Fracture zone multi-point displacement meter deep hole multi-stage grouting and fullness cooperative detection method

Abstract

The present application relates to the technical field of tunnel engineering monitoring, and discloses a broken zone multi-point displacement meter deep hole multi-stage grouting and fullness degree cooperative detection method, which comprises the following steps: S1: drilling, and spraying slurry on the deep hole wall to block the fissure by using a spraying device; S2: installing a multi-point displacement meter at a predetermined position of the deep hole, installing a grouting pipe and a transparent exhaust pipe; S3: grouting into the deep hole from the grouting pipe; S4: inserting a detection lens into the exhaust pipe to detect the grouting state of the deep hole; S5: supplementing the deep hole through the exhaust pipe by using the grouting device; S6: detecting the cavity again, and if there is a cavity, supplementing the grouting again until there is no cavity in the deep hole; S7: testing the pressure of the deep hole from the exhaust pipe by using a pressure testing device; S8: if the pressure changes, supplementing the grouting into the deep hole again through the exhaust pipe; and S9: if the pressure is stable, ending the hole detection and grouting. The present application has the effects of fuller deep hole grouting and more reliable detection.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering monitoring technology, and in particular to a method for the coordinated detection of deep-hole multi-stage grouting and fullness of multi-point displacement gauges in fractured zones. Background Technology

[0002] Intelligent monitoring during tunnel operation is a core means to ensure safety and efficient operation and maintenance. Through a closed-loop system of "perception-early warning-maintenance," the safety and economy of the tunnel throughout its entire life cycle can be significantly improved. As my country's transportation engineering projects continue to be built, tunnels inevitably pass through fractured zones, increasing the displacement of surrounding rock and the stress on the support structure. In particular, the continuous displacement of active fault fractured zones can damage the safety of tunnel lining during operation. Multi-point displacement gauges can be used to monitor and provide early warning of changes in fault displacement around the tunnel in real time.

[0003] Multi-point displacement gauges are installed and grouted in deep boreholes. Their monitoring accuracy is directly affected by the fullness of the grout. Especially in fractured zones, when drilling upwards at an angle, grout leakage, runoff, and volume shrinkage of the cement during solidification are common problems. This makes it more difficult to fill the far-end measuring points of the sensor, resulting in unstable anchoring of the measuring point. Furthermore, close adhesion between the grout and the borehole wall is essential to effectively improve the coordinated deformation capacity of the grout body and the surrounding rock, thus ensuring more accurate measurements by the multi-point displacement gauge. Current grouting processes rely heavily on empirical indicators (such as grouting pressure and return grout volume) to determine fullness, lacking methods for detecting the fullness of deep-hole cement after solidification. Especially for deep boreholes, traditional resistivity methods and acoustic detection methods are easily affected by borehole depth and grout material characteristics. Core sampling and pre-embedded detection sensors are costly and complex.

[0004] Regarding grouting, existing patents for multi-point displacement gauge grouting propose a dual-grouting pipe method with distal and proximal anchor heads. However, in fractured zones, cement grout still diffuses extensively from the borehole wall, failing to guarantee fullness and resulting in waste of grouting pipes and cement materials. Current grouting processes often employ blind high-pressure grouting or repeated grouting throughout the entire borehole, lacking positioning and shrinkage compensation mechanisms. This not only wastes materials but may also damage the initial grout and cause secondary defects. As the borehole extends deeper, the fracturing path of the splitting grouting method becomes invisible, potentially infiltrating adjacent boreholes. High-pressure jet grouting, with its excessive pressure, may damage the sensor and significantly disturb the surrounding rock strata, altering the monitored rock deformation. Therefore, a high-precision, positionable grout fullness detection method and a dynamically controllable grout fullness enhancement method are urgently needed to ensure the long-term reliability of multi-point displacement gauges and address the severe challenges of high-precision monitoring of deep sensors. Summary of the Invention

[0005] The purpose of this invention is to provide a method for the coordinated detection of deep hole multi-stage grouting and fullness in fractured zones using a multi-point displacement gauge, which has the effect of achieving fuller deep hole grouting and more reliable detection.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] A method for coordinating multi-stage grouting and fullness detection in deep holes using multi-point displacement gauges in fractured zones, characterized by the following steps:

[0008] S1: Drill holes according to the pre-designed measuring point depth, and use a grouting equipment to spray grout onto the deep hole wall to seal the cracks in the deep hole wall;

[0009] S2: Install the multi-point displacement gauge at the predetermined position in the deep hole, and install the grouting pipe and transparent vent pipe in the deep hole. Extend the vent pipe into the bottom of the deep hole, and lead the grouting port and the end of the vent pipe out from the opening of the deep hole. Then seal the opening of the deep hole.

