A coal seam roof pulse high pressure grouting working face water inrush prevention technology

Abstract

The present invention provides a coal seam roof low-frequency pulse high-pressure grouting working face water inrush prevention process. The process steps include: establishing a drilling site and a grouting station; making a grouting shaft and a plurality of grouting fissures between the ground of the drilling site and the coal seam roof, the grouting shaft is vertically arranged, the grouting fissures are located between the grouting shaft and the coal seam roof, and the plurality of grouting fissures and the grouting fissures are connected to the grouting shaft; using pulse high-pressure grouting to make 1.03-1.05g / cm 3 The slurry diffuses into the coal seam around the grouting fissure, filling the grouting fissure with 1.1-1.3g / cm 3 The thick slurry is formed to form a complete plane grouting reinforcement area on the coal seam roof. By setting a grouting well and grouting fissures between the ground and the coal seam, the pores of the sandstone formation on the top of the working face are discontinuously and locally enlarged by continuous pulse high-pressure grouting to the grouting well and grouting fissures, and the water accumulation conditions can be destroyed after filling.

Description

Technical Field

[0001] The invention relates to the technical field of coal mines, and in particular to a coal seam roof pulse high-pressure grouting working face water inrush prevention process. Background Art

[0002] At present, the water hazards of the sandstone aquifers on the roof of some coal seams in mines are different from the conventional floor Ordovician ash water inrush and old empty water seepage types. The underground water outlet is the mining face and goaf area, which has the characteristics of high roof water inrush intensity and long duration. When the coal seam begins to be mined, the water pressure conditions in the sandstone aquifer on the roof are destroyed, and it will gush out through the working face and the roof of the goaf formed, causing the aquifer water to enter the underground and cause mine water inrush. As the mining face continues, the amount of water inrush from the coal seam roof usually increases gradually, but due to the heterogeneity of the sandstone strata, water inrush from the mining face occurs from time to time. In severe cases, it will cause the mining face to stop production, posing a serious threat to the normal safety production of the mine. Summary of the invention

[0003] The invention provides a coal seam roof pulse high-pressure grouting working face water inrush prevention process, which is used to reduce the water inrush risk of the mining working face.

[0004] The specific scheme is: a coal seam roof pulse high pressure grouting working face water inrush prevention process, the process comprises the following steps:

[0005] Step 1: Establish a drilling site and grouting station;

[0006] Step 2: a grouting shaft and a plurality of grouting fissures are made between the ground of the drilling site and the roof of the coal seam, wherein the grouting shaft is vertically arranged, the grouting fissures are located between the grouting shaft and the roof of the coal seam, and the plurality of grouting fissures and the grouting fissures are connected to each other;

[0007] Step three: first, inject thin slurry into the grouting fissures through the grouting wellbore, so that the thin slurry diffuses into the coal seam around the grouting fissures; then inject thick slurry into the grouting wellbore, so that the thick slurry fills the grouting fissures, thereby forming a complete plane grouting reinforcement area on the coal seam roof.

[0008] Preferably, the method for making the grouting shaft is:

[0009] First, drilling operations are carried out from the ground to the coal seam roof. The borehole diameter is 89-152mm, and the distance between the borehole and the coal seam roof is 5-20m. Then, casing is installed in the inner wall of the borehole and fixed on the inner wall of the borehole to form a grouting wellbore.

[0010] Preferably, the method for making the grouting fissure is:

[0011] First, the hydraulic cutting device is lowered into the grouting wellbore and the coal seam roof through the drill pipe;

[0012] Then the hydraulic cutting device is connected to the power device, and the hydraulic cutting device is driven by the power device to perform strong operations on the stratum to form grouting cracks in the coal seam roof.

[0013] Preferably, the grouting station is provided with a high-pressure pump group.

[0014] The high-pressure pump group includes at least one group of a first pulse high-pressure grouting pump body and a second pulse high-pressure grouting pump body;

[0015] A four-way device is provided at one end of the grouting shaft located on the ground;

[0016] The two horizontal ends of the four-way device are respectively connected to the output ends of the first pulse high-pressure grouting pump body to serve as grouting channels; the two ports in the vertical direction of the four-way device are respectively connected to the output end of the second pulse high-pressure grouting pump body and the orifice casing to serve as power devices for the hydraulic cutting device.

[0017] Preferably, the width of the grouting fissure is 10 times the particle size of the solid particles in the grouting slurry.

[0018] Preferably, the density of the thin slurry is 1.03-1.05 g / cm3; the density of the thick slurry is 1.1-1.3 g / cm3.

[0019] Preferably, in step three, the injection of thin slurry and thick slurry is performed by pulse high-pressure grouting.

