True triaxial stress relief test device under large-scale hydraulic coupling condition

Abstract

The utility model discloses a true triaxial stress relief test device under a large-scale hydraulic coupling condition, which comprises a high-pressure water tank, two groups of opposite horizontal preformed holes and two groups of opposite lateral preformed holes are arranged on the side wall of the high-pressure water tank, opposite vertical preformed holes are formed in the top and the bottom of the high-pressure water tank, a stress relief preformed hole is formed in the top of the high-pressure water tank, and a strain gauge is arranged in the test rock sample and electrically connected with a data acquisition device; the three-way force loading device is used for applying three-way force to the test rock sample; the stress relieving device comprises a drilling machine, a drilling rod connected with the drilling machine and located at the top of the tank body and a drilling tool arranged on the end side of the drilling rod, the drilling machine device is started, the drilling rod pushes the drilling tool to drill holes in the test rock sample to which the three-dimensional stress is applied so as to relieve the stress, and a strainometer senses stress data on the test rock sample and transmits the stress data to the data acquisition device. According to the utility model, the real stress condition and the water environment condition of the rock mass can be simulated, so that the stress condition of the rock mass can be accurately obtained.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of rock mechanics test, specifically relates to a true triaxial stress release test device under large scale hydraulic coupling condition. BACKGROUND

[0002] In-situ stress is a natural force which is objectively endowed in the crustal rock mass and is not disturbed by engineering, also called original rock stress, and it is the basic force which leads to the deformation, fracture, fold and even earthquake of the crustal rock mass. In-situ stress measurement is a very important problem in major construction project, and accurate measurement of the in-situ stress of rock mass is the basis for correct and reasonable calculation of the excavation load of underground engineering, so in-situ stress measurement is very important. There are mainly two methods for in-situ stress measurement on site at present: stress relief method and hydraulic fracturing method. However, the existing test equipment and test theory have many basic assumptions, and it is difficult to accurately evaluate whether the in-situ stress result measured by the existing instrument and method meets the actual stress condition of surrounding rock, and only through a large number of field tests, combined with different test methods, can the evaluation be made. Therefore, how to accurately measure the in-situ stress and whether the in-situ stress measured by the existing instrument and equipment is reliable is a problem that must be solved when the related research on rock mass in-situ stress is carried out. SUMMARY

[0003] The utility model discloses to the technical deficiency of prior art, provide a kind of true triaxial stress release test device under large scale hydraulic coupling condition, the device can simulate the real stress condition of rock sample, accurately obtain the in-situ stress condition of high stress area in true triaxial stress release process under high stress condition.

[0004] To solve the above technical problems, the utility model adopts the following technical scheme:

[0005] A kind of true triaxial stress release test device under large scale hydraulic coupling condition, it include:

[0006] High-pressure water tank, two groups of opposite horizontal reserved holes, two groups of opposite lateral reserved holes are arranged on the side wall of high-pressure water tank, and the radian between lateral reserved hole and horizontal reserved hole is 90 °, and opposite vertical reserved holes are arranged on the top and bottom of high-pressure water tank and stress release reserved hole is arranged on the top thereof, test rock sample is arranged in high-pressure water tank during test and high-pressure water is filled in it, strain gauge is arranged in test rock sample, and strain gauge is electrically connected with data acquisition device;

[0007] The three-way force loading device comprises a horizontal force loading device, a vertical force loading device and a lateral force loading device perpendicular to the horizontal force and the vertical force, the horizontal force loading device applies a horizontal force to the test rock sample through a horizontal reserved hole on the high-pressure water tank, the vertical force loading device applies a vertical force to the test rock sample through a vertical reserved hole on the high-pressure water tank, and the lateral force loading device applies a lateral force to the test rock sample through a lateral reserved hole on the high-pressure water tank.

[0008] The stress relief device comprises a drilling machine, a drill rod connected to the drilling machine and located at the top of the tank body, and a drill tool arranged at the end side of the drill rod, in the stress relief simulation test, the drilling machine is started, the drill rod pushes the drill tool to drill a hole in the test rock sample subjected to three-way stress through the stress relief reserved hole to realize stress relief, and a strain gauge senses stress data on the test rock sample during the stress relief process and transmits the stress data to a data acquisition device.

