A system and method for measuring micro-deformation of deep rock mass in situ

Abstract

The present invention provides a field measurement system and method for micro-deformation of deep rock mass, the system comprises a fixed seat, a measuring tube, a central transmission rod, a transmission assembly, a connecting sleeve, a micrometer, a magnetic table seat, a measuring bracket and an anchor point, the central transmission rod is located in the measuring tube, the fixed seat is located at the bottom of the measuring hole, the bottom of the fixed seat is connected to the surrounding rock at the bottom of the measuring hole, and the fixed seat and the bottom of the measuring tube form a strong release buckle, the fixed seat and the bottom of the central transmission rod are connected to each other, the transmission assembly clamps the central transmission rod and can roll on the inner wall of the measuring tube, the probe of the micrometer is connected to the top of the central transmission rod to measure the displacement of the central transmission rod, the micrometer is fixed on the measuring bracket through the magnetic table seat, and the measuring bracket is supported by the anchor point. The present invention can be used as an effective and reliable means for measuring micro-deformation of deep rock mass in field rock mass tests, and improves the sensitivity, accuracy and range of measurement.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering, and in particular to a system and method for measuring micro-deformation of deep rock mass on-site. Background Art

[0002] Due to their importance and particularity, hydropower projects, bridge projects and other projects often carry out on-site rock mass tests. On the one hand, they accurately obtain the deformation modulus and shear strength parameters of the rock mass, and on the other hand, they conduct on-site scale model tests to verify the rationality of the engineering design plan.

[0003] On-site rock mass tests mainly evaluate the parameters and stability of rock mass by measuring the displacement of rock mass at different depths. The larger the deformation modulus of the rock mass, the smaller its deformation. The deformation value of high modulus rock blocks or rock masses under stress and load can reach micrometer level. The micro deformation measurement of the rock mass surface is simple and can be measured by micrometer or grating sensor. The displacement measurement of deep rock mass is more difficult, and it is necessary to realize the continuous measurement of the micro deformation of deep rock mass. The measuring device needs to have a large range, high sensitivity and high precision (μm level), and at the same time have the characteristics of easy installation and high reliability. Summary of the invention

[0004] The purpose of the present invention is to provide a system and method for measuring the micro-deformation of deep rock mass in field rock mass tests. The system and method can be used as an effective and reliable means for measuring the micro-deformation of deep rock mass in field rock mass tests, thereby improving the measurement sensitivity, measurement accuracy and measurement range.

[0005] To achieve this purpose, the present invention provides a field measurement system for deep rock micro-deformation, comprising a fixed seat, a measuring tube, a central transmission rod, a transmission assembly, a connecting sleeve, a micrometer, a magnetic seat, a measuring bracket and an anchor point, wherein the central transmission rod is located in the measuring tube, the fixed seat is located at the bottom of the measuring hole, the bottom of the fixed seat is connected to the surrounding rock at the bottom of the measuring hole, and the fixed seat and the bottom of the measuring tube form a strong release buckle, the fixed seat and the bottom of the central transmission rod are connected to each other, the transmission assembly clamps the central transmission rod and can roll on the inner wall of the measuring tube, the probe of the micrometer is connected to the top of the central transmission rod to measure the displacement of the central transmission rod, the micrometer is fixed to the measuring bracket through the magnetic seat, and the measuring bracket is supported by the anchor point.

[0006] Furthermore, the fixing seat includes a base, an annular protrusion arranged around the side wall of the base, and a bolt located at the top of the base. The base is connected to the surrounding rock at the bottom of the measuring hole by grouting. The bottom of the center transmission rod is provided with an internal thread. The bolt on the top of the base is firmly threadedly connected to the internal thread of the center transmission rod. The annular protrusion on the side wall of the fixing seat and the annular protrusion on the measuring tube form a strong release buckle.

[0007] Furthermore, the measuring pipe is formed by connecting segmented pipes of the same length, and two adjacent segmented pipes of the measuring pipe are connected by a connecting sleeve.