[0010] S3: Use grouting equipment to inject grout into the deep hole from the grouting pipe. When the grout flows at a constant speed through the vent pipe, stop grouting and seal the grouting port. The grout in the vent pipe flows out freely and is emptied to ensure that it is not blocked by grout.

[0011] S4: Insert the probe into the exhaust pipe to detect the grouting status of the deep hole. If the probe detects a cavity in the deep hole, proceed to step S5; if the probe detects no cavity in the deep hole, proceed to step S7.

[0012] S5: Remove the probe lens, use the grouting equipment to fill the deep hole with grout through the exhaust pipe. If the grouting pressure rises to the set value, stop the grouting and empty the exhaust pipe.

[0013] S6: After the grout solidifies, perform void detection again. If there are voids, add grout again until there are no voids in the deep hole. If there are no voids in the deep hole, proceed to step S7.

[0014] S7: Use pressure testing equipment to test the pressure in the deep hole through the exhaust pipe and observe the pressure changes;

[0015] S8: If the test pressure changes, the deep hole is slurried again through the exhaust pipe until the pressure stabilizes during the deep hole pressure test.

[0016] S9: If the test pressure is stable, then end the borehole drilling and grouting, and complete the test.

[0017] As a further feature of the present invention, in step S1, the grouting equipment includes a grouting device and a rotating nozzle. The rotating nozzle is disposed at the end of the grout outlet pipe of the grouting device and is used to spray grout onto the wall of the deep hole in 360°.

[0018] As a further feature of the present invention, in step S1, the slurry includes cement slurry and water glass, and the spraying pressure of the slurry is 0.5 MPa.

[0019] As a further feature of the present invention, in step S1, after the first layer of slurry is sprayed, it needs to be sprayed 1-3 times, and after each spraying, it needs to be left to stand for 5-10 minutes.

[0020] As a further provision of the present invention, in step S3, the grouting material includes cement grout with a water-cement ratio of 1:1, and the grouting pressure during grouting is less than or equal to 1.5 MPa; in steps S5 to S9, the grouting material for patching includes cement grout with a water-cement ratio of 1:0.5, and the patching pressure during patching is less than or equal to 1 MPa. In the above steps, an expansion agent is added to the cement grout, and the mass of the expansion agent accounts for 6% of the total mass of cement and expansion agent.

[0021] As a further feature of the present invention, the expanding agent includes calcium sulfoaluminate expanding agents.

[0022] As a further feature of the present invention, the detection lens includes a miniature endoscope consisting of a direct-viewing lens, a side-viewing lens, and an illumination component.

[0023] As a further feature of the present invention, the shotcrete equipment includes a small dual-liquid grouting machine, and the pressure testing equipment includes a manual pressure testing pump.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention provides a deep hole detection method for multi-point displacement gauges. A transparent vent pipe is installed in the deep hole. Through the transparent vent pipe, the deep hole can be probed, grouted, and pressure tested. During probed operation, the probe is inserted through the vent pipe. Because the vent pipe is transparent, the probe can comprehensively probe the deep hole through the vent pipe to detect whether there are voids. If voids are found and grouting is needed, grouting can be done through the vent pipe. After grouting, pressure testing can also be performed through the vent pipe. The vent pipe serves three purposes, making full use of its value, saving costs, and ensuring the quality of the deep hole without damaging the borehole or the multi-point displacement gauge. This method is simple and convenient to operate, low in cost, and easy to promote.

[0026] 2. To address the issues of grout leakage and volume shrinkage during deep-hole grouting in fractured zones, a multi-stage grouting approach combining water glass + cement slurry quick-setting grout spraying, cement + expansion agent grouting, and supplementary grouting is employed for deep-hole multi-point displacement gauges in fractured zones. This approach ensures full grouting at the sensor's distal measuring points and promotes close adhesion between the grout and the borehole wall, effectively improving the coordinated deformation capacity between the grout and the surrounding rock, as well as the accuracy of multi-point displacement measurement. Furthermore, deep-hole grouting is low-cost, safe, precise, practical, and easy to promote.

