Geotechnical test cavern capable of providing super-large counter-force support

Abstract

The utility model discloses a geotechnical test chamber capable of providing super-large counter-force support, relates to the field of underground structures, solves the problem that counter-force provided by a column type counter-force frame is not large enough, and adopts the technical scheme that a tunnel communicated with the outside is arranged on the side wall of a chamber of the geotechnical test chamber capable of providing super-large counter-force support; reinforced concrete linings are arranged on the top, the bottom and the side walls of the chamber, a first bearing plate is arranged on the surface of the lining on the top of the chamber, and the top face of the first bearing plate is fixedly connected with a first anchoring part; two second bearing plates are arranged on the surface of a lining of the side wall of the chamber, two planes corresponding to the two second bearing plates are vertical and parallel to each other, and the faces, back to the chamber, of the two second bearing plates are fixedly connected with second anchoring parts respectively. According to the utility model, the chamber surrounding rock is used as a counter-force foundation of a soil test, and strong counter-force can be provided for vertical pressure and horizontal pressure required by the soil test. The full-graded coarse-grained soil mechanical property test device is used for full-graded coarse-grained soil mechanical property tests.

Description

Technical Field

[0001] The utility model relates to the field of underground structures, in particular to a geotechnical test chamber that uses the rock wall of a deep underground chamber buried in hard rock as a support body to apply an ultra-large axial pressure and horizontal shear force in a reverse pressure manner. Background Technique

[0002] The mechanical strength and deformation characteristics of foundations, filling materials, slopes and underground chambers can be measured through direct shear tests and compression tests. For the compression test and direct shear test of coarse-grained soil, a large geotechnical compressor and a large geotechnical direct shear apparatus are required.

[0003] The existing large geotechnical compressor and large geotechnical direct shear apparatus apply a vertical pressure through a hydraulic device. Generally, columns are used to balance the reaction force of the hydraulic jack. The maximum vertical pressure that can be applied to the specimen is about 750 kN, and the maximum horizontal shear force that can be applied to the specimen is about 310 kN. It is applicable to specimens with a maximum diameter of about 500 mm. For the large geotechnical direct shear apparatus, since the hydraulic jack for applying the horizontal shear force relies on the base and the cross beam to provide the reaction force, the horizontal shear force that can be applied is limited, and a direct shear test can only be carried out on specimens with a maximum diameter of about 500 mm. The maximum allowable particle size of a 500-mm specimen is about 100 mm.

[0004] The maximum particle size of the rockfill widely used in high earth-rock dams generally reaches 600 - 800 mm. The requirements for the allowable particle size of the coarse-grained soil specimen by the existing large geotechnical compressor are very different from the maximum particle size and particle gradation of the actual filled rockfill. For several currently planned and under-construction 300-m-class extra-high earth-rock dams, the maximum stress of the dam body exceeds 5 MPa. Exploring the mechanical strength and deformation characteristics of the rockfill under such high confining pressures is a key technical issue for the design, construction and safety evaluation of extra-high earth-rock dams. There is an urgent need to develop a test device with an ultra-large size and capable of applying an ultra-large pressure suitable for the full gradation test of rockfill. The key to realizing such a device lies in developing a test equipment system with an ultra-large size, ultra-high pressure, easy to operate and meeting the accuracy requirements, especially a reaction force support system that can provide the reaction force required for applying an ultra-high vertical pressure (such as 40,000 kN) and horizontal shear force (such as 20,000 kN). Content of the Utility Model

[0005] The utility model provides a geotechnical test chamber that can provide an ultra-large reaction force support, and solves the problem that the reaction force provided by the column-type reaction frame for indoor geotechnical tests is not large enough.