[0008] Furthermore, the connecting sleeve includes a first port and a second port, and the two ports are provided with threaded holes corresponding to the threaded holes of the measuring tube, and an annular protrusion for auxiliary positioning is provided in the middle. The upper and lower segmented pipes are positioned by the annular protrusion in the middle of the connecting sleeve, so that the threaded holes of the upper and lower segmented pipes are in the same position as the threaded holes of the connecting sleeve, and the two threaded holes are connected by bolts.

[0009] Furthermore, the center transfer rod is formed by connecting segmented rods of the same length, the internal thread of the upper segmented center transfer rod is connected to the external bolt of the lower segmented center transfer rod, each segmented center transfer rod is provided with an annular groove, and a transmission assembly is provided on the annular groove.

[0010] Furthermore, the transmission assembly includes a first annular clamp, a second annular clamp and four symmetrical pulleys. The first annular clamp and the second annular clamp are installed in the annular groove of the center transfer rod. The annular clamp is positioned and installed using male and female stoppers. The male stopper and the female stopper are provided with internal threads at the same position and are fixed with bolts. The four pulleys of the transmission assembly are respectively located on the vertical guide grooves of the inner wall of the measuring tube, so that the transmission assembly clamps the center transfer rod and rolls on the guide grooves through the pulleys.

[0011] Furthermore, the anchor point is buried outside the influence range of the on-site rock mass test stress.

[0012] Furthermore, the central transmission rod is made of an alloy material with an extremely small linear expansion coefficient.

[0013] The present invention also provides a method for measuring micro-deformation of deep rock mass on-site, comprising the following steps:

[0014] Step 1: Construction of observation holes;

[0015] Step 2, assemble and lower the fixing seat: the bolts on the fixing seat are connected with the inner thread of the lowermost center transmission rod, and the transmission assembly is installed on the annular groove of the center transmission rod and fixed with bolts; the lowermost measuring tube is inserted into the outer side of the transmission assembly, so that the pulley of the transmission assembly is in the guide groove of the measuring tube, and the measuring tube is pressed downward, so that the annular protrusion on the inner side wall of the lower port of the measuring tube and the annular protrusion of the fixing seat form a strong release buckle, and after the assembly is completed, the fixing seat is lowered into the measuring hole;

[0016] Step 3: Extend and lower the measuring tube and the central transmission rod: the measuring tube and the central transmission rod are both composed of small sections connected from bottom to top;

[0017] Step 4, installation of measuring device: install the anchor point outside the influence range of rock mass test stress, install a measuring bracket on the anchor point, fix a magnetic base on the measuring bracket, install a micrometer on the magnetic base, and the micrometer probe is in close contact with the end of the central transmission rod 3 of the orifice;

[0018] Step 5, deformation measurement: the fixed seat is located at the bottom of the measuring hole and is connected to the surrounding rock grouting at the bottom of the measuring hole. The deformation of the surrounding rock at the bottom of the measuring hole drives the fixed seat to displace, and the fixed seat transmits it to the lowest center transfer rod connected to it. The transmission assembly clamps the center transfer rod and slides on the guide groove of the measuring tube through the pulley, transmits the displacement to the next center transfer rod, and then transmits it to the hole mouth in turn. The hole mouth displacement is measured by a micrometer.

[0019] Furthermore, the step three specifically includes:

[0020] Step 201: Bolt the inner thread of the next section of the center transfer rod to the installed center transfer rod, install a transmission assembly on the annular groove of the next section of the center transfer rod and fix it with bolts, insert a connecting sleeve into the outer side of the transmission assembly, rotate the connecting sleeve so that the inner thread of its lower port is at the same position as the inner thread of the upper port of the installed measuring tube, install the next section of the measuring tube, connect the sleeve and the upper and lower segmented measuring tubes with bolts, and after assembly, lower the segmented measuring tube and the center transfer rod into the measuring hole;

[0021] Step 202: Repeat step 201 in sequence for multiple times until all the measuring tubes and the center transfer rod are installed. At this time, the base of the fixing seat is in contact with the surrounding rock of the measuring hole, the measuring tube and the center transfer rod are exposed at the hole mouth, the center transfer rod port of the hole mouth is fixed, the measuring tube is pulled out of the hole to force the lowermost measuring tube to break away from the buckle of the fixing seat, the measuring tube is pulled out to a certain height and fixed, grouting is injected into the bottom of the hole to make the fixing seat fully contact with the surrounding rock at the bottom of the hole, and the measuring tube is lowered after the slurry is completely fixed.

