Experimental device for monitoring on-way attenuation of grouting pressure

Abstract

The invention relates to the field of fluid mechanics experiment devices, in particular to an experiment device for monitoring on-way attenuation of grouting pressure, which comprises a grouting pump, a grouting hose and an open hole grouting pipe, a pressure line pipe used for containing a pressure sensor is arranged in the open hole grouting pipe in the axial direction, the pressure line pipe is used for storing a pressure measuring line, and the pressure sensor is directly in contact with flowing grouting slurry. Meanwhile, the pressure line pipe and the detachable pipe grooves work cooperatively, the different detachable pipe grooves correspondingly simulate rock masses of different lithology, the multiple sections of open hole grouting pipes are arranged to simulate open hole grouting holes of different lengths, and according to the thicknesses of different rock stratums through which the open hole grouting holes penetrate, the open hole grouting holes can be simulated according to the thicknesses of the different rock stratums through which the open hole grouting holes penetrate. Arranging an open hole grouting pipe with a detachable pipe groove with a corresponding length and a corresponding characteristic; the hole sealing plug is provided with a gap used for simulating that grout flows into a rock stratum from an open hole during open hole grouting, and corresponding shapes are set according to different crack shapes. According to the invention, the measurement accuracy of the on-way attenuation of the grouting pressure can be greatly improved.

Description

Technical Field

[0001] The invention relates to the field of fluid mechanics experimental devices, in particular to an experimental device for monitoring the attenuation of grouting pressure along the process. Background Art

[0002] In open-hole grouting in mining projects, the pressure at the orifice is often used as the overall grouting pressure. However, due to frictional resistance within the rock wall during the grouting process, the in-hole grouting pressure is lower than the orifice pressure. This is especially true for long open-holes, where the grouting pressure decays more with distance from the orifice. Using the orifice pressure as the overall grouting pressure is inaccurate. Furthermore, due to the layered structure of sedimentary rocks, deep grouting boreholes may penetrate multiple strata. Different lithologies have varying frictional resistance, leading to significant errors in theoretical calculations. Therefore, accurately determining the in-hole grouting pressure decay for open-hole grouting projects that penetrate multiple strata is crucial for guiding practical grouting operations. Summary of the Invention

[0003] In response to the above technical problems, the present invention proposes an experimental device for monitoring the attenuation of grouting pressure along the process, comprising a plurality of open-hole grouting pipes, wherein the open-hole grouting pipe comprises a circular outer wall of the grouting pipe, and a plurality of pressure line pipes extending along the axis are arranged on the inner wall surface of the outer wall of the grouting pipe at intervals in the circumferential direction, and the pressure line pipe comprises an inner arc-shaped wall coaxial with the outer wall of the circular grouting pipe and two symmetrical waist walls connecting the inner arc-shaped wall and the outer wall of the grouting pipe; a detachable pipe groove is provided between adjacent pressure line pipes, and the inner arc wall of the detachable pipe groove is detachable from the pressure line pipe. The inner arc-shaped wall forms the circular inner wall of the open hole grouting pipe; the detachable pipe groove is made of different materials to simulate the inner wall of the open hole drilled in different rock types; a plurality of pressure sensors are arranged at intervals along the axial direction on the inner arc-shaped wall of the pressure line pipe, and the pressure sensors are connected to the pressure measuring line, and the pressure measuring line is located in the pressure line pipe; two adjacent open hole grouting pipes are connected by nuts; the pressure measuring line is connected to the pressure acquisition device, and a sealing plug is provided in the inner wall of the last section of the open hole grouting pipe, and the sealing plug is provided with a slurry outlet hole.

[0004] Preferably, the width between the two symmetrical waist walls of the pressure line pipe gradually decreases toward the axial center direction of the outer wall of the circular grouting pipe.

[0005] Preferably, the detachable pipe groove matches the shape of the pressure line pipe and the outer wall of the circular grouting pipe, including an inner arc wall and an outer arc wall coaxial with the outer wall of the circular grouting pipe, and two symmetrical waist walls connecting the inner arc wall and the outer arc wall.

[0006] Preferably, external threads are provided on the outer periphery of both ends of the outer wall of the grouting pipe, and lead holes for leading out the pressure measuring line are provided inside the external threads at both ends of the outer wall of the grouting pipe, and one end of the pressure measuring line is connected to the pressure collection device.

[0007] Preferably, the detachable pipe groove and the waist wall of the pressure line pipe are both covered with sealing materials.

[0008] Preferably, both ends of the pressure line pipe adopt detachable sealing material density.

[0009] Preferably, an annular sealing gasket adapted to the wall thickness of the open hole grouting pipe is provided at the connecting end of adjacent open hole grouting pipes.

