A static pressure coring device and method for grouting reinforcement of tunnel faces in altered rock masses.

Abstract

This invention provides a grouting-reinforced static pressure coring device and method for tunnel faces in altered rock masses. The grouting-reinforced static pressure coring device includes a reaction frame, a hydraulic drive system, a coring device, and external equipment. The hydraulic drive system is mounted on the reaction frame and connected to the coring device. The hydraulic drive system includes a main hydraulic cylinder and a secondary hydraulic cylinder. The coring device includes a ring cutter and a grout injector. The grout injector is located outside the ring cutter and connected to the external equipment. The ring cutter is connected to the main telescopic rod of the main hydraulic cylinder, and the grout injector is connected to the secondary telescopic rod of the secondary hydraulic cylinder. The grout injector has grouting holes. This invention combines "grouting reinforcement" with "static pressure injection," completely eliminating the impact disturbance caused by traditional drilling methods and effectively solving the technical problems of low coring rate and easy borehole wall collapse in altered rock masses.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering geological exploration and tunnel construction safety technology, specifically relating to a grouting reinforcement static pressure coring device and method for altered rock tunnel faces. Background Technology

[0002] In underground engineering, direct core sampling of the rock mass at the tunnel face for subsequent laboratory physical and mechanical testing is the most direct and reliable technical means to obtain key parameters such as rock mass strength and deformation modulus. It plays an irreplaceable role in evaluating surrounding rock stability, dynamically optimizing support schemes, and providing early warning of geological hazards. Currently, rock mass sampling at the tunnel face mainly relies on two techniques: one is impact drilling using handheld rock drills, pneumatic picks, or excavator teeth; the other is rotary drilling using geological drilling rigs equipped with diamond or alloy drill bits. These techniques, after long-term development, have become industry standard processes and have shown good results in intact and medium-hard rock formations.

[0003] However, when tunnels traverse weak and fractured geological sections such as altered rock, the aforementioned traditional coring techniques have certain limitations, mainly in three aspects. First, traditional impact and rotary drilling methods generate severe vibrations during construction, causing further disintegration and collapse of the altered rock mass around the core hole, ultimately resulting in the inability to obtain a complete and continuous columnar core. Second, after coring at the fractured face, traditional methods create a cavity with loosened surrounding rock mass. This cavity disrupts the local stress balance at the face, easily inducing spalling, exfoliation, or even large-scale roof collapse, seriously threatening the safety of personnel and equipment on site. Finally, traditional methods are prone to borehole collapse and drill bit jamming, requiring construction personnel to spend a significant amount of time changing coring points, slowing down the coring process and severely extending the project cycle. Summary of the Invention

[0004] The first objective of this invention is to provide a static pressure coring device for grouting reinforcement of tunnel faces in altered rock masses, addressing the aforementioned problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A grouting reinforcement static pressure coring device for the tunnel face of altered rock mass includes a reaction frame, a hydraulic drive system, a coring device, and external equipment. The hydraulic drive system is mounted on the reaction frame and connected to the coring device. The hydraulic drive system includes a main hydraulic cylinder and a secondary hydraulic cylinder. The coring device includes a ring cutter and a grout injector. The grout injector is located outside the ring cutter and connected to the external equipment. The ring cutter is connected to the main telescopic rod of the main hydraulic cylinder, and the grout injector is connected to the secondary telescopic rod of the secondary hydraulic cylinder. The grout injector is provided with grouting holes.

[0007] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0008] As a preferred technical solution of the present invention: the reaction frame is a portal steel structure frame, including a base plate, support columns, a top crossbeam, auxiliary beams, diagonal supports and an adjustment plate. Two vertical support columns are vertically fixed on the base plate of the reaction frame. The diagonal supports and auxiliary beams are used to reinforce the support columns. The top crossbeam is used to connect and fix the two support columns. The hydraulic drive system is fixed on the adjustment plate.

[0009] As a preferred embodiment of the present invention: the adjusting plate is fixed in the adjusting hole of the support column by bolts, and the height of the adjusting plate is adjusted according to the core extraction height.

[0010] As a preferred technical solution of the present invention: the ring cutter and the grouting device are made of high-strength steel, the outer end face of the grouting device has a sharp wedge-shaped cutting edge, and the outer end face of the grouting device is closed by a steel sheet.

[0011] As a preferred technical solution of the present invention: the external device is a grouting pump, the grouting pump is filled with cement-based grout, and the grouting pump is connected to the grouting device through a high-pressure grouting hose.