[0022] The beneficial effects achieved by the present invention are:

[0023] 1. The high-rigidity central transmission rod and the measuring system form a high-precision and high-sensitivity displacement sensor, which improves the measurement sensitivity, measurement accuracy and measurement range;

[0024] 2. The use of assembled measuring tube and central transmission rod effectively simplifies the instrument installation process and improves the depth of accurate measurement of rock displacement;

[0025] 3. The use of peripheral anchor points to support the measurement bracket reduces the impact of geotechnical engineering tests on the test results and improves the reliability of the measurement;

[0026] 4. A transmission assembly is provided between the center transfer rod and the measuring tube, which prevents the deformation of the center transfer rod caused by the impact of external force on the measuring tube, thereby improving the reliability of the instrument; the transmission assembly between the center transfer rod and the measuring tube clamps and fixes the center transfer rod, reducing the influence of the deflection change of the center transfer rod on the measurement results. Guide rollers are provided around the transmission assembly, which can slide easily in the guide groove of the measuring tube, reducing the influence of friction on the measurement results;

[0027] 5. The central transfer rod is made of alloy steel with a very small linear expansion coefficient, which improves the stability of the instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of one embodiment of the in-situ measurement system for micro-deformation of deep rock mass of the present invention;

[0029] Figure 2 It is a schematic diagram of the installation of the fixing seat in the present invention;

[0030] Figure 3 It is a schematic diagram of the installation of the connecting sleeve in the present invention;

[0031] Figure 4 It is a cross-sectional view of the connection position between the connecting sleeve and the measuring tube in the present invention;

[0032] Figure 5 It is a schematic diagram of the connection between the central transmission rod and the transmission assembly in the present invention;

[0033] Figure 6 It is a structural schematic diagram of the transmission component in the present invention.

[0034] The reference numerals in the figures are described as follows:

[0035] 1—fixed seat; 1a—base; 1b—bolt; 1c—annular protrusion; 2—measuring tube; 2a—guide groove; 2b—threaded hole; 2c—annular protrusion; 3—center transmission rod; 3a—bolt; 3b—internal thread; 3c—annular groove; 4—transmission assembly; 4a—first annular clamp; 4b—second annular clamp; 4c—pulley; 4d—threaded hole; 5—connecting sleeve; 5a—internal thread; 5b—annular protrusion; 6—micrometer; 7—magnetic base; 8—measuring bracket; 9—anchor point. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention.

[0037] Figure 1The figure shows a schematic structural diagram of one embodiment of a deep rock mass micro-deformation field measurement system of the present invention, wherein the deep rock mass micro-deformation field measurement system comprises a fixing base 1, a measuring tube 2, a center transmission rod 3, a transmission assembly 4, a connecting sleeve 5, a micrometer 6, a magnetic base 7, a measuring bracket 8 and an anchor point 9.

[0038] like Figure 2 As shown, the fixing seat 1 is located at the bottom of the measuring hole, and the fixing seat 1 includes a base 1a, an annular protrusion 1c arranged around the side wall of the base 1a, and a bolt 1b located at the top of the base 1a. The base 1a is connected to the surrounding rock at the bottom of the measuring hole by grouting, and the bolt 1b is firmly threaded with the internal thread 3b of the center transmission rod 3. The deformation of the surrounding rock at the bottom of the measuring hole is transmitted to the base 1a, and the base 1a is transmitted to the center transmission rod 3 connected thereto. The annular protrusion 1c on the side wall of the fixing seat 1 and the annular protrusion 2c on the measuring tube 2 form a strong release buckle. During the installation process, the connection between the fixing seat 1 and the measuring tube 2 maintains the integrity of the measuring system. After the installation is completed, the measuring tube 2 breaks free from the fixing seat 1.

