A rock creep testing device

Abstract

This utility model relates to the field of rock creep testing technology, and more particularly to a rock creep testing device, comprising a specimen box, a water storage tank, and a rock specimen; the specimen box is vertically arranged, with a closed bottom and an open top; a pad is provided at the bottom of the specimen box; the rock specimen is pressed against the top of the pad by a pressure rod; the water storage tank includes a box body and a piston that is slidably sealed inside the box body, the piston dividing the interior of the box body into a relatively independent first chamber and a second chamber, the first chamber being connected to the specimen box; the top of the first chamber is not higher than the top of the pad, and moving the position of the piston can squeeze the water in the first chamber into the interior of the specimen box. This utility model completes the creep experiment of rock specimens under the action of cyclic water flooding-stress coupling, filling a gap in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of rock creep testing technology, specifically a rock creep testing device. Background Technology

[0002] Rock creep refers to the phenomenon that rocks, under long-term constant stress, will continue to deform over time even when the stress level is below their instantaneous failure strength. Creep occurs in rocks such as sandstone and shale when the load reaches 12.5% ​​to 80% of their failure strength. Therefore, studying rock creep is crucial for predicting geological hazards (such as landslides) and assessing the long-term stability of engineering projects.

[0003] Chinese patent document CN215492900U discloses a rock creep testing device, including five pressure cylinders, five displacement gauges, and five cameras mounted on a support. The five pressure cylinders are five identical stainless steel cylinders, vertically spaced and evenly distributed on the support. The five displacement gauges are all positioned with their probes pointing vertically downwards and are fixed above the five pressure cylinders to detect the downward displacement of the pressure cylinders. The five cameras are each positioned in front of the five pressure cylinders, with each camera fixed to the support with its lens pointing horizontally towards the pressure cylinder to acquire images of the rock sample pressed under the pressure cylinder.

[0004] According to the technical solutions described in the aforementioned patents, existing devices have significant limitations in their environmental simulation capabilities: their testing environment is limited to dry conditions, failing to realistically replicate the complexity of the natural environment in which rocks exist. For example, in typical scenarios such as rocky bank slopes in drawdown zones, slopes of water conservancy and hydropower projects, and coastal geotechnical engineering projects, rocks are exposed to multiple coupled environments of water level fluctuations and alternating wet and dry conditions for extended periods. Their creep characteristics differ fundamentally from those in dry environments. If the aforementioned methods are still used for testing, the following technical problems arise:

[0005] 1. Limited Environmental Simulation: Existing devices cannot simulate key environmental factors such as high humidity and wet-dry cycles, resulting in test results that deviate from actual working conditions and making it difficult to support the reliability verification of engineering designs under complex geological conditions.

[0006] II. Gaps in Special Scenarios: In special scenarios such as rocky bank slopes in drawdown zones, the softening effect and accelerated crack propagation caused by the periodic water immersion and drying of rocks cannot be observed with existing devices, which restricts the development of key technologies such as landslide early warning and bank slope stability assessment. Utility Model Content

[0007] The purpose of this invention is to provide a rock creep testing device to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] A rock creep testing apparatus includes a specimen box, a water tank, and a rock specimen;

[0010] The specimen box is vertically arranged, with a closed bottom and an open top; a pad is provided at the bottom of the specimen box; the rock specimen is pressed against the top of the pad by a pressure rod;

[0011] The water storage tank includes a tank body and a piston component that is slidably sealed inside the tank body. The piston component divides the interior of the tank body into a relatively independent first chamber and a second chamber. The first chamber is connected to the specimen box.

[0012] The height of the top of the first chamber is not higher than the height of the top of the pad column. By moving the position of the piston, water in the first chamber can be squeezed into the interior of the test specimen box, or water can be drawn back into the first chamber from the interior of the test specimen box.

[0013] Preferably, the end of the box body away from the test specimen box is threaded with a sealing cap to isolate the second chamber from the external environment;

[0014] A branch pipe is fixed on the sealing cover, a valve is installed on the branch pipe, the branch pipe is connected to the main pipe, and the main pipe is connected to the air pump.

[0015] Preferably, the piston component includes a support plate and a rubber sleeve fitted on the outside of the support plate, wherein the outer peripheral wall of the rubber sleeve is slidably and sealingly connected to the inner peripheral wall of the housing.

[0016] Preferably, one end of the support plate is fixedly connected to a bracket, and a roller is rotatably mounted on the bracket, the roller being in rolling connection with the inner peripheral wall of the box.

[0017] Preferably, a frustum block is fixed to the bottom end of the pressure rod, a gasket is provided between the frustum block and the rock specimen, and a vertical column is provided on one side of the gasket.

[0018] Preferably, the specimen box includes a lower box and an upper box that is sealed and connected to the top of the lower box. The bottom of the lower box is sealed, and the upper box is made of a transparent material.

[0019] Preferably, a drain pipe is connected to one side of the bottom of the specimen box, and a drain valve is installed on the drain pipe.

