Device and method for continuously measuring three-dimensional in-situ crustal stress of deep stratum

Abstract

The invention discloses a deep stratum three-dimensional in-situ crustal stress continuous measurement device and method, and belongs to the technical field of crustal stress measurement. The device comprises a shell, wherein a plurality of cameras, a plurality of water jet heads, an image acquisition module, a water jet supply module and a data transmission module are connected in the shell; the cameras are arranged in the circumferential direction and used for shooting images of the periphery of the shell, the water jet cutter heads are arranged on the shell corresponding to the cameras, the cameras are electrically connected with the image acquisition module, the image acquisition module is electrically connected with the data transmission module, and the water jet cutter heads communicate with the water jet cutter supply module. The device can be used for continuously monitoring the ground stress, can be used under complex geological conditions, is simple and convenient to operate and high in efficiency, and greatly reduces the test cost and time investment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of in-situ stress measurement, and particularly relates to a device and method for continuous measurement of in-situ stress in deep strata. BACKGROUND

[0002] With the gradual advancement of deep mines, underground storage facilities and geothermal energy utilization into the deep crust, it is essential to master the in-situ stress state of rock mass to ensure the safety and stability of engineering. The stress distribution of rock mass directly affects the stability judgment in engineering design and construction, as well as the deformation and damage prediction of surrounding rock under external disturbance. Traditional in-situ stress measurement methods, such as stress relief method and hydraulic fracturing method, can only measure discrete points and cannot provide continuous spatial distribution information of rock mass stress. For example, the commonly used hollow inclusion stress relief method is to drill a hole around the chamber and install a hollow cylinder, then gradually relieve the stress on it, and then calculate the original rock stress. Although this method is mature and widely used, the construction process is relatively complex, and each measurement from drilling to stress relief to data collection takes a long time. Especially when operating in deep holes, the pasting of the inclusion, stress relief and data collection must be completed in a narrow space, which requires high precision for operation. The test process is also easily disturbed by the external environment, affecting the accuracy of the measurement results. In addition, the stress of rock mass changes dynamically with geological movement and engineering construction, and this method can only obtain discrete stress data during the relief process, and cannot monitor in real time.

[0003] If the existing method needs to obtain stress data at different stages, it must repeat the process of drilling and installing the inclusion multiple times, which greatly increases the time cost and economic investment of construction. In deep strata, due to complex geological conditions, high temperature and pressure, rock mass has obvious anisotropy and nonlinearity, making the limitations of single-point measurement more prominent. This makes researchers and engineers urgently need a continuous stress measurement technology in three-dimensional space and time to improve the accuracy and coverage of the stress field.

[0004] Therefore, a device and method for continuous measurement of in-situ stress in deep strata are proposed. SUMMARY

[0005] To solve the above technical problems, the present application provides a device and method for continuous measurement of in-situ stress in deep strata.

[0006] To achieve the above-mentioned objectives, the present invention provides a three-dimensional in-situ continuous measurement device for deep strata stress, comprising: a shell, in which are connected a plurality of cameras, a plurality of water jet heads, an image acquisition module, a water jet supply module and a data transmission module; the plurality of cameras are circumferentially arranged for capturing images of the outer periphery of the shell, the plurality of water jet heads are arranged on the shell corresponding to the cameras, the plurality of cameras are electrically connected to the image acquisition module, the image acquisition module is electrically connected to the data transmission module, and the plurality of water jet heads are connected to the water jet supply module.

[0007] According to a deep stratum three-dimensional in-situ continuous stress measurement device provided by the present invention, the two ends of the shell are fixedly connected to the limit bracket, and the limit bracket is provided with a plurality of support legs in the circumference. The support legs are arc-shaped and can be telescopically connected to the limit bracket body.

[0008] According to the deep stratum three-dimensional in-situ continuous stress measurement device provided by the present invention, the water jet head is an annular cutter head, the inner diameter of the water jet head is larger than the outer diameter of the camera, and the camera is arranged on the inner ring of the water jet head.

[0009] According to the deep stratum three-dimensional in-situ continuous stress measurement device provided by the present invention, the camera is a high-definition camera, and the lens of the camera is retractable.