[0009] Further, the main frame is provided with a hollow area for accommodating the high-pressure tank body during the test and a through hole communicating with the hollow area at the top of the main frame, and the drill rod drives the drill tool to pass through the through hole at the top of the main frame to relieve the stress of the test rock sample.

[0010] Further, the horizontal loading frame is provided with a fixed high-pressure accommodation groove through which the through hole at the top of the main frame passes, and in addition, a slide rail transversely passing through the hollow area is arranged on the main frame, and the horizontal loading frame is slidably connected to the slide rail, during the test, the horizontal loading frame drives the high-pressure water tank to move to the test working position in the hollow area for testing.

[0011] Further, the horizontal force loading device is arranged on the opposite sides of the horizontal loading frame, the horizontal force loading device comprises a first loading oil cylinder fixed on the side surface of the horizontal loading frame, a first force transmission column in contact connection with the first loading oil cylinder through a horizontal reserved hole, and a first force transmission plate connected with the first force transmission column, during the test, the first force transmission plate is located in the high-pressure water tank and abuts against the test rock sample, and the first loading oil cylinder drives the first force transmission column and the first force transmission plate to apply a horizontal force to the test rock sample.

[0012] Further, the vertical force loading device is arranged on the top and the bottom of the hollow area, the vertical force loading device comprises a second loading oil cylinder fixed on the top surface or the bottom surface, a second force transmission column in contact connection with the second loading oil cylinder through a vertical reserved hole, and a second force transmission plate connected with the second force transmission column, during the test, the second force transmission plate is located in the high-pressure water tank and abuts against the test rock sample, and the second loading oil cylinder drives the second force transmission column and the second force transmission plate to apply a vertical force to the test rock sample.

[0013] Further, the lateral force loading device is fixed on the opposite side wall of the hollow area, and the lateral force loading device comprises a third loading oil cylinder fixed on the side wall of the hollow area, a third force transmission column in contact connection with the third loading oil cylinder through the lateral reserved hole, and a third force transmission plate connected with the third force transmission column, and during the test, the third force transmission plate is located in the high-pressure water tank and presses on the test rock sample, and the third loading oil cylinder pushes the third force transmission column and the third force transmission plate to exert lateral force on the test rock sample.

[0014] Further, the water pressure applying device for pressurizing the high-pressure water tank and the water pressure measuring device for measuring the water pressure of the high-pressure water tank are further included, and the water pressure measuring device is arranged in the high-pressure water tank.

[0015] Further, the high-pressure water tank comprises a hollow tank body and a sealing cover covering and sealing the tank body, and the horizontal reserved hole and the lateral reserved hole are arranged on the side wall of the tank body, and the vertical reserved hole and the stress relief reserved hole are fixed on the sealing cover.

[0016] Compared with the prior art, the beneficial effects of the utility model are that: the utility model can simulate the real stress condition and water environment of the rock mass through the three-way stress device and the high-pressure water applied to the high-pressure water tank, and then the stress relief of the rock sample is carried out, and the strain value in the stress relief process is obtained, so that the three-dimensional stress state of the drilling position can be accurately obtained through the test; the utility model can not only carry out the simulation test of the true triaxial stress relief process under the high stress condition, and the highest stress can reach 100MPa; meanwhile, the high external water pressure (the highest can reach 5MPa, equivalent to the water head pressure of 500m) is also considered; the sample size can reach 50cm*50cm*100cm, and the simulation test of the true triaxial stress relief process under the high stress condition can verify the field stress test result of the high stress area, and the strain gauge can also be calibrated. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structure schematic view of the true triaxial stress relief test device under the large-scale water force coupling condition of the utility model embodiment;

[0018] Figure 2 It is a vertical section schematic view of the stress relief simulation test device of the utility model embodiment;

[0019] Figure 3 It is a horizontal section schematic view of the stress relief simulation test device of the utility model embodiment;

[0020] Figure 4 It is a vertical section view of the loading on the rock sample of the utility model embodiment;

[0021] Figure 5 It is a horizontal section view of the loading on the rock sample of the utility model embodiment. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0024] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the present invention.