[0039] The measuring tube 2 and the central transmission rod 3 are both formed by connecting small sections of the same length up and down. Figure 3 As shown, the segmented pipe of the measuring pipe 2 includes a first port and a second port located at the upper and lower ends. The first port and the second port are both open, and the two ports are symmetrically provided with threaded holes 2b and guide grooves 2a vertically arranged along the inner wall of the pipe. The two adjacent segmented pipes of the measuring pipe 2 are connected by a connecting sleeve 5. The connecting sleeve 5 includes a first port and a second port. The two ports are provided with threaded holes 5a corresponding to the threaded holes 2b of the measuring pipe 2, and a ring-shaped protrusion 5b for auxiliary positioning is provided in the middle, which ensures that the threaded holes of the measuring pipe 2 and the connecting sleeve 5 are in the same position, and the two are firmly connected with bolts. As shown Figure 4 As shown, the line connecting the two threaded holes 2b of the measuring tube 2 and the line connecting the adjacent guide grooves 2a through the center of the measuring tube are 45 degrees apart, which is conducive to uniform force on the measuring tube 2.

[0040] The central transmission rod 3 is located in the measuring tube 2, and the transmission assembly 4 clamps the central transmission rod 3 and rolls on the guide groove 2a of the measuring tube 2 through the pulley 4c. Figure 5 As shown, the segmented rod of the center transfer rod 3 includes a first end and a second end, the first end is a bolt 3a, the second end is an internal thread 3b that can cooperate with the bolt 3a, and the outer wall of each segmented center transfer rod 3 is surrounded by an annular groove 3c, the internal thread of the upper segmented center transfer rod is connected to the external bolt of the lower segmented center transfer rod, and the transmission assembly 4 is installed on the annular groove 3c.

[0041] The transmission assembly 4 includes a first annular clamp 4a, a second annular clamp 4b and four symmetrical pulleys 4c. Figure 6As shown, the two annular clamps (4a, 4b) can be assembled into a complete circular clamp, and the ports are respectively a male stop and a female stop, which are used for radial positioning and tightly clamping the center transfer rod. The first annular clamp 4a and the second annular clamp 4b are installed in the annular groove 3c of the center transfer rod 3. A threaded hole 4d is provided at the contact point between the first annular clamp 4a and the second annular clamp 4b and is connected by bolts. The four pulleys 4c of the transmission assembly 4 are respectively located on the guide groove 2a of the measuring tube 2.

[0042] A displacement measuring device is provided outside the measuring hole, and the displacement measuring device includes a micrometer 6 and a magnetic base 7. The probe of the micrometer 6 is in close contact with the end of the hole of the center transfer rod 3, and is used to measure the displacement of the center transfer rod. The micrometer 6 is mounted on the magnetic base 7, and the magnetic base 7 is mounted on a measuring bracket 8, and the measuring bracket 8 is fixed by an anchor point 9.

[0043] The anchor point 9 is installed outside the influence range of the rock mass test stress, avoiding the influence of the deformation of the measuring bracket 8 on the measurement result, and improving the accuracy of the measurement result. The central transfer rod 3 is made of an alloy material with a very small linear expansion coefficient (such as nickel steel alloy), which reduces the influence of temperature changes on the measurement result. The magnetic base 7 is magnetically attracted to the measuring bracket 8. By adjusting the position of the magnetic base 7 and the shape of its bracket, the measuring rod of the micrometer 6 is parallel to the central transfer rod 3 and its axial displacement is measured.

