Uniaxial apparatus auxiliary device for providing hydraulic coupling and seepage conditions

Abstract

The invention provides a uniaxial apparatus auxiliary device for providing hydraulic coupling and seepage conditions, and overcomes the technical defects of rock mechanical strength test in a seepage environment generated in the process that the water level in a reservoir region flows from high to low, namely, the auxiliary device provides a dynamic water pressure two-dimensional horizontal seepage field test condition. The device is composed of a pressure chamber, a piston plate, a pressure bearing plate, a flow guide plate, a fixing rod, a flow guide pipe, a water flow meter and a water pressure gauge, is matched with a water injection machine to jointly realize test conditions in hydraulic coupling and seepage environments, and is matched with a uniaxial apparatus to carry out corresponding rock mechanical strength tests. The auxiliary device can realize different test conditions such as water flow migration velocity change, water flow impact angle change and water flow pressure change, and truly simulate geological conditions and environmental conditions of rock mass in the water-level-fluctuating zone of the reservoir area. The method has important theoretical value and practical significance for revealing the instability mechanism of the rock mass in the hydro-fluctuation belt influenced by reservoir area water level fluctuation.

Description

Technical Field

[0001] The present invention belongs to the technical field of rock mechanics testing, and specifically relates to an auxiliary device for testing the rock mechanics strength of rock masses in different height difference drawdown zones formed due to flood control, power generation and shipping in a reservoir area under the condition of considering the influence of reservoir water seepage. The auxiliary device can cooperate with a water injection machine and a uniaxial instrument to realize the testing conditions under hydraulic coupling and seepage environment. Background Art

[0002] A large number of river systems are distributed around the world. The construction and operation of water conservancy projects have important social and economic value for the utilization of river system resources in various regions. Affected by natural climate change and human engineering activities, the water level in the reservoir area formed by the water conservancy project changes periodically, that is, the water level in the reservoir area decreases, which has different degrees of impact on the rock mass of the slopes on both sides of the reservoir area. The affected spatial range is called the drawdown zone. The drawdown of the reservoir water level is not conducive to the long-term stability of the slopes on both sides of the reservoir area, the natural ecological environment and the capacity of the reservoir area.

[0003] Research on the rock mechanical strength of rock mass in the drawdown zone is crucial to maintaining the long-term stability of the reservoir area. Under the geological and environmental conditions of the drawdown zone, there are many factors that affect the rock mechanical strength, such as seismic motion, saturation, pH, stress state, joint and fissure development, stratum occurrence, reservoir water level drawdown and human engineering activities. Among them, the effect of reservoir water level drawdown on rock mechanical strength is persistent. For example, after the 175m elevation test water storage in 2008, the rock mass in the drawdown zone of the Three Gorges Reservoir in my country showed significant deterioration and damage for 16 years, which indirectly reflects that the reservoir water level drawdown has become the main influencing factor of the stability of the rock mass in the drawdown zone today.

[0004] The influence of the water level fluctuation in the reservoir area on the stability of the rock mass in the drawdown zone is two-fold. On the one hand, the periodic change of the water level in the reservoir area leads to the periodic change of the wind drying and saturation of the rock mass, that is, the dry-wet cycle. On the other hand, the seepage environment is generated during the flow of the water level from high to low in the reservoir area, which has different degrees of influence on the rock mass in the drawdown zone.

[0005] So far, a large number of researchers have conducted rock mechanical strength tests under dry-wet cycle conditions and revealed the relevant laws and characteristics. The main conclusions are: (1) The degree of rock mechanical strength degradation gradually decreases and tends to be stable with the increase of dry-wet cycles, which conforms to the characteristics of negative exponential change law; (2) The stress-strain curve of rock conforms to the Weibull distribution model, and the creep deformation capacity gradually increases with the increase of dry-wet cycles; (3) The peak strength and residual strength of rock are lower under hydraulic coupling conditions, and the failure time occurs earlier; (4) The continuous increase of microscopic pores inside the rock under dry-wet cycle conditions is the essential cause of macroscopic degradation damage. In summary, the rock mechanics test technology used by researchers can achieve hydraulic coupling test conditions.

[0006] The researchers have made a lot of simplifications in the rock mechanical strength tests under dry-wet cycle conditions. On the one hand, this makes the dry-wet cycle test results inconsistent with the actual situation. On the other hand, it ignores the seepage environment generated by the flow of water levels from high to low in the reservoir area. The impact of the seepage environment on the geological and environmental conditions of the rock mass in the drawdown zone cannot be ignored, but researchers often ignore the impact of the seepage environment on the mechanical strength of the rock.