[0020] Preferably, a positioning ring is fitted and fixed to the outer side of the top of the pad column, and the positioning ring cooperates with the pad column to form a positioning groove, and the bottom end of the rock specimen is inserted into the positioning groove.

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] This invention, by setting up an interconnected specimen box and a water storage tank, and installing a piston inside the water storage tank, allows for the water immersion of rock specimens at a fixed frequency according to experimental requirements. Then, by combining this with an axial compressive force applied to the rock specimens by a pressurizing device, a creep experiment under cyclic water immersion-stress coupling can be completed, filling a gap in the existing technology. In addition, changing the water level in the specimen box through the piston has the advantage of fast response speed. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0024] Figure 2 This is a cross-sectional three-dimensional structural diagram of the specimen box and water storage tank of this utility model;

[0025] Figure 3 This is a schematic diagram of the positioning ring of this utility model;

[0026] Figure 4 This is a schematic diagram of the piston component of this utility model.

[0027] In the diagram: 1. Specimen box; 101. Lower box; 102. Upper box; 2. Water storage tank; 201. Box body; 202. Piston; 2021. Support plate; 2022. Rubber sleeve; 2023. Bracket; 2024. Roller; 203. Sealing cover; 204. First chamber; 205. Second chamber; 3. Rock specimen; 4. Pressure rod; 5. Frustum block; 6. Gasket; 7. Vertical column; 8. Drain pipe; 9. Drain valve; 10. Branch pipe; 11. Valve; 12. Main pipe; 13. Pad column; 14. Positioning ring; 15. Positioning groove. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Please see Figures 1-4 This utility model provides a technical solution:

[0030] A rock creep testing device includes a specimen box 1, a water storage tank 2, and a rock specimen 3; wherein, the specimen box 1 is used to place the rock specimen 3; and the water storage tank 2 is used to store water.

[0031] The specimen box 1 is vertically arranged, with a closed bottom and an open top. The specimen box 1 includes a lower box 101 and an upper box 102 sealed and connected to the top of the lower box 101. Specifically, both the lower box 101 and the upper box 102 are cylindrical. In some embodiments, the inner diameters of the lower box 101 and the upper box 102 are equal, and their outer diameters are also equal. The difference between the lower box 101 and the upper box 102 is that the bottom of the lower box 101 is sealed to prevent leakage. The lower box 101 can be made of stainless steel. Both ends of the upper box 102 are open. The bottom of 2 is sealed to the top of the lower box 101 with sealant, so that the upper box 102 and the lower box 101 work together to form a chamber for accommodating the rock specimen 3. In this embodiment, the upper box 102 is made of a transparent material, such as tempered glass or transparent acrylic. Thus, a camera for filming the creep process of the rock specimen 3 can be installed on the outside of the upper box 102 to perform the filming operation. Since the upper box 102 is cylindrical, the rock specimen 3 can be filmed from any angle without any deviation in the filming.

[0032] A drain pipe 8 is connected to one side of the bottom of the specimen box 1. A drain valve 9 is installed on the drain pipe 8. The drain pipe 8 and the drain valve 9 can be used to easily change the water.

[0033] A support column 13 is provided at the bottom of the specimen box 1. The support column 13 can be made of stainless steel, and its bottom end can be fixed to the inner bottom surface of the lower box 101 by welding. The rock specimen 3 is pressed against the top of the support column 13 by a pressure rod 4. The top end of the pressure rod 4 is connected to a pressure device, which can be a hydraulic cylinder or a servo pressure system, etc. The pressure device is used to clamp the rock specimen 3 between the pressure rod 4 and the support column 13, and to apply a constant axial compressive force to the rock specimen 3 through the pressure rod 4.

[0034] A frustum block 5 is fixed to the bottom of the pressure rod 4. A shim 6 is provided between the frustum block 5 and the rock specimen 3. A vertical column 7 is provided on one side of the shim 6. The vertical column 7 is used to connect to the displacement gauge to facilitate the measurement of the displacement of the rock specimen 3.

[0035] The water storage tank 2 is also cylindrical. In this embodiment, the water storage tank 2 is arranged horizontally, and the height of its bottom end is not lower than the height of the bottom end of the specimen box 1. In this way, the bottom surface of the specimen box 1 can directly contact the bottom surface, and the squeezing force exerted by the pressurizing device on the rock specimen 3 will not damage the bottom wall of the lower box 101. The water storage tank 2 includes a box body 201 and a piston 202 that is slidably sealed inside the box body 201. The piston 202 divides the interior of the box body 201 into a relatively independent first chamber 204 and a second chamber 205. The first chamber 204 is connected to the specimen box 1. Furthermore, in this embodiment, the height of the top of the first chamber 204 is not higher than the height of the top of the pad column 13. When all the water is stored inside the first chamber 204, the lowest point of the rock specimen 3 is above the water surface. The position of the moving piston 202 can squeeze the water in the first chamber 204 into the specimen box 1, or pump the water from the specimen box 1 back into the first chamber 204. Specifically, under normal conditions, all the water is stored inside the first chamber 204, and the rock specimen 3 is only subjected to a constant axial compressive force generated by the pressurizing device. When it is necessary to simulate a water flooding environment, the piston 202 can be pushed towards the specimen box 1. At this time, the water in the first chamber 204 will be quickly squeezed into the specimen box 1, causing the water level in the specimen box 1 to rise rapidly until the rock specimen 3 is completely submerged. Specifically, in this embodiment, the water flooding frequency and the duration of each water flooding can be adjusted. Furthermore, multiple sets of specimen box 1 and water storage tank 2 can be set up simultaneously, so that multiple rock specimens 3 can be subjected to creep experiments under cyclic water flooding-stress coupling at the same time, and the process can be recorded.