[0010] Preferably, the head end of the first section of the open hole grouting pipe is connected to the grouting pump through a grouting hose, and the sealing plug is sealed with the inner wall of the last section of the open hole grouting pipe; the slurry outlet hole is used to simulate the slurry flowing from the open hole into the cracks of the rock formation during open hole grouting, and the slurry outlet hole is set to a corresponding shape according to different crack shapes.

[0011] Preferably, according to the thickness of different rock layers passed by the open hole grouting hole, an open hole grouting pipe with a detachable pipe groove of corresponding length and corresponding characteristics is provided.

[0012] The present invention also provides an experimental method for detecting the attenuation of grouting pressure along the injection path, using the experimental device described above, comprising the following steps:

[0013] a. Determine the length of the open hole grouting hole to be simulated, as well as the number of rock layers that the open hole grouting hole to be simulated passes through in the length direction and the thickness of each rock layer;

[0014] b. Determine the number of open hole grouting pipe sections required to simulate each rock layer based on the length of each rock layer, select the corresponding detachable pipe slots for simulating the corresponding rock properties, and assemble all open hole grouting pipes;

[0015] c. Set the grouting hole of the corresponding shape on the sealing plug according to the grouting crack of the open hole grouting hole, and insert the sealing plug into the last section of the open hole grouting pipe;

[0016] d. Connect the grouting pump to one end of the first section of the open hole grouting pipe through the grouting hose, and connect the pressure line to the pressure acquisition device; place the open hole grouting pipe at the same angle as the desired simulated open hole grouting hole;

[0017] e. Use a grouting pump to perform grouting, simulate the actual grouting process, record the pressure data collected by each pressure sensor, and obtain the attenuation of grouting pressure along the process.

[0018] The beneficial technical effects of the present invention are as follows: a pressure line pipe for placing a pressure sensor is axially arranged in the open hole grouting pipe of the present invention, the pressure line pipe can be used to store the pressure measuring line, and the pressure sensor can directly contact the flowing grouting slurry to greatly improve the measurement accuracy; at the same time, the pressure line pipe works together with the detachable pipe groove, and different detachable pipe grooves simulate rock masses with different lithology. Further, by setting up multiple sections of open hole grouting pipes, it can be used to simulate open hole grouting holes of different lengths, and according to the thickness of different rock layers passed by the open hole grouting hole, open hole grouting pipes with corresponding lengths and corresponding characteristic detachable pipe grooves can be set.

[0019] The present invention arranges a sealing plug in the inner wall of the last section of the open hole grouting pipe. The sealing plug is provided with a slurry outlet hole for simulating the slurry flowing from the open hole into the gap of the rock formation during open hole grouting. The slurry outlet hole is set with corresponding shapes according to different crack shapes, so that the simulated working conditions are more in line with reality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the experimental device of the present invention;

[0021] Figure 2 This is a schematic structural diagram of a bare hole grouting pipe and its connection method according to the present invention;

[0022] Figure 3 This is a schematic diagram of the disassembled structure of the open hole grouting pipe of the present invention;

[0023] Figure 4 This is a schematic diagram of the partial internal structure of the open hole grouting pipe of the present invention;

[0024] Figure 5 This is a schematic diagram of the assembly structure of the tail open hole grouting pipe of the present invention;

[0025] Figure 3 and Figure 5 The external threads on the outer periphery of both ends of the outer wall of the grouting pipe are omitted;

[0026] In the figure, 1-grouting pump; 2-grouting hose; 3-open hole grouting pipe; 4-nut; 5-pressure measuring line; 6-pressure acquisition device; 7-pressure line pipe; 8-detachable pipe groove; 9-pressure sensor (pressure measuring point); 10-outer wall of grouting pipe; 11-sealing plug; 12-slurry outlet hole. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] Example 1

[0029] like Figure 1-5As shown, the present invention proposes an experimental device for monitoring the attenuation of grouting pressure along the process, comprising a grouting pump 1, a grouting hose 2, a multi-section open hole grouting pipe 3 and a pressure measuring device; the pressure measuring device comprises a pressure measuring line 5, a pressure sensor 9 and a pressure acquisition device 6;