[0025] like Figure 1 , Figure 2 , Figure 3 As shown in the figure, this utility model discloses a true triaxial stress relief test device under large-scale hydraulic coupling conditions, including a high-pressure water tank, a triaxial force loading device, and a stress relief device. The high-pressure water tank 1 includes a hollow tank body 100 and sealing caps 101 that cover and seal both ends of the tank body 100. Two sets of opposing horizontal reserved holes and two sets of opposing lateral reserved holes are provided on the side wall of the tank body 100, and the arc between the lateral reserved holes and the horizontal reserved holes is 90°. Opposing vertical reserved holes are provided on the two sealing caps 101. The reserved holes facilitate the triaxial force loading device to load the test rock sample 2. The test rock sample 2 can be a sample of similar material or a rock sample retrieved from the field. During the stress relief test, the test rock sample 2 is placed in the high-pressure water tank 1 and high-pressure water 104 is added to it. The high-pressure water tank 1 is used to provide a water pressure environment for the test rock sample 2. To this end, a water pressure application device connected to the high-pressure water tank 1 for injecting and pressurizing the high-pressure water tank 1, and a water pressure measuring device for measuring the water pressure of the high-pressure water tank are also provided. The water pressure measuring device is located inside the tank body 100. In addition, a stress relief reserved hole 102 is provided on the sealing cover at the top of the tank body. In order to facilitate the acquisition of stress and strain conditions on the test rock sample during stress relief, an installation hole is pre-made inside the test rock sample, and then the strain gauge 3 is fixed in the installation hole. The installed strain gauge 3 is connected to the data acquisition device 4 via a cable 400. Multiple strain bundles are embedded on the surface of the strain gauge 3, and each strain bundle includes multiple strain gauges. During the test, the data acquisition device 4 collects the strain data of each strain gauge.

[0026] In order to fix the three-way force loading device and the high-pressure water tank 1, a main frame 5, a horizontal loading frame 6 and an auxiliary frame 9 opposite to the horizontal loading frame are further included. The main frame 5 is a frame structure, and a hollow area 500 providing a test space for the high-pressure water tank 1 is arranged at the center of the main frame 5. A slide rail 501 crossing the hollow area 500 is arranged at the bottom of the hollow area 500, and the horizontal loading frame 6 and the auxiliary frame 9 are slidably connected to the slide rail 501 through pulleys or sliding blocks. A recess 600 for fixing the high-pressure water tank 1 is arranged on the horizontal loading frame 6. During the test, the high-pressure water tank 1 is fixed in the recess 600, and the horizontal loading frame 6 is pushed to drive the high-pressure water tank 1 to move on the slide rail 501 to a test station in the hollow area 500.

[0027] The three-way force loading device includes a horizontal force loading device, a vertical force loading device and a lateral force loading device perpendicular to the horizontal force and the vertical force. The horizontal force loading device is fixed on the horizontal loading frame 6 and the auxiliary frame 9, and the horizontal force loading device fixed on the horizontal loading frame 6 is opposite to the horizontal force loading device fixed on the auxiliary frame 9. The horizontal force loading device includes a first loading oil cylinder 700 fixed on the side of the horizontal loading frame 6 or the auxiliary frame 9, a first force transmission column 701 in contact with the first loading oil cylinder 700 through a horizontal reserved hole and a first force transmission plate 702 connected with the first force transmission column 701. During the test, the first force transmission plate 702 is located in the high-pressure water tank 1 and abuts against two opposite sides of the test rock sample 2, and the first loading oil cylinder 700 drives the first force transmission column 701 and the first force transmission plate 702 to apply a horizontal force to the test rock sample 2.