[0007] For the rock mass in the drawdown zone at a certain elevation, the impact of the periodic changes in the water level in the reservoir area is short-lived, and the resulting seepage field is vertical, while the impact of the seepage environment generated by the flow of the water level in the reservoir area from high to low is long-term, and the resulting seepage field is horizontal. The periodic changes in wind drying and saturation caused by the short-term vertical seepage field can be achieved by dry-wet cycle pretreatment. Up to now, researchers are often unable to achieve rock mechanical strength testing under hydraulic coupling and seepage conditions, resulting in an inability to clearly understand the extent of the impact of the horizontal seepage field on the rock mechanical strength.

[0008] CN 111024577 B provides a test device for the influence of immersion-undermining coupling on the mechanical properties of soil. The patent uses a pressure system, a water supply system, a sand-water separation measurement system and an automated confining pressure system to study the mechanical strength of soil under the conditions of confining pressure, immersion and seepage coupling test. However, the method for implementing the immersion and seepage coupling test conditions is a one-dimensional vertical seepage mode, while the rock mass in the drawdown zone of the reservoir area is mainly affected by the two-dimensional horizontal seepage field, resulting in a narrow scope of application of the test device and method. In addition, the pressure system involved in the patent is only applicable to soils with low mechanical strength. Compared with conventional uniaxial instruments, the scope of application and test accuracy of the pressure system involved in the patent cannot meet the mechanical strength test of harder carbonate rocks in the drawdown zone of the reservoir area.

[0009] In summary, in order to achieve a rock mechanics strength test condition suitable for the geological and environmental conditions of the rock mass in the drawdown zone of the reservoir area, it is necessary to invent a rock mechanics test technology that realizes the test conditions, that is, to provide a test condition of hydraulic coupling and seepage environment. The present invention is an innovation based on the conventional uniaxial instrument. With the help of the axial pressure system of the uniaxial instrument, an auxiliary device that provides hydraulic coupling and seepage conditions is invented, which cooperates with the function of the water injection machine to realize the test conditions. The present invention has important theoretical value and practical significance for revealing the instability mechanism of the rock mass in the drawdown zone affected by the drawdown of the reservoir water level, which is the driving force and original intention of the design of the present invention. Summary of the invention

[0010] In order to overcome the above-mentioned defects of the prior art, the inventors conducted in-depth investigations, scientific demonstrations and comparative analyses, and completed the present invention after putting in a lot of creative work.

[0011] Specifically, the technical problem to be solved by the present invention is that after the rock test sample has undergone dry-wet cycle pretreatment using the existing technology, the periodic change of the water level in the reservoir area has been realized to affect the rock mass in the drawdown zone. On this basis, a uniaxial instrument rock mechanics strength test auxiliary device for rock test samples under hydraulic coupling and seepage conditions is provided, and the test conditions are jointly realized in conjunction with a water injection machine and a uniaxial instrument, that is, a two-dimensional horizontal seepage field test condition of dynamic water pressure is provided. The auxiliary device can realize different test conditions such as changes in water flow migration speed, changes in water flow impact angle, and changes in water flow pressure.

[0012] In order to achieve the above object, the present invention provides the following technical solutions:

[0013] A uniaxial instrument auxiliary device for providing hydraulic coupling and seepage conditions comprises a pressure chamber, a piston plate, a pressure plate, a guide plate, a fixed rod, a guide tube, a water flow meter and a water pressure gauge. The pressure chamber provides test conditions of hydraulic coupling and seepage environment for mechanical strength test of rock test samples. The piston plate is located above the pressure chamber, and plays a role in transmitting force between the rock test sample and the uniaxial instrument. At the same time, the sealing ring installed inside plays a role in blocking water leakage, and keeps the water flow movement speed, water flow impact angle and water flow pressure inside the pressure chamber stable, and the guide belt installed inside keeps the piston movement stable. The pressure plate is located below the pressure chamber, and plays a role in transmitting force between the rock test sample and the uniaxial instrument. The fixed rod is installed between the piston plate and the pressure plate, connecting the two together, and cooperates with the type I silicone ring and the type III silicone ring to provide sealed test conditions for the pressure chamber. The guide plate is installed inside the pressure chamber and is limited to the position of the protruding parts of the piston plate and the pressure plate, providing directional guide for different water flow impact angle changes. The guide pipe is installed in the preset circular hole of the pressure chamber to provide a two-dimensional horizontal seepage field in the pressure chamber. The water flow meter and water pressure gauge are installed at the port of the guide pipe in sequence with the pressure water pipe to monitor the water flow speed and water pressure value inside the pressure chamber in real time.

