Drilling tool for landfill leachate water level monitoring hole and construction method

Abstract

The invention discloses a drilling tool for a landfill leachate water level monitoring hole and a construction method, and belongs to the technical field of environment monitoring. The construction method comprises the steps that after the position of a monitoring point is determined, drilling investigation is conducted; a casing pipe is arranged in the drilling process; lowering a pipe; a monitoring pipe is arranged in the drill hole, the monitoring pipe is formed by sequentially connecting a water permeable pipe and multiple sections of solid pipes, the water permeable pipe is located at the lowermost garbage layer for long-term observation, the solid pipe located on the uppermost side is a top solid pipe, the rest solid pipes are middle solid pipes, and the outer side of the water permeable pipe is wrapped with a filter screen; filling gaps among the pipe holes, filling the gaps between the permeable pipe at the bottom and the drill hole with coarse sand, and then filling the gaps between the middle solid pipe and the drill hole and between the top solid pipe and the drill hole with bentonite balls; a pipe opening of the top solid pipe exposed out of the earth surface is closed and marked; covering the top cover; checking a drill hole; and after burying, the drilled hole is inspected. The method has the advantages of being wider in application range, not limited by hole depth, higher in durability, more convenient to operate, lower in cost and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental monitoring, and in particular relates to a drilling tool and a construction method for a landfill leachate water level monitoring hole. Background Art

[0002] As an important facility for treating urban waste, the stability and environmental safety of landfills have always been widely concerned. During the degradation of waste, landfills will produce a large amount of landfill gas and leachate. The increase in leachate level will have an extremely adverse effect on the stability of the waste pile, and the drilling of monitoring holes is a key link in leachate level monitoring.

[0003] The geological conditions of landfills are complex and changeable. The lithology, permeability, stability and other characteristics of different strata have an important impact on the stability of landfills and the spread of pollution. Drilling technology can directly obtain samples and in-situ data of underground rock strata, providing a scientific basis for the design, construction and operation management of landfills.

[0004] In order to effectively monitor the generation and migration of leachate in landfills and changes in groundwater levels, it is necessary to regularly drill monitoring holes in or around the landfill and install corresponding monitoring equipment.

[0005] However, existing drilling methods often have problems such as small borehole diameter and low stability in the landfill garbage pile, and repeated drilling, which leads to very low drilling efficiency, insufficient monitoring accuracy, high cost, and damage to the landfill structure. It is difficult to meet the increasingly stringent environmental protection requirements. Summary of the invention

[0006] The main purpose of the present invention is to provide a drilling tool and construction method for a landfill leachate water level monitoring hole, so as to solve the problems of small hole diameter, low stability, and widespread repeated drilling in garbage piles in landfills, resulting in very low hole-forming efficiency.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A drilling tool for a landfill leachate water level monitoring hole comprises a drill pipe and a drill bit connected thereto, wherein the drill bit comprises:

[0009] Drill bit body;

[0010] A plurality of steel blocks, each of which is fixed to the front end of the inner wall of the drill body, and the plurality of steel blocks are arranged at intervals along the circumferential direction of the drill body;

[0011] A plurality of wedge-shaped protrusions are fixed to the front end of the drill body, and the plurality of wedge-shaped protrusions are arranged at intervals along the circumferential direction of the drill body.

[0012] A method for constructing a landfill leachate water level monitoring hole, using the above-mentioned drilling tool for the landfill leachate water level monitoring hole, the method comprising the following steps:

[0013] S10. After determining the location of the monitoring point, conduct drilling survey, and drill holes from top to bottom to penetrate the garbage accumulation layer above the borehole, the middle covering soil layer, and the garbage layer for long-term observation; set casing during the drilling process;

[0014] S20, lowering the pipe; lowering the monitoring pipe in the borehole, wherein the monitoring pipe is formed by connecting a water-permeable pipe and multiple sections of solid pipes in sequence, wherein the water-permeable pipe is located at the lowest end of the garbage layer for long-term observation, the solid pipe located at the uppermost side is the top solid pipe, and the rest are middle solid pipes, and the outer side of the water-permeable pipe is wrapped with a filter screen;

[0015] S30, filling the gaps between the pipe holes, filling the gap between the bottom permeable pipe and the borehole with coarse sand, and then filling the gaps between the middle solid pipe and the borehole, and between the top solid pipe and the borehole with bentonite balls;

[0016] S40, the pipe opening of the top solid pipe exposed on the ground is closed and marked; a top cover is put on, and the top cover is fixed to the top solid pipe;

[0017] S50, inspection of the borehole; after burial, inspect the borehole to confirm whether it is tightly sealed. If not, fill the hole with bentonite balls, add water appropriately until it is tightly filled, fix the monitoring point with cement mortar, and mark the measuring point number on the mortar.