[0044] The embodiment of the present invention further provides a method for measuring micro-deformation of deep rock mass on-site, which is performed by using the above-mentioned measurement system. The method comprises the following steps:

[0045] Step 1: Construction of observation holes: Use a drilling rig to drill a hole at the point to be measured, use a high-pressure water pump to flush the hole wall, and use a compressed air machine to blow out the water in the hole after flushing;

[0046] Step 2, assemble and lower the fixing seat 1: connect the bolt 1b on the fixing seat 1 with the internal thread 3b of the lowermost center transmission rod 3, install three transmission components 4 on the three annular grooves 3c of the lowermost center transmission rod 3 and fix them with bolts; insert the lowermost measuring tube 2 on the outer side of the transmission component 4, so that the four pulleys 4c of the transmission component are respectively in the four guide grooves 2a of the measuring tube 2; press the measuring tube 2 downward, so that the annular protrusion 2c on the inner side wall of the lower port of the measuring tube 2 and the annular protrusion 1c of the fixing seat 1 form a strong release buckle; after the assembly is completed, lower the fixing seat 1 into the measuring hole;

[0047] Step 3: Lengthen and lower the measuring tube 2 and the central transmission rod 3: The measuring tube 2 and the central transmission rod 3 are both composed of small sections connected from bottom to top. The specific installation process is as follows:

[0048] Step 201: Connect the inner thread 3b of the next section of the central transmission rod 3 with the bolt 3a of the installed central transmission rod 3, install three transmission components 4 on the three annular grooves 3c of the next section of the central transmission rod 3, axially rotate the transmission component 4 so that its pulley 4c is on the same axis as the pulley 4c of the installed transmission component 4, and fix the transmission component with bolts. Insert the connecting sleeve 5 outside the transmission component 4, rotate the connecting sleeve 5 so that the inner thread 5a of its lower port is at the same position as the threaded hole 2b of the upper port of the installed measuring tube 2 and fix it with bolts. Then install the next section of the measuring tube 2, axially rotate the next section of the measuring tube 2 so that the inner side wall guide groove is on the same axis as the pulley 4c of the transmission component 4, put the measuring tube 2 into the connecting sleeve 5, and at this time, the threaded hole 2b of the lower port of the next section of the measuring tube 2 is at the same position as the inner thread 5a of the upper end of the connecting sleeve and fix it with bolts. After the assembly is completed, lower the current section of the measuring tube 2 and the central transmission rod 3 into the measuring hole.

[0049] Step 202: Repeat step 201 in sequence for multiple times until all the measuring tubes 2 and the center transfer rod 3 are installed. At this time, the base 1a of the fixing seat 1 is in contact with the surrounding rock of the measuring hole, and the measuring tube 2 and the center transfer rod 3 are exposed at the hole mouth. Fix the outer end of the center transfer rod 3 at the hole mouth, pull the measuring tube 2 out of the hole to force the lowermost measuring tube 2 to break away from the buckle of the fixing seat 1, continue to pull the measuring tube 2 outward for about 20cm and fix it, grout the bottom of the hole to make the fixing seat 1 fully contact with the surrounding rock at the bottom of the hole, and lower the measuring tube 2 after the grout is completely fixed.

[0050] Step 4, installation of measuring device: the anchor point 9 is installed outside the influence range of rock mass test stress, the measuring bracket 8 is installed on the anchor point, the micrometer 6 is installed on the magnetic base 7, and the magnetic base 7 is magnetically attracted to the measuring bracket 8. Adjust the position of the magnetic base 7 and the shape of its bracket so that the probe of the micrometer 6 is in close contact with the end of the central transmission rod 3 of the orifice.

[0051] Step 5, deformation measurement: the fixed seat 1 is located at the bottom of the measuring hole and is connected to the surrounding rock grouting at the bottom of the measuring hole. The deformation of the surrounding rock at the bottom of the measuring hole drives the fixed seat 1 to displace, and the fixed seat 1 transmits it to the lowest center transfer rod 3 connected to it. The transmission component 4 clamps the center transfer rod 3 and slides on the guide groove 2a of the measuring tube 2 through the pulley 4c, and transmits the displacement to the next center transfer rod 3, and then transmits it to the hole mouth in turn. The hole mouth displacement is measured by the micrometer 6.