[0012] As a preferred embodiment of the present invention, a propulsion plate is provided between the main and auxiliary hydraulic cylinders and the main and auxiliary telescopic rods.

[0013] As a preferred embodiment of the present invention, guide rods are provided between the four corners of the push plate and the adjustment plate.

[0014] As a preferred embodiment of the present invention, a transfer device is provided between the auxiliary telescopic rod and the grouting device.

[0015] The second objective of this invention is to provide a static pressure coring method for grouting reinforcement of tunnel faces in altered rock masses.

[0016] Therefore, the above-mentioned objective of the present invention is achieved through the following technical solution:

[0017] A static pressure coring method for grouting reinforcement of tunnel faces in altered rock masses includes the following steps:

[0018] S1. Install the core-taking device on the working face and align the ring cutter of the device with the predetermined core-taking point;

[0019] S2. Start the main hydraulic cylinder and drive the ring cutter with hydrostatic pressure to press the ring cutter into the rock mass to the designed depth;

[0020] S3. Keep the ring cutter in a fixed position, start the auxiliary hydraulic cylinder, and drive the annular grouting device to press into the rock mass along the outer wall of the ring cutter until the cutting edge of the right end face of the grouting device reaches the predetermined position.

[0021] S4. Close the right end face of the grouting device, and then inject the reinforcing grout into the grouting device. The grout will evenly penetrate and diffuse into the surrounding rock mass through the grouting holes distributed on the surface of the grouting device to reinforce the rock mass around the ring cutter.

[0022] S5. After the grout has initially solidified, retrieve the grouting device and ring cutter, and remove the original rock core sample from the ring cutter.

[0023] This invention provides a grouting-reinforced static pressure coring device and method for tunnel faces in altered rock masses, offering the following advantages: The invention improves the integrity of the obtained core samples: Through the "grouting-reinforced static pressure coring" process, a consolidation zone with higher strength than the original fractured rock mass is first formed in the core sampling area, fundamentally eliminating the common problem of borehole collapse during coring. The vibration-free and impact-free static pressure method effectively avoids rock mass disturbance, thereby obtaining complete core samples and providing a reliable data foundation for laboratory experiments. The invention enhances the safety and efficiency of the operation: Since the coring operation is carried out within the stabilized rock mass after grouting reinforcement and using a static pressure method, the risk of face instability induced by drilling vibration is avoided. Simultaneously, the method of this invention avoids the cumbersome process of dealing with borehole collapse and repeated borehole sweeping in traditional methods, effectively improving the overall efficiency of sampling work. Attached Figure Description

[0024] Figure 1 This is an overall schematic diagram of the static pressure coring device for grouting reinforcement of altered rock tunnel face provided by the present invention.

[0025] Figure 2 This is a schematic diagram of the coring process.

[0026] Figure 3 This is a schematic diagram of the reaction frame height adjustment.

[0027] Figure 4 A front view of the arrangement of the grouting device and the ring cutter.

[0028] Figure 5 This is a side view of the grouting device when the right end face is not closed.

[0029] Figure 6 This is a front view of the grouting device after the right end face is closed.

[0030] Figure 7 This is a schematic diagram of the static pressure rotation process of the grouting machine.

[0031] In the diagram: 1-Top crossbeam; 2-Support column; 3-Diagonal support; 4-Auxiliary beam; 5-Base plate; 6-High-strength bolt; 7-Adjusting hole; 8-Adjusting plate; 9-Grouting pump; 10-High-pressure grouting hose; 11-Guide rod; 12-Secondary hydraulic cylinder; 13-Main hydraulic cylinder; 14-Propeller plate; 15-Steel sheet; 16-Ring cutter; 17-Cutting edge; 18-Grouting device; 19-Grouting hole; 20-Secondary telescopic rod; 21-Main telescopic rod; 22-Transfer device. Detailed Implementation

[0032] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0033] A static pressure coring device for grouting reinforcement of altered rock tunnel faces includes a reaction frame, a hydraulic drive system, a coring device, and external equipment. The hydraulic drive system is mounted on the reaction frame and connected to the coring device. The hydraulic drive system includes a main hydraulic cylinder and an auxiliary hydraulic cylinder. The coring device includes a ring cutter and a grout injector. The grout injector is located outside the ring cutter and connected to the external equipment. The ring cutter is connected to the main telescopic rod of the main hydraulic cylinder, and the grout injector is connected to the auxiliary telescopic rod of the auxiliary hydraulic cylinder. The grout injector is provided with grouting holes.