[0018] Furthermore, in step S10, the bottom of the landfill leachate water level monitoring hole must be more than 2 m away from the bottom of the middle covering soil layer.

[0019] Further, in S20, the depth of the drilled hole reaches 50% of the designed hole depth, and then the casing is buried, and the buried depth of the casing is 50% of the designed hole depth.

[0020] Furthermore, for the first 50% of the designed hole depth, a 146mm drill bit body is used for drilling, and then casing is buried to protect the wall. The buried depth of the casing is 50% of the designed hole depth. The remaining 50% of the designed hole depth is drilled using a 108mm drill bit body to complete the drilling, form a hole, and determine the position and thickness of the intermediate covering layer, the thickness of the garbage accumulation layer above the borehole, and the lower elevation a and upper elevation b of the hole section where the garbage layer is located under long-term observation, and finally the casing is pulled out.

[0021] Further, in step S20, the diameter of the drilled hole is larger than the diameters of the middle solid pipe, the top solid pipe and the permeable pipe.

[0022] Furthermore, in step S20, the bottom of the permeable pipe is first connected to the bottom cover, and then the permeable pipe is connected to the middle solid pipe of the adjacent section. After being connected and fixed, it is placed in the drill hole, and a part is leaked out and then connected to the second section of the middle solid pipe; pipes are placed in the drill hole in turn, and then the pipes are connected, and so on; the height of the top solid pipe of the last section exposed above the ground does not exceed 1m, and the excess part is sawed off with a wire saw, and the pipe mouth needs to be sawed flat.

[0023] Further, in step S30, the sum of the top solid tube and the filling thickness of the bentonite balls is equal to the aperture of the top of the borehole, the sum of the diameter of the middle solid tube and the filling thickness of the bentonite balls is equal to the aperture of the upper part of the borehole, and the sum of the diameter of the permeable tube and the filling thickness of the coarse sand is equal to the aperture of the bottom of the borehole.

[0024] Furthermore, in step S30, water is brought in when filling the sand, but no water is brought in when filling the bentonite balls, so as to prevent the bentonite balls from expanding and blocking the hole openings, causing the lower pores to be emptied. When placing the bentonite balls, a few are placed at a time to prevent them from getting stuck together and the lower part from being filled with the bentonite balls. After the bentonite balls are filled, a small amount of clean water is poured in.

[0025] Further, in step S50, after burial, observe whether there is any subsidence around the borehole each time, and shake the pipe to observe whether it shakes. If such a phenomenon occurs, it means that the area around the hole is not filled densely, and then fill the bentonite ball to seal the hole, add water appropriately to facilitate the expansion of the bentonite ball to seal the hole. After observing for a week, confirm that the hole is sealed densely, and then fix the monitoring point with cement mortar, and mark the measuring point number on the mortar. After no problems are found, the drilling of the landfill leachate water level monitoring hole is completed.

[0026] Beneficial effects:

[0027] The present invention can specifically identify the leachate level and underground stratified settlement of the landfill garbage pile, and then evaluate the safety and stability of the garbage pile, provide safety monitoring technical services for maintaining the stability of the landfill garbage pile, and ensure the reliability and safety of the landfill operation. Compared with the prior art, the present invention has the advantages of wider application range, no limitation on hole depth, higher durability, more convenient operation, lower cost, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of drilling holes in the present invention;

[0029] Figure 2 This is a schematic diagram of a monitoring pipe under a borehole according to the present invention;

[0030] Figure 3 This is a schematic diagram of drilling and plugging according to the present invention;

[0031] Figure 4It is a schematic diagram of the drilling tool of the present invention;

[0032] Explanation of the reference numerals: 1 - permeable pipe, 2 - middle solid pipe, 3 - bottom cover, 4 - top solid pipe, 5 - top cover, 6 - coarse sand, 7 - bentonite ball, 8 - garbage layer for long-term observation, 9 - borehole, 10 - garbage accumulation layer above the borehole, 11 - middle covering soil layer, 12 - casing, 13 - drill bit body, 14 - steel block, 15 - wedge-shaped protrusion, 16 - drill pipe. DETAILED DESCRIPTION

[0033] Example 1

[0034] refer to Figure 4 , a drilling tool for a landfill leachate water level monitoring hole, comprising: a drill pipe 16 and a drill bit connected thereto, the drill bit comprising:

[0035] Drill body 13;

[0036] A plurality of steel blocks 14, each of which is fixed to the front end of the inner wall of the drill body 13, and the plurality of steel blocks 14 are arranged at intervals along the circumferential direction of the drill body 13;

[0037] Preferably, three steel blocks 14 are provided and are evenly distributed along the circumferential direction of the drill body 13 .

