A method for preventing seepage of cement slurry and slurry in a waste coal mine well drilling

Abstract

The application discloses a kind of abandoned coal mine well drilling hole cement slurry and mud anti-seepage construction method, comprising the following steps: drilling into the depth of quaternary floor at wellhead, and drilling hole cement slurry at the position 4m-5m below quaternary floor, drilling hole mud at the position 1m-4m below quaternary floor;Continue to drill into 1 / 2 depth of well depth, and drilling hole cement slurry at the position 0m-1m above 1 / 2 depth of well depth, drilling hole mud at the position 1m-4m above 1 / 2;Continue to drill into the depth of well bottom, and drilling hole cement slurry at the position 0m-1m above well bottom, drilling hole mud at the position 1m-4m above well bottom;In the foregoing steps, each time drilling, open downhole television hole, detect in downhole television hole and after the last detection is completed, downhole television hole is lowered into air pipe.The abandoned coal mine well drilling hole cement slurry and mud anti-seepage construction method can block the hydraulic connection of surface pollutants and groundwater, control goaf water pollution problem to karst water layer.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of waste mine reconstruction, and particularly relates to a drilling and grouting cement slurry and mud anti-seepage construction method for a waste coal mine. BACKGROUND

[0002] A large number of waste coal mines serve as migration channels for connecting surface and underground water aquifers, seriously damaging the regional underground water system and environmental quality and safety. Coal mining activities cause dramatic changes in regional hydrogeological conditions and surface and underground water systems and environmental patterns, increase the risk of groundwater pollution, and cause a series of ecological and environmental problems such as deterioration of surface water quality, pollution of drinking water wells, karst collapse, and spring drying up.

[0003] At present, waste coal mines generally have no anti-seepage measures, forming a channel for surface pollutants and underground karst water, which seriously threatens the safety of underground water. The present application can block the hydraulic connection between surface pollutants and underground water and control the pollution of goaf water to the karst water layer through in-well anti-seepage and wellhead sealing measures. SUMMARY

[0004] The present application aims to provide a drilling and grouting cement slurry and mud anti-seepage construction method for a waste coal mine to solve the above problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution:

[0006] A drilling and grouting cement slurry and mud anti-seepage construction method for a waste coal mine, comprising the following steps:

[0007] S1, drilling down to the depth of the Quaternary floor at the wellhead and drilling and grouting cement slurry at a position 4m-5m below the Quaternary floor and drilling and grouting mud at a position 1m-4m below the Quaternary floor;

[0008] S2, continuing to drill down to 1 / 2 of the well depth and drilling and grouting cement slurry at a position 0m-1m above 1 / 2 of the well depth and drilling and grouting mud at a position 1m-4m above 1 / 2 of the well depth;

[0009] S3, continuing to drill down to the well bottom depth and drilling and grouting cement slurry at a position 0m-1m above the well bottom and drilling and grouting mud at a position 1m-4m above the well bottom;

[0010] S4, in the aforementioned steps, a downhole television hole is opened each time the drilling is down, and a gas guide pipe is lowered into the downhole television hole after the last detection is completed;

[0011] S5, excavating a pit groove 1.3m-1.5m deep within a range of 1m from the wellhead.

[0012] S6, covering 0.5m thick well lid in the pit slot;

[0013] S7, layering ramming over the well lid to the ground level;

[0014] S8, reclamation of the temporary road and site by loose ploughing and leveling, and setting up signboards, and completing the acceptance.

[0015] Further, before the step S1, the construction site is leveled, the temporary road is built, and the fence is constructed; the temporary road comprises a plurality of one-way lanes and a meeting island, the width of the one-way lane is at least 3.5m, and the width of the meeting island is at least 6.5m.

[0016] Further, the cement slurry adopts 425# ordinary portland cement, the water-cement ratio is divided into six levels of 5, 3, 2, 1, 0.8 and 0.5, the water quality pH value should be ≥4, and the slurry is filled by static pressure through the slurry conveying system, and the thickness is ≥1m, and the cement setting time exceeds 12 hours before the next operation.

[0017] Further, the three indexes of the slurry are respectively specific gravity 1.03-1.10, viscosity 17-20 and sand content less than 2%, the colloidal rate of the slurry is greater than 98%, the water quality pH value of the slurry is at least 4, and the slurry is filled by static pressure through the slurry conveying system.

[0018] Further, the well lid is made of reinforced concrete, the concrete grade is C40, and the thickness is at least 1m, and the initial setting is covered and maintained, and water is sprayed after final setting for 12h, and the maintenance time is at least 5 days.

[0019] Further, the construction environment temperature is 5 ℃~35 ℃, and rainproof measures should be taken before the concrete solidification.