[0052] After the deep rock micro-deformation field measurement system is installed, the measuring tube 2 can slide axially. The measuring tube 2 serves as a protective tube and guide rail for the central transfer rod 3. On the one hand, it prevents the rock blocks on the inner wall of the measuring hole from falling and causing the central transfer rod 3 to vibrate and displace. On the other hand, it ensures its axial stability by limiting the deflection deformation of the central transfer rod 3.

[0053] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A deep rock mass micro-deformation field measurement system, characterized by: The invention comprises a fixing seat (1), a measuring tube (2), a central transmission rod (3), a transmission assembly (4), a connecting sleeve (5), a micrometer (6), a magnetic table seat (7), a measuring bracket (8) and an anchor point (9); the central transmission rod (3) is located in the measuring tube (2); the fixing seat (1) is located at the bottom of the measuring hole; the bottom of the fixing seat (1) is connected to the surrounding rock at the bottom of the measuring hole; the fixing seat (1) and the bottom of the measuring tube (2) form a strong release buckle; the fixing seat (1) and the bottom of the central transmission rod (3) are connected to each other; the transmission assembly (4) clamps the central transmission rod (3) and can roll on the inner wall of the measuring tube (2); the probe of the micrometer (6) is connected to the top of the central transmission rod (3) to measure the displacement of the central transmission rod (3); the micrometer (6) is fixed to the measuring bracket (8) through the magnetic table seat (7); the measuring bracket (8) is supported by the anchor point (9); the central transmission rod (3) is The central transmission rod (3) is connected by segmented rods of the same length. The internal thread of the upper segmented central transmission rod is connected with the external bolt of the lower segmented central transmission rod. Each segmented central transmission rod (3) is provided with an annular groove (3c). A transmission assembly (4) is provided on the annular groove (3c). The transmission assembly (4) comprises a first annular clamp (4a), a second annular clamp (4b) and four symmetrical pulleys (4c). The first annular clamp (4a) and the second annular clamp (4b) are installed in the annular groove (3c) of the central transmission rod (3). The annular clamp is positioned and installed by using male and female stoppers. The male stopper and the female stopper are provided with internal threads (4d) at the same position and fixed by bolts. The four pulleys (4c) of the transmission assembly (4) are respectively located on the vertical guide groove (2a) of the inner wall of the measuring tube (2), so that the transmission assembly clamps the central transmission rod (3) and rolls on the guide groove (2a) through the pulleys (4c).

2. The deep rock mass micro-deformation field measurement system according to claim 1, characterized in that: The fixing seat (1) comprises a base (1a), an annular protrusion (1c) arranged around the side wall of the base (1a), and a bolt (1b) located at the top of the base (1a); the base (1a) is connected to the surrounding rock at the bottom of the measuring hole by grouting; the bottom of the central transmission rod (3) is provided with an internal thread (3b); the bolt (1b) at the top of the base (1a) is firmly threadedly connected with the internal thread (3b) of the central transmission rod (3); the annular protrusion (1c) on the side wall of the fixing seat (1) and the annular protrusion (2c) on the measuring tube (2) form a strong release buckle.

3. The deep rock mass micro-deformation field measurement system according to claim 1, characterized in that: The measuring pipe (2) is formed by connecting segmented pipes of the same length, and two adjacent segmented pipes of the measuring pipe (2) are connected by a connecting sleeve (5).

4. The deep rock mass micro-deformation field measurement system according to claim 3, characterized in that: The connecting sleeve (5) comprises a first port and a second port, wherein the two ports are provided with threaded holes (5a) corresponding to the threaded holes (2b) of the measuring tube (2), and an annular protrusion (5b) for auxiliary positioning is provided in the middle, and the upper and lower segmented pipes are positioned by the annular protrusion (5b) in the middle of the connecting sleeve (5), so that the threaded holes (2b) of the upper and lower segmented pipes and the threaded holes (5a) of the connecting sleeve (5) are at the same position, and the two threaded holes (2b, 5a) are connected by bolts.