[0034] After the auxiliary hydraulic cylinder is started, it will drive the auxiliary telescopic rod to extend. There is a transfer device between the auxiliary telescopic rod and the grouting device. The transfer device can be rotated by the built-in motor, thereby driving the grouting device to rotate during the static pressure process, which facilitates the removal of broken rock and soil outside the ring cutter.

[0035] The reaction frame is a portal steel structure used to provide supporting reaction force for the device. It includes a base plate, support columns, a top crossbeam, auxiliary beams, diagonal supports, and an adjusting plate. Two vertical support columns are fixed vertically to the base plate of the reaction frame. The diagonal supports and auxiliary beams are used to reinforce the support columns. The top crossbeam is used to connect and fix the two support columns. The hydraulic drive system is fixed on the adjusting plate. The external equipment is a grouting pump, which is filled with cement-based grout. The grouting pump is connected to the grouting device through a high-pressure grouting hose.

[0036] The adjusting plate is fixed to six equally spaced adjusting holes in the support column using high-strength bolts. The height of the adjusting plate is adjusted according to the core sampling height. Corresponding fixing holes are provided on the adjusting plate. Before sampling, the adjusting holes and fixing holes are precisely aligned, and a locating pin is inserted for initial positioning. After confirming the hole alignment, the locating pin is removed, and high-strength bolts are inserted and tightened twice in a diagonal sequence to a torque of 300 N·m. This achieves height adjustment of the hydraulic drive system to adapt to different working face conditions.

[0037] The ring cutter and grouting device are made of high-strength steel. They are arranged in a concentric circular shape, with the ring cutter positioned inside the grouting device. Both can extend and retract independently via a hydraulic drive. When the right end face of the grouting device is not closed, the protruding length of the right end face of the ring cutter is slightly less than that of the right end face of the grouting device, facilitating the movement of the built-in steel plate on the right end face of the grouting device to achieve closure. The right end face of the grouting device has a sharp wedge-shaped cutting edge, facilitating the pressing of the grouting device into the rock mass. The inner wall of the ring cutter 16 is highly polished and coated with an epoxy resin anti-stick coating, greatly reducing the adhesion between the rock sample and the inner wall, ensuring the sample can be removed intact.

[0038] The right end face of the grouting device is equipped with a closing mechanism, which consists of six rotatable steel plates. The steel plates can be rotated 90 degrees by an internal cam mechanism, thereby mechanically closing the right end of the grouting device and preventing grout from leaking into the ring cutter.

[0039] The external equipment is a grouting pump, which is filled with cement-based grout. The grouting pump is connected to the grouting device through a high-pressure grouting hose. After the grouting pump is turned on, the cement-based grout is slowly pumped into the grouting device at an initial pressure of 1~2 MPa. After the air is expelled, the pressure is gradually increased to 5~6 MPa and maintained for 10 minutes, so that the grout can fully penetrate into the internal fissures of the rock mass through the grouting hole. Then the valve is closed, and the grout is allowed to solidify and be cured for 45 minutes.

[0040] A propulsion plate is provided between the main and auxiliary hydraulic cylinders and the main and auxiliary telescopic rods. Guide rods are provided between the four corners of the propulsion plate and the adjustment plate. The guide rods are fixed to the propulsion plate by oil-free lubricated copper sleeves and are symmetrically arranged around the hydraulic drive system to ensure the stability of the static pressure process of the ring cutter and the grouting device and prevent deviation.

[0041] like Figure 1As shown, the gantry reaction frame of the device is welded from Q345B high-strength steel. Its top crossbeam 1 and two heavy vertical support columns 2 form the main frame, which is reinforced by auxiliary beams 4 and diagonal supports 3, thus providing sufficient reaction force to the hydraulic drive system. The bottom of the support columns 2 is welded to the base plate 5 with anti-slip teeth to effectively prevent the device from slipping during operation. The hydraulic drive system is installed on the aforementioned reaction frame via an adjusting plate 8 and consists of a main hydraulic cylinder 13 and an auxiliary hydraulic cylinder 12, with a maximum output thrust of 5 t. The main hydraulic cylinder 13 is responsible for driving the ring cutter 16 to press into the rock mass, and the auxiliary hydraulic cylinder 12 is responsible for driving the grout injector 18 to press into the rock mass. To ensure that the ring cutter 16 and the grout injector 18 press into the rock mass in a straight line, four guide rods 11 are fixed to the propulsion plate 14 with oil-free lubricated copper sleeves. The grouting device 18 is located outside the ring cutter 16, and grouting holes 19 are distributed around the grouting device 18. Cement-based grout is pumped into the grouting device 18 by the grouting pump 9 through the high-pressure hose 10. The working principle of this device is based on the core concept of "pre-positioning, peripheral reinforcement, and non-destructive extraction". First, the ring cutter is pressed into the rock mass using static pressure to form an original sample. Then, it is pressed into the grouting device, and a hard "reinforced zone" is formed around the sample through high-pressure grouting. Finally, under the premise of ensuring the absolute stability of the borehole wall, the ring cutter containing the intact sample is safely removed.

