Grouting method for underground high-pressure-bearing weak water-rich aquifer

Abstract

The invention belongs to the crossing field of the field of mine water disaster prevention and control and the field of mining engineering, and particularly discloses an underground high-pressure-bearing weak water-rich aquifer grouting method which comprises the following steps: implementing associated drilling; a main grouting hole is formed; forming a water distributing and discharging hole; water pressure monitoring devices and ball valves capable of adjusting the water discharge amount are arranged at orifices of the branch water discharge holes and the main grouting holes; a high-pressure blowout preventer and a closed drainage system are mounted at the opening of the water distribution and drainage hole; a high-pressure grouting system is connected to the opening of the main grouting hole; main grouting holes are formed in the high-pressure-bearing weak water-rich aquifer; opening a water distributing and discharging hole ball valve to discharge water, and continuously monitoring the water pressure; grouting and hole sealing are conducted on the associated drill holes; opening a main grouting hole orifice ball valve, and starting a high-pressure grouting system. The grouting method for the underground high-pressure-bearing weak water-rich aquifer is more scientific, accurate, practical and easy to implement, and can meet the urgent requirements of mine safety production and geological disaster prevention and control.

Description

Technical Field

[0001] The present invention belongs to the intersection of the field of mine water hazard prevention and control and the field of mining engineering, and specifically relates to a grouting method for an underground high-pressure weak water-rich aquifer. Background Art

[0002] As my country's mining development extends deeper, the water pressure of the aquifer gradually increases, but the water-richness gradually decreases, forming a high-pressure weak-water-rich characteristic. In order to prevent and control mine water disasters, grouting is performed on high-pressure weak-water-rich aquifers, but traditional grouting methods have the following problems:

[0003] (1) In traditional drilling, a permeable pipe is left for the grouting aquifer, while other areas are casing. This causes the pressure of the aquifer to be directly transmitted to the borehole mouth, and the water pressure is too high, which is dangerous.

[0004] (2) Traditional drilling will leave anti-water spray devices, which can reduce the harm of water pressure to people, but are restricted by the influence of materials and space, and the anti-high-pressure effect is limited, that is, the scope of application is limited.

[0005] (3) Traditional grouting drilling is mainly based on grouting. Due to the high water pressure in the aquifer, 2-3 times the pressure must be injected to implement effective grouting, which places higher requirements on the grouting equipment and is therefore unsafe.

[0006] Therefore, there is a need in the art to develop a method for grouting underground high-pressure weak water-rich aquifers that can effectively solve the above problems. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for grouting underground high-pressure weak water-rich aquifers, which is more scientific, accurate, practical and easy to implement, and can meet the urgent needs of mine safety production and geological disaster prevention and control.

[0008] To achieve the above object, the present invention provides a method for grouting a high-pressure, weakly water-rich aquifer in an underground well, comprising the following steps:

[0009] Step S1, performing associated drilling;

[0010] The implementation of the linked drilling applies the principle of Bernoulli's equation. The water pressure of the two aquifers is balanced, thereby reducing the pressure at the borehole mouth. This process is affected by the head difference and the hydraulic conductivity, so the layer with the largest product of the two is selected.

[0011] Step S2, implementing the main grouting hole;

[0012] The main grouting hole adopts the method of reducing the water pressure in the mine. After the diameter is reduced, it becomes larger near the borehole mouth. According to the principle of hydraulics, the corresponding water pressure is reduced. Combined with the Bernoulli equation, there is a corresponding calculation formula for the percentage of hole diameter reduction corresponding to the water pressure reduction.

[0013] Step S3, implementing the water discharge hole;

[0014] The water discharge holes increase the water flow area and further reduce the water pressure.