[0014] In the present invention, the pressure chamber is made of acrylic material, and the quantity is 1. The dimensions of the pressure chamber are as follows: the inner diameter of the core part is 200mm, the outer diameter is 260mm, and the height is 165mm; the inner diameter of the upper raised part is 201mm, the outer diameter is 259mm, and the height is 10mm; the inner diameter of the lower turning part is 140mm, the outer diameter is 260mm, and the height is 30mm; there are a total of 8 preset circular holes in the core part, and the dimensions of the preset circular holes are as follows: the diameter is 20mm, and 2 vertical preset circular holes are arranged as a group, and the distances from the bottom surface of the lower turning part are 64.5mm and 114.5mm respectively. The angles between the preset circular holes in each group are 45°, 90°, 90°, and 135° respectively in the top view.

[0015] In the present invention, the piston plate is composed of a piston rod, a guide belt, a sealing ring and a flat cylinder. The piston rod and the flat cylinder are both made of stainless steel, and the quantity is 1 each. The piston rod size specifications: from bottom to top, the gasket diameter is 60mm, the height is 10mm, the lower connecting part diameter is 50mm, the height is 15mm, the piston part diameter is 58mm, the height is 80mm, the upper connecting part diameter is 50mm, the height is 75mm, the support plate diameter is 100mm, the height is 20mm, the guide belt and the sealing ring are both physical products, the quantity is 1 each, the flat cylinder size specifications: the upper end face diameter of the flat plate is 260mm, the lower end face diameter of the flat plate is 270mm, the upper and lower end faces are 30mm high, and the outer periphery of the lower end face of the flat plate is designed with 3 fixed rod connecting parts. The size specifications of the fixed rod connecting parts are: length 30.87mm, width 30mm, height 20mm, punched in the middle, the hole diameter is 10mm, each The top view angle of the connection part of the two fixed rods is 120°. A pressure chamber groove is designed on the lower end face of the flat plate. The dimensions of the pressure chamber groove are: inner diameter 200mm, outer diameter 260mm, depth 5mm. There is a cylinder in the middle of the flat cylinder, with cylinder dimensions: inner diameter 59mm, outer diameter 80mm. It is designed to be vertically centered between the flat plate. A guide belt and a sealing ring groove are arranged in the cylinder. The dimensions of the guide belt groove are: inner diameter 59mm, outer diameter 63mm, height 15mm, and the distance from the bottom surface of the cylinder is 28mm. The dimensions of the sealing ring groove are: inner diameter 59mm, outer diameter 68mm, height 8mm, and the distance from the bottom surface of the cylinder is 53mm. The entire piston plate is located above the pressure chamber, and an I-type silicone ring is installed between the two. The number is 1, and the dimensions of the I-type silicone ring are: inner diameter 201mm, outer diameter 259mm, and thickness 5mm, so that it matches the raised part at the upper end of the pressure chamber.

[0016] In the present invention, the pressure plate is made of stainless steel material, the quantity is 1, the dimensions of the pressure plate are: diameter 260mm, height 30mm, a convex part is designed on the upper end surface, the dimensions of the convex part are: diameter 80mm, height 50mm, three fixed rod connecting parts are designed on the periphery of the pressure plate, the dimensions of the fixed rod connecting parts are: length 30.87mm, width 30mm, height 20mm, a hole is punched in the middle, the hole diameter is 10mm, the top view angle of each fixed rod connecting part is the same as 120°, the pressure plate is located under the pressure chamber, and a Type III silicone ring is installed between the two, the quantity is 1, the dimensions of the Type III silicone ring are: inner diameter 140mm, outer diameter 260mm, thickness 5mm, so that it matches the upper end surface of the pressure chamber.