[0028] The lateral force loading device is arranged on the side wall of the hollow area 500 of the main frame 5, and specifically, the lateral force loading device is fixed on the two opposite side walls of the hollow area 500, and the lateral force loading device comprises a third loading oil cylinder 703 fixed on the side wall of the hollow area 500, a third force transmission column 704 in contact with the third loading oil cylinder 703 through a lateral reserved hole, and a third force transmission plate 705 connected with the third force transmission column 704, and in the test, the third force transmission plate 705 is located in the high-pressure water tank 1 and presses on the other two opposite sides of the test rock sample 2, and the third loading oil cylinder 703 pushes the third force transmission column 704 and the third force transmission plate 705 to exert a lateral force on the test rock sample 2. In addition, the vertical force loading device is also fixed on the main frame 5, and specifically, the vertical force loading device is arranged on the top and bottom of the hollow area 500, and the vertical force loading device comprises a second loading oil cylinder 706 fixed on the top surface or bottom surface of the hollow area 500, a second force transmission column 707 in contact with the second loading oil cylinder 706 through a vertical reserved hole, and a second force transmission plate 708 connected with the second force transmission column 707, and in the test, the second force transmission plate 708 is located in the high-pressure water tank 1 and presses on the top surface and bottom surface of the test rock sample 2, and the second loading oil cylinder 706 pushes the second force transmission column 707 and the second force transmission plate 708 to exert a vertical force on the test rock sample 2.

[0029] The stress relief device comprises a drilling machine 800 arranged on the main frame, a drill rod 801 connected with the drilling machine 800 and located on the top of the main frame 3, and a drill tool 802 arranged on the end side of the drill rod 801. Correspondingly, a through hole 103 is arranged on the top of the main frame 5 and communicates with the hollow area 500 and is used for the drill rod 801 to pass through, and when the stress is relieved, the drill rod 801 drives the drill tool 802 to pass through the through hole on the top of the main frame 5 to drill the test rock sample 2 in the high-pressure water tank 1 to realize stress relief. In order to facilitate the stress relief of the test rock sample, the stress relief reserved hole 102 is arranged on the sealing cover 101 on the top of the tank body 100, and the drill rod 801 pushes the drill tool to pass through the stress relief hole to relieve the stress of the test rock sample 2.

[0030] The stress relief simulation test method according to the stress relief simulation test device described above comprises the following steps:

[0031] Step 1, a strain gauge mounting hole is prepared in the center of the test rock sample 2, and a strain gauge 3 is arranged in the hole, and the strain gauge 3 is connected with the data acquisition device 4;

[0032] Step 2, move the horizontal loading rack 6 away from the hollow area 500 (i.e. the installation station), place the test rock sample 2 obtained in step 1 in the groove 600 of the horizontal loading rack 6, and fit the tank body 100 on the test rock sample 2, install the upper force plates on the six faces of the test rock sample 2 respectively and connect the force plates with the force columns, the first force column 701 is passed out of the horizontal reserved hole on the tank body 1, the third force column 704 is passed out of the lateral reserved hole on the tank body, and the two end covers of the tank body 100 are covered with the sealing cover 101, and the second force column 707 is passed out of the vertical reserved hole on the sealing cover;

[0033] Step 3, push the horizontal loading rack 6 to the test station in the hollow area 500, and push the auxiliary rack 9 into the hollow area so that the two horizontal force loading devices are in place, and set the drilling machine and the drill rod 801 on the top of the main rack 5, wherein the drill rod 801 is arranged corresponding to the through hole on the main rack 5;

[0034] Step 4, start the first loading oil cylinder 700, the second loading oil cylinder 703, the third loading oil cylinder, and the loading oil cylinder 706 at the same time, and each loading oil cylinder pushes the force column and the force plate to apply loading to the test rock sample in each direction. Of course, one of the loading oil cylinders in one direction can be started first, and when the loading reaches the preset stress, the loading oil cylinder in the second direction is started, and so on. While applying three-directional loading, water is injected into the high-pressure water tank 1 to a specified water pressure value,

[0035] Step 5, see Figure 4 and Figure 5 When the stress in each direction reaches the preset value, the drilling machine is started, the drilling machine pushes the drill rod 801 to drive the drill 802 to pass through the through hole and the stress relief reserved hole on the sealing cover 101 to drill the test rock sample 2 in the high-pressure tank body 1 to perform stress relief, and the data acquisition device 4 collects the data sensed by each strain gauge on the strain gauge during the whole process until the stress relief is completed.

[0036] Step 5, calculate the three-dimensional stress state at the drilling position of the drill by calculating the strain change values obtained before and after the stress relief; wherein the calculation method of the three-dimensional stress state at the drilling position is as follows:

[0037] Firstly, according to the determined coordinate axis, in this embodiment, the coordinate axis is defined as follows: the horizontal loading direction σ2 is the X axis, the lateral loading direction σ3 is the Y axis, and the vertical loading direction σ1 is the Z axis.