[0020] Compared with the prior art, the beneficial effects of this application are:

[0021] The present application sets up a grouting shaft, lowers a hydraulic cutting device into one end of the grouting shaft located underground, connects a second pulse high-pressure grouting pump body to the other end of the grouting shaft located on the ground, and drives the hydraulic cutting device as a power device. The high-pressure grouting of the high-pressure grouting pump body drives the hydraulic cutting device to form a continuous rated pressure impact on the void structure of the coal seam roof aquifer through high-intensity, continuous, and uninterrupted pulse high-pressure grouting, causing the intermittent local increase of the pores in the sandstone formation on the top of the working face, thereby forming grouting fissures, and then the first grouting pump body is used to inject slurry into the grouting fissures in a high-intensity, continuous, and uninterrupted pulse manner. The slurry can be diffused to the far end under the action of pulse extrusion and impact, that is, the grouting 3

[0022] Around the cracks, 1.1-1.3g / cm slurry is used to fill the formed cracks, and finally a relatively complete plane grouting reinforcement area can be formed above the coal seam roof, destroying the water accumulation conditions of the coal seam roof; transforming the water-richness of the coal seam roof, reducing the risk of water inrush in the mining face, and improving the mining speed of the working face and the safety production conditions of the mine;

[0023] A pulse high-pressure grouting pump is used to facilitate the adjustment of the specific gravity of the grouting slurry.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 Schematic diagram of a coal seam roof pulse high pressure grouting working face water inrush prevention process in an embodiment of the present invention.

[0027] Among them, 1-four-way device, 2-upper end, 3-two horizontal ends, 4-rock layer, 5-coal seam roof, 6-hydraulic cutting device, 7-coal seam, 8-drill rod, 9-casing, 10-reinforcement area. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] According to the attached Figure 1 A coal seam roof pulse high pressure grouting working face water inrush prevention process is shown, the process comprising the following steps:

[0030] Step 1: Establish a drilling site and grouting station;

[0031] Step 2: a grouting shaft and a plurality of grouting fissures are made between the ground of the drilling site and the coal seam roof 5, wherein the grouting shaft is vertically arranged, the grouting fissures are located between the grouting shaft and the coal seam roof, and the plurality of grouting fissures and the grouting fissures are connected to each other;

[0032] Step three: first, inject thin slurry into the grouting fissures through the grouting shaft, so that the thin slurry diffuses into the coal seam around the grouting fissures; then inject thick slurry into the grouting shaft, so that the thick slurry fills the grouting fissures, thereby forming a complete planar grouting reinforcement area 10 on the coal seam roof 5.

[0033] In the present invention, the method for making the grouting shaft is:

[0034] First, drilling is performed from the ground to the coal seam roof 5, the borehole diameter is 89-152mm, and the distance between the borehole and the coal seam roof 5 is 5-20m; then casing 9 is installed in the inner wall of the borehole and fixed on the inner wall of the borehole to form a grouting wellbore.

[0035] In the present invention, the method for making the grouting fissure is:

[0036] First, the hydraulic cutting device 6 is lowered into the grouting wellbore and the coal seam roof 5 through the drill pipe 8;

[0037] Then the hydraulic cutting device 6 is connected to the power device, and the hydraulic cutting device 6 is driven by the power device to perform strong operations on the stratum, so as to form grouting cracks in the coal seam roof 5.

[0038] In the present invention, a high-pressure pump group is provided in the grouting station, and the high-pressure pump group includes at least one group of a first pulse high-pressure grouting pump body and a second pulse high-pressure grouting pump body;

[0039] A four-way device 1 is provided at one end of the grouting shaft located on the ground;

[0040] The two horizontal ends 3 of the four-way device 1 are respectively connected to the output ends of the first pulse high-pressure grouting pump body, serving as grouting channels; the two vertical ports of the four-way device 1 are respectively connected to the output ends of the second pulse high-pressure grouting pump body and the orifice casing 9, serving as power devices for the hydraulic cutting device 6.

[0041] In the present invention, the width of the grouting fissure is 10 times the particle size of the solid particles in the grouting slurry.

[0042] In the present invention, the density of the thin slurry is 1.03-1.05 g / cm3; the density of the thick slurry is 1.1-1.3 g / 3cm3.

[0043] In the present invention, in step three, the injection of thin slurry and thick slurry is performed by pulse high-pressure grouting.

[0044] It should be noted that the distance between the underground end of the grouting shaft and the coal seam roof 5 is 5-20 m, that is, from the ground to the rock layer 4 above the coal seam roof 5 .

[0045] It should be noted that the coal seam roof 5 is located at the top of the coal seam 7. The area within the coal seam roof 5 is a sandstone layer. The pores in the sandstone layer have certain opening and contraction properties, which are determined by the physical properties of the rock layer. Therefore, under the action of the ground high-pressure pump group, that is, when the pressure acting on the rock layer pores is greater than the closing pressure of the rock layer pores, the pores will open a part, and when the pressure acting on the rock layer pores is less than the closing pressure of the rock layer pores, the pores will return to their original state. However, since the high-pressure grouting method adopted in this application is an uninterrupted pulse grouting, it will cause the pores to be discontinuously locally enlarged, thereby achieving the discontinuous local enlargement of the pores of the sandstone formation of the working face roof 5 of the coal seam 7, and the water accumulation conditions can be destroyed after filling;

[0046] In the present application, a high-pressure pump group is also provided in the high-pressure station and is also equipped with its auxiliary device, namely, an automatic slurry tank. Since the high-pressure pump group has a specific gravity adjustment device, according to the program setting, there is an automatic stirring device in the slurry tank, which automatically adjusts the concentration of the slurry in the slurry tank, thereby realizing rapid adjustment of the specific gravity of the slurry;

[0047] In this application, one end of the grouting wellbore located on the ground is connected to a ground high-pressure pump group, and the through pressure can reach 100MPa. The borehole of the grouting wellbore can also be of other sizes. This application uses a borehole with a diameter of 152mm, which is more versatile.