[0017] In the present invention, the guide plate is divided into type I, type II and type III guide plates, all of which are made of acrylic material, and the number of each is 1. The water flow impact angle provided by the type I guide plate is 0°, and the size specifications are: the inner diameter of the sleeve at both ends is 82mm, the outer diameter is 92mm, the upper end is 25mm high, and the lower end is 20mm high. The guide plate wall thickness is 5mm, the two walls are equal in length and are 176mm, the angle between the two walls is 180° (no angle), and the height is 170mm. The top view is an "H"-shaped design. The water flow impact angle provided by the type II guide plate is 45°, and the size specifications are: the inner diameter of the sleeve at both ends is 82mm, the outer diameter is 92mm, and the upper end is high. 25mm, 20mm high at the lower end, the guide plate wall thickness is 5mm, the two walls are of unequal length, 137.9mm and 176mm respectively, the angle between the two walls is 135° (obtuse angle), the height is 170mm, and the top view is approximately "H"-shaped design. The water flow impact angle provided by the III-type guide plate is 90°. The dimensions are as follows: the inner diameter of the sleeve at both ends is 82mm, the outer diameter is 92mm, the upper end is 25mm high, the lower end is 20mm high, the guide plate wall thickness is 5mm, the two walls are of unequal length, 117.16mm and 176mm respectively, the angle between the two walls is 90° (right angle), the height is 170mm, and the top view is "fishbone" design.

[0018] In the present invention, the fixing rod is composed of a straight rod and a straight rod nut, both of which are made of stainless steel. One fixing rod includes one straight rod and two straight rod nuts. The straight rod dimensions are as follows: the middle non-threaded section is 210 mm long and 10 mm in diameter, the threaded sections at both ends are 40 mm long and the outer thread diameter is 9 mm. The straight rod nut dimensions match the threaded portion of the straight rod.

[0019] In the present invention, the diversion pipe is composed of a hollow screw, a hollow screw nut, a type II silicone ring, a valve, a type I pressure water pipe, a type II pressure water pipe and a diversion water pipe. The hollow screw, the hollow screw nut, the valve, the type I pressure water pipe, the type II pressure water pipe and the diversion water pipe are all made of stainless steel. The size of the hollow screw is: the threaded section is 50mm long, the outer thread diameter is 19mm, the non-threaded section is 35mm long, the diameter is 19mm, the non-threaded section connection part has a diameter of 40mm and a thickness of 5mm, the screw is punched in the middle, and the diameter is 16mm. The size of the type II silicone ring is: the inner diameter is 20mm, the outer diameter is 40mm, and the thickness is 5mm. The size of the hollow screw nut matches the threaded part of the hollow screw. The valve is a DN15 type water pressure valve, which is a physical product. The size of the type I pressure water pipe is: the inner diameter is 16mm, the outer diameter is 20mm, and the non-threaded section is 45mm long , one end interface matches DN15 type water pressure valve, and the other end interface matches diversion water pipe. The size specifications of diversion water pipe are: one-type two-type diversion water pipe, the double outlet center height and interface size specifications match type I pressure water pipe, and the single outlet interface size specifications match type II pressure water pipe. The size specifications of type II pressure water pipe are: inner diameter 16mm, outer diameter 20mm, non-threaded section length 60mm, one end interface matches diversion water pipe, and the other end interface matches water flow meter. The overall design is arc-shaped, the water inlet diversion pipe includes 2 hollow screws, 2 hollow screw nuts, 4 type II silicone rings, 2 valves, 2 type I pressure water pipes, 1 type II pressure water pipe and 1 diversion water pipe, the water outlet diversion pipe includes 2 hollow screws, 2 hollow screw nuts, 4 type II silicone rings, 2 type I pressure water pipes, 1 type II pressure water pipe and 1 diversion water pipe.

[0020] In the present invention, the Type III pressure water pipe is made of stainless steel, the number is 2, the size of the Type III pressure water pipe is: inner diameter 16mm, outer diameter 20mm, non-threaded section length 30mm, one end interface matches the water flow meter, and the other end interface matches the water pressure gauge. The water flow meter and the water pressure gauge are both physical products, the number is 2 each.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The device of the present application can realize the test conditions under hydraulic coupling and seepage environment, especially solving the technical defects of rock mechanical strength testing under seepage environment generated during the flow of water level from high to low in the reservoir area.

[0023] (2) The device of the present application is designed with a pressure chamber. In combination with a piston plate, a pressure plate, a guide plate, a fixed rod and a guide tube, the device can provide a two-dimensional horizontal seepage field, which can truly simulate the horizontal seepage environment generated during the flow of water level from high to low in the reservoir area. Practice has proved that the pressure chamber has a good seepage effect.