5. The deep rock mass micro-deformation field measurement system according to claim 1, characterized in that: The anchor point (9) is buried outside the stress influence range of the on-site rock mass test.

6. The deep rock mass micro-deformation field measurement system according to claim 1, characterized in that: The central transmission rod (3) is made of an alloy material with an extremely small linear expansion coefficient.

7. A method for measuring micro-deformation of deep rock mass in situ, characterized in that The system according to any one of claims 1 to 6 is used for measurement, and the method comprises the following steps: Step 1: Construction of observation holes; Step 2, assembling and lowering the fixing seat (1): the bolt (1b) on the fixing seat (1) is connected to the inner thread (3b) of the lowermost center transmission rod, and the transmission assembly (4) is installed on the annular groove (3c) of the center transmission rod and fixed with bolts; the lowermost measuring tube (2) is inserted into the outer side of the transmission assembly (4), so that the transmission assembly pulley (4c) is in the measuring tube guide groove (2a), and the measuring tube (2) is pressed downward, so that the annular protrusion (2c) on the inner side wall of the lower end of the measuring tube (2) and the annular protrusion (1c) of the fixing seat (1) form a strong release buckle, and after the assembly is completed, the fixing seat (1) is lowered into the measuring hole; Step 3: Extending and lowering the measuring tube (2) and the central transmission rod (3): The measuring tube (2) and the central transmission rod (3) are both composed of small sections connected from bottom to top; Step 4, installation of the measuring device: the anchor point (9) is installed outside the influence range of the rock mass test stress, the measuring bracket (8) is installed on the anchor point (9), the magnetic base (7) is fixed on the measuring bracket (8), the micrometer (6) is installed on the magnetic base (7), and the probe of the micrometer (6) is in close contact with the end of the central transmission rod (3) of the orifice; Step 5, deformation measurement: the fixed seat (1) is located at the bottom of the measuring hole and connected to the surrounding rock at the bottom of the measuring hole by grouting. The deformation of the surrounding rock at the bottom of the measuring hole drives the fixed seat (1) to move, and the fixed seat (1) transmits the displacement to the lowest center transmission rod (3) connected to it. The transmission component (4) clamps the center transmission rod (3) and slides on the guide groove (2a) of the measuring pipe (2) through the pulley (4c), and transmits the displacement to the next center transmission rod (3), and then transmits it to the hole mouth in turn. The hole mouth displacement is measured by a micrometer (6); The step three specifically includes: Step 201: Connect the inner thread (3b) of the next section of the central transmission rod with the bolt (3a) of the installed central transmission rod, install the transmission assembly (4) on the annular groove (3c) of the next section of the central transmission rod and fix it with bolts, insert the connecting sleeve (5) on the outside of the transmission assembly (4), rotate the connecting sleeve (5) so that the inner thread of its lower port is at the same position as the inner thread of the upper port of the installed measuring tube (2), install the next section of the measuring tube (2), connect the sleeve (5) and the upper and lower section measuring tubes (2) with bolts, and after the assembly is completed, lower the current section measuring tube (2) and the central transmission rod (3) into the measuring hole; Step 202: Repeat step 201 in sequence for multiple times until all the measuring tubes (2) and the center transfer rod (3) are installed. At this time, the base (1a) of the fixing seat is in contact with the surrounding rock of the measuring hole, and the measuring tube (2) and the center transfer rod (3) are exposed at the hole mouth. The end of the center transfer rod (3) at the hole mouth is fixed, and the measuring tube (2) is pulled out of the hole so that the lowermost measuring tube (2) is forcibly released from the buckle of the fixing seat (1). The measuring tube (2) is further pulled out to a certain height and fixed. Grouting is injected into the bottom of the hole so that the fixing seat (1) is fully in contact with the surrounding rock at the bottom of the hole. After the grout is completely fixed, the measuring tube (2) is lowered.

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