[0042] like Figure 2 As shown, the coring process can be divided into four stages.

[0043] ① Ring cutter static pressure stage: The operator needs to slowly push the reversing valve of the main hydraulic cylinder 13 so that its telescopic rod extends smoothly at a speed of 2~5cm / min, and statically press the ring cutter 16 into the altered rock mass to the designed depth. At this time, the auxiliary hydraulic cylinder 12 remains closed and the grouting device 18 remains stationary.

[0044] ② Static pressure stage of grouting device: The operator switches to the working state of the auxiliary hydraulic cylinder 12, so that its extension rod drives the grouting device 18 to extend along the outer wall of the ring cutter 16 until the cutting edge 17 of the grouting device 18 is flush with the working face.

[0045] ③ Pressure grouting and curing stage: The grouting pump 9 slowly pumps the cement-based grout into the grouting device 18 at an initial pressure of 1~2 MPa. After the air is expelled, the pressure is gradually increased to 5~6 MPa and maintained for 10 min, so that the grout can fully penetrate into the internal fissures of the rock mass through the grouting hole 19. Then the valve is closed, and the grout is allowed to solidify and cured for 45 min.

[0046] ④ Sampling stage: First, slowly retrieve the grouting device 18, then pull the ring cutter 16 and the core sample completely out of the rock mass at a low speed. After removing the ring cutter 16, the complete sample can be obtained by utilizing its internal anti-stick coating, and it should be immediately vacuum sealed and packaged to provide accurate original rock samples for subsequent indoor tests.

[0047] like Figure 3 As shown, the height of the hydraulic drive system is adjusted via six sets of adjustment holes 7 on the support column 2. During operation, a laser rangefinder is first used to assess the working face height and determine the range of the sampling area. Then, the holes on the adjustment plate 8 are precisely aligned with the adjustment holes 7 on the support column 2, and a locating pin is inserted for initial positioning. After confirming alignment, the locating pin is removed, and a high-strength bolt 6 is inserted and tightened twice in a diagonal sequence to a torque of 300 N·m to ensure that the connection between the adjustment plate 8 and the support column 2 does not slip during hydraulic drive system operation.

[0048] like Figure 4 As shown, the grouting device 18 and the ring cutter 16 are arranged in a concentric circular shape, with the ring cutter 16 located inside the grouting device 18. The two can extend and retract independently via a hydraulic drive device.

[0049] like Figure 5 As shown, when the right end face of the grouting device 18 is not closed, the extension length of the right end face of the ring cutter 16 is slightly less than that of the right end face of the grouting device 18, which facilitates the movement of the built-in steel plate 15 on the right end face of the grouting device 18.

[0050] like Figure 6 As shown, the right end face of the grout injector 18 can rotate the six steel plates 15 by 90 degrees through the internal cam mechanism, thereby mechanically closing the right end of the grout injector 18 to form a closed bottom cover to prevent grout from leaking forward, and then the grouting step is carried out.

[0051] like Figure 7 As shown, the main hydraulic cylinder 13 controls the extension and retraction of the ring cutter 16, and the auxiliary hydraulic cylinder 12 controls the extension and retraction of the grout injector 18. After the hydraulic drive device is activated, the main telescopic rod 21 on the right side of the push plate 14 will be pushed out by the main hydraulic cylinder 13, and the auxiliary telescopic rod 20 will be pushed out by the auxiliary hydraulic cylinder 12. The main telescopic rod 21 and the auxiliary telescopic rod 20 are arranged in a concentric ring shape, with the main telescopic rod 21 located outside the auxiliary telescopic rod 20. The auxiliary telescopic rod 20 and the grout injector 18 are connected through a transfer device 22. The transfer device 22 can be rotated by a built-in motor, thereby driving the grout injector 18 to rotate during the static pressure process. The main telescopic rod 21 is directly connected to the ring cutter 16. After the static pressure of the grout injector 18 and the ring cutter 16 is completed, the grouting hose 10 is connected to the transfer device 22 to start the grouting operation.

