Slurry leakage prevention grouting method for coal seam roadway bottom plate
Through quantitative intermittent grouting and grouting technology and ground area management technology, the problem of slurry running on the bottom plate of the coal seam tunnel is solved, rapid treatment and stratigraphic reinforcement are achieved, and normal production of the mine is ensured.
Patent Information
- Application Number
- CN202411359063.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-02-11
AI Technical Summary
During deep mining of coal mines, the slurry problem of coal seam tunnel bottom plates is serious, resulting in waste of grouting materials and affecting mine production. It is difficult to solve the problem quickly and effectively in the existing technology.
The quantitative intermittent grouting and grouting process is adopted, and by adjusting the grouting volume, grouting batch and slurry ratio, combined with ground area management technology, the bottom plate of the coal seam tunnel is quickly treated, and the slurry running channels are blocked to ensure normal production of the mine.
It has achieved rapid control of the slurry running of coal seam tunnel floors, saved manpower and material resources, reduced waste of grouting materials, ensured normal production of mines, and effectively strengthened the formation.
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Figure CN119412098A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of coal mine floor water hazard prevention and control, and in particular to a grouting method for preventing slurry leakage from a coal seam tunnel floor. Background Art
[0002] As shallow coal resources in the North my country coalfields are exhausted, deep coal resources are seriously threatened by floor limestone karst water hazards. The conventional underground coal seam floor grouting method for water hazard control has a series of problems such as limited construction location, short target hole section when drilling into aquifers, low efficiency, inaccurate target location, poor grouting effect, and high safety risks of high-pressure aquifers faced during construction, making it difficult to efficiently explore and control coal seam floor water hazards.
[0003] To this end, in 2012, Jizhong Energy Fengfeng Group introduced the mature horizontal directional drilling technology of the petroleum system, invented the ground regional governance technology of integrated exploration, treatment and verification of water hazard in the coal seam floor pressure aquifer, and successfully explored it in the 15445N working face of Jiulong Mine, greatly increasing the length of the grouting hole section, improving the drilling exposure of the target layer fracture zone and water-bearing area, reducing the grouting blind area, and improving the quality of grouting reinforcement transformation. After that, practical research and promotion and application were carried out in Yangdong Mine, Wutongzhuang Mine, Xin'an Mine, Sunzhuang Mine, etc., and further promoted to Xingdong Mine, Dongpang Mine and Gequan Mine of Jizhong Energy Co., Ltd., achieving good governance results and effectively solving the technical problems of water hazard prevention and control in deep coal mining.
[0004] In engineering practice, the process of grouting reinforcement and transformation of the coal seam floor using ground area management technology is often faced with a series of technical difficulties due to the influence of geological conditions such as stratum lithology, fault fissures, and compressive strength of surrounding rocks in the management area. For example, long-term lack of pressure during grouting, slurry running on the ground, slurry running in the shaft and tunnel, bulging of the shaft and tunnel, abnormal increase in water level in the long observation hole, and increased water inflow from adjacent working faces. In particular, slurry running on the floor of the coal seam tunnel not only causes unnecessary waste of grouting materials, but also has adverse effects on coal mine shaft and tunnel engineering, requiring additional manpower and material resources to deal with it. In severe cases, it may even affect the normal production of the mine. Therefore, it is particularly important to quickly and effectively solve the problem in the early stage of slurry running. Summary of the invention
[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a grouting method for preventing slurry leakage in the bottom plate of a coal seam tunnel. The grouting method of the present invention is used to carry out grouting reinforcement and transformation of the coal seam bottom plate, and the quantitative intermittent grouting process of adjusting the grouting amount, grouting interval, and slurry ratio is used to quickly treat the slurry leakage of the bottom plate of the coal seam tunnel during grouting, taking into account both strengthening the stratum and blocking the slurry leakage channel, which will not affect the normal production of the mine, and saves manpower, material resources, and grouting materials.