[0038] A plurality of wedge-shaped protrusions 15 are fixed to the front end of the drill body 13 , and the plurality of wedge-shaped protrusions 15 are arranged at intervals along the circumferential direction of the drill body 13 .

[0039] Preferably, the wedge-shaped protrusion 15 is a wedge-shaped metal protrusion, and six wedge-shaped protrusions 15 are provided, with one wedge-shaped protrusion 15 being provided on both sides of each steel block 14 .

[0040] During specific implementation, a steel block 14 is welded at the front end of the inner wall of the drill body 13, so that the loose garbage drilled by the drill body 13 will not easily slip out of the drill pipe 16 after entering the drill pipe 16; a wedge-shaped protrusion 15 is welded at the front end of the drill body 13, so that the drill body 13 can easily cut off garbage such as cloth and woven bags when drilling into the garbage body.

[0041] Example 2

[0042] refer to Figure 1 - Figure 4 This embodiment provides a method for constructing a landfill leachate water level monitoring hole, using the drilling tool for the landfill leachate water level monitoring hole in Embodiment 1, and the method includes the following steps:

[0043] S10, after determining the location of the monitoring point, conduct drilling survey, and drill hole 9 penetrates the garbage accumulation layer 10 above the borehole, the middle covering soil layer 11, and the garbage layer 8 for long-term observation from top to bottom; and set a casing 12 during the drilling process;

[0044] In this embodiment, in step S10, the bottom of the landfill leachate water level monitoring hole must be more than 2 m away from the bottom of the middle covering soil layer.

[0045] S20, lowering the pipe; lowering the monitoring pipe in the borehole 9, wherein the monitoring pipe is formed by a water-permeable pipe 1 and multiple sections of solid pipes connected in sequence, wherein the water-permeable pipe 1 is located at the lowest end of the long-term observed garbage layer 8, the solid pipe located at the uppermost side is the top solid pipe 4, and the rest are the middle solid pipes 2, and the outer side of the water-permeable pipe 1 is wrapped with a filter screen;

[0046] During specific implementation, the outer side of the water-permeable pipe 1 is wrapped and tied with a corrosion-resistant filter mesh.

[0047] Preferably, the permeable pipe 1 and the solid pipe are both HDPE pipes with an inner diameter of 50 mm and an outer diameter of 65 mm, and the length of the permeable pipe 1 and the length of each section of the solid pipe are both 2 m.

[0048] In this embodiment, in S20, the depth of the drilled hole 9 reaches 50% of the designed hole depth, and then the casing 12 is buried, and the buried depth of the casing 12 is 50% of the designed hole depth.

[0049] In this embodiment, a 146 mm drill bit body 13 is used for drilling the first 50% of the designed hole depth, and then a casing 12 is buried to protect the wall. The buried depth of the casing 12 is 50% of the designed hole depth. A 108 mm drill bit body 13 is used to complete the drilling of the remaining 50% of the designed hole depth. A mechanical rotary drilling and full-hole continuous coring construction process is adopted to form a hole and determine the position and thickness of the middle covering layer 11, the thickness of the garbage accumulation layer 10 above the borehole, and the lower elevation a and upper elevation b of the hole section where the garbage layer 8 is located that has been observed for a long time. Finally, the casing 12 is pulled out.

[0050] In this embodiment, in step S20 , the diameter of the drilled hole 9 is larger than the diameters of the middle solid pipe 2 , the top solid pipe 4 and the water-permeable pipe 1 .

[0051] In this embodiment, in step S20, the bottom of the water-permeable pipe 1 is first connected to the bottom cover 3, and then the water-permeable pipe 1 is connected to the middle solid pipe 2 of the adjacent section. After connection and fixing, the pipe is placed in the borehole 9, and a portion is leaked out and then connected to the second middle solid pipe 2; pipes are placed in the borehole 9 in sequence, and then the pipes are connected, and so on; the height of the top solid pipe 4 of the last section exposed above the ground does not exceed 1m, and the excess part is sawed off with a wire saw, and the pipe mouth needs to be sawed flat.