[0010] On the other hand, the present invention also provides a method for continuous three-dimensional in-situ geostress measurement in deep formations, which can be cross-referenced with the above-mentioned device for continuous three-dimensional in-situ geostress measurement in deep formations:

[0011] Step 1: Drill holes at the points where deep ground stress monitoring is required and measure the borehole coordinate system;

[0012] Step 2: Installing the deep stratum three-dimensional in-situ continuous stress measurement device at the monitoring point, assuming that the section where the monitoring point is located at this time is the first monitoring section;

[0013] Step 3: The camera captures an initial image of the first monitoring section and transmits it to the image acquisition module. The image acquisition module preprocesses the initial image data and transmits it to the data transmission module. The data transmission module transmits the captured initial image data. Subsequently, the water jet supply module provides water flow and pressure to the water jet head. The high-pressure water flow ejected by the water jet head cuts the rock mass around the measuring point to form a cutting line, thereby relieving stress. At the same time, the camera, image acquisition module, and data transmission module obtain data on changes in the characteristics of the measuring point before and after stress relief, completing the first measurement.

[0014] Step 4: lifting the deep formation three-dimensional in-situ continuous in-situ stress measurement device and fixing the deep formation three-dimensional in-situ continuous in-situ stress measurement device to the hole wall again, and setting the cross section where the monitoring point at this position is located as the second monitoring section;

[0015] Step 5: Turn on the camera, the image acquisition module, and the data transmission module to start long-term measurement of cross-sectional data, continuously acquire hole wall images, and obtain long-term change data of continuous measurement point features;

[0016] Step 6: Based on the initial data of the first measurement and the real-time data of continuous measurement, the stress state of the monitoring point is calculated using elasticity theory and the least squares method.

[0017] According to a method for continuous three-dimensional in-situ geostress measurement in deep formations provided by the present invention, in step six, the initial strain of the deep hole measuring point is first calculated using the data of the first monitoring section and the basic parameters of the characteristic line segment in the second monitoring section; the initial strain data of the second monitoring section is superimposed with the continuous strain increment to obtain the full strain of the second monitoring section, and the elasticity theory and the least squares method are again used to obtain the full strain of the second monitoring section, which is the full stress of the deep hole.

[0018] According to the method for continuous three-dimensional in-situ geostress measurement in deep formations provided by the present invention, in step six, the three-dimensional in-situ geostress continuous measurement device in deep formations is lifted to a height of 5 to 10 times the height of the cutting range.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] This measuring device is placed in the borehole to be measured, and is used to collect image data of the measuring points in the borehole through the camera and image acquisition module, and transmit the image data to the data transmission module, which is used to transmit the collected image data outward; the water jet supply module provides high-pressure water flow to the water jet head, and the water jet head can cut the rock mass around the monitoring point to relieve stress, and then the camera and image acquisition module collect image data of the measuring points in the borehole again, and further obtain the change data of the measuring point characteristics before and after stress relief. The deep stratum three-dimensional in-situ ground stress continuous measurement device of the present invention replaces the traditional drilling relief method with the water jet head cutting relief, which solves the problem of deep hole stress relief. The camera, image acquisition module and data transmission module can perform real-time data collection and transmission, realizing the long-term continuous measurement demand of deep surrounding rock stress, thereby monitoring the changing law of deep original rock stress under geological movement and engineering influence. The present invention has the advantages of simple operation and high efficiency, which significantly reduces the testing cost and time investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the arrangement of the first monitoring section and the second monitoring section in the present invention;

[0023] Figure 2 This is a schematic structural diagram of the deep formation three-dimensional in-situ continuous stress measurement device of the present invention;

[0024] Figure 3 This is a cross-sectional view of the device for continuous measurement of three-dimensional in-situ stress in deep formations according to the present invention;

[0025] Figure 4 This is a schematic diagram of identification points and characteristic line segments of the present invention.

[0026] In the figure: 1. First monitoring section; 2. Second monitoring section; 3. Cutting line; 4. Image acquisition module; 5. Camera; 6. Water jet head; 7. Water jet supply module; 8. Limit bracket; 9. Data transmission module. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figures 1 to 4 As shown, this embodiment provides a three-dimensional in-situ continuous stress measurement device for deep formations, including: a shell, in which are connected a plurality of cameras 5, a plurality of water jet heads 6, an image acquisition module 4, a water jet supply module 7 and a data transmission module 9; the plurality of cameras 5 are circumferentially arranged for capturing images of the outer periphery of the shell, the plurality of water jet heads 6 are arranged on the shell corresponding to the cameras 5, the plurality of cameras 5 are electrically connected to the image acquisition module 4, the image acquisition module 4 is electrically connected to the data transmission module 9, and the plurality of water jet heads 6 are connected to the water jet supply module 7.