[0015] Step S4: Install a water pressure monitoring device and a ball valve with adjustable water discharge at the openings of the branch drain hole and the main grouting hole, and keep the valve in a closed state;

[0016] Step S5: Install a high-pressure blowout prevention device and a closed drainage system at the outlet of the water distribution hole;

[0017] Step S6: connecting a high-pressure grouting system to the main grouting hole;

[0018] Step S7: On the basis of step S2, continue to implement the main grouting hole in the high-pressure weak water-rich aquifer;

[0019] Step S8: Open the ball valve of the water drain hole to drain water, and continuously monitor the water pressure. When the water pressure drops to 0.1 MPa or the water pressure drops by more than 80%, close the ball valve of the water drain hole to stop draining water.

[0020] Step S9: grouting and sealing the associated boreholes;

[0021] Step S10: open the ball valve at the main grouting hole and start the high-pressure grouting system. The injection pressure is 3 to 4 times the water pressure at the main grouting hole. The grouting completion time is controlled within 3 to 10 hours.

[0022] According to the principle of slurry diffusion, the pressure of high-pressure weak water-rich aquifers is easy to drop after drainage. Grouting after the water pressure drops can reduce the grouting pressure and increase the diffusion range. After the water is released, the stone rate can also be increased, and the grouting effect is better.

[0023] Preferably, step S1 is specifically as follows: carrying out associated drilling from the ground or a higher level mining working space to the high-pressure weakly water-rich aquifer, the associated boreholes are permeable flower pipes in the associated aquifer and the high-pressure weakly water-rich aquifer sections, and the remaining sections are waterproof casings, and the aperture of the associated boreholes is less than 50 mm.

[0024] Preferably, the associated aquifer refers to the aquifer between the highly pressurized weakly water-rich aquifer and the ore body, and has the largest H×T value, where H is the head of the highly pressurized weakly water-rich aquifer minus the head of the associated aquifer, obtained through hydrogeological exploration; T is the hydraulic conductivity of the associated aquifer, obtained through pumping experiments.

[0025] Preferably, the number of associated drillings is ≥ N, and N is calculated as follows:

[0026]

[0027] Where R is the influence radius; K is the permeability coefficient of the highly confined weakly water-rich aquifer, obtained through pumping experiments; H is the hydraulic head of the highly confined weakly water-rich aquifer minus the hydraulic head of the associated aquifer, obtained through hydrogeological exploration;

[0028]

[0029] Where N is the number of associated drillings implemented; F is the designed grouting reinforcement area, obtained through grouting design; and R is the impact radius.

[0030] Preferably, step S2 is specifically as follows: implementing the main grouting hole vertically upward from the current horizontal mining working space, and stopping when it reaches 0.2 to 0.5 times the distance D between the working space and the high-pressure weak water-rich aquifer, and the hole diameter is greater than 200 mm.

[0031] Preferably, step S3 is specifically as follows: each main grouting hole is equipped with 3 to 5 drainage holes, which are implemented at an inclination angle of 10° to 30° from the horizontal mining working space and are connected to the main grouting hole, with a hole diameter of 90 to 120 mm.

[0032] Preferably, in step S7, the range drilling space is reduced once every time 0.1 times of the distance between the effective space and the high-pressure weak water-rich aquifer is implemented, and each time the original aperture of step S2 is reduced by X percent until the high-pressure weak water-rich aquifer is drilled.

[0033] Preferably, the calculation method of X is specifically as follows:

[0034]

[0035] Where, P0 is the maximum pressure of the drainage hole, which is obtained through the pressure description of the equipment; k1 is the safety factor, which is 0.8-0.9; P1 is the initial pressure of the high-pressure weak water-rich aquifer on the orifice, which is obtained through hydrological observation; n is the number of times the main grouting hole changes in diameter, which is determined in step S2.

[0036] The present invention adopts the above-mentioned underground high-pressure weak water-rich aquifer grouting method, and the beneficial effects are as follows:

[0037] (1) The method of the present invention does not require high-pressure grouting equipment and is simple and easy to implement.

[0038] (2) Although the present invention implements multiple drilling holes, the grouting efficiency is improved and it is more economically feasible.

[0039] (3) The present invention takes into account the reduction of water pressure by changing the diameter and reducing the water pressure by multiple branch holes, does not rely too much on the grouting drilling orifice device, and has a wider range of applications.