[0024] (3) The device of the present application is designed with a pressure chamber. In conjunction with the piston plate, pressure plate, guide plate, fixed rod and guide tube, the device can provide a seepage environment with different water flow impact angles, including 0°, 45° and 90°, and can truly simulate the geological conditions and environmental conditions of the rock mass in the drawdown zone of the reservoir area. Practice has proved that the pressure chamber has a good diversion effect.

[0025] (4) The device of the present application is designed with a pressure chamber. In conjunction with the piston plate, pressure plate, guide plate, fixed rod, guide tube, water flow meter and water pressure gauge, the device can provide a seepage environment with different water flow velocity changes and different water flow pressure changes, and can truly simulate the water flow pressure changes caused by the different height difference conditions of the rock mass in the drawdown zone of the reservoir area, that is, hydraulic coupling and seepage conditions. Practice has proved that the pressure chamber has a good anti-seepage effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the device of the present invention, the following is a brief introduction to the drawings required for describing the device of the present invention. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale. For ordinary technicians in the field of rock mechanics testing technology, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a schematic diagram of a uniaxial instrument auxiliary device that provides hydraulic coupling and seepage conditions.

[0028] Figure 2 is a schematic diagram of the pressure chamber.

[0029] Figure 3 It is a schematic diagram of the piston rod.

[0030] Figure 4 It is a schematic diagram of a flat cylinder.

[0031] Figure 5 It is a schematic diagram of type I, type II and type III silicone rings.

[0032] Figure 6 It is a schematic diagram of the pressure plate.

[0033] Figure 7 Schematic diagram of type I, type II and type III guide plates.

[0034] Figure 8 It is a schematic diagram of a straight rod.

[0035] Fig. 9 This is a schematic diagram of a hollow screw.

[0036] Fig.10 It is a schematic diagram of Type I, Type II and Type III pressure water pipes.

[0037] Fig.11 This is a schematic diagram of the water diversion pipe.

[0038] Fig.12 It is a schematic diagram of the test condition with a water flow impact angle of 0°.

[0039] Fig.13 It is a schematic diagram of the test condition with a water flow impact angle of 45°.

[0040] Fig.14 It is a schematic diagram of the test condition with a water flow impact angle of 90°.

[0041] Legend:

[0042] 1. Rock test sample; 2. Pressure chamber; 3. Piston rod; 4. Guide belt; 5. Sealing ring; 6. Flat cylinder; 7-1. Type I silicone ring; 7-2. Type II silicone ring; 7-3. Type III silicone ring; 8. Pressure plate; 9. Guide plate; 10. Straight rod; 11. Straight rod nut; 12. Hollow screw; 13. Hollow screw nut; 14. Valve; 15-1. Type I pressure water pipe; 15-2. Type II pressure water pipe; 15-3. Type III pressure water pipe; 16. Diversion water pipe; 17. Water flow meter; 18. Water pressure gauge; 19. Preset circular hole in pressure chamber; 20. Type I guide plate; 21. Type II guide plate; 22. Type III guide plate. DETAILED DESCRIPTION

[0043] In order to enable technicians in the field of rock mechanics testing technology to better understand the content of the invention in the device of the present invention, the content of the invention in the device of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments. The described embodiments are only part of the embodiments of the device of the present invention, not all of the embodiments. The following embodiments are only used to more clearly illustrate the content of the invention in the device of the present invention, and are only used as examples, and cannot be used to limit the scope of protection of the present invention.

[0044] like Figure 1 As shown, a uniaxial instrument auxiliary device providing hydraulic coupling and seepage conditions comprises a pressure chamber, a piston plate, a pressure bearing plate, a guide plate, a fixing rod, a guide tube, a water flow meter and a water pressure gauge.

[0045] The pressure chamber comprises a pressure chamber 2 and a pressure chamber preset circular hole 19. There are 8 pressure chamber preset circular holes 19 in total.

[0046] The piston plate includes a piston rod 3, a guide belt 4, a sealing ring 5 and a flat cylinder 6. According to the grooves provided in the flat cylinder 6, one guide belt 4 and one sealing ring 5 are installed in sequence, and finally one piston rod 3 is installed, and the piston plate is formed together.

[0047] The pressure plate is an independent structural component.

[0048] The guide plates include type I guide plates 20, type II guide plates 21 and type III guide plates 22. Various guide plates are used according to the purpose of rock mechanics test, and only one type of guide plate is used at a time. The guide plates are located inside the pressure chamber, and the top view position is connected to the position of the preset circular hole 19 of the pressure chamber, and is limited to the position of the flat cylinder 6 and the convex part of the pressure plate 8.