[0030] This measuring device is placed in the borehole to be measured, and is used to collect image data of the measuring points in the borehole through the camera 5 and the image acquisition module 4, and transmit the image data to the data transmission module 9, which is used to transmit the collected image data outward; the water jet supply module 7 provides water flow and pressure to the water jet head 6, and the water jet head 6 can cut the rock around the monitoring point to relieve stress, and then the camera 5 and the image acquisition module 4 collect the image data of the measuring points in the borehole again, and the change data of the measuring point characteristics before and after the stress is relieved can be obtained.

[0031] Reference Figure 4 As shown, ~ It is the original feature identification point; ~ is the feature identification point after deformation; , , , It is the line connecting the original feature identification points, that is, the feature line segment; , , , is the characteristic line segment after deformation.

[0032] The deep stratum three-dimensional in-situ continuous stress measurement device of the present invention replaces the traditional drilling release method by cutting and releasing with a water jet head 6, thereby solving the problem of deep hole stress release. Real-time data collection and transmission can be performed through the camera 5, image acquisition module 4 and data transmission module 9, realizing the long-term continuous measurement demand of deep surrounding rock stress, thereby monitoring the changing law of deep rock stress under geological movement and engineering influence.

[0033] According to a deep formation three-dimensional in-situ continuous stress measurement device provided by this embodiment, the two ends of the shell are fixedly connected to the limit bracket 8, and the limit bracket 8 is provided with multiple support legs in the circumference. The support legs are arc-shaped and can be telescopically connected to the main body of the limit bracket 8.

[0034] The limiting bracket 8 limits the position of the device in the deep hole to prevent disturbances from affecting image acquisition and the cutting process of the water jet head 6. The curvature of the supporting legs of the limiting bracket 8 is the same as the curvature of the hole wall, which is conducive to stable support.

[0035] According to the deep formation three-dimensional in-situ continuous stress measurement device provided by this embodiment, the water jet head 6 is an annular cutter head, the inner diameter of the water jet head 6 is larger than the outer diameter of the camera 5, and the camera 5 is arranged on the inner ring of the water jet head 6.

[0036] The annular water jet head 6 surrounds the camera 5 , facilitating stress relief at the monitoring point corresponding to the camera 5 .

[0037] According to the deep stratum three-dimensional in-situ continuous stress measurement device provided by this embodiment, the camera 5 is a high-definition camera, and the lens of the camera 5 is retractable.

[0038] The lens of camera 5 is retractable and the lens length can be adjusted according to the inner diameter of the deep hole. After adjustment, the wall measurement can be achieved to solve the problem that the groundwater inside the deep hole affects the image clarity.

[0039] On the other hand, this embodiment also provides a method for continuous three-dimensional in-situ geostress measurement in deep formations, which can be cross-referenced with the above-mentioned device for continuous three-dimensional in-situ geostress measurement in deep formations:

[0040] Step 1: Drill holes at the points where deep ground stress monitoring is required and measure the borehole coordinate system;

[0041] Step 2: Install a deep stratum three-dimensional in-situ continuous ground stress measurement device at the monitoring point, and assume that the section where the monitoring point is located at this time is the first monitoring section 1;

[0042] The deep stratum three-dimensional in-situ continuous ground stress measurement device is installed through the limiting bracket 8.

[0043] Step 3: The camera 5 captures an initial image of the first monitoring section 1 and transmits it to the image acquisition module 4. The image acquisition module 4 preprocesses the initial image data and transmits it to the data transmission module 9. The data transmission module 9 transmits the captured initial image data. Subsequently, the water jet supply module 7 provides water flow and pressure to the water jet head 6. The high-pressure water flow ejected by the water jet head 6 cuts the rock mass around the measuring point to form a cutting line 3, thereby relieving stress. At the same time, the camera 5, image acquisition module 4, and data transmission module 9 obtain data on changes in the characteristics of the measuring point before and after stress relief, completing the first measurement.

[0044] Before collecting images, the lens length can be adjusted according to the inner diameter of the deep hole to obtain clearer images.

[0045] Step 4: Lift the deep formation three-dimensional in-situ continuous in-situ stress measurement device and fix it to the hole wall again. The section where the monitoring point is located at this position is set as the second monitoring section 2.

[0046] Step 5: Turn on the camera 5, the image acquisition module 4 and the data transmission module 9 to start long-term measurement of cross-sectional data, continuously collect hole wall images, and obtain long-term change data of continuous measurement point features;

[0047] Step 6: Based on the initial data of the first measurement and the real-time data of continuous measurement, the stress state of the monitoring point is calculated using elasticity theory and the least squares method.