[0036] To improve the positioning accuracy between the rock specimen 3 and the pad column 13, a positioning ring 14 is fixedly fitted on the outer side of the top of the pad column 13. The positioning ring 14 and the pad column 13 form a positioning groove 15, and the bottom end of the rock specimen 3 is inserted into the positioning groove 15.

[0037] In the above scheme, by setting up a specimen box 1 and a water storage tank 2 that are interconnected, and by setting a piston 202 inside the water storage tank 2, the rock specimen 3 can be submerged in water at a fixed frequency according to experimental requirements. Then, by using a pressurizing device to apply axial compressive force to the rock specimen 3, the creep experiment of the rock specimen 3 under the action of cyclic water submersion-stress coupling can be completed, filling the gap in the existing technology. In addition, changing the water level in the specimen box 1 by using the piston 202 has the advantage of fast response speed.

[0038] A sealing cover 203 is threaded onto the end of the housing 201 furthest from the test specimen chamber 1, isolating the second chamber 205 from the external environment; thus, the second chamber 205 is a sealed space. A branch pipe 10 is fixed to the sealing cover 203, and a valve 11 is installed on the branch pipe 10. The branch pipe 10 is connected to the main pipe 12, and the main pipe 12 is connected to the air pump. Specifically, the air pump is a three-phase variable frequency air pump, and its model can be the GLA series permanent magnet variable frequency screw compressor from Ningbo Mingcheng Technology Co., Ltd. The advantage of using gas-controlled piston 202 is that it can save some space.

[0039] The piston component 202 includes a support plate 2021 and a rubber sleeve 2022 sleeved on the outside of the support plate 2021. The outer peripheral wall of the rubber sleeve 2022 is slidably and sealingly connected to the inner peripheral wall of the housing 201. Furthermore, in order to improve the stability of the piston component 202 during the sliding process, a bracket 2023 is fixedly connected to one end of the support plate 2021. A roller 2024 is rotatably mounted on the bracket 2023. The roller 2024 is slidably connected to the inner peripheral wall of the housing 201.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rock creep test apparatus, characterized by, Includes specimen boxes and water tanks, as well as rock specimens; The specimen box is vertically arranged, with a closed bottom and an open top; a pad is provided at the bottom of the specimen box; the rock specimen is pressed against the top of the pad by a pressure rod; The water storage tank includes a tank body and a piston component that is slidably sealed inside the tank body. The piston component divides the interior of the tank body into a relatively independent first chamber and a second chamber. The first chamber is connected to the specimen box. The height of the top of the first chamber is not higher than the height of the top of the pad column. By moving the position of the piston, water in the first chamber can be squeezed into the interior of the test specimen box, or water can be drawn back into the first chamber from the interior of the test specimen box.

2. The rock creep test apparatus according to claim 1, wherein The end of the box body away from the test specimen box is threaded with a sealing cap to isolate the second chamber from the external environment; A branch pipe is fixed on the sealing cover, a valve is installed on the branch pipe, the branch pipe is connected to the main pipe, and the main pipe is connected to the air pump.

3. The rock creep test apparatus according to claim 1, wherein The piston component includes a support plate and a rubber sleeve fitted on the outside of the support plate, wherein the outer peripheral wall of the rubber sleeve is slidably and sealingly connected to the inner peripheral wall of the housing.

4. The rock creep test apparatus according to claim 3, wherein One end of the support plate is fixedly connected to a bracket, and a roller is rotatably mounted on the bracket, with the roller rollingly connected to the inner peripheral wall of the box.

5. The rock creep test apparatus of claim 1, wherein A frustum block is fixed to the bottom end of the pressure rod, a gasket is provided between the frustum block and the rock specimen, and a vertical column is provided on one side of the gasket.

6. The rock creep testing device according to claim 1, characterized in that, The specimen box includes a lower box and an upper box that is sealed and connected to the top of the lower box. The bottom of the lower box is sealed, and the upper box is made of a transparent material.

7. The apparatus of claim 1, wherein A drain pipe is connected to one side of the bottom of the specimen box, and a drain valve is installed on the drain pipe.

8. The apparatus of claim 1, wherein, A positioning ring is fixedly fitted to the outer side of the top of the pad column, and the positioning ring cooperates with the pad column to form a positioning groove. The bottom end of the rock specimen is inserted into the positioning groove.

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