[0006] The technical solution adopted by the utility model is as follows: a geotechnical test chamber that can provide a super-large reaction support, with a tunnel communicating with the outside at the end of the chamber. The top, bottom, and side walls of the chamber are all provided with reinforced concrete linings. The surface of the lining at the top of the chamber is provided with a first bearing plate, the plane corresponding to the first bearing plate is horizontal, and at least one first anchor is fixedly connected to the top surface of the first bearing plate. One section of the first anchor is buried in the lining at the top of the chamber, and the other section is inserted into the rock mass at the top of the chamber; on the surface of the lining on the side wall of the chamber, there are two second bearing plates. The two planes corresponding to the two second bearing plates are both vertical and parallel to each other. On the surfaces of the two second bearing plates facing away from the chamber, at least one second anchor is fixedly connected respectively. One section of the second anchor is buried in the lining on the side wall of the chamber, and the other section is inserted into the rock mass on the side wall of the chamber.

[0007] The first bearing plate needs to directly hang and install test equipment. In order to ensure that all parts of the first bearing plate can be firmly anchored in the lining at the top of the chamber, further: the bottom surface of the first bearing plate is coplanar with the bottom surface of the lining at the top of the chamber, a fixing frame is fixedly connected to the top surface of the first bearing plate, and the first anchor is fixedly connected to the fixing frame; or, multiple hooks are also fixedly connected to the top surface of the first bearing plate, and the hooks are buried in the lining at the top of the chamber. For example, one end of the hook is fixedly connected to the first bearing plate, and the other end of the hook is provided with a bend and is connected to the reinforcement bars of the lining at the top of the chamber.

[0008] In order to ensure the fixing effect of the hook on the first bearing plate, specifically: the hooks are arranged in rows and columns on the top surface of the first bearing plate, the row and column spacing is 1.00 m to 2.00 m, and the length of a single hook is not less than 32 cm.

[0009] Both the first anchor and the second anchor play a role in support and reinforcement. Specifically: both the first anchor and the second anchor are anchor rods.

[0010] In order to ensure the support and reinforcement effects of the first anchor and the second anchor, specifically: the rock-in depth of the anchor rod is not less than 4.50 m.

[0011] In the early stage of geotechnical tests, samples are first prepared outside the chamber and then moved into the chamber for geotechnical tests. In order to facilitate the movement of the samples, further: continuous tracks are horizontally laid on the lining at the bottom of the chamber and the lining at the bottom of the tunnel.

[0012] In order to facilitate the construction of the lining and ensure the structural safety of the lining, specifically: the reinforcement bars of the lining are HRB400 steel bars, and double-layer reinforcement is arranged both in the cross-section of the circular tunnel and in the direction of the tunnel axis. Double-layer reinforcement.

[0013] To ensure that the linings of the top, bottom, and side walls of the chamber have sufficient strength, specifically: the lining is made of C40 concrete. The thickness of the linings of the top and side walls of the chamber is not less than 80 cm, the thickness of the directly stressed area of the lining at the bottom of the chamber is not less than 132 cm, and the thickness of the non-directly stressed area of the lining at the bottom of the chamber is not less than 60 cm.

[0014] To ensure that the first bearing plate and the second bearing plate can provide a large enough reaction force, specifically: both the first bearing plate and the second bearing plate are made of steel plates. Generally, the thickness of the steel plate is not less than 4 cm.

[0015] The beneficial effects of the present utility model are as follows: The present utility model utilizes the rock wall of a deeply buried underground chamber in hard rock as a support body to apply an ultra-large axial pressure and shear force by backpressure. The layout of the deeply buried chamber is determined based on engineering geology, rock wall stability, the magnitude of the backpressure support force provided for the test, and the requirements for the test space. The top, bottom, and side walls of the chamber are all lined with reinforced concrete and are an integral whole to ensure the stability of the chamber during the test loading process. The surface of the reinforced concrete lining at the top of the chamber is provided with a first bearing plate, and inside there is a fixed bearing plate and anchor bolts implanted into the rock wall. The bearing plate, anchor bolts, lining, and rock wall form a stable support system for cooperative force and force transmission, which can provide strong support and reaction force for the vertically arranged hydraulic device. On the surfaces of the linings of two opposite side walls of the chamber, second bearing plates are respectively provided. The surface of the lining of the side wall of the chamber is provided with a second bearing plate, and inside there is a fixed bearing plate and anchor bolts implanted into the rock wall. The bearing plate, anchor bolts, lining, and rock wall form a stable support system for cooperative force and force transmission. The chamber is located in a hard and stable mountain body or underground. The overburden thickness, strength, and modulus of the surrounding rock of the chamber are large. As a reaction force support body for geotechnical tests, the deformation is very small, which can provide a strong reaction force for the vertical pressure and horizontal shear force required for geotechnical tests, realizing mechanical strength and deformation tests under ultra-large-sized specimens and ultra-high loads, and breakthroughly solving the problem that it is difficult to apply ultra-high vertical pressure (such as 40000 kN) and horizontal shear force (such as 20000 kN) in the full-graded geotechnical test of large-grained coarse-grained soil. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of an embodiment of a geotechnical test chamber that can provide an ultra-large reaction force support of the present utility model.