[0048] According to a method for continuous three-dimensional in-situ stress measurement of deep formations provided by this embodiment, in step six, the initial strain of the deep hole measuring point is first calculated using the data of the first monitoring section 1 and the basic parameters of the characteristic line segment in the second monitoring section 2; the initial strain data of the second monitoring section 2 is superimposed with the continuous strain increment to obtain the full strain of the second monitoring section 2, and the full strain of the second monitoring section 2 is again obtained using elasticity theory and the least squares method, which is the full stress of the deep hole.

[0049] The specific calculation process is:

[0050] S1: Stress component of the first monitoring section 1 、 、 、 、 、 Calculation. Based on the data obtained from the first monitoring section 1, calculate the stress components of the first monitoring section 1 and establish the equation based on elastic theory:

[0051] Where, .

[0052] make: ,but:

[0053]

[0054] Where, the subscript 1 represents the relevant parameters of the characteristic line segment in the first monitoring section 1, i=1~3 is the cluster number of each characteristic line segment in the first group of measuring points; j=1~4 is the number of each characteristic line segment in each characteristic line segment cluster; is the initial length of the characteristic line segment of the first monitoring section 1, is the length of the characteristic line segment of the first monitoring section 1 after release, is the strain of the characteristic line segment 1 of the first monitoring section; is the polar angle of the characteristic line segment cluster of the first monitoring section 1; is the angle of the characteristic line segment of the first monitoring section 1; E is the elastic modulus of rock; is the Poisson's ratio of rock; 、 、 、 、 、 The six ground stress components of the first monitoring section 1; 、 ...... is the coefficient of the equation.

[0055] Based on the least squares principle, the normal equation of the strain equation of the characteristic line segment is constructed, and the stress component 1 of the first monitoring section is obtained. 、 、 、 、 、 for:

[0056]

[0057] Where s is the number of observation equations, that is, the number of characteristic line segments, and ; i is the number of characteristic line segment clusters of a single monitoring section; j is the number of characteristic line segments in different directions contained in each characteristic line segment cluster; To eliminate the strain difference between the front and rear characteristic segments.

[0058] S2: Initial strain of the second monitoring section 2 Calculation. Based on the stress components obtained from the first monitoring section 1 and the characteristic line segment cluster polar angle and characteristic line segment angle of the second monitoring section 2, the initial strain of the second monitoring section 2 is calculated, and the equation is established based on elastic theory:

[0059]

[0060] Where:

[0061]

[0062] Where, subscript 1 represents the relevant parameters of the characteristic line segment in the first monitoring section 1, and subscript 2 represents the relevant parameters of the characteristic line segment in the second monitoring section 2; i = 1 to 3 is the cluster number of each characteristic line segment in the second group of measuring points; j = 1 to 4 is the number of each characteristic line segment in each characteristic line segment cluster; is the initial strain of the characteristic line segment 2 of the second monitoring section; is the polar angle of the characteristic line segment cluster 2 of the second monitoring section; is the angle of the characteristic line segment 2 of the second monitoring section; E is the elastic modulus of the rock; is the Poisson's ratio of rock; 、 、 、 、 、 The six ground stress components of the second monitoring section 2; 、 ...... is the coefficient of the equation.

[0063] S3: Full amount of initial strain at the second monitoring section 2 Calculate and establish the following equation:

[0064]

[0065]

[0066] Where, is the total strain of the characteristic line segment 2 of the second monitoring section during the continuous monitoring process; is the strain increment of the characteristic line segment 2 of the second monitoring section during the continuous monitoring process; is the initial length of the characteristic line segment of the second monitoring section 2, It is the characteristic line segment length of the second monitoring section 2 at any moment during the continuous measurement process as it changes with time and space.

[0067] S4: Full stress measurement of the second monitoring section 2 、 、 、 、 、 Calculation. Based on elasticity theory, the following equation is established:

[0068]

[0069] make: ,but:

[0070]

[0071] Where, the subscript 2 represents the relevant parameters of the characteristic line segment in the second monitoring section 2; i = 1 to 3 is the cluster number of each characteristic line segment in the second group of measuring points; j = 1 to 4 is the number of each characteristic line segment in each characteristic line segment cluster; is the polar angle of the characteristic line segment cluster; is the angle of the characteristic line segment; E is the elastic modulus of rock; is the Poisson's ratio of rock; 、 、 、 、 、 are the six components of ground stress; 、 ...... is the coefficient of the equation.

[0072] Based on the least squares principle, the normal equation of the strain equation of the characteristic line segment is constructed, and the total stress of the deep hole measuring point can be obtained by sorting it out. 、 、 、 、 、 for:

[0073]

[0074] The total stress of the second monitoring section 2 、 、 、 、 、 That is the total stress of the deep hole.