[0052] A static pressure coring method for grouting reinforcement of tunnel faces in altered rock masses, comprising the following steps:

[0053] S1. Install the core-taking device on the working face and align the ring cutter of the device with the predetermined core-taking point;

[0054] S2. Start the main hydraulic cylinder and drive the ring cutter with hydrostatic pressure to press the ring cutter into the rock mass to the designed depth;

[0055] S3. Keep the ring cutter in a fixed position, start the auxiliary hydraulic cylinder, and drive the annular grouting device to press into the rock mass along the outer wall of the ring cutter until the cutting edge of the right end face of the grouting device reaches the predetermined position.

[0056] S4. Close the right end face of the grouting device, and then inject the reinforcing grout into the grouting device. The grout will evenly penetrate and diffuse into the surrounding rock mass through the grouting holes distributed on the surface of the grouting device to reinforce the rock mass around the ring cutter.

[0057] S5. After the grout has initially solidified, retrieve the grouting device and ring cutter, and remove the original rock core sample from the ring cutter.

[0058] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A static pressure coring device for grouting reinforcement of tunnel faces in altered rock masses, characterized in that: The device includes a reaction frame, a hydraulic drive system, a core sampling device, and external equipment. The hydraulic drive system is mounted on the reaction frame and connected to the core sampling device. The hydraulic drive system includes a main hydraulic cylinder and a secondary hydraulic cylinder. The core sampling device includes a ring cutter and a grout injector. The grout injector is located outside the ring cutter and connected to the external equipment. The ring cutter is connected to the main telescopic rod of the main hydraulic cylinder, and the grout injector is connected to the secondary telescopic rod of the secondary hydraulic cylinder. The grout injector is provided with grouting holes.

2. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 1, characterized in that: The reaction frame is a portal steel structure frame, including a base plate, support columns, a top crossbeam, auxiliary beams, diagonal supports, and an adjustment plate. Two vertical support columns are fixed vertically to the base plate of the reaction frame. The diagonal supports and auxiliary beams are used to reinforce the support columns. The top crossbeam is used to connect and fix the two support columns. The hydraulic drive system is fixed on the adjustment plate.

3. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 2, characterized in that: The adjusting plate is fixed in the adjusting hole of the support column by bolts, and the height of the adjusting plate is adjusted according to the core extraction height.

4. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 1, characterized in that: The ring cutter and the grouting device are made of high-strength steel. The outer end face of the grouting device has a sharp wedge-shaped cutting edge, and the outer end face of the grouting device is closed by a steel sheet.

5. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 1, characterized in that: The external device is a grouting pump, which is filled with cement-based grout. The grouting pump is connected to the grouting device through a high-pressure grouting hose.

6. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 1, characterized in that: A push plate is provided between the main and auxiliary hydraulic cylinders and the main and auxiliary telescopic rods.

7. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 6, characterized in that: Guide rods are provided between the four corners of the push plate and the adjustment plate.

8. The static pressure coring device for grouting reinforcement of altered rock tunnel faces according to claim 1, characterized in that: A transfer device is provided between the secondary telescopic rod and the grouting device.

9. A method for static pressure coring for grouting reinforcement of tunnel faces in altered rock masses, characterized in that: The method is based on the apparatus as described in any one of claims 1-8 and includes the following steps: S1. Install the core-taking device on the working face and align the ring cutter of the device with the predetermined core-taking point; S2. Start the main hydraulic cylinder and drive the ring cutter with hydrostatic pressure to press the ring cutter into the rock mass to the designed depth; S3. Keep the ring cutter in a fixed position, start the auxiliary hydraulic cylinder, and drive the annular grouting device to press into the rock mass along the outer wall of the ring cutter until the cutting edge of the right end face of the grouting device reaches the predetermined position. S4. Close the right end face of the grouting device, and then inject the reinforcing grout into the grouting device. The grout will evenly penetrate and diffuse into the surrounding rock mass through the grouting holes distributed on the surface of the grouting device to reinforce the rock mass around the ring cutter. S5. After the grout has initially solidified, retrieve the grouting device and ring cutter, and remove the original rock core sample from the ring cutter.

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