[0020] Further, the compaction coefficient of the layering ramming in step S7 is at least 0.94, and the elevation is consistent with the periphery.

[0021] Further, in step S8, the loose ploughing and leveling reclamation of the temporary road and site is farmland or woodland, and the farmland soil thickness is at least 0.5m, and the woodland soil thickness is at least 0.3m.

[0022] Further, in step S4, the air guide pipe is made of N100 steel pipe, the lower end extends to the slurry above 4m at the bottom of the well, and is at least 0.5m above the ground surface, the top end of the air guide pipe is provided with a protective plug, which is convenient for subsequent water level monitoring and sampling.

[0023] Beneficial effects: This invention, through seepage prevention and wellhead sealing measures, can block the hydraulic connection between surface pollutants and groundwater, control the pollution of karst aquifers by accumulated water in mining areas, and implement three layers of seepage prevention and sealing: cement grouting and mud grouting for seepage prevention at the bottom of the well, cement grouting and mud grouting for seepage prevention at half the depth of the well, and cement grouting and mud grouting for seepage prevention at the bottom plate of the Quaternary system. Combined with reinforced well covers, the final ecological reclamation solves the problem of seepage prevention in abandoned coal mines filled with slag, and achieves the protection of groundwater. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the layered pouring of cement slurry and mud in this invention.

[0025] Attached reference numerals: 1. Cement slurry; 2. Mud; 3. Air pipe; 4. Manhole cover; 5. Pit. Detailed Implementation

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0027] Example:

[0028] like Figure 1 As shown, this embodiment provides a method for seepage prevention construction by drilling and grouting cement slurry 1 and mud 2 in abandoned coal mine shafts, including the following steps:

[0029] S1. Drill down to the depth of the Quaternary bottom plate at the wellhead, and drill a hole 4m-5m below the Quaternary bottom plate to inject cement grout 1, and drill a hole 1m-4m below the Quaternary bottom plate to inject mud grout 2.

[0030] S2. After the cement slurry 1 and mud slurry 2 from the previous step have solidified, continue drilling downwards to a depth of 1 / 2 of the well. Drill holes at a depth of 1 / 2 of the well and inject cement slurry 1 at a depth of 0m-1m above the depth of 1 / 2 of the well. Drill holes at a depth of 1m-4m above the depth of 1 / 2 of the well and inject mud slurry 2.

[0031] S3. After the cement slurry 1 and mud slurry 2 from the previous step have solidified, continue drilling down to the bottom depth of the well, and drill holes at a position of 0m-1m above the bottom of the well to inject cement slurry 1, and drill holes at a position of 1m-4m above the bottom of the well to inject mud slurry 2.

[0032] S4. In the aforementioned steps, a downhole television hole is opened each time the drilling proceeds downwards. The downhole television hole is used to probe the inside of the downhole television hole. After the last probe is completed, a gas guide pipe 3 is lowered into the downhole television hole. Hydrological monitoring can be carried out through the gas guide pipe 3.

[0033] S5. Excavate a pit 5 1.3m-1.5m deep within 1m of the outer edge of the wellhead. The pit 5 has a conical structure and is opened along the edge of the wellhead.

[0034] S6. Cover the pit 5 with a 0.5m thick manhole cover 4, the outer diameter of the manhole cover 4 matching the inner diameter of the pit 5.

[0035] S7. Compact the soil in layers above the manhole cover 4 until it is level with the ground.

[0036] S8. Loosen, level, and reclaim the temporary roads and sites, erect signboards, and complete the final acceptance inspection.

[0037] In another embodiment of the present invention, before step S1, the construction site is leveled, temporary roads are built and fences are erected; the temporary roads include multiple one-way streets and passing islands, the width of the one-way streets is at least 3.5m, and the width of the passing islands is at least 6.5m.

[0038] In another embodiment of the present invention, the cement slurry 1 uses 425# ordinary Portland cement with a water-cement ratio of 5, 3, 2, 1, 0.8, and 0.5, which are gradually changed from thin to thick during grouting. The pH value of the water should be ≥4. It is injected statically through the grouting system with a thickness ≥1m. The cement setting time must exceed 12 hours before the next step can be carried out.

[0039] In another embodiment of the present invention, the three main indicators of the mud are a specific gravity of 1.03-1.10, a viscosity of 17-20, and a sand content of less than 2%, respectively. The colloid content of the mud is greater than 98%, and the pH value of the mud water is at least 4. The mud is injected statically through a slurry delivery system.

[0040] In another embodiment of the present invention, the manhole cover is made of reinforced concrete with a concrete grade of C40 and a thickness of at least 1m. After initial setting, it is covered and cured, and water is sprayed after 12 hours of final setting. The curing time is at least 5 days.

[0041] In another embodiment of the present invention, the construction environment temperature is 5 ℃~35 ℃, and rain protection measures should be taken before the concrete cures.

