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

Abstract

The invention relates to the technical field of tunnel engineering monitoring, and discloses a fracture zone multi-point displacement meter deep hole multi-stage grouting and fullness cooperative detection method, which comprises the following steps: S1, drilling, and spraying slurry to the hole wall of a deep hole by utilizing slurry spraying equipment to plug cracks; s2, a multi-point displacement meter is installed at the preset position of the deep hole, and a grouting pipe and a transparent exhaust pipe are installed; s3, grouting is conducted in the deep hole from the grouting pipe; s4, a detection lens extends into the deep hole from the exhaust pipe, and the grouting state of the deep hole is detected; s5, grouting equipment is used for supplementing grout to the deep hole through the exhaust pipe; s6, hole detection is conducted again, and if holes exist, grout supplementing is conducted again till no hole exists in the deep hole; s7, performing pressure test on the deep hole from the exhaust pipe by using pressure test equipment; s8, if the pressure of the test pressure is changed, the deep hole is subjected to slurry supplementation again through the exhaust pipe; and S9, if the test pressure is stable, hole exploration and grouting are ended. The device has the advantages that deep hole grouting is fuller, and detection is more reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering monitoring, and in particular to a method for coordinated detection of deep hole multi-stage grouting and fullness of a broken zone using a multi-point displacement meter. Background Art

[0002] Implementing intelligent monitoring during tunnel operation is a core means of ensuring safe and efficient operation and maintenance. Through a closed-loop "perception-warning-maintenance" system, the safety and economic efficiency of tunnels throughout their lifecycle can be significantly improved. With the continuous construction of transportation projects in my country, tunnels inevitably pass through fracture zones, increasing the displacement of surrounding rock and the stress on support structures. In particular, the continued movement of active fault fracture zones can damage the safety of tunnel linings during operation. Multi-point displacement meters can be used to monitor and warn of changing fault displacement characteristics around tunnels in real time.

[0003] Multi-point displacement meters are installed and grouted through deep boreholes. Their monitoring accuracy is directly affected by the grouting fullness. This is especially true when drilling obliquely upward in fractured zones, where grouting is prone to leakage, slurry leakage, and cement solidification volume shrinkage. This makes it more difficult to fill the sensor's distal measuring point, resulting in a loose anchoring of the measuring point anchor. Furthermore, close contact between the grouting cement and the borehole wall effectively enhances the coordinated deformation capacity of the grouting body and the surrounding rock, leading to more accurate multi-point displacement meter measurements. Current grouting processes rely heavily on empirical indicators (such as grouting pressure and return grouting volume) to determine fullness, lacking a means of detecting the fullness of deep-hole cement after solidification. For deep boreholes in particular, traditional resistivity and acoustic detection methods are susceptible to interference from hole depth and grouting material properties. Core sampling and pre-embedded detection sensor methods are costly and complex.