[0017] Figure 2 is Figure 1 A sectional view taken along the A-A direction.

[0018] Reference numerals: lining 1, first bearing plate 2, first anchor bolt 3, second bearing plate 4, second anchor bolt 5, fixing frame 6, track 7. Detailed Implementation Modes

[0019] The present utility model will be further described below in conjunction with the accompanying drawings.

[0020] Referring to Figure 1 and Figure 2 , the present utility model can provide a geotechnical test chamber with a super-large reaction force support, including a chamber buried deep underground, a lining of reinforced concrete, and embedded parts. A tunnel communicating with the outside is provided at the end of the chamber, and linings 1 of reinforced concrete are provided on the top, bottom, and side walls of the chamber. For example, in Figure 1 the illustrated embodiment, the relatively small space on the left side and located at Figure 1 is the chamber of the geotechnical test chamber, and the relatively large space on the right side and located at Figure 1 is the tunnel. The tunnel is not only a passage for entering and leaving the chamber but can also be used as a sample preparation site. The chamber is located in a mountain body or underground with a certain burial depth. For example, it is required that the modulus of the surrounding rock is above 20 GPa. The chamber is a space roughly in the shape of a cuboid. For example, the spatial dimensions of the chamber are: the depth of the hole is 10 m × the width is 7.75 m × the height is 7.01 m. Before conducting geotechnical tests, such as before conducting compression tests or direct shear tests, samples can be prepared outside the chamber and then moved into the chamber for geotechnical tests. In order to facilitate the movement of the samples, continuous tracks 7 are laid on the lining 1 at the bottom of the chamber and the lining at the bottom of the tunnel, and the tracks 7 are laid horizontally. There are at least two tracks 7 and they are parallel to each other. The tracks 7 are generally two steel rails. In order to ensure the bearing capacity of the tracks 7, steel bars are continuously embedded in the lining 1 at the bottom of the chamber. The bottom of the steel bar is fixedly connected with a hook, and the hook is located in the lining 1 at the bottom of the chamber or the lining at the bottom of the tunnel, and the steel rail is installed on the top of the steel bar.

[0021] The linings 1 on the top, bottom, and side walls of the chamber are connected as a whole to ensure the stability of the chamber. The outer surfaces of the linings 1 on the top and side walls of the chamber are planes that meet the requirements of structural accuracy to facilitate the provision of reaction force, that is, the bottom surface of the lining 1 on the top of the chamber is horizontal, and the outer surface of the lining 1 on the side wall of the chamber is vertical. The lining 1 is a reinforced concrete structure. In order to ensure that the linings 1 on the top, bottom, and side walls of the chamber have sufficient strength, after calculating the stress, the lining 1 can adopt C40 concrete. The thickness of the lining 1 at different positions is determined according to the calculation. For example, the thicknesses of the linings 1 on the top and side walls of the chamber are not less than 80 cm, the thickness of the directly stressed area of the lining 1 at the bottom of the chamber is not less than 132 cm, and the thickness of the non-directly stressed area of the lining 1 at the bottom of the chamber is not less than 60 cm. The steel reinforcement of the lining 1 should meet the requirements of applying vertical pressure and horizontal shear force in geotechnical tests. In order to facilitate the construction of the lining 1 and ensure the structural safety of the lining 1, after calculating the stress, the steel reinforcement of the lining 1 can be HRB400 steel bars, and both the circular cross-section of the tunnel and the direction of the tunnel axis are double-layer steel reinforced.