[0040] (4) The present invention connects the target aquifer and other aquicludes, effectively reducing the orifice pressure and providing high safety.

[0041] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The present invention is a flowchart of an embodiment of a method for grouting a high-pressure weakly water-rich aquifer underground. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0044] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0045] like Figure 1 As shown, a method for grouting a high-pressure weak water-rich aquifer in a well comprises the following steps:

[0046] Step S1: Implementing cross-drilling. Cross-drilling is performed from the ground or a higher level mining operation space to the highly pressurized weakly water-rich aquifer. The cross-drilling section between the linked aquifer and the highly pressurized weakly water-rich aquifer is a permeable flower pipe, and the remaining section is a waterproof casing. The diameter of the cross-drilling hole is less than 50 mm.

[0047] The associated aquifer is the aquifer between the highly confined, weakly water-rich aquifer and the ore body, with the largest H × T value. H is the hydraulic head of the highly confined, weakly water-rich aquifer minus the hydraulic head of the associated aquifer, obtained through hydrogeological exploration. T is the hydraulic conductivity of the associated aquifer, obtained through pumping experiments.

[0048] The number of associated drilling holes must be ≥ N, and N is calculated as follows:

[0049]

[0050] Where R is the influence radius. K is the hydraulic conductivity of the highly confined, weakly water-rich aquifer, obtained through pumping experiments. H is the hydraulic head of the highly confined, weakly water-rich aquifer minus the hydraulic head of the associated aquifer, obtained through hydrogeological exploration.

[0051]

[0052] Where N is the number of associated drillings. F is the designed grouting reinforcement area, obtained through grouting design. R is the impact radius.

[0053] Step S2: Implement main grouting holes. Implement main grouting holes vertically upward from the current horizontal mining operation space until the hole diameter is greater than 200 mm.

[0054] Step S3: Implement drainage holes. Each main grouting hole is equipped with 3 to 5 drainage holes, which are implemented at an inclination of 10° to 30° from the horizontal mining working space and connected to the main grouting hole. The hole diameter is 90 to 120 mm.

[0055] Step S4: Install a water pressure monitoring device and a ball valve with adjustable water discharge volume at the orifices of the branch discharge hole and the main grouting hole, and keep the valve in a closed state.

[0056] Step S5: Install a high-pressure blowout prevention device and a closed drainage system at the outlet of the water distribution hole.

[0057] Step S6: Connect the high-pressure grouting system to the main grouting hole.

[0058] Step S7: Based on step S2, continue to implement the main grouting holes in the high-pressure weak water-rich aquifer.

[0059] Every time 0.1 times of the distance between the effective space and the high-pressure weak water-rich aquifer is implemented, the range drilling space is reduced by 1 time, and each time the original aperture in step S2 is reduced by X percent until the high-pressure weak water-rich aquifer is drilled.

[0060] The calculation method of X is as follows:

[0061]

[0062] Where P0 is the maximum pressure of the taphole, obtained from the equipment pressure data. k1 is the safety factor, ranging from 0.8 to 0.9. P1 is the initial pressure of the highly confined, weakly water-rich aquifer on the orifice, obtained from hydrological observations. n is the number of diameter changes of the main grouting hole, determined in step S2.

[0063] Step S8: Open the ball valve of the water drain hole to drain water, and continuously monitor the water pressure. When the water pressure drops to 0.1 MPa or the water pressure drops by more than 80%, close the ball valve of the water drain hole to stop draining water.

[0064] Step S9: grouting and sealing the associated boreholes.

[0065] Step S10: open the ball valve at the main grouting hole and start the high-pressure grouting system. The injection pressure is 3 to 4 times the water pressure at the main grouting hole. The grouting completion time is controlled within 3 to 10 hours.