[0004] In terms of grouting, a patent for grouting multi-point displacement meters has proposed a dual grouting pipe method with distal and proximal anchor heads. However, this method will still cause the cement slurry to diffuse in large quantities from the hole wall to the surrounding areas in the fracture zone, and the fullness cannot be guaranteed, resulting in waste of grouting pipes and cement materials. Existing grouting processes mostly use blind high-pressure grouting or repeated grouting of the entire hole section, lacking positioning and shrinkage compensation mechanisms. This not only causes material waste, but may also easily damage the primary grouting body and cause secondary defects. As the borehole extends deeper, the splitting path of the splitting grouting method is invisible and may penetrate into adjacent boreholes. The high pressure of the high-pressure rotary jet grouting method may damage the sensor and cause significant disturbance to the properties of the rock formations near the sensor, resulting in changes in the deformation of the monitored rock formations. Therefore, there is an urgent need for a high-precision, positionable grouting fullness detection method and a dynamically controllable grouting fullness improvement method to ensure the long-term reliability of the multi-point displacement meter and to meet the severe challenges of high-precision monitoring of deep sensors. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for collaboratively detecting multi-stage grouting and fullness of deep holes using a multi-point displacement meter in a broken zone, which has the effect of making deep hole grouting fuller and detection more reliable.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: The method for collaborative detection of deep hole multi-stage grouting and fullness of a broken zone using a multi-point displacement meter is characterized by comprising the following steps: S1: Drill holes according to the pre-designed measuring point depth, and use the grouting equipment to spray slurry on the deep hole wall to seal the cracks in the deep hole wall; S2: Install the multi-point displacement meter at the predetermined position of the deep hole, and install the grouting pipe and the transparent exhaust pipe in the deep hole. Extend the exhaust pipe into the bottom of the deep hole, and lead the grouting port and the exhaust pipe end out from the deep hole opening. Then, seal the deep hole opening. S3: Use grouting equipment to inject grouting into the deep hole from the grouting pipe. When the exhaust pipe is flowing with slurry at a uniform speed, stop grouting and seal the grouting port. The slurry in the exhaust pipe can flow out freely and be emptied to ensure that it is not blocked by the slurry. S4: Insert a detection lens through the exhaust pipe to detect the grouting status of the deep hole. If the detection lens detects a cavity in the deep hole, proceed to step S5; if the detection lens detects no cavity in the deep hole, proceed to step S7; S5: Remove the detection lens and use the grouting equipment to fill the deep hole through the exhaust pipe. If the grouting pressure rises to the set value, stop filling and empty the exhaust pipe. S6: After the slurry solidifies, perform cavity detection again. If there are cavities, perform grouting again until there are no cavities in the deep hole. If there are no cavities in the deep hole, proceed to step S7; S7: Use pressure test equipment to conduct pressure test on the deep hole from the exhaust pipe and observe the pressure changes; S8: If the test pressure changes, the deep hole is grouted again through the exhaust pipe until the pressure is stable during the deep hole pressure test; S9: If the test pressure is stable, the drilling and grouting are terminated and the test is completed.

[0007] As a further configuration of the present invention, in step S1, the spraying equipment includes a grouting equipment and a rotary nozzle, the rotary nozzle is arranged at the end of the slurry outlet pipe of the grouting equipment, and the rotary nozzle is used to perform 360° spraying on the deep hole wall.

[0008] As a further configuration 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.

[0009] As a further configuration of the present invention, in step S1, after the first layer of slurry is sprayed, it is necessary to spray it again 1-3 times, and it is necessary to stand for 5-10 minutes after each spraying.

[0010] As a further configuration of the present invention, in step S3, the grouting slurry includes cement slurry 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 slurry during grouting includes cement slurry with a water-cement ratio of 1:0.5, and the grouting pressure during grouting is less than or equal to 1 MPa. In the above steps, an expansion agent is added to the cement slurry, and the mass of the expansion agent accounts for 6% of the total mass of the cement and the expansion agent.

[0011] As a further configuration of the present invention, the expansion agent includes a calcium sulfoaluminate expansion agent.

[0012] As a further configuration of the present invention, the detection lens includes a micro endoscope consisting of a direct-view lens, a side-view lens and an illumination component.

[0013] As a further configuration of the present invention, the spraying equipment includes a small dual-liquid grouting machine, and the pressure testing equipment includes a manual pressure testing pump.

[0014] The beneficial effects of the present invention are: 1. The present invention provides a deep hole detection method for a multi-point displacement meter. A transparent exhaust pipe is arranged in the deep hole. Through the transparent exhaust pipe, the deep hole can be detected, grouting and pressure tested. During detection, the detection probe is inserted through the exhaust pipe. Since the exhaust pipe is transparent, the probe can fully detect the deep hole through the exhaust pipe to detect whether there are cavities in the deep hole. When there are cavities that need grouting, grouting can be performed through the exhaust pipe. After grouting is completed, pressure testing can also be performed through the exhaust pipe. The exhaust pipe has three uses, making full use of its value and saving costs. At the same time, it can also ensure the quality of the deep hole without damaging the drilled hole and the multi-point displacement meter. This method is simple and convenient to operate, low in cost, and easy to promote.

[0015] 2. To address the issues of grout leakage and volume shrinkage of cement solidification during deep-hole grouting in fractured zones, multi-point displacement meter deep-hole grouting in fractured zones employs a multi-stage grouting method that combines water glass and cement slurry with rapid-setting slurry spraying, cement and expansion agent grouting, and grouting. This ensures that the grouting at the sensor's distal measuring point is fully grouted and promotes close contact between the grouting and the borehole wall, effectively improving the coordinated deformation capacity of the grouting body and the surrounding rock, and the measurement accuracy of the multi-point displacement meter. Deep-hole grouting is also low-cost, safe, accurate, highly practical, and easy to promote.