[0030] like Figure 2-5 As shown, the open hole grouting pipe 3 includes a circular grouting pipe outer wall 10, and a plurality of pressure line pipes 7 extending along the axis are arranged on the inner wall surface of the grouting pipe outer wall 10 at intervals in the circumferential direction. In this embodiment, four pressure line pipes 7 extending along the axial direction are arranged at equal intervals in the circumferential direction; the pressure line pipe 7 includes an inner arc wall coaxial with the circular grouting pipe outer wall 10 and two symmetrical waist walls connecting the inner arc wall and the grouting pipe outer wall 10, and the width between the two symmetrical waist walls gradually decreases toward the axial direction of the circular grouting pipe outer wall 10; a detachable pipe groove 8 is provided between adjacent pressure line pipes 7, and the detachable pipe groove 8 can be tightly placed between two adjacent pressure line pipes 7 and match the shape of the pressure line pipe 7 and the circular grouting pipe outer wall 10. Specifically, the detachable pipe groove 8 includes an inner arc wall coaxial with the circular grouting pipe outer wall 10, an outer arc wall, and a waist wall connecting the inner arc wall and the outer arc wall. The two symmetrical waist walls of the wall, the inner arc wall of the detachable pipe groove 8 and the inner arc wall of the pressure line pipe 7 enclose the circular inner wall of the open hole grouting pipe 3; the detachable pipe groove 8 can be made of different materials to simulate the inner wall of the open hole drilled in different rock properties; a plurality of pressure sensors (pressure measuring points) 9 are arranged at intervals along the axial direction on the inner arc wall of the pressure line pipe 7, and the pressure sensors 9 are connected to the pressure measuring line 5, and the pressure measuring line 5 is located in the pressure line pipe 7; external threads are provided on the outer periphery of both ends of the grouting pipe outer wall 10, and lead holes for leading out the pressure measuring line 5 are provided at both ends of the grouting pipe outer wall 10 inside the external threads (where no external threads are provided), and one end of the pressure measuring line 5 is connected to the pressure acquisition device 6; two adjacent open hole grouting pipes 3 are connected by a nut 4, and the nut 4 is provided with an internal thread connected to the external thread on the adjacent grouting pipe outer wall 10;

[0031] Preferably, the waist wall of the detachable pipe groove 8 and the pressure line pipe 7 are both covered with sealing material to improve the sealing performance of the connection between the two;

[0032] Preferably, both ends of the pressure line pipe 7 are made of detachable sealing material density;

[0033] Preferably, an annular sealing gasket adapted to the wall thickness of the open hole grouting pipe 3 is provided at the connecting end of the adjacent open hole grouting pipe 3 to improve the sealing performance of the connecting end of the adjacent open hole grouting pipe 3;

[0034] Preferably, the pressure sensor 9 in the same pressure line pipe 7 is connected to one pressure measuring line 5, and the pressure measuring lines 5 of the corresponding pressure line pipes 7 of adjacent open hole grouting pipes 3 are connected in sequence, and the pressure measuring line 5 of the last section of open hole grouting pipe 3 is connected to the pressure acquisition device 6;

[0035] The head end of the first section of the open hole grouting pipe 3 (serving as the grouting port of the multi-section open hole grouting pipe connector), that is, the end not connected to the other open hole grouting pipe 3, is connected to the grouting pump 1 through a grouting hose 2. The grouting pump 1 is used to simulate the grouting pump during actual grouting, and the grouting hose 2 is used to simulate the grouting pipe connecting the grouting hole and the grouting pump during actual grouting; a sealing plug 11 is provided in the inner wall of the last section of the open hole grouting pipe 3, and the sealing plug 11 is sealed with the inner wall of the last section of the open hole grouting pipe 3; the sealing plug 11 is provided with a slurry outlet 12, and the slurry outlet 12 is used to simulate the slurry flowing from the open hole into the cracks of the rock formation during open hole grouting, and the slurry outlet 12 is set in a corresponding shape according to different crack shapes;

[0036] By setting up multiple sections of open hole grouting pipes 3, it is possible to simulate open hole grouting holes of different depths (lengths), and open hole grouting pipes 3 with corresponding lengths and corresponding characteristics of detachable pipe grooves 8 can be set according to the thickness of different rock formations passed by the open hole grouting holes.

[0037] Example 2

[0038] The present invention also provides an experimental method for detecting the attenuation of grouting pressure along the injection path, using the experimental device described in the first embodiment, comprising the following steps:

[0039] a. Determine the length of the open hole grouting hole to be simulated, as well as the number of rock layers that the open hole grouting hole to be simulated passes through in the length direction and the thickness of each rock layer;

[0040] b. Determine the number of 3 sections of open hole grouting pipe required to simulate each rock layer according to the length of each rock layer, and select the corresponding detachable pipe groove 8 for simulating the corresponding lithology, and assemble all the open hole grouting pipes 3;

[0041] c. According to the grouting cracks of the open hole grouting hole, the corresponding shape of the cracks is set in the sealing plug 11, and the sealing plug 11 is inserted into the last section of the open hole grouting pipe 3;

[0042] d. Connect the grouting pump 1 to one end of the first section of the open hole grouting pipe 3 (the slurry inlet of the multi-section open hole grouting pipe connector) through the grouting hose 2, and connect the pressure line 5 to the pressure acquisition device 6; place the open hole grouting pipe 3 at the same angle as the open hole grouting hole to be simulated;

[0043] e. Use the grouting pump 1 to perform grouting, simulate the actual grouting process, and record the pressure data collected by each pressure sensor 9, based on which the attenuation of the grouting pressure along the process can be obtained.