[0027] 3. The combination of a small dual-liquid grouting machine and a rotary nozzle forms a small shotcrete machine, which can uniformly cover the walls of deep holes in the fracture zone with grout in 360°. The dynamic pressure generated by the rotary jet helps the grout penetrate into the micro-cracks, improving the reinforcement effect on the hole walls in the fracture zone, thus saving materials and reducing time during grouting. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a logic flowchart of this embodiment;

[0030] Figure 2 This is a schematic diagram of the installation and grouting of the deep-hole multi-point displacement gauge at the fracture zone in this embodiment;

[0031] Figure 3 This is a schematic diagram of the first stage of deep-hole jet grouting in this embodiment;

[0032] Figure 4 This is a schematic diagram of the second stage of deep hole grouting and grouting in this embodiment;

[0033] Figure 5 This is a schematic diagram of the deep hole fullness measurement test in the third stage of this embodiment;

[0034] In the diagram, 1. Deep hole, 2. Exhaust pipe, 3. Multi-point displacement gauge, 4. Grouting pipe, 5. Tunnel, 6. Quick-setting grout, 7. Multi-point displacement gauge anchor head, 8. Initial support, 9. Rotary nozzle, 10. Cavity, 11. Sealing cement, 12. Crack, 13. Mixed grout of cement slurry and expansion agent. Detailed Implementation

[0035] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] A method for coordinating deep-hole multi-stage grouting and fullness detection using multi-point displacement gauges in fractured zones (reference) Figures 1 to 3 It includes the following steps,

[0037] S1: Drill deep hole 1 according to the pre-designed measuring point depth, and use a grouting equipment to spray grout onto the hole wall of deep hole 1 to seal the cracks in the hole wall.

[0038] Drilling is performed according to the pre-designed measuring point depth. The drilling depth should be a distance greater than the deepest anchor head of the multi-point displacement meter 3. In this embodiment, the drilling depth should be at least 1 meter greater than the deepest anchor head of the multi-point displacement meter 3. After drilling, the grout outlet pipe of the small dual-liquid grouting machine is connected to the rotating nozzle 9 to form a small shotcrete machine for deep hole 1 shotcreting. This can uniformly cover the hole wall of deep hole 1 in the fracture zone with 360°. The dynamic pressure generated by the rotating shotcrete jet helps the grout penetrate into the micro-cracks. Cement slurry and water glass are added to the dual slurry tanks of the shotcrete machine, respectively. The rotating nozzle 9 is pushed into the bottom of the borehole. The slurry output adjustment button is turned and the grouting pressure gauge is observed. The initial grouting pressure is 0.5 MPa. The water glass + cement slurry quick-setting grout 6 is sprayed onto the borehole wall at a uniform speed of 10 cm / s from the bottom of the borehole to the borehole opening, quickly forming the first layer of barrier zone on the borehole wall and sealing the surface cracks. After the first layer of grouting, it is left to stand for 5-10 minutes, and the borehole wall is sprayed 1-3 times to reduce slurry diffusion during deep hole 1 grouting. In other embodiments, the shotcrete equipment can have other structures, and the quick-setting grout can have other formulations, as long as the same technical effect can be achieved.

[0039] S2: Install the multi-point displacement meter 3 at the predetermined position in the deep hole 1, and install the grouting pipe 4 and the transparent vent pipe 2 in the deep hole 1. Extend the vent pipe 2 into the bottom of the deep hole 1, and lead the grouting port and the end of the vent pipe 2 out from the opening of the deep hole 1. Then seal the opening of the deep hole 1.

[0040] Assemble the multi-point displacement meter 3 according to the pre-designed measuring point depth, and push it into the borehole. The grouting pipe 4 and the vent pipe 2 are led out from the gap between the base of the multi-point displacement meter 3 and the borehole wall. The borehole opening elevation is lower than the bottom of the hole. A 10mm diameter transparent vent pipe 2 is extended into the bottom of the hole, and the grouting pipe 4, made of 25mm diameter galvanized steel pipe, is extended into the hole to at least half its depth. Then, fill the gap between the multi-point displacement meter 3 and the borehole wall at the opening with cement grout and seal it. The sealing length should be 30cm or more.

[0041] In other embodiments, the diameter of the exhaust pipe 2, the diameter and material of the grouting pipe 4, and the sealing length can be similar to the specific numerical range indicated in this embodiment, or can be set to match the diameter of the deep hole, all of which can achieve the same technical effect.

[0042] S3: Grouting is performed from grouting pipe 4 into deep hole 1 using grouting equipment. When grout flows at a constant speed through vent pipe 2, grouting is stopped and the grouting port is blocked. The grout in vent pipe 2 flows out freely and is emptied to ensure that it is not blocked by grout.