[0016] 3. A small double-liquid grouting machine is combined with a rotary nozzle to form a small shotcrete machine, which can spray 360° evenly on the deep hole wall in the broken zone. The dynamic pressure generated by the rotary spraying helps the slurry penetrate into the micro-cracks and enhance the reinforcement effect of the hole wall in the broken zone, so as to save materials and reduce time during grouting. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a logic flow diagram of this embodiment; Figure 2 This is a schematic diagram of the installation and grouting of a deep hole multi-point displacement meter in the broken zone of this embodiment; Figure 3 This is a schematic diagram of deep hole spraying in the first stage of this embodiment; Figure 4 Schematic diagram of deep hole grouting and grouting in the second stage of this embodiment; Figure 5 This is a schematic diagram of deep hole fullness measurement in the third stage of this embodiment; In the figure, 1. deep hole, 2. exhaust pipe, 3. multi-point displacement meter, 4. grouting pipe, 5. tunnel, 6. quick-setting slurry, 7. multi-point displacement meter anchor head, 8. initial support, 9. rotary nozzle, 10. cavity, 11. sealing cement, 12. crack, 13. mixed slurry of cement slurry and expansion agent. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention will be described clearly and completely below with reference to specific embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0020] Broken zone multi-point displacement meter deep hole multi-stage grouting and fullness collaborative detection method, reference Figures 1 to 3 , including the following steps, S1: Drill deep hole 1 according to the pre-designed measuring point depth, and use the grouting equipment to spray slurry on the wall of deep hole 1 to seal the cracks in the wall of the deep hole; Drilling is performed according to the pre-designed measuring point depth. The drilling depth should extend some distance beyond the deepest anchor of the multi-point displacement meter 3. In this embodiment, the drilling depth should be at least one meter beyond the deepest anchor of the multi-point displacement meter 3. After drilling, the slurry outlet pipe of the small dual-liquid grouting machine is connected to the rotary nozzle 9, forming a small shotcrete machine for spraying deep hole 1. This can achieve 360-degree uniform coverage of the deep hole 1 wall in the fracture zone. The dynamic pressure generated by the rotary spraying helps the slurry penetrate into micro-cracks. Add cement slurry and water glass to the double slurry barrels of the spraying machine respectively, push the rotary nozzle 9 into the bottom of the borehole, turn the slurry output adjustment button and observe the grouting pressure gauge. The first layer of spraying pressure is 0.5MPa. Spray water glass + cement slurry quick-setting slurry 6 on the hole wall at a uniform speed of 10cm / s from the bottom of the borehole to the hole mouth, quickly forming a first layer of barrier zone on the hole wall and sealing the surface cracks. After the first layer of spraying, let it stand for 5-10 minutes, and spray the hole wall 1-3 times to reduce the slurry diffusion during grouting of the deep hole 1. In other embodiments, the spraying equipment can be of other structures, and the quick-setting slurry can be of other formulas, as long as the same technical effect can be achieved.

[0021] S2: Install the multi-point displacement meter 3 at the predetermined position of the deep hole 1, and install the grouting pipe 4 and the transparent exhaust pipe 2 in the deep hole 1, extend the exhaust pipe 2 into the bottom of the deep hole 1, and lead the grouting port and the end of the exhaust pipe 2 out from the opening of the deep hole 1, and then seal the opening of the deep hole 1; Assemble the multi-point displacement meter 3 according to the pre-designed measurement point depth and push it into the borehole. The grouting pipe 4 and exhaust pipe 2 are routed through the gap between the base of the multi-point displacement meter 3 and the borehole wall. With the borehole opening at a lower elevation than the bottom, extend the 10mm diameter transparent exhaust pipe 2 into the bottom of the hole. The grouting pipe 4, a 25mm diameter galvanized steel pipe, is extended to at least half the hole depth. Then, fill the gap between the multi-point displacement meter 3 and the hole wall at the opening with cement slurry and seal it. The sealing length should be at least 30cm.

[0022] 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 numbers within the specific numerical range specified in this embodiment, or can be set to match the deep hole diameter, so as to achieve the same technical effect.