[0044] Of course, the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above-mentioned embodiments. It should be noted that all equivalent substitutions and obvious deformation forms made by any technician familiar with this field under the guidance of this specification fall within the substantive scope of this specification and should be protected by the present invention.

Claims

1. An experimental device for monitoring the attenuation of grouting pressure along the injection process, comprising a multi-section open hole grouting pipe, characterized in that: The open hole grouting pipe comprises an outer wall of a circular grouting pipe, and a plurality of pressure line pipes extending along the axis are arranged at intervals in the circumferential direction on the inner wall surface of the outer wall of the grouting pipe, and the pressure line pipe comprises an inner arc wall coaxial with the outer wall of the circular grouting pipe and two symmetrical waist walls connecting the inner arc wall and the outer wall of the grouting pipe; a detachable pipe groove is provided between adjacent pressure line pipes, and the inner arc wall of the detachable pipe groove and the inner arc wall of the pressure line pipe enclose the circular inner wall of the open hole grouting pipe; the detachable pipe groove is made of different materials to simulate the inner wall of the open hole drilled in different rock types; a plurality of pressure sensors are arranged at intervals in the axial direction on the inner arc wall of the pressure line pipe, and the pressure sensors are connected to the pressure measuring line, and the pressure measuring line is located in the pressure line pipe; two adjacent open hole grouting pipes are connected by nuts; the pressure measuring line is connected to the pressure acquisition device, and a sealing plug is provided in the inner wall of the last section of the open hole grouting pipe, and the sealing plug is provided with a slurry outlet hole.

2. The experimental device according to claim 1, characterized in that The width between the two symmetrical waist walls of the pressure line pipe gradually decreases toward the axial center direction of the outer wall of the circular grouting pipe.

3. The experimental device according to claim 1 or 2, characterized in that: The detachable pipe groove matches the shape of the pressure line pipe and the outer wall of the circular grouting pipe, and includes an inner arc wall and an outer arc wall coaxial with the outer wall of the circular grouting pipe, and two symmetrical waist walls connecting the inner arc wall and the outer arc wall.

4. The experimental device according to claim 1, characterized in that External threads are provided on the outer periphery of both ends of the outer wall of the grouting pipe, and lead holes for leading out the pressure measuring line are provided inside the external threads at both ends of the outer wall of the grouting pipe. One end of the pressure measuring line is connected to the pressure collection device.

5. The experimental device according to claim 1, characterized in that: The detachable pipe groove and the waist wall of the pressure line pipe are both covered with sealing materials.

6. The experimental device according to claim 1, characterized in that Both ends of the pressure line pipe adopt detachable sealing material density.

7. The experimental device according to claim 1, characterized in that An annular sealing gasket adapted to the wall thickness of the open hole grouting pipe is arranged at the connecting end of the adjacent open hole grouting pipe.

8. The experimental device according to claim 1, characterized in that: The head end of the first section of the open hole grouting pipe is connected to the grouting pump through the grouting hose, and the sealing plug is sealed with the inner wall of the last section of the open hole grouting pipe; the slurry outlet hole is used to simulate the slurry flowing from the open hole into the gap of the rock formation during open hole grouting, and the slurry outlet hole is set to a corresponding shape according to different crack shapes.

9. The experimental device according to claim 1 or 2, characterized in that: According to the thickness of different rock layers passed by the open hole grouting hole, an open hole grouting pipe with corresponding length and corresponding characteristics of the detachable pipe groove is set.

10. An experimental method for detecting the attenuation of grouting pressure along the injection path, using the experimental device according to any one of claims 1 to 9, characterized in that: The steps include: a. Determine the length of the open hole grouting hole to be simulated, as well as the number of rock layers that the open hole grouting hole to be simulated passes through in the length direction and the thickness of each rock layer; b. Determine the number of open hole grouting pipe sections required to simulate each rock layer based on the length of each rock layer, select the corresponding detachable pipe slots for simulating the corresponding rock properties, and assemble all open hole grouting pipes; c. Set the grouting hole of the corresponding shape on the sealing plug according to the grouting crack of the open hole grouting hole, and insert the sealing plug into the last section of the open hole grouting pipe; d. Connect the grouting pump to one end of the first section of the open hole grouting pipe through the grouting hose, and connect the pressure line to the pressure acquisition device; place the open hole grouting pipe at the same angle as the desired simulated open hole grouting hole; e. Use a grouting pump to perform grouting, simulate the actual grouting process, record the pressure data collected by each pressure sensor, and obtain the attenuation of grouting pressure along the process.

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