[0049] The fixing rod includes a straight rod 10 and a straight rod nut 11. The straight rod 10 connects the flat cylinder 6 and the fixing rod connection part of the pressure plate 8, and the straight rod nut 11 is respectively installed at the upper end of the fixing rod connection part of the flat cylinder 6 and the lower end of the fixing rod connection part of the pressure plate 8, and is connected with the straight rod 10, a total of 3 fixing rods, the spatial combination relationship of the fixing rod, the pressure plate 8, the piston plate and the pressure chamber 2 ensures that the straight rod 10 does not block the preset circular hole 19 of the pressure chamber.

[0050] The diversion pipe includes a hollow screw 12, a hollow screw nut 13, a type II silicone ring 7-2, a valve 14, a type I pressure water pipe 15-1, a type II pressure water pipe 15-2 and a diversion water pipe 16. A hollow screw 12 is connected with a type II silicone ring 7-2 to pass through the preset circular hole 19 of the pressure chamber, and is connected with a type II silicone ring 7-2 again. A hollow screw nut 13 tightly fixes the above structural components together. All the preset circular holes in the pressure chamber 2 are installed with the hollow screw 12, the hollow screw nut 13 and the type II silicone ring 7-2 according to the above steps. At one end of the water inlet of the device of the present invention, the valve 14 and the type I pressure water pipe 15-1 are installed in sequence on the threaded section of the hollow screw 12, and the diversion water pipe 16 and the type II pressure water pipe 15-2 are installed in sequence between the type I pressure water pipe 15-1 on the same vertical side. The valve 14 is not installed at one end of the water outlet of the device of the present invention, and the threaded section of the hollow screw 12 on the same vertical side is also installed with the diversion pipe 16 and the II type pressure water pipe 15-2 in sequence, and the guide pipe is installed before the fixing rod and the guide plate.

[0051] The water flow meter is a physical product. It is connected to the diversion water pipe 16 through the II type pressure water pipe 15-2, and is connected to the water pressure meter 18 through the III type pressure water pipe 15-3. There are two water flow meters 17 in total.

[0052] The water pressure gauge is a physical product. It is connected to the water flow meter 17 through the III type pressure water pipe 15-3. A valve 14 is installed again at the other end of the water pressure gauge at one end of the water outlet of the device of the present invention. There are two water pressure gauges 18 in total.

[0053] The rock mechanics strength test method of this embodiment is as follows:

[0054] Wet-dry cycles, hydraulic coupling and water flow migration were all considered during the rock mechanical strength test, and are also multi-factor coupling test conditions that the device of the present invention can provide. In order to test the mechanical strength damage law of the rock mass under geological and environmental conditions in the drawdown zone of the reservoir area, this test was divided into two groups, the first group was hydraulic coupling conditions, and the second group was water flow migration conditions. Test variables: The number of wet-dry cycles were 1 / 3 / 6 / 12 / 24 / 48 respectively; the preset values ​​of hydraulic coupling confining pressure were 0.10, 0.20 and 0.30 MPa respectively (calculated according to the head difference of 10, 20 and 30m drawdown zones, and the calculation formula is: σ=(h w -h s )·g·ρ, where: σ represents the hydrostatic pressure value (Pa) under different height difference conditions, h w Represents the water level elevation of the reservoir area (m), h s represents the elevation of the rock mass (rock test sample) in the drawdown zone of the reservoir area (m), and g represents the acceleration of gravity (9.8m / s 2 ), ρ represents the water density (kg / m 3 ), different hydraulic coupling confining pressures represent the water flow pressure values ​​brought about by different height difference conditions of the rock mass in the drawdown zone of the reservoir area, and the method for calculating the dynamic water pressure is the same), which is controlled and realized by the device of the present invention; taking the Three Gorges Reservoir area as an example, the average water velocity of the Yangtze River after the Three Gorges Dam is filled with water is 0.5m / s, and on this basis, the difference is 0.4m / s, and the preset values ​​of the water flow migration velocity are 0.1 / 0.5 / 0.9m / s respectively, which are controlled and realized by the device of the present invention; the water flow impact angles provided by the device of the present invention are 0°, 45° and 90° respectively; distilled water is used as the water required for the test, and the aqueous solution factor is not considered this time; the water temperature is constant at 25°C, and the temperature factor is not considered this time.