[0048] The present application can form a relatively complete plane grouting reinforcement area 10 above the coal seam roof 5 to avoid the sudden release of a stream of water above the coal seam roof 55 without any buffer, causing flooding of wells and tunnels.

[0049] The construction process of the coal seam roof 5 pulse high pressure grouting working face water inrush prevention technology described in the present invention is as follows:

[0050] First, a drilling site and grouting station were established on the ground, and two high-pressure pumps with pulse high-pressure grouting function were installed;

[0051] Secondly, drilling a hole from the ground to a distance of 5-20m from the coal seam roof 5 to complete the construction of the grouting shaft;

[0052] Then, the drill rod 8 is used to carry the hydraulic cutting device 6 and is lowered from the grouting wellbore to the coal seam roof 5;

[0053] Next, install a four-way device 1 at one end of the grouting shaft located on the ground, and connect the input end and output end of the first pulse high-pressure grouting pump body to the port 3 in the horizontal direction of the four-way device 1 respectively; connect the second pulse high-pressure grouting pump body and the casing 9 to the two interfaces in the vertical direction of the four-way device 1 respectively, wherein the upper end 2 is connected to the output port of the second pulse high-pressure grouting pump body, and the lower end is connected to the casing 9;

[0054] Subsequently, the second pulse high-pressure grouting pump is turned on to drive the hydraulic cutting device 6 to perform a strong operation on the working surface (i.e., the coal seam roof 5), so as to form a crack of a certain width in the coal seam roof 5;

[0055] Finally, in the early stage, 1.03-1.05g / cm3 of slurry was used for pulse high-pressure grouting.

[0056] The slurry can be diffused to the far end under the impact, and the 1.1-1.3g / cm slurry is used to fill the formed cracks in the later stage, so that a relatively complete plane grouting reinforcement area 10 can be formed above the coal seam roof 5;

[0057] Repeating the above steps to complete the planar grouting reinforcement area above multiple groups of coal seam roofs 5 can effectively prevent water inrush problems in the mining face and increase the mining speed of the face.

[0058] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A coal seam roof pulse high pressure grouting working face water inrush prevention process, characterized in that: The process comprises the following steps: Step 1: Establish a drilling site and grouting station; Step 2: a grouting shaft and a plurality of grouting fissures are made between the ground of the drilling site and the roof of the coal seam, wherein the grouting shaft is arranged vertically, the grouting fissures are located between the grouting shaft and the roof of the coal seam, and the plurality of grouting fissures and the grouting fissures are connected to each other; Step 3: First, inject thin slurry into the grouting fissures through the grouting wellbore, so that the thin slurry diffuses into the coal seam around the grouting fissures; then inject thick slurry into the grouting wellbore, so that the thick slurry fills the grouting fissures, thereby forming a complete plane grouting reinforcement area on the coal seam roof; The distance between the grouting shaft and the coal seam roof is 5-20m; The method for making the grouting fissure is as follows: First, the hydraulic cutting device is lowered into the grouting wellbore and the coal seam roof through the drill pipe; Then the hydraulic cutting device is connected to the power device, and the hydraulic cutting device is driven by the power device to perform strong operations on the formation to form grouting cracks in the roof of the coal seam; The grouting station is provided with a high-pressure pump group. The high-pressure pump group includes at least one group of a first pulse high-pressure grouting pump body and a second pulse high-pressure grouting pump body; A four-way device is provided at one end of the grouting shaft located on the ground; The two horizontal ends of the four-way device are respectively connected to the output ends of the first pulse high-pressure grouting pump body to serve as grouting channels; the two ports in the vertical direction of the four-way device are respectively connected to the output end of the second pulse high-pressure grouting pump body and the orifice casing to serve as power devices for the hydraulic cutting device.

2. A coal seam roof pulse high pressure grouting working face water inrush prevention process according to claim 1, characterized in that: First, drilling operations are carried out from the ground to the coal seam roof. The borehole diameter is 89-152mm, and the distance between the borehole and the coal seam roof is 5-20m. Then, casing is installed in the inner wall of the borehole and fixed on the inner wall of the borehole to form a grouting wellbore.

3. A coal seam roof pulse high pressure grouting working face water inrush prevention process according to claim 1, characterized in that: The width of the grouting fissure is 10 times the particle size of the solid particles in the grouting slurry.

4. A coal seam roof pulse high pressure grouting working face water inrush prevention process according to claim 1, characterized in that: The density of the thin slurry is 1.03-1.05 g / cm3; the density of the thick slurry is 1.1-1.3 g / cm3.

5. A coal seam roof pulse high pressure grouting working face water inrush prevention process according to claim 1, characterized in that: In step three, both thin slurry and thick slurry are injected by pulse high-pressure grouting.

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