[0052] During specific implementation, the pipes are connected by joints, and the sides of the joints are tightened by self-tapping screws.

[0053] S30, filling the gaps between the pipe holes, filling the gap between the bottom permeable pipe 1 and the borehole 9 with coarse sand 6, and then filling the gaps between the middle solid pipe 2 and the borehole 9, and between the top solid pipe 4 and the borehole 9 with bentonite balls 7;

[0054] In this embodiment, in step S30, the sum of the top solid tube 4 and the filling thickness of the bentonite balls 7 is equal to the aperture of the top of the borehole 9, the sum of the diameter of the middle solid tube 2 and the filling thickness of the bentonite balls 7 is equal to the aperture of the upper part of the borehole 9, and the sum of the diameter of the permeable pipe 1 and the filling thickness of the coarse sand 6 is equal to the aperture of the bottom of the borehole 9.

[0055] In this embodiment, in step S30, water is brought in when filling the sand, but no water is brought in when filling the bentonite balls 7, so as to prevent the bentonite balls 7 from expanding and blocking the hole opening, causing the lower pores to be emptied. When placing the bentonite balls 7, a few are placed at a time to prevent them from getting stuck together. The lower part is not filled with bentonite balls 7, and a small amount of clean water is poured in after the bentonite balls 7 are filled.

[0056] In this embodiment, after drilling is completed, it is necessary to conduct long-term observation of the leachate water level in a certain hole section of the garbage pile. A 2m permeable pipe 1 is set at the bottom of the borehole, and only the leachate produced by the long-term observed garbage layer 8 is allowed to enter the permeable pipe 1. The permeable pipe section is filled with coarse sand, and the remaining upper part is sealed with bentonite balls 7.

[0057] S40, the pipe opening of the top solid pipe 4 exposed on the ground is closed and marked; the top cover 5 is covered, and the top cover 5 is fixed to the top solid pipe 4;

[0058] During the specific implementation, use a marker to mark the number and depth of the monitoring hole at the top cover 5, and make a layout diagram. The number of the measuring point should be consistent with the on-site burial to avoid confusion of the observation point later. To prevent missing marks, wrap yellow insulating tape on the pipe and write the monitoring hole number and depth on the tape as a backup mark.

[0059] S50, inspection of the borehole 9; after being buried, the borehole 9 is inspected to confirm whether the hole is sealed tightly. If not, the bentonite ball 7 is filled to seal the hole, and water is added appropriately until it is filled tightly. The monitoring point is fixed with cement mortar, and the measuring point number is marked on the mortar.

[0060] In this embodiment, in step S50, after burial, observe whether there is any subsidence around the borehole 9 each time, and shake the pipe to observe whether it shakes. If such a phenomenon occurs, it means that the area around the hole is not filled densely, and then fill the bentonite ball 7 to seal the hole, and add water appropriately to facilitate the expansion of the bentonite ball 7 to seal the hole. After observing for a week, confirm that the hole is sealed densely, and then fix the monitoring point with cement mortar, and mark the measuring point number on the mortar. After no problem is found, the drilling of the landfill leachate water level monitoring hole is completed.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A drilling tool for a landfill leachate water level monitoring hole, comprising a drill pipe (16) and a drill bit connected thereto, characterized in that: The drill bit comprises: Drill bit body (13); A plurality of steel blocks (14), each of which is fixed to the front end of the inner wall of the drill body (13), and the plurality of steel blocks (14) are arranged at intervals along the circumferential direction of the drill body (13); A plurality of wedge-shaped protrusions (15) are fixed to the front end of the drill body (13), and the plurality of wedge-shaped protrusions (15) are arranged at intervals along the circumferential direction of the drill body (13).