[0022] The hydraulic device vertically arranged in the chamber provides vertical pressure for geotechnical tests, and the linings 1 at the top and bottom of the chamber provide a strong reaction force for the vertically arranged hydraulic device. For example, the linings 1 at the top and bottom of the chamber can provide a reaction force of up to 40000 kN for the vertically arranged hydraulic device. The hydraulic device horizontally arranged in the chamber provides horizontal shear force for geotechnical tests, and the linings 1 located on the side walls of the chamber and arranged oppositely provide a strong reaction force for the horizontally arranged hydraulic device. For example, the lining 1 on the side wall of the chamber can provide a reaction force of up to 24000 kN for the horizontally arranged hydraulic device.

[0023] In order to prevent the pressure of the vertically arranged hydraulic device on the lining 1 at the top of the chamber from directly acting on the reinforced concrete of the lining 1, a first bearing plate 2 is provided on the surface of the lining 1 at the top of the chamber. The plane corresponding to the first bearing plate 2 is horizontal, and at least one first anchor 3 is fixedly connected to the top surface of the first bearing plate 2. One section of the first anchor 3 is buried in the lining 1 at the top of the chamber, and the other section is inserted into the rock mass at the top of the chamber. In order to prevent the pressure of the horizontally arranged hydraulic device on the lining 1 on the side wall of the chamber from directly acting on the reinforced concrete of the lining 1, two second bearing plates 4 are provided on the surface of the lining 1 on the side wall of the chamber. The two planes corresponding to the two second bearing plates 4 are both vertical and parallel to each other, that is, the two second bearing plates 4 are located on the opposite sides of the chamber, and at least one second anchor 5 is fixedly connected to the surfaces of the two second bearing plates 4 facing away from the chamber. One section of the second anchor 5 is buried in the lining 1 on the side wall of the chamber, and the other section is inserted into the rock mass on the side wall of the chamber.

[0024] To ensure that the first bearing plate 2 and the second bearing plate 4 can provide a large enough reaction force, the first bearing plate 2 and the second bearing plate 4 are generally made of steel plates. For example, both the first bearing plate 2 and the second bearing plate 4 are steel plates with a thickness of not less than 4 cm. Both the first anchor 3 and the second anchor 5 play a role in supporting and reinforcing. Generally, the first anchor 3 and the second anchor 5 are both anchor rods. To ensure the supporting and reinforcing effects of the first anchor 3 and the second anchor 5, the rock penetration depth of the anchor rod is not less than 4.50 m. The first bearing plate 2 needs to directly suspend and install the test equipment. For example, considering that the test equipment weighs about 30 t, the diameter and length of the first anchor 3 are greater than those of the second anchor 5. The first anchors 3 are arranged vertically, and the first anchors 3 are arranged in rows and columns with a row and column spacing of 1.00 m to 2.00 m. To facilitate the installation of the test equipment, the bottom surface of the first bearing plate 2 is horizontal and coplanar with the bottom surface of the lining 1 of the top of the chamber. To ensure that all parts of the first bearing plate 2 can be firmly anchored in the lining 1 of the top of the chamber, a fixing frame 6 is fixedly connected to the top surface of the first bearing plate 2, the first anchor 3 is fixedly connected to the fixing frame 6, and the fixing frame 6 can also be connected to the reinforcement bars of the lining 1 of the top of the chamber. To facilitate construction, one end of the first anchor 3 can be connected to the fixing frame 6 through a nut. Alternatively, a plurality of hooks are also fixedly connected to the top surface of the first bearing plate 2. The hooks are generally made of metal, such as bent steel bars. The hooks are buried in the lining 1 of the top of the chamber. For example, one end of the hook is fixedly connected to the first bearing plate 2. When the first bearing plate 2 is a steel plate, one end of the hook can be welded to the first bearing plate 2. The other end of the hook is provided with an elbow and is within a depth range of 24 cm on the surface layer of the lining 1. For example, the elbow is bent at 90°. The elbow of the hook is preferably connected to the reinforcement bars of the lining 1 of the top of the chamber. To ensure the fixing effect of the hook on the first bearing plate 2, the hooks are arranged in rows and columns on the top surface of the first bearing plate 2 with a row and column spacing of 1.00 m to 2.00 m, and the length of a single hook is not less than 10 times its diameter. For example, the length of a single hook is not less than 32 cm.

