out. If the test termination condition is still not met after applying to the 4th level, it is necessary to continue to apply the load according to the previous level until the test termination condition is met. According to the "Field Direct Shear Test Procedure" (YS522122000), when the shear deformation continues to increase, the pressure value of the horizontal pressure gauge decreases, or the ratio of the lateral displacement to the width of the specimen reaches 1 / 10, it is shear failure.

[0020] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A rock and soil direct shear test device, characterized in that: The invention comprises a foundation pit, wherein displacement grooves are provided at the edge positions on both sides of the foundation pit, a specimen is provided inside the foundation pit, pressure plates are provided on the top and one side of the specimen, wherein a horizontal hydraulic jack is provided on the outer side of the pressure plate on one side of the specimen, a reaction plate is provided on the outer side of the horizontal hydraulic jack, steel plates are provided on both sides above the pressure plate above the specimen, and a rolling belt is provided above each side of the steel plate, steel plates are placed on both sides above the rolling belt correspondingly, and a pressure plate with a vertical hydraulic jack is tightly connected above the steel plate, the vertical hydraulic jack is pressed against the center of the top plate through a force transmission steel column, a reaction plate and an I-beam in sequence, a number of sandbags are placed above the top plate, and both sides of the top plate are pressed into the displacement groove, a semicircular groove is provided at the center position of the upper surface of the pressure plate above the specimen, and the center of the lower surface of the pressure plate above the corresponding position is provided. A semicircular reset head is connected to the position through a connecting column, and the reset head is sunk into the semicircular groove. A guide device is provided between the horizontal hydraulic jack and the vertical hydraulic jack, and the guide device comprises a mounting plate with a plug plate and a mounting head with a slot, and the slot is embedded in the plug plate and fixed, and the rear of the mounting plate is pre-buried in the side wall of the foundation pit, and the mounting head is in the shape of a cube and has rectangular grooves processed on the bottom and outer sides, and a sliding rod is welded inside the rectangular groove, and the sliding rods are respectively equipped with guide rods, one end of the guide rod is provided with a through hole and is mounted on the sliding rod, and the other end is respectively mounted on the telescopic sections of the horizontal hydraulic jack and the vertical hydraulic jack through a ring, and a buffer belt is provided on the inner side of the displacement groove, and one end of the outer reaction plate of the horizontal hydraulic jack is provided with an L-shaped slot plate, and the inner side of the L-shaped slot plate is a fill layer and the reaction plate is mounted on the outer side.

2. A rock and soil direct shear test device according to claim 1, characterized in that: A percentage detection gauge is provided above the pressure plate of the vertical hydraulic jack and on the other side of the sample piece.

3. A rock and soil direct shear test device according to claim 1, characterized in that: An anti-slip ring is arranged inside the ferrule.

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