[0043] When grouting deep hole 1 at the fracture zone, a low-pressure slow grouting process is adopted. A small dual-liquid grouting machine is used to grout deep hole 1, with a grouting pressure ≤1.5MPa. The material is cement grout with a water-cement ratio of 1:1, in which calcium sulfoaluminate expansive agent is added. Specifically, the expansive agent accounts for 6% of the total mass of cement and expansive agent to compensate for shrinkage, improve the adhesion between the grout and the hole wall, and reduce the risk of voids. The initial filling is indicated by the uniform flow of grout through vent pipe 2. After grouting is completed, the grouting pipe 4 is sealed, and the grout in vent pipe 2 flows out freely and is emptied to ensure that it is not blocked by grout.

[0044] S4: Insert the probe lens into the exhaust pipe 2 to detect the grouting status of the deep hole 1. If the probe lens detects a cavity in the deep hole 1, proceed to step S5; if the probe lens detects no cavity in the deep hole 1, proceed to step S7.

[0045] After the grout solidifies, the transparent vent pipe 2 serves as a detection channel. A miniature endoscope, equipped with direct and side-viewing lenses, a diameter ≤6mm, a high-resolution camera, and illumination, is used to detect any voids 10 in the deep hole 1 grouting process, from the borehole opening to the bottom. The pushing speed of the miniature endoscope must be controlled to prevent it from getting stuck or damaging the vent pipe 2. During detection, suspected void areas should be dynamically observed, photographed from multiple angles, and the void locations recorded.

[0046] To determine if there are voids in deep hole grouting, attention should be paid to areas such as voids at the bottom of the hole, separation of grout from the pipe wall, and honeycomb-like pores. Using a micro-endoscope, if the interface between the hole wall and the vent pipe separates, with a sudden color change and the appearance of a black cavity, a void area at the bottom of the hole can be identified. If annular black gaps are present, with a rough interface and a clear boundary line, it can be considered that the grout has separated from the pipe wall.

[0047] S5: Remove the probe lens, use the grouting equipment to fill the deep hole 1 with grout through the exhaust pipe 2. If the grouting pressure rises to the threshold, stop the grouting and empty the exhaust pipe 2.

[0048] S6: After the grout solidifies, perform void detection again. If there are voids, add grout again until there are no voids in deep hole 1. If there are no voids in deep hole 1, proceed to step S7.

[0049] For deep hole 1 with voids after grouting, vent pipe 2 serves as a grout replenishment channel. A small dual-liquid grouting machine is used with a low-pressure, slow-injection process to inject cement grout into deep hole 1. During grouting, the grout outlet pipe of the small dual-liquid grouting machine is connected to vent pipe 2 via a connector. Cement grout with a water-cement ratio of 1:0.5 is added to both grout tanks, including a mixed grout containing calcium sulfoaluminate-based expanding agent. Specifically, the expanding agent accounts for 6% of the total mass of cement and expanding agent. The grout volume adjustment button is turned and the grouting pressure gauge is observed to ensure that the grouting pressure is ≤1MPa. Grouting should be stopped when the pressure rises from 0 to 1MPa. After replenishment grouting, the hole is left to stand for 6 hours. Vent pipe 2 serves as a detection channel, and a miniature endoscope is used to re-detect the presence of voids in deep hole 1. Grouting continues until deep hole 1 is free of voids. After grouting is completed, the grout in vent pipe 2 flows freely and is emptied, ensuring that it is not blocked by grout.

[0050] S7: Use a pressure testing device to perform a pressure test on the deep hole 1 from the exhaust pipe 2 and observe the pressure change;

[0051] After grouting deep hole 1 to ensure there are no voids, a manual pressure testing pump is used to test the pressure of deep hole 1 through the vent pipe 2, and the pressure changes are observed. During the pressure test, the test pipe of the manual pressure testing pump is connected to the vent pipe 2 through a connector. The water tank of the pressure testing machine is filled with water, and the water enters the vent pipe 2 through the test pipe, and finally flows into deep hole 1 from the bottom of the hole. Carefully observe the changes in the pressure gauge and the water flow rate.

[0052] S8: If the test pressure changes, then fill the deep hole 1 with grout again through the exhaust pipe 2 until the pressure of the deep hole 1 is stable during the pressure test.

[0053] To determine whether the grouting in deep hole 1 is complete, record the changes in pressure and water volume during the pressure test. If the pressure rises and the grouting volume drops sharply, and the pressure gauge remains stable for a period of time after the manual pressure test is stopped, it indicates that the grouting in deep hole 1 is complete.