[0066] Example

[0067] A mine is threatened by a high-pressure weak-water-rich aquifer. The drainage effect of this aquifer is not good, so grouting is needed to reinforce and transform the aquifer. However, since the high-pressure grouting pressure is low, it cannot be pressed into the aquifer, and the weak-water-rich aquifer also results in a very low grouting volume. Therefore, the technology of the present invention is used for grouting. The specific steps are as follows:

[0068] Step S1: Implementing associated drilling. Implement associated drilling from the ground to the high-pressure weakly water-rich aquifer. The associated drilling holes are permeable flower pipes in the associated aquifer and the high-pressure weakly water-rich aquifer, and the remaining sections are waterproof casings. The diameter of the associated drilling holes is 40 mm.

[0069] The associated aquifer is between the high-pressure weak-water-rich aquifer and the ore body, and H×T=3770m 3 / dThe largest aquifer, where H = 58m is the head of the highly confined weakly water-rich aquifer minus the head of the associated aquifer, obtained through hydrogeological exploration, and T = 65m 2 / d is the hydraulic conductivity of the associated aquifer, obtained through pumping experiments. The number of associated boreholes implemented is 10, not less than N = 5.7, and the calculation method of N is:

[0070]

[0071] Where R is the influence radius, K = 0.02 m / d is the hydraulic conductivity of the highly confined weakly water-rich aquifer, obtained through pumping experiments, and H = 58 m is the hydraulic head of the highly confined weakly water-rich aquifer minus the hydraulic head of the associated aquifer, obtained through hydrogeological exploration.

[0072]

[0073] Where F = 120000m 2 The designed grouting reinforcement area is obtained through grouting design; R=82m is the affected radius.

[0074] Step S2: Implement main grouting holes. Implement main grouting holes vertically upward from the current horizontal mining operation space until it reaches 0.5 times the distance D = 32 meters between the operation space and the high-pressure weakly water-rich aquifer (i.e., 16 meters). The hole diameter is 210 mm.

[0075] Step S3: Implement drainage holes. Each main grouting hole is equipped with three drainage holes, which are implemented from the horizontal mining working space at an inclination of 10°, 20°, and 30° and connected to the main grouting hole. The hole diameter is 97mm.

[0076] Step S4: Install a water pressure monitoring device and a ball valve with adjustable water discharge volume at the orifices of the branch discharge hole and the main grouting hole, and keep the valve in a closed state.

[0077] Step S5: Install a high-pressure blowout prevention device and a closed drainage system at the outlet of the water distribution hole.

[0078] Step S6: Connect the high-pressure grouting system to the main grouting hole.

[0079] Step S7: Based on step S2, continue drilling the main grouting holes into the highly pressurized weakly water-rich aquifer. The drilling space is reduced once every 0.1D = 3.2 meters, and each time the hole diameter is reduced by 3.4 percent of the original hole diameter in step 2, until the highly pressurized weakly water-rich aquifer is reached.

[0080] The calculation method of X is as follows:

[0081]

[0082] Where P0 = 3 MPa is the maximum pressure of the drainage hole, obtained from the equipment pressure data. k1 is the safety factor, set to 0.8. P1 = 5 MPa is the initial pressure of the high-pressure, weakly water-rich aquifer on the orifice, obtained from hydrological observations. n = 5 is the number of diameter changes for the main grouting hole, determined in step S2.

[0083] Step S8: Open the ball valve of the water drain hole to drain water, and continuously monitor the water pressure. When the water pressure drops to 0.1 MPa, close the ball valve of the water drain hole to stop draining water.

[0084] Step S9: grouting and sealing the associated boreholes.

[0085] Step S10: Open the ball valve at the main grouting hole and start the high-pressure grouting system. The injection pressure is 4 times the water pressure at the main grouting hole. The grouting completion time is controlled within 10 hours.