[0075] According to the method for continuous three-dimensional in-situ geostress measurement in deep formations provided by this embodiment, in step six, the device for continuous three-dimensional in-situ geostress measurement in deep formations is raised to a height 5 to 10 times the height of the cutting range.

[0076] When the lifting height is 5 to 10 times the cutting range, the effect of the initial stress relief can be eliminated.

[0077] Any details not provided in the present invention are conventional technical means known to those skilled in the art.

[0078] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0079] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A three-dimensional in-situ continuous ground stress measurement device for deep formations, characterized in that: include: A shell, wherein a plurality of cameras (5), a plurality of water jet heads (6), an image acquisition module (4), a water jet supply module (7) and a data transmission module (9) are connected to the shell; the plurality of cameras (5) are arranged circumferentially for capturing images of the outer periphery of the shell, the plurality of water jet heads (6) are arranged on the shell corresponding to the cameras (5), the plurality of cameras (5) are electrically connected to the image acquisition module (4), the image acquisition module (4) is electrically connected to the data transmission module (9), and the plurality of water jet heads (6) are in communication with the water jet supply module (7).

2. The deep stratum three-dimensional in-situ continuous stress measurement device according to claim 1, characterized in that: The two ends of the housing are fixedly connected to a limiting bracket (8), and the limiting bracket (8) is provided with a plurality of supporting legs in a circumferential direction. The supporting legs are arc-shaped and are telescopically connected to the main body of the limiting bracket (8).

3. The deep stratum three-dimensional in-situ continuous stress measurement device according to claim 1 is characterized by: The water jet head (6) is an annular blade head, the inner diameter of the water jet head (6) is larger than the outer diameter of the camera (5), and the camera (5) is arranged on the inner ring of the water jet head (6).

4. The deep stratum three-dimensional in-situ continuous stress measurement device according to claim 1 is characterized in that: The camera (5) is a high-definition camera, and the lens of the camera (5) is retractable.

5. A method for continuous three-dimensional in-situ geostress measurement in deep formations, using the device for continuous three-dimensional in-situ geostress measurement in deep formations according to any one of claims 1 to 4, characterized in that: Step 1: Drill holes at the monitoring points where deep ground stress needs to be measured and measure the borehole coordinate system; Step 2: Install the deep stratum three-dimensional in-situ continuous stress measurement device at the monitoring point, and set the section where the monitoring point is located at this time as the first monitoring section (1); Step 3: The camera (5) collects the initial image of the first monitoring section (1) and transmits it to the image acquisition module (4); the image acquisition module (4) pre-processes the data of the initial image and transmits it to the data transmission module (9); the data transmission module (9) transmits the collected initial image data; Then, the water jet supply module (7) provides high-pressure water flow to the water jet head (6), and the high-pressure water flow ejected by the water jet head (6) cuts the rock mass around the measuring point to form a cutting line (3) to relieve stress. At the same time, the camera (5), the image acquisition module (4) and the data transmission module (9) obtain the change data of the measuring point characteristics before and after the stress is relieved, thereby completing the first measurement; Step 4: lifting the deep formation three-dimensional in-situ continuous ground stress measuring device and fixing the deep formation three-dimensional in-situ continuous ground stress measuring device to the hole wall again, and setting the section where the monitoring point at this position is located as the second monitoring section (2); Step 5: Turn on the camera (5), the image acquisition module (4) and the data transmission module (9) to start long-term measurement of cross-sectional data, continuously acquire hole wall images, and obtain long-term variation data of continuous measurement point features; Step 6: Based on the initial data of the first measurement and the real-time data of continuous measurement, the stress state of the monitoring point is calculated using elasticity theory and the least squares method.

6. The method for continuous three-dimensional in-situ stress measurement in deep formations according to claim 5, characterized in that: In step six, the initial strain of the deep hole measuring point is first calculated using the data of the first monitoring section (1) and the basic parameters of the characteristic line segment in the second monitoring section (2); the initial strain data of the second monitoring section (2) is superimposed with the continuous strain increment to obtain the full strain of the second monitoring section (2); and the full strain of the second monitoring section (2) is obtained again using the elasticity theory and the least squares method, which is the full stress at the deep hole monitoring point.

7. The method for continuous three-dimensional in-situ stress measurement in deep formations according to claim 5, characterized in that: In step six, the deep formation three-dimensional in-situ continuous stress measurement device is lifted to a height of 5 to 10 times the height of the cutting range.

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