[0038] In this embodiment, three strain clusters are embedded on the surface of the strain gauge, and the serial number is represented by i, and the corresponding polar angle is θ i Each strain cluster is composed of three strain gauges, and the serial number is represented by j, and the corresponding angle is According to the strain observation value ε k and the relationship between the stress state of the rock mass, the following observation equation group can be obtained:

[0039] E·ε k = A k1 σ x + A k2 σ y + A k3 σ z + A k4 τ xy + A k5 τ yz + A k6 τ zx (1)

[0040] k = 4(i - 1) + j, i = 1 ~ 3, j = 1 ~ 3

[0041] In the formula:

[0042]

[0043] In the formula: σ x is the normal stress in X direction, σ y is the normal stress in Y direction, σ z is the normal stress in Z direction, and τ xy is the shear stress in xy plane, τ yz is the shear stress in yz plane, and τ zx is the shear stress in zx plane, respectively, K1, K2, K3, K4 are correction coefficients, R is the borehole radius, R1 is the strain gauge inner diameter, ρ is the radius of the strain gauge embedding part, E is the elastic modulus of the surrounding rock, μ is the Poisson's ratio, and E1 is the elastic modulus of the epoxy resin layer (the material of the strain gauge), and μ1 is the Poisson's ratio; wherein, the following calculations are determined:

[0044]

[0045] In the formula:

[0046]

[0047] In the formula, χ is a constant determined according to the Poisson's ratio of the surrounding rock, χ1 is a constant determined according to the Poisson's ratio of the epoxy resin, m is a constant determined according to the ratio of the strain gauge inner diameter to the borehole radius, and ζ is a constant determined according to the elastic modulus and Poisson's ratio of the surrounding rock and the epoxy resin;

[0048] Three times of 9 pieces of hollow inclusion type borehole three-way strain gauges can obtain 9 observation values equations, and 6 unknown stress components are solved. The normal equation group for solving the best value of the stress component is obtained by using the least square method principle:

[0049]

[0050] In the formula, n represents the number of strain gauges participating in the calculation of three-dimensional stress;

[0051] Thus, the six stress components of the rock mass expressed in the borehole coordinate system are solved, and they are converted into the geodetic coordinate system, and then three principal stresses are solved according to the following formula:

[0052]

[0053] In the formula:

[0054]

[0055] In the formula: J1, J2 and J3 respectively correspond to the first, second and third invariants of the stress tensor.

[0056] The principal stress direction is expressed by the following formula:

[0057]

[0058] Any two of the formulae and the direction cosine relationship formula are:

[0059]

[0060] The inclination angle α of the principal stress is solved by: i and the azimuth angle β is: i

[0061]

[0062] In the formula, l i represents the direction cosine of the σ i direction on the X axis, m i represents the direction cosine of the σ i direction on the Y axis, n i represents the direction cosine of the σ i direction on the Z axis, i = 1 ~ 3, and β0 is the azimuth angle of the X axis of the geodetic coordinate system. If the X axis is the north direction, then β0 = 0.

[0063] The test device can not only carry out the simulation test of the true triaxial stress relief process under high stress conditions, and the maximum stress can reach 100 MPa; but also considers the high external water pressure (the maximum can reach 5 MPa, equivalent to the water head pressure of 500 m); and the sample size can reach 50 cm x 50 cm x 100 cm. Through the simulation test of the true triaxial stress relief process under high stress conditions, the in-situ geostress test results in the high stress area can be verified.

[0064] The test device can also carry out calibration tests on strain gauges to study the variation law of the four correction coefficients of the strain gauges under the true triaxial state.

[0065] ​The above merely describes preferred embodiments of the present application, and is not intended to limit the implementation and protection scope of the present application. For those skilled in the art, it should be understood that any equivalent substitutions and obvious changes made according to the content of the present application should be included in the protection scope of the present application.