[0055] Step 1: Place the rock test sample in an oven and dry it at 105℃ for 24h, then transfer it to a moisturizing cylinder, cool it to room temperature 25℃, and then dry it again for 2h. The drying is completed when the difference in mass between the two does not exceed 0.1% of the former mass. The saturation methods of the dry-wet cycle pretreatment process of rock mass in the drawdown zone of the reservoir area include layered immersion method, complete immersion method and vacuum saturation method. This time, the vacuum saturation method is used. At room temperature of 25℃, the rock test sample that has undergone drying is soaked in distilled water in a vacuum cylinder of 0.10, 0.20 and 0.30MPa (calculated according to the head difference of 10, 20 and 30m drawdown zone) for 6h until saturated, and wipe off the excess water droplets on the surface of the rock test sample with a paper towel. A complete dry-wet cycle is one drying and one saturation. The technicians prepared the rock test samples after n dry-wet cycle pretreatments according to the test variables, all of which were in a saturated state.

[0056] Step 2: Place the rock test sample at the raised position of the pressure plate of the device of the present invention, and install the various structural components according to the specific implementation method of the device of the present invention, with the order of placement being the guide plate, I-type silicone ring, and piston plate, and finally the structural components are tightly combined together through the fixing rod. In this step, the water injection machine docking interface is installed according to the test variable of the water flow impact angle, and the valves of the other guide pipes remain closed. Then place the entire auxiliary device at the uniaxial instrument test position, and adjust the uniaxial instrument bearing plate to make it in close contact with the piston rod and the pressure plate of the device of the present invention.

[0057] Step 3: Inject distilled water solution into the water injection machine, and the water injection machine provides a water temperature environment of 25°C.

[0058] Step 4: Close the valve at one end of the water outlet of the device of the present invention, and the water injection machine provides water source and water flow motive force to make the pressure chamber full of water. By adjusting the water pump power and the water pressure gauge at one end of the water inlet of the device of the present invention, the confining pressure in the pressure chamber is increased to the hydraulic coupling confining pressure test variable at a rate of 0.01MPa / s. After the hydraulic coupling confining pressure is stable, close the valve of the guide pipe connected to the water injection machine. The confining pressure formed is the static water pressure, and then start the first group of tests (hydraulic coupling test) rock mechanics strength test.

[0059] Step 5: After the first set of tests are completed, open the valve at one end of the water outlet of the device of the present invention, and the water injection machine provides water source and water flow movement power to make the pressure chamber full of water. By adjusting the water pump power and the water pressure gauge at one end of the water outlet of the device of the present invention, the confining pressure in the pressure chamber is increased to the hydraulic coupling confining pressure test variable at a rate of 0.01MPa / s. Then, adjust the water flowmeters at one end of the water inlet and outlet of the device of the present invention to increase the water flow in the pressure chamber to the water flow movement speed test variable at a rate of 0.01m / s. The confining pressure formed is the dynamic water pressure, and then start the second set of tests (water flow movement test) rock mechanics strength test.

[0060] Step 6: Repeat steps 4 and 5, and vertically load two groups of test rock test samples until they are destroyed according to the purpose, loading method and loading rate of the rock mechanics test, and the test is completed.

[0061] Step 7: The stress-strain and displacement-time data of the rock test sample are recorded and stored in real time by the uniaxial instrument. The water flow pressure is monitored in real time by the water pressure gauge. The water flow velocity is monitored in real time by the water flow meter. During the test, the acoustic emission instrument, high-speed camera and thermal infrared equipment can be used to record the whole process of rock test sample failure characteristics in real time.