[0086] Therefore, the present invention adopts the above-mentioned underground high-pressure weak water-rich aquifer grouting method, which is more scientific, accurate, practical and easy to implement, and can meet the urgent needs of mine safety production and geological disaster prevention and control.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for grouting underground high-pressure weak water-rich aquifers, characterized in that: The following steps are involved: Step S1, performing associated drilling; Step S2, implementing the main grouting hole; Step S3, implementing the water discharge hole; Step S4: Install a water pressure monitoring device and a ball valve with adjustable water discharge at the openings of the branch drain hole and the main grouting hole, and keep the valve in a closed state; Step S5: Install a high-pressure blowout prevention device and a closed drainage system at the outlet of the water distribution hole; Step S6: connecting a high-pressure grouting system to the main grouting hole; Step S7: On the basis of step S2, continue to implement the main grouting hole in the high-pressure weak water-rich aquifer; Step S8: Open the ball valve of the water drain hole to drain water, and continuously monitor the water pressure. When the water pressure drops to 0.1 MPa or the water pressure drops by ≥80%, close the ball valve of the water drain hole to stop draining water. Step S9: grouting and sealing the associated boreholes; Step S10: open the ball valve at the main grouting hole and start the high-pressure grouting system. The injection pressure is 3 to 4 times the water pressure at the main grouting hole. The grouting completion time is controlled within 3 to 10 hours.

2. A method for grouting underground high-pressure weak water-rich aquifers according to claim 1, characterized in that: Step S1 is specifically as follows: carrying out associated drilling from the ground or a higher level mining operation space to the high-pressure weakly water-rich aquifer. The associated boreholes are permeable flower pipes in the associated aquifer and the high-pressure weakly water-rich aquifer sections, and the remaining sections are waterproof casings. The aperture of the associated boreholes is less than 50 mm.

3. A method for grouting a high-pressure, weakly water-rich underground aquifer according to claim 2, characterized in that: The associated aquifer refers to the aquifer between the highly confined weakly water-rich aquifer and the ore body, and has the largest H×T value, where H is the head of the highly confined weakly water-rich aquifer minus the head of the associated aquifer, obtained through hydrogeological exploration; T is the hydraulic conductivity of the associated aquifer, obtained through pumping experiments.

4. A method for grouting a high-pressure, weakly water-rich underground aquifer according to claim 3, characterized in that: The number of associated drilling holes must be ≥ N, and N is calculated as follows: Where R is the influence radius; K is the permeability coefficient of the highly confined weakly water-rich aquifer, obtained through pumping experiments; H is the hydraulic head of the highly confined weakly water-rich aquifer minus the hydraulic head of the associated aquifer, obtained through hydrogeological exploration; Where N is the number of associated drillings implemented; F is the designed grouting reinforcement area, obtained through grouting design; and R is the impact radius.

5. The underground high-pressure weak water-rich aquifer grouting method according to claim 1, characterized in that: Step S2 is specifically as follows: implement the main grouting hole vertically upward from the current horizontal mining operation space, and stop when it reaches 0.2 to 0.5 times the distance D between the action space and the high-pressure weak water-rich aquifer, and the hole diameter is greater than 200 mm.

6. A method for grouting underground high-pressure weak water-rich aquifers according to claim 1, characterized in that: Step S3 is specifically as follows: each main grouting hole is equipped with 3 to 5 drainage holes, which are implemented at an inclination angle of 10° to 30° from the horizontal mining working space and connected to the main grouting hole, with a hole diameter of 90 to 120 mm.

7. The underground high-pressure weak water-rich aquifer grouting method according to claim 1, characterized in that: In step S7, the range drilling space is reduced by 1 time every time 0.1 times of the distance between the effective space and the high-pressure weak water-rich aquifer is implemented, and each time the original hole diameter in step S2 is reduced by X percent until the high-pressure weak water-rich aquifer is drilled.

8. A method for grouting underground high-pressure weak water-rich aquifers according to claim 7, characterized in that: The calculation method of X is as follows: Where, P0 is the maximum pressure of the drainage hole, which is obtained through the pressure description of the equipment; k1 is the safety factor, which is 0.8-0.9; P1 is the initial pressure of the high-pressure weak water-rich aquifer on the orifice, which is obtained through hydrological observation; n is the number of times the main grouting hole changes in diameter, which is determined in step S2.

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