[0023] S3: Grouting is performed from the grouting pipe 4 into the deep hole 1 using a grouting device. When the exhaust pipe 2 is flowing at a uniform speed, the grouting is stopped and the grouting port is blocked. The slurry in the exhaust pipe 2 flows out freely and is emptied to ensure that it is not blocked by the slurry. Grouting of Deep Hole 1 in the fracture zone was performed using a low-pressure slow injection process. A small dual-liquid grouting machine was used, with a grouting pressure of ≤1.5MPa. The grouting material was a cement slurry with a water-cement ratio of 1:1, to which a calcium sulfoaluminate expansive agent was added. Specifically, the expansive agent accounted for 6% of the total mass of the cement and expansive agent to compensate for shrinkage, improve the adhesion of the grouting body to the hole wall, and reduce the risk of voiding. Initial filling was indicated by a uniform flow of slurry from exhaust pipe 2. After grouting was completed, grouting pipe 4 was sealed, allowing the slurry to flow freely out of exhaust pipe 2 and drain, ensuring that it was not blocked by slurry.

[0024] S4: Insert a detection lens from the exhaust pipe 2 to detect the grouting status of the deep hole 1. If the detection lens detects a cavity in the deep hole 1, proceed to step S5; if the detection lens detects no cavity in the deep hole 1, proceed to step S7; After the slurry solidifies, the transparent exhaust pipe 2 serves as a detection channel. A micro-endoscope with direct-view and side-view lenses, a diameter ≤6 mm, and a high-resolution camera and lighting is used to detect the presence of cavities 10 during deep hole grouting from the hole mouth to the bottom. The micro-endoscope's push speed must be controlled to prevent it from getting stuck or damaging the exhaust pipe 2. During detection, the suspected cavity area must be dynamically observed, photographed from multiple angles, and the cavity location recorded.

[0025] To determine whether deep hole grouting has voids, pay attention to areas such as bottom hole voids, separation between the slurry and the pipe wall, and honeycomb-like holes. Using a micro-endoscope, if the interface between the hole wall and the exhaust pipe is separated, with a sudden color change and the appearance of a black cavity, the presence of a bottom hole void can be determined. If the interface is annular black gaps, a rough interface, and a clear boundary line, the slurry can be considered to be separated from the pipe wall.

[0026] S5: Remove the detection lens and use the grouting equipment to grout the deep hole 1 through the exhaust pipe 2. If the grouting pressure rises to a threshold, stop grouting and empty the exhaust pipe 2. S6: After the slurry solidifies, perform cavity detection again. If there is a cavity, perform grouting again until there is no cavity in the deep hole 1. If there is no cavity in the deep hole 1, proceed to step S7; For Deep Hole 1 that has voids after grouting, exhaust pipe 2 serves as a grouting channel. A small dual-liquid grouting machine is used to inject cement slurry into Deep Hole 1 using a low-pressure slow injection process. During grouting, the grouting pipe of the small dual-liquid grouting machine is connected to exhaust pipe 2 via a connector. Cement slurry with a water-cement ratio of 1:0.5 and a calcium sulfoaluminate expansive agent is added to both slurry barrels. Specifically, the expansive agent accounts for 6% of the total mass of the cement and expansive agent. The grouting volume adjustment knob is turned and the grouting pressure gauge is monitored to ensure that the grouting pressure is ≤1 MPa. Grouting should be stopped when the pressure continuously rises from 0 to 1 MPa. After the grouting is completed, the grouting in Deep Hole 1 is allowed to stand for 6 hours. Exhaust pipe 2 is then used as a detection channel. A microendoscope is used to detect voids in Deep Hole 1 again. Grouting is continued until there are no voids in Deep Hole 1. After grouting is completed, the slurry is allowed to flow freely out of exhaust pipe 2 and drain to ensure it is not blocked by slurry.

[0027] S7: Use pressure testing equipment to perform pressure testing on the deep hole 1 from the exhaust pipe 2 to observe the pressure change; After grouting deep hole 1 and eliminating voids, use a manual pressure test pump to conduct a water pressure test on deep hole 1 through exhaust pipe 2 and observe the pressure changes. During the pressure test, the manual pressure test pump pressure test pipe is connected to exhaust pipe 2 via a connector. The pressure test machine water tank is filled with water. Water enters exhaust pipe 2 through the pressure test pipe and finally flows into deep hole 1 from the bottom of the hole. Pay attention to the changes in the pressure test pressure gauge and water flow rate.