[0006] The technical solution of the present invention to solve the above technical problems is as follows:
[0007] The present invention provides a method for grouting to prevent slurry leakage of a coal seam tunnel floor, comprising the following steps:
[0008] (1) drilling holes for grouting into the alluvial layer on the ground to form a straight hole section; installing a primary casing in the straight hole section and sealing it; directional drilling is performed in the primary casing to enter the target limestone layer to form a deflection section; installing a secondary casing in the deflection section and sealing it; drilling along the upper part of the target limestone layer in the secondary casing to form branch holes, and then grouting is performed in the branch holes to treat the target aquifer;
[0009] (2) When slurry leaks from the coal seam tunnel above the branch borehole, the control grouting is stopped, the slurry leaking location is determined, and the borehole volume to the slurry leaking location is calculated to obtain a single grouting volume, and then plugging grouting is performed. After the slurry fills the orifice of the straight hole section, a pause is made for a period of time, and then the grouting is continued until the orifice of the straight hole section is filled. The grouting cycle is continued until the grouting volume reaches the single grouting volume, and then the grouting is stopped and paused, and then the next grouting is performed. When the slurry leaking from the slurry leaking location becomes thick slurry, the grouting is stopped;
[0010] (3) After the grouting is completed, the drill is lowered to sweep the hole to the front of the branch borehole and wait for solidification, and then the hole is swept to the branch borehole, and step (2) is repeated;
[0011] (4) Repeat step (3) to perform plugging grouting until slurry leakage stops and the plugging process is completed.
[0012] The beneficial effects of the present invention are as follows: the coal seam floor is grouting reinforced and transformed by the grouting method of the present invention, and the grouting amount, grouting interval, and slurry ratio are adjusted by a quantitative intermittent grouting process to quickly deal with the slurry leakage from the coal seam tunnel floor during grouting, while taking into account both strengthening the stratum and blocking the slurry leakage channel, without affecting the normal production of the mine, and saving manpower, material resources, and grouting materials.
[0013] Preferably, the branch drill holes are horizontal branch holes. Before construction, the spatial position relationship between the branch holes and the coal seams and shaft and tunnel engineering is analyzed according to the branch hole design trajectory and design plan and cross-section drawings, the structural development characteristics within the treatment range are analyzed, the possibility of shaft and tunnel slurry leakage is determined, and the grouting sections that may cause slurry leakage during the construction process are divided.
[0014] Preferably, during grouting, if there are tunnels or goafs in the overlying rock layer or nearby areas of the grouting area, the mine should strengthen underground inspections and promptly notify the grouting construction unit if grouting is found; during grouting, the ground unit should strengthen the observation of wellhead pressure changes. When the pressure rises or falls abnormally (the pressure change in half an hour is greater than 0.5MPa), it should communicate with the mine's underground inspection personnel in a timely manner and analyze the reasons for the abnormal pressure change. During grouting, observe the changes in wellhead pressure.
[0015] Based on the above technical solution, the present invention can also be improved as follows.
[0016] Furthermore, the aperture of the straight hole section in step (1) is 300-330 mm; the outer diameter of the primary casing is 240-250 mm, and the tube thickness is 8-10 mm; the aperture of the inclined section is 210-220 mm, the outer diameter of the secondary casing is 170-180 mm; the tube thickness is 7.5-8.5 mm; the branch borehole is a bare hole with a aperture of 150-155 mm.
[0017] The beneficial effect of adopting the above further scheme is: ensuring the borehole diameter can guarantee the smooth progress of the subsequent grouting process and provide a basis for grouting reinforcement of the coal seam floor.
[0018] Furthermore, in the treatment grouting in step (1), the grouting material used is clay mixed slurry, and the specific gravity of the grouting material is 1.20-1.22.
[0019] Furthermore, the grouting end standard is a grouting pressure of 5-10MPa.
[0020] Furthermore, during the plugging grouting in step (2), P42.5 cement is selected as the grouting material, and the specific gravity of the grouting material is 1.5-1.65.
[0021] The beneficial effect of adopting the above-mentioned further scheme is: using high-specific-gravity grouting materials for grouting in the form of small and medium pump volumes can significantly reduce the phenomenon of shrinkage cracks caused by the solidification of the grouting materials in the borehole, effectively block the shrinkage cracks of the grouting materials and the cracks in the surrounding rocks around the borehole, which is conducive to achieving the best grouting effect and preventing the slurry from losing to non-treated parts or areas.
[0022] Furthermore, the grouting volume of each plugging grouting in step (2) is greater than 1.2-1.3 times the volume of the borehole.
[0023] Furthermore, before stopping the grouting in step (2), the slurry discharged from the slurry discharge point becomes thick slurry 30 minutes to 60 minutes later.
[0024] The beneficial effect of adopting the above further scheme is that it indicates that the slurry leakage channel has been completely filled with cement slurry and the slurry leakage situation has been quickly controlled.
[0025] Furthermore, after reaching the single grouting volume in step (2), the grouting is stopped for an interval of 12 hours to 72 hours.