2. A method for constructing a landfill leachate level monitoring hole, characterized in that: Using the drilling tool for monitoring the water level of landfill leachate in claim 1, the method comprises the following steps: S10, after determining the location of the monitoring point, drilling survey is carried out, and the borehole (9) penetrates the upper garbage accumulation layer (10), the middle covering soil layer (11), and the garbage layer (8) for long-term observation from top to bottom; and a casing (12) is set under the drilling process; S20, lowering the pipe; lowering the monitoring pipe in the borehole (9), wherein the monitoring pipe is formed by connecting a water-permeable pipe (1) and a plurality of solid pipes in sequence, wherein the water-permeable pipe (1) is located at the bottom of the garbage layer (8) to be observed for a long time, the solid pipe located at the top is the top solid pipe (4), and the rest are middle solid pipes (2), and the outer side of the water-permeable pipe (1) is wrapped with a filter screen; S30, filling the gaps between the pipe holes, filling the gap between the bottom permeable pipe (1) and the borehole (9) with coarse sand (6), and then filling the gaps between the middle solid pipe (2) and the borehole (9), and between the top solid pipe (4) and the borehole (9) with bentonite balls (7); S40, the pipe opening of the top solid pipe (4) exposed on the ground surface is closed and marked; the top cover (5) is covered, and the top cover (5) is fixed to the top solid pipe (4); S50, inspection of the borehole (9); after being buried, the borehole (9) is inspected to confirm whether the hole is sealed tightly. If not, the bentonite ball (7) is filled to seal the hole, and water is added appropriately until the hole is filled tightly. The monitoring point is fixed with cement mortar, and the measurement point number is marked on the mortar.

3. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In step S10, the bottom of the landfill leachate level monitoring hole must be more than 2m away from the bottom of the middle covering soil layer.

4. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In S20, the depth of the drill hole (9) reaches 50% of the designed hole depth, and then the casing (12) is buried, and the buried depth of the casing (12) is 50% of the designed hole depth.

5. The method for constructing a landfill leachate level monitoring hole according to claim 4, characterized in that: For the first 50% of the designed hole depth, a 146 mm drill bit body (13) is used for drilling, and then a casing (12) is buried to protect the wall. The buried depth of the casing (12) is 50% of the designed hole depth. For the remaining 50% of the designed hole depth, a 108 mm drill bit body (13) is used to complete the drilling, form a hole, and determine the position and thickness of the intermediate covering layer (11), the thickness of the garbage accumulation layer (10) above the borehole, and the lower elevation a and upper elevation b of the hole section where the garbage layer (8) under long-term observation is located. Finally, the casing (12) is pulled out.

6. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In step S20, the diameter of the drilled hole (9) is larger than the diameters of the middle solid pipe (2), the top solid pipe (4) and the water-permeable pipe (1).

7. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In step S20, the bottom of the water-permeable pipe (1) is first connected to the bottom cover (3), and then the water-permeable pipe (1) is connected to the middle solid pipe (2) of the adjacent section. After being connected and fixed, the water-permeable pipe (1) is placed in the borehole (9), and a portion is leaked out and then connected to the second section of the middle solid pipe (2); pipes are placed in the borehole (9) in sequence, and then the pipes are connected, and so on; the height of the top solid pipe (4) of the last section exposed above the ground does not exceed 1m, and the excess portion is cut off with a wire saw, and the pipe mouth needs to be sawed flat.

8. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In step S30, the sum of the thickness of the top solid tube (4) and the filling thickness of the bentonite balls (7) is equal to the aperture of the top of the borehole (9), the sum of the diameter of the middle solid tube (2) and the filling thickness of the bentonite balls (7) is equal to the aperture of the upper part of the borehole (9), and the sum of the diameter of the permeable tube (1) and the filling thickness of the coarse sand (6) is equal to the aperture of the bottom of the borehole (9).

9. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In step S30, water is brought in when filling the sand, but no water is brought in when filling the bentonite balls (7) to prevent the bentonite balls (7) from expanding and blocking the hole opening, causing the lower pores to be emptied. When placing the bentonite balls (7), a few are placed at a time to prevent them from getting stuck together and the lower part from being filled with the bentonite balls (7). After the bentonite balls (7) are filled, a small amount of clean water is poured in.

10. The method for constructing a landfill leachate level monitoring hole according to claim 2, characterized in that: In step S50, after the burial, each time observation is made, observe whether there is any subsidence around the borehole (9), and shake the pipe to observe whether it shakes. If such a phenomenon occurs, it means that the area around the hole is not filled tightly, and then fill the bentonite ball (7) to seal the hole, and add water appropriately to facilitate the expansion of the bentonite ball (7) to seal the hole. After observing for a week, confirm that the hole is sealed tightly, and then fix the monitoring point with cement mortar, and mark the measuring point number on the mortar. After no problem is found, the drilling of the landfill leachate water level monitoring hole is completed.

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