[0028] S8: If the test pressure changes, grouting is performed again on the deep hole 1 through the exhaust pipe 2 until the pressure of the deep hole 1 is stable during the pressure test; To determine whether the grouting in deep hole 1 is full, record the changes in pressure and water injection volume during the pressure test. If the pressure rises and the grouting volume drops sharply, and the pressure test pressure gauge remains stable for a period of time after stopping the manual pressure test, it indicates that the grouting in deep hole 1 is full.

[0029] If the deep hole 1 is not full after grouting, use a small double-liquid grouting machine to grout the deep hole 1. Note that the grouting at this stage is small in quantity and small in range. When grouting, after the pressure gauge has pressure, turn down the slurry output adjustment button, grout slowly, and observe the changes in the grouting pressure gauge to prevent the exhaust pipe 2 from being compressed and burst.

[0030] S9: If the test pressure is stable, the drilling and grouting are terminated and the test is completed.

[0031] It should be noted that the various determined numbers provided in this embodiment are designed as a preferred embodiment. In other embodiments, they may be values ​​similar to those of this embodiment as long as they can achieve the same technical effects as this embodiment.

[0032] It will be easily understood by those skilled in the art 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 in the scope of protection of the present invention.

Claims

1. A method for collaboratively detecting deep hole multi-stage grouting and fullness in a fractured zone using multi-point displacement meters, characterized by: The following steps are included: S1: Drill holes according to the pre-designed measuring point depth, and use the grouting equipment to spray slurry on the deep hole wall to seal the cracks in the deep hole wall; S2: Install the multi-point displacement meter at the predetermined position of the deep hole, and install the grouting pipe and the transparent exhaust pipe in the deep hole. Extend the exhaust pipe into the bottom of the deep hole, and lead the grouting port and the exhaust pipe end out from the deep hole opening. Then, seal the deep hole opening. S3: Use grouting equipment to inject grouting into the deep hole from the grouting pipe. When the exhaust pipe is flowing with slurry at a uniform speed, stop grouting and seal the grouting port. The slurry in the exhaust pipe can flow out freely and be emptied to ensure that it is not blocked by the slurry. S4: Insert a detection lens through the exhaust pipe to detect the grouting status of the deep hole. If the detection lens detects a cavity in the deep hole, proceed to step S5; if the detection lens detects no cavity in the deep hole, proceed to step S7; S5: Remove the detection lens and use the grouting equipment to fill the deep hole through the exhaust pipe. If the grouting pressure rises to the set value, stop filling and empty the exhaust pipe. S6: After the slurry solidifies, perform cavity detection again. If there are cavities, perform grouting again until there are no cavities in the deep hole. If there are no cavities in the deep hole, proceed to step S7; S7: Use pressure test equipment to conduct pressure test on the deep hole from the exhaust pipe and observe the pressure changes; S8: If the test pressure changes, the deep hole is grouted again through the exhaust pipe until the pressure is stable during the deep hole pressure test; S9: If the test pressure is stable, the drilling and grouting are terminated and the test is completed.

2. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 1 is characterized by: In step S1, the grouting equipment includes a grouting equipment and a rotary nozzle. The rotary nozzle is arranged at the end of the slurry outlet pipe of the grouting equipment, and the rotary nozzle is used to perform 360° grouting on the wall of the deep hole.

3. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 1 is characterized by: In step S1, the slurry includes cement slurry and water glass, and the spraying pressure of the slurry is 0.5 MPa.

4. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 1 is characterized by: In step S1, after the first layer of slurry is sprayed, it needs to be sprayed again 1-3 times, and it needs to be left to stand for 5-10 minutes after each spraying.

5. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 1 is characterized by: In step S3, the grouting slurry includes cement slurry 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 slurry during grouting includes cement slurry with a water-cement ratio of 1:0.5, and the grouting pressure during grouting is less than or equal to 1 MPa. In the above steps, an expansive agent is added to the cement slurry, and the mass of the expansive agent accounts for 6% of the total mass of the cement and the expansive agent.

6. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 5 is characterized by: The expansion agent includes a calcium sulfoaluminate expansion agent.

7. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 1 is characterized by: The detection lens comprises a micro endoscope consisting of a direct-view lens, a side-view lens and a lighting component.

8. The method for collaboratively detecting deep hole multi-stage grouting and fullness of a fractured zone using a multi-point displacement meter according to claim 1 is characterized by: The grouting equipment includes a small double-liquid grouting machine, and the pressure testing equipment includes a manual pressure testing pump.

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