[0026] The beneficial effects of adopting the above further solution are: intermittent grouting can effectively prevent the occurrence of grouting phenomenon, improve the grouting effect and safety, and can achieve rapid solidification and strengthen the formation, thereby improving the stability and bearing capacity of the formation.
[0027] Preferably, if the single grouting volume cannot be reached and the slurry stops sinking, a hole grouting device can be added to slightly increase the pressure to grout to the single grouting volume.
[0028] Furthermore, the waiting time for coagulation in step (3) is 48h-60h.
[0029] The beneficial effect of adopting the above further scheme is that after grouting, the grouting material can be evenly diffused into the surrounding soil to form a consolidated body with certain strength and stability to meet the needs of strengthening the stratum and blocking the slurry leakage channel.
[0030] Furthermore, the distance from the drilling and hole sweeping to the grouting section in step (4) is 100m-200m.
[0031] Preferably, if step (4) fails to achieve the plugging effect, the process of the above step (3) is repeated again, and an appropriate amount of sawdust is added during the slurry preparation process to perform plugging grouting until the slurry no longer leaks from the shaft and the plugging process is completed. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 This is a schematic diagram of ground area management according to Example 1 of the present invention;
[0033] Figure 2 This is a schematic diagram of slurry running on the bottom plate of a coal seam roadway according to Example 1 of the present invention;
[0034] Figure 3 This is a schematic diagram of the drilling structure of Example 1 of the present invention. DETAILED DESCRIPTION
[0035] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.
[0036] Example 1: Anti-slurry grouting of coal seam tunnel floor
[0037] (1) A grouting drilling was carried out on the ground of a mine in Henan Province, with a hole diameter of φ311 mm into the alluvial layer to form a straight hole section; a J55 casing with a diameter of φ244.5×8.94 mm was installed in the straight hole section as the primary casing and firmly consolidated to isolate the alluvial layer; directional drilling was continued in the primary casing, and after entering the target limestone layer, a deflection section with a hole diameter of φ215.9 mm was formed; a J55 casing with a specification of not less than φ177.8×8.05 mm was installed in the straight hole section and the deflection section as the secondary casing and firmly consolidated;
[0038] Before constructing horizontal branch holes, first analyze the spatial position relationship between the branch holes and the coal seam and the shaft and tunnel engineering according to the branch hole design trajectory and design plan and section drawings, analyze the structural development characteristics within the treatment range, preliminarily judge the possibility of shaft and tunnel slurry leakage, and divide the grouting sections that may cause slurry leakage during the construction process;
[0039] Continue to drill along the upper 3-5m of the target limestone layer in the secondary casing to form a bare hole with a hole diameter of φ152mm, which is a branch hole. Use clay mixed slurry with a slurry specific gravity of 1.20-1.22 to treat the L8 limestone aquifer. The grouting end standard is 8MPa. During grouting, if there are tunnels or goafs in the overlying rock layer or nearby areas of the grouting section, the mine should strengthen underground inspections and promptly notify the grouting construction unit if slurry leakage is found. During grouting, the ground unit should strengthen the observation of wellhead pressure changes. When the pressure change is greater than 0.5MPa in half an hour, communicate with the mine's underground inspection personnel in a timely manner and analyze the reasons for the abnormal pressure change.
[0040] (2) When the grouting pressure at the grouting point reaches 5.4 MPa, slurry leakage occurs on the floor of the underground coal seam tunnel, and the amount of slurry leakage is 2m 3 / h, stopped grouting, and analyzed the cause of grouting leakage. It was found that the grouting point at 1180m of the X-6 branch was close to the weak zone of the 3D seismic fault, where cracks were developed and the compressive strength of the bottom plate was reduced. Under the action of high-pressure grouting pressure, the cracks between the L8 limestone aquifer and the underground roadway were pressed open, connecting with the underground roadway and causing grouting leakage.
[0041] The volume of the borehole to the slurry leakage site and the single grouting volume of the plugging grouting are calculated. The single grouting volume is 30 cubic meters. The grouting material is PC42.5 cement. The specific gravity of the grouting material is determined to be 1.30 according to the slurry leakage situation. The plugging grouting is carried out in the form of quantitative intermittent grouting grouting process. After the slurry fills the orifice of the straight hole section, it is paused for a period of time. After the slurry sinks to a certain distance from the orifice of the straight hole section, it continues to grout until it fills the orifice of the straight hole section. Then, the grouting is stopped and the next grouting is carried out after a 12-hour pause. Repeat the above-mentioned plugging grouting process. During the process, the slurry characteristics of the underground slurry leakage site are continuously observed. When the slurry leaking out of the underground slurry leakage site becomes thick slurry for more than 30 minutes, the grouting is stopped.