[0025] The implementation of the present utility model involves the design and construction of a deep underground chamber in hard rock. The depth of the chamber is determined according to the reaction force required for the reverse pressure support of the chamber wall. The surrounding rock of the chamber is evaluated for its stability based on exploration and excavation revelations and necessary treatments are carried out. The size of the chamber is determined by the space requirements for the layout of the test device, etc.

Claims

1. A geotechnical test chamber capable of providing a super-large reaction force support, with a tunnel communicating with the outside at the end of the chamber, and reinforced concrete linings (1) are provided on the top, bottom and side walls of the chamber, and it is characterized in that: On the surface of the lining (1) at the top of the chamber, a first bearing plate (2) is provided. The plane corresponding to the first bearing plate (2) is horizontal. At least one first anchor (3) is fixedly connected to the top surface of the first bearing plate (2). One section of the first anchor (3) is buried in the lining (1) at the top of the chamber, and the other section is inserted into the rock mass at the top of the chamber. On the surface of the lining (1) on the side wall of the chamber, two second bearing plates (4) are provided. The two planes corresponding to the two second bearing plates (4) are both vertical and parallel to each other. At least one second anchor (5) is fixedly connected to the surfaces of the two second bearing plates (4) facing away from the chamber. One section of the second anchor (5) is buried in the lining (1) on the side wall of the chamber, and the other section is inserted into the rock mass on the side wall of the chamber.

2. The geotechnical test chamber capable of providing an ultra-large reaction force support according to claim 1, characterized in that: The bottom surface of the first bearing plate (2) is coplanar with the bottom surface of the lining (1) at the top of the chamber. A fixing frame (6) is fixedly connected to the top surface of the first bearing plate (2), and the first anchor (3) is fixedly connected to the fixing frame (6); alternatively, a plurality of hooks are also fixedly connected to the top surface of the first bearing plate (2), and the hooks are buried in the lining (1) at the top of the chamber.

3. The geotechnical test chamber capable of providing an ultra-large reaction force support according to claim 2, characterized in that: The hooks are arranged in rows and columns on the top surface of the first bearing plate (2). The row and column spacing is 1.00 m to 2.00 m, and the length of a single hook is not less than 32 cm.

4. The geotechnical test chamber capable of providing a super-large reaction force support according to claim 1, characterized in that: Both the first anchor (3) and the second anchor (5) are anchor bolts.

5. The geotechnical test chamber capable of providing an ultra-large reaction force support according to claim 4, characterized in that: The rock-in depth of the anchor bolt is not less than 4.50 m.

6. The geotechnical test chamber capable of providing an ultra-large reaction force support according to claim 1, characterized in that: A continuous track (7) is horizontally laid on the lining (1) at the bottom of the chamber and the lining at the bottom of the tunnel.

7. The geotechnical test chamber capable of providing an ultra-large reaction force support according to any one of claims 1 to 6, characterized in that: The reinforcement of the lining (1) is HRB400 steel bars, and double-layer reinforcement is adopted in both the circular tunnel section and the tunnel axis direction. Double-layer reinforcement.

8. The geotechnical test tunnel capable of providing super-large reaction force support according to any one of claims 1 to 6, characterized in that: The lining (1) is C40 concrete. The thickness of the lining (1) at the top of the chamber and on the side wall of the chamber is not less than 80 cm. The thickness of the directly stressed area of the lining (1) at the bottom of the chamber is not less than 132 cm, and the thickness of the non-directly stressed area of the lining (1) at the bottom of the chamber is not less than 60 cm.

9. The geotechnical test chamber capable of providing an ultra-large reaction force support according to any one of claims 1 to 6, characterized in that: Both the first bearing plate (2) and the second bearing plate (4) are steel plates.

10. The geotechnical test chamber capable of providing an ultra-large reaction force support according to claim 9, characterized in that: The thickness of the steel plate is not less than 4 cm.

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