[0054] If the grouting of deep hole 1 is not full, use a small double-liquid grouting machine to replenish the grout in deep hole 1. Note that the replenishment of grout in this stage is small and in a small area. After the pressure gauge has pressure during grouting, turn down the grout flow adjustment button, grout slowly, and observe the change of grouting pressure gauge to prevent the exhaust pipe 2 from being crushed.

[0055] S9: If the test pressure is stable, then end the borehole drilling and grouting, and complete the test.

[0056] It should be noted that the various specific numbers provided in this embodiment are designed as a preferred embodiment. In other embodiments, the values ​​can be similar to those in this embodiment, as long as they can achieve the same technical effect as this embodiment.

[0057] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for coordinating multi-stage grouting and fullness detection in deep holes using multi-point displacement gauges in fractured zones, characterized by: Includes the following steps, S1: Drill holes according to the pre-designed measuring point depth, and use a grouting equipment to spray grout onto the deep hole wall to seal the cracks in the deep hole wall; S2: Install the multi-point displacement gauge at the predetermined position in the deep hole, and install the grouting pipe and transparent vent pipe in the deep hole. Extend the vent pipe into the bottom of the deep hole, and lead the grouting port and the end of the vent pipe out from the opening of the deep hole. Then seal the opening of the deep hole. S3: Use grouting equipment to inject grout into the deep hole from the grouting pipe. When the grout flows at a constant speed through the vent pipe, stop grouting and seal the grouting port. The grout in the vent pipe flows out freely and is emptied to ensure that it is not blocked by grout. S4: Insert the probe into the exhaust pipe to detect the grouting status of the deep hole. If the probe detects a cavity in the deep hole, proceed to step S5; if the probe detects no cavity in the deep hole, proceed to step S7. S5: Remove the probe lens, use the grouting equipment to fill the deep hole with grout through the exhaust pipe. If the grouting pressure rises to the set value, stop the grouting and empty the exhaust pipe. S6: After the grout solidifies, perform void detection again. If there are voids, add grout again until there are no voids in the deep hole. If there are no voids in the deep hole, proceed to step S7. S7: Use pressure testing equipment to test the pressure in the deep hole through the exhaust pipe and observe the pressure changes; S8: If the test pressure changes, the deep hole is slurried again through the exhaust pipe until the pressure stabilizes during the deep hole pressure test. S9: If the test pressure is stable, then end the borehole drilling and grouting, and complete the test.

2. The method for multi-stage grouting and fullness detection in deep holes using a multi-point displacement gauge in fractured zones according to claim 1, characterized in that: In step S1, the shotcrete equipment includes a grouting device and a rotating nozzle. The rotating nozzle is located at the end of the grout outlet pipe of the grouting device and is used to spray grout onto the wall of the deep hole in 360°.

3. The method for multi-stage grouting and fullness detection in deep holes using a multi-point displacement gauge in fractured zones according to claim 1, characterized in that: In step S1, the slurry comprises cement slurry and water glass, and the spraying pressure of the slurry is 0.5 MPa.

4. The method for multi-stage grouting and fullness detection in deep holes using a multi-point displacement gauge in fractured zones according to claim 1, characterized in that: In step S1, after the first layer of slurry is sprayed, it needs to be sprayed 1-3 times, and after each spraying, it needs to be left to stand for 5-10 minutes.

5. The method for multi-stage grouting and fullness detection in deep holes using a multi-point displacement gauge in fractured zones according to claim 1, characterized in that: In step S3, the grouting material includes cement grout with a water-cement ratio of 1:1, and the grouting pressure during grouting is less than or equal to 1.5 MPa; in steps S5 to S9, the grouting material for patching includes cement grout with a water-cement ratio of 1:0.5, and the patching pressure during patching is less than or equal to 1 MPa. In the above steps, an expansion agent is added to the cement grout, and the mass of the expansion agent accounts for 6% of the total mass of cement and expansion agent.

6. The method for multi-stage grouting and fullness detection in deep holes using a multi-point displacement gauge in a fractured zone according to claim 5, characterized in that: The expanding agent includes calcium sulfoaluminate expanding agents.

7. The method for multi-stage grouting and fullness detection in deep holes using a multi-point displacement gauge in fractured zones according to claim 1, characterized in that: The detection lens is a miniature endoscope consisting of a direct-viewing lens, a side-viewing lens, and an illumination component.

8. The method for coordinated detection of deep hole multi-stage grouting and fullness in fractured zones using multi-point displacement gauges according to claim 1, characterized in that: The grouting equipment includes a small dual-liquid grouting machine, and the pressure testing equipment includes a manual pressure testing pump.

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