[0042] (3) After grouting is completed, drill down and sweep the hole to the range 100-200m before the grouting section, wait for 60 hours, and then sweep the hole to the grouting section and repeat the above step (2).
[0043] (4) After repeating the above step (3) twice, the hole was swept to the 1180m grouting point for normal grouting. During the process, no grout leakage occurred in the underground tunnel, and the plugging process was completed.
[0044] The schematic diagram of the drilling structure of Example 1 is as follows Figure 1 , 3 As shown in the figure, the pulp running situation is as follows Figure 2 As shown in the figure, after the above operation, the crack between the target layer and the underground tunnel was blocked, and the slurry flow rate of the tunnel floor was reduced from 2m3 / h to 0m 3 / h, no slurry leakage was found in the subsequent normal grouting process, and the sealing effect was good.
[0045] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.
Claims
1. A method for preventing grouting of coal seam tunnel floor, characterized in that: The grouting method comprises the following steps: (1) drilling holes for grouting into the alluvial layer on the ground to form a straight hole section; installing a primary casing in the straight hole section and sealing it; directional drilling is performed in the primary casing to enter the target limestone layer to form a deflection section; installing a secondary casing in the deflection section and sealing it; drilling along the upper part of the target limestone layer in the secondary casing to form branch holes, and then grouting is performed in the branch holes to treat the target aquifer; (2) When slurry leaks from the coal seam tunnel above the branch borehole, the control grouting is stopped, the slurry leaking location is determined, and the borehole volume to the slurry leaking location is calculated to obtain a single grouting volume, and then plugging grouting is performed. After the slurry fills the orifice of the straight hole section, a pause is made for a period of time, and then the grouting is continued until the orifice of the straight hole section is filled. The grouting cycle is continued until the grouting volume reaches the single grouting volume, and then the grouting is stopped and paused, and then the next grouting is performed. When the slurry leaking from the slurry leaking location becomes thick slurry, the grouting is stopped; (3) After the grouting is completed, the drill is lowered to sweep the hole to the front of the branch borehole and wait for solidification, and then the hole is swept to the branch borehole, and step (2) is repeated; (4) Repeat step (3) to perform plugging grouting until slurry leakage stops and the plugging process is completed.
2. The method for preventing grouting of coal seam tunnel floor according to claim 1, characterized in that: The aperture of the straight hole section in step (1) is 300-330mm; the outer diameter of the primary casing is 240-250mm, and the tube thickness is 8-10mm; the aperture of the inclined section is 210-220mm, the outer diameter of the secondary casing is 170-180mm; the tube thickness is 7.5-8.5mm; the branch borehole is a bare hole with an aperture of 150-155mm.
3. The method for preventing grouting of coal seam tunnel floor according to claim 2, characterized in that: During the treatment grouting in step (1), the grouting material used is clay mixed slurry, and the specific gravity of the grouting material is 1.20-1.
22.
4. The method for preventing grouting of coal seam tunnel floor according to claim 3, characterized in that: The grouting end standard is a grouting pressure of 5-10MPa.
5. The method for preventing grouting of coal seam tunnel floor according to claim 1, characterized in that: During the plugging grouting in step (2), P.C42.5 cement is selected as the grouting material, and the specific gravity of the grouting material is 1.5-1.
65.
6. The method for preventing grouting of coal seam tunnel floor according to claim 5, characterized in that: The grouting volume of each plugging grouting in step (2) is greater than 1.2-1.3 times the volume of the borehole.
7. The method for preventing grouting of coal seam tunnel floor according to claim 6, characterized in that: Before stopping the grouting in step (2), the slurry discharged from the slurry discharge point becomes thick slurry 30 minutes to 60 minutes.
8. The method for preventing grouting of coal seam tunnel floor according to claim 7, characterized in that: After reaching the single grouting volume in step (2), the grouting is stopped for an interval of 12h-72h.
9. The method for preventing grouting of coal seam tunnel floor according to claim 1, characterized in that: The waiting time for coagulation in step (3) is 48h-60h.
10. The method for preventing grouting of coal seam tunnel floor according to claim 1, characterized in that: The distance from the drilling and hole sweeping to the grouting section in step (4) is 100m-200m.