[0042] In another embodiment of the invention, such as Figure 1 As shown, the soil compaction coefficient in step S7 is at least 0.94, and the elevation is consistent with the surrounding area.

[0043] In another embodiment of the present application, in step S8, the temporary road and site are reclaimed as farmland or forest land by loose plowing and leveling, and the thickness of the farmland soil is at least 0.5 m, and the thickness of the forest land soil is at least 0.3 m.

[0044] In another embodiment of the present application, as shown in Figure 1 In step S4, the gas guide pipe 3 is made of N100 steel pipe, the lower end extends to the top of the mud 4 m above the bottom of the well, and is at least 0.5 m above the ground surface, and the top end of the gas guide pipe 3 is provided with a protective plug to facilitate subsequent water level monitoring and sampling.

[0045] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the scope of protection of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preventing seepage of cement slurry and slurry in a waste coal mine shaft drilling, characterized in that, The method comprises the following steps: S1, drilling down to the depth of the Quaternary bottom at the wellhead, and drilling and pouring cement slurry at the position 4m-5m below the Quaternary bottom, and drilling and pouring mud at the position 1m-4m below the Quaternary bottom; S2, continuing to drill down to the depth of 1 / 2 of the well depth, and drilling and pouring cement slurry at the position 0m-1m above the depth of 1 / 2 of the well depth, and drilling and pouring mud at the position 1m-4m above the depth of 1 / 2 of the well depth; S3, continuing to drill down to the bottom of the well, and drilling and pouring cement slurry at the position 0m-1m above the bottom of the well, and drilling and pouring mud at the position 1m-4m above the bottom of the well; S4, in the foregoing steps, a downhole television hole is opened each time when drilling down, and a gas guide pipe is lowered into the downhole television hole after the last detection is completed; S5, a pit groove with a depth of 1.3m-1.5m is excavated within 1m of the outer edge of the wellhead; S6, a well cover with a thickness of 0.5m is covered in the pit groove; S7, the soil above the well cover is layered and compacted to be flush with the ground surface; S8, the temporary road and the site are cultivated and leveled for reclamation, and a signboard is erected, and the completion acceptance is completed.

2. The method for drilling and injecting cement slurry and slurry into a waste coal mine shaft according to claim 1, characterized in that, Before the step S1, the construction site is leveled, the temporary road is built, and the fence is constructed; the temporary road comprises a plurality of one-way lanes and a meeting island, the width of the one-way lane is at least 3.5m, and the width of the meeting island is at least 6.5m.

3. The method for drilling and injecting cement slurry and slurry into a waste coal mine shaft according to claim 1, characterized in that, The cement slurry adopts 425# ordinary portland cement, the water-cement ratio is 5, 3, 2, 1, 0.8, and 0.5, the water quality pH value should be greater than or equal to 4, the thickness is greater than or equal to 1m, and the cement setting time is more than 12 hours before the next operation.

4. The method for drilling and injecting cement slurry and slurry into a waste coal mine shaft according to claim 1, characterized in that, The three indexes of the mud are respectively specific gravity 1.03-1.10, viscosity 17-20, and sand content less than 2%, the colloidal rate of the mud is greater than 98%, the water quality pH value of the mud is at least 4, and the mud is filled by the static pressure of the slurry conveying system.

5. The method for drilling and injecting cement slurry and slurry into a waste coal mine shaft according to claim 1, characterized in that, The well cover is made of reinforced concrete, the concrete grade is C40, and the thickness is at least 1m, the cover is cured after initial setting, water is sprayed after final setting for 12 hours, and the curing time is at least 5 days.

6. The method of claim 5, wherein the method further comprises the step of: The construction environment temperature is 5 ℃-35 ℃, and rainproof measures should be taken before the concrete solidification. ​ 7. The method for drilling and injecting cement slurry and slurry into a waste coal mine shaft according to claim 1, characterized in that, The compaction coefficient of the layered compaction in the step S7 is at least 0.94, and the elevation is consistent with the periphery.

8. The method for drilling and grouting cement slurry and mud for preventing seepage in abandoned coal mine shafts according to claim 1, characterized in that, In the step S8, the temporary road and the site are cultivated and leveled for reclamation as farmland or woodland, the farmland soil thickness is at least 0.5m, and the woodland soil thickness is at least 0.3m.

9. The method for drilling and grouting cement slurry and mud for preventing seepage in abandoned coal mine shafts according to claim 1, characterized in that, In the step S4, the gas guide pipe is made of N100 steel pipe, the lower end extends to the position 4m above the bottom of the well and above the mud, and is at least 0.5m above the ground surface, a protective plug is arranged at the top end of the gas guide pipe, and the subsequent water level monitoring and sampling are facilitated.

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