Claims

1. A large-scale true triaxial stress unloading test device under hydraulic coupling conditions, characterized in that, The utility model relates to a three-dimensional stress release simulation test device for rock sample, which comprises the following parts: a high-pressure water tank, two sets of opposite horizontal reserved holes and two sets of opposite lateral reserved holes are arranged on the side wall of the high-pressure water tank, the angle between the lateral reserved hole and the horizontal reserved hole is 90 degrees, and opposite vertical reserved holes are arranged on the top and bottom of the high-pressure water tank, and a stress release reserved hole is arranged on the top of the high-pressure water tank; during the stress release test, the test rock sample is arranged in the high-pressure water tank, and high-pressure water is filled in the tank; a strain gauge is arranged in the test rock sample, and the strain gauge is electrically connected with a data acquisition device; a three-dimensional force loading device, which comprises a horizontal force loading device, a vertical force loading device and a lateral force loading device perpendicular to the horizontal force and the vertical force; the horizontal force loading device passes through the horizontal reserved hole on the high-pressure water tank to apply a horizontal force to the test rock sample; the vertical force loading device passes through the horizontal reserved hole on the high-pressure water tank to apply a vertical force to the test rock sample; and the lateral force loading device passes through the lateral reserved hole on the high-pressure water tank to apply a lateral force to the test rock sample; a stress release device, which comprises a drilling machine, a drill rod connected with the drilling machine and located on the top of the high-pressure water tank, and a drill tool arranged on the end side of the drill rod; during the stress release simulation test, the drilling machine is started, the drill rod pushes the drill tool to drill a hole in the test rock sample subjected to three-dimensional stress through the stress release reserved hole to realize stress release, and the strain gauge senses the stress data of the test rock sample during the stress release process and transmits the stress data to the data acquisition device.

2. The apparatus according to claim 1, wherein The main frame is provided with a hollow area for providing a test space for the high-pressure water tank, and a through hole is arranged on the top of the main frame and communicates with the hollow area; during the test, the drill rod drives the drill tool to pass through the through hole on the top of the main frame to release the stress of the test rock sample.

3. The apparatus according to claim 2, wherein The horizontal loading frame and the auxiliary frame are oppositely arranged, and the high-pressure water tank is fixed in the accommodation groove on the horizontal loading frame; in addition, a slide rail is arranged on the main frame and crosses the hollow area; the horizontal loading frame and the auxiliary frame are slidably connected to the slide rail; during the test, the horizontal loading frame drives the high-pressure water tank to move to the test position in the hollow area for testing.

4. The apparatus according to claim 3, wherein The horizontal force loading device is oppositely arranged on the horizontal loading frame and the auxiliary frame, and comprises a first loading oil cylinder fixed on the side surface of the horizontal loading frame or the auxiliary frame, a first force transmission column in contact with the first loading oil cylinder and passing through the horizontal reserved hole, and a first force transmission plate connected with the first force transmission column; during the test, the first force transmission plate is located in the high-pressure water tank and abuts against the test rock sample, and the first loading oil cylinder drives the first force transmission column and the first force transmission plate to apply a horizontal force to the test rock sample.

5. The apparatus according to claim 2, wherein The vertical force loading device is oppositely arranged on the top and bottom of the hollow area, and comprises a second loading oil cylinder fixed on the top surface or the bottom surface, a second force transmission column in contact with the second loading oil cylinder and passing through the vertical reserved hole, and a second force transmission plate connected with the second force transmission column; during the test, the second force transmission plate is located in the high-pressure water tank and abuts against the test rock sample, and the second loading oil cylinder drives the second force transmission column and the second force transmission plate to apply a vertical force to the test rock sample.

6. The apparatus according to claim 2, wherein The lateral force loading device is fixed on the opposite side walls of the hollowed-out area, and includes a third loading oil cylinder fixed on the side wall of the hollowed-out area, a third force transmission column in contact connection with the third loading oil cylinder through the lateral reserved hole, and a third force transmission plate connected with the third force transmission column.

7. The apparatus according to claim 1, wherein The water pressure applying device in communication with the high-pressure water tank is used for water injection and pressurization of the high-pressure water tank, and the water pressure measuring device is used for measuring the water pressure of the high-pressure water tank and is arranged in the high-pressure water tank.

8. The apparatus according to claim 1, wherein The high-pressure water tank includes a hollow tank body and sealing covers sealingly covering two ends of the tank body, the horizontal reserved hole and the lateral reserved hole are arranged on the side wall of the tank body, and the vertical reserved hole and the stress relief reserved hole are fixed on the sealing covers.

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