[0062] The above is only an embodiment of the rock mechanics strength testing method of the present invention, and the protection scope of the present invention is not limited to the above embodiment. For those skilled in the art, improvements and changes obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A uniaxial instrument auxiliary device providing hydraulic coupling and seepage conditions, characterized in that: It includes a pressure chamber, a piston plate, a pressure plate, a guide plate, a fixing rod, a guide pipe, a water flow meter and a water pressure meter; The pressure chamber also includes a preset circular hole in the pressure chamber; a total of 8 preset circular holes in the pressure chamber; The piston plate includes a piston rod, a guide belt, a sealing ring and a flat cylinder; a guide belt and a sealing ring are installed in the grooves in the flat cylinder in sequence, and finally a piston rod is installed, which are assembled together to form a piston plate; The pressure plate is an independent structural component; The guide plate is a type I guide plate, a type II guide plate or a type III guide plate; only one type of guide plate is used at a time, the guide plate is located inside the pressure chamber, and the top view position is connected to the preset circular hole position of the pressure chamber, and is limited to the flat cylinder and the convex part of the pressure plate; the difference between the three guide plates is that the angles between the guide plates on both sides are 0°, 45° and 90° respectively; The fixing rod includes a straight rod and a straight rod nut; the straight rod connects the flat cylinder and the pressure plate fixing rod connection part, the straight rod nut is respectively installed at the upper end of the flat cylinder fixing rod connection part and the lower end of the pressure plate fixing rod connection part, and is connected with the straight rod, a total of 3 fixing rods, the spatial combination relationship of the fixing rod, the pressure plate, the piston plate and the pressure chamber ensures that the straight rod does not block the preset circular hole of the pressure chamber; The flow guide pipe includes a hollow screw, a hollow screw nut, a type II silicone ring, a valve, a type I pressure water pipe, a type II pressure water pipe and a diversion water pipe; a hollow screw is sleeved with a type II silicone ring and passes through a preset circular hole in the pressure chamber, and then a type II silicone ring is sleeved again, and finally a hollow screw nut is sleeved, and all preset circular holes in the pressure chamber are installed with hollow screws, type II silicone rings and hollow screw nuts; At one end of the water inlet of the device, a valve and a type I pressure water pipe are sequentially installed on the hollow screw thread section, a diversion water pipe is installed between the type I pressure water pipes on the same vertical side, and the other end of the diversion water pipe is connected to the type II pressure water pipe; no valve is installed at one end of the water outlet of the device, and the other hollow screw thread sections on the same vertical side are also sequentially installed with a diversion water pipe and a type II pressure water pipe, and the diversion pipe is installed before the fixing rod and the guide plate; The water flow meter is connected to the diversion water pipe through the type II pressure water pipe, and is connected to the water pressure gauge through the type III pressure water pipe; there are 2 water flow meters in total; the type II pressure water pipe and the type III pressure water pipe are curved pipes and straight pipes respectively; The water pressure gauge is connected to the water flow meter through a Type III pressure water pipe. A valve is installed again at the other end of the water pressure gauge at one end of the water outlet of the device; there are 2 water pressure gauges in total.

2. A method for applying the device according to claim 1, characterized in that The following steps are involved: Step 1: Place the rock test sample in an oven to dry; The saturation methods of the dry-wet cycle pretreatment process of the rock mass in the drawdown zone of the reservoir area include layered immersion method, complete immersion method or vacuum saturation method; Prepare rock test samples pretreated by n dry-wet cycles, all in saturated state; Step 2: Place the rock test sample at the raised position of the pressure plate of the device and install the various structural components; install the water injection machine interface according to the test variable of the water flow impact angle, and keep the valves of the other diversion pipes closed; Step 3: Inject distilled water solution into the water injection machine, and the water injection machine provides a water temperature environment of 25°C; Step 4: close the valve at one end of the water outlet of the device of the present invention, and the water injection machine provides water source and water flow transportation power, so that the pressure chamber is full of water. By adjusting the water pump power and the water pressure gauge at one end of the water inlet of the device, the confining pressure in the pressure chamber is increased to the hydraulic coupling confining pressure test variable. When the hydraulic coupling confining pressure is stable, close the valve of the guide pipe connected to the water injection machine. The confining pressure formed is the hydrostatic pressure, and then start the first group of tests, namely the hydraulic coupling test rock mechanical strength test; Step 5: After the first set of tests are completed, the valve at one end of the water outlet of the device of the present invention is opened, and the water injection machine provides water source and water flow movement power, so that the pressure chamber is full of water. The confining pressure in the pressure chamber is increased to the hydraulic coupling confining pressure test variable by adjusting the water pump power and the water pressure gauge at one end of the water outlet. Then, the water flowmeter at one end of the water inlet and the water outlet of the device is adjusted to increase the water flow in the pressure chamber to the water flow movement speed test variable. The confining pressure formed is the dynamic water pressure, and then the second set of tests, namely the water flow movement test and the rock mechanics strength test, are started; Step 6: Repeat steps 4 and 5, and vertically load two groups of test rock test samples until they are destroyed according to the purpose, loading method and loading rate of the rock mechanics test, and the test is finished; The stress-strain and displacement-time data of the rock test samples are recorded and stored in real time by the uniaxial instrument; the water flow pressure is monitored in real time by the water pressure gauge; and the water flow migration speed is monitored in real time by the water flow meter.

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