Construction method for cement soil waterproof curtain used on household garbage landfill

Abstract

The invention relates to a cement soil waterproof curtain construction method for a household garbage landfill. The cement soil waterproof curtain construction method comprises the following steps that S1, construction preparation work is conducted; s2, construction equipment enters a site; s3, according to the TRD cement soil stirring wall construction scheme, a cement soil waterproof curtain is constructed and formed through a three-step method; s4, an HDPE film construction scheme is constructed; s5, molding the bentonite composite wall; s6, construction is completed; the construction method has the beneficial effects that the HDPE film construction scheme and the TRD cement soil stirring wall construction scheme are applied to closure of the domestic waste landfill beside the rivers and the lakes, the HDPE film construction scheme is adopted on the side of the domestic waste landfill beside the rivers and the lakes, and the TRD cement soil stirring wall construction scheme is adopted on the side, away from the side of the domestic waste landfill beside the rivers and the lakes, of the domestic waste landfill beside the rivers and the lakes; in this way, the effects of water seepage organization and supporting can be achieved, and the field sealing effect is more stable.

Description

Technical Field

[0001] The invention belongs to the technical field of cement soil water-stop curtain construction, and in particular relates to a cement soil water-stop curtain construction method for a domestic waste landfill. Background Art

[0002] The closure of some old landfills requires the construction of new vertical barriers. Due to site restrictions, the vertical barriers cannot enclose the existing landfills and must pass through the landfills. There is a lot of domestic garbage in the landfills. If a wall is formed in the landfills and suspended matter such as plastic bags are not removed, the solidified cement soil water-stop curtain will contain plastic bags, which will destroy the uniformity of the cement soil water-stop curtain and affect the reinforcement effect of the trench wall of the vertical barrier. In particular, some old landfills are located near rivers and lakes. The soil solidification of the old landfills near rivers and lakes will be relatively poor. After the construction of the water-stop curtain, water seepage is likely to occur, which will greatly affect the reinforcement effect of the trench wall of the vertical barrier. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for constructing a cement soil waterproof curtain on a domestic waste landfill to solve the adverse effects of large particles of suspended garbage on the cement soil waterproof curtain and the water seepage phenomenon of old landfills located near rivers and lakes.

[0004] The objective of the present invention is achieved through the following technical solution. The construction method of cement soil water-stop curtain for domestic waste landfill comprises the following steps:

[0005] S1. Construction preparation: According to the distribution of the domestic waste landfill, survey and stake out and determine the construction process. The domestic waste landfill located near the river and lake adopts the HDPE membrane construction plan, and the domestic waste landfill far from the river and lake adopts the TRD cement soil mixing wall construction plan. The TRD cement soil mixing wall construction plan is constructed first, and then the HDPE membrane construction plan is constructed after completion, and the area to be constructed is staked out on the domestic waste landfill;

[0006] S2. Construction equipment enters the site: a long-arm excavator with an extended grille bucket and a TRD pile driver enter the site, and the TRD pile driver is located on the side of the cement soil water-stop curtain to be constructed, and the long-arm excavator is located directly above the cement soil water-stop curtain to be constructed. During the construction process, the long-arm excavator moves in the same direction as the TRD pile driver, and the two are vertically distributed on the cement soil water-stop curtain to be constructed;

[0007] S3, Construction of TRD cement soil mixing wall construction plan, that is, three-step construction:

[0008] Step 1: The TRD pile driver moves forward along the length direction of the cement soil water-stop curtain to be constructed. When moving forward, the cutting fluid is injected for cutting. The long-arm excavator follows the TRD pile driver. When the TRD pile driver cuts through the chain saw-type cutting box, when the projection of the swing arm of the long-arm excavator on the horizontal plane coincides with the designed cement soil water-stop curtain, the long-arm excavator uses the extended grille bucket to scoop up large suspended particles. After scooping out, pour the garbage out of the grille bucket. When the grille bucket is lifted out of the trench and no more suspended garbage appears, the scooping can be stopped. During the moving process, the long-arm excavator sets up a heavy roadbed box above the trench after scooping out the large suspended particles. The scooping process of the long-arm excavator ends until the construction of the TRD pile driver is completed;

[0009] Step 2: The main engine of the TRD pile driver cuts back along the trench after the long-arm excavator has scooped up the soil to further mix and stir the cut soil. During the cutting back process, the heavy roadbed box is lifted out of the trench, and the long-arm excavator moves away from the original position and decides whether to scoop up the large suspended garbage particles in the trench again according to the on-site conditions. If necessary, the long-arm excavator is driven to the other side of the TRD pile driver and follows it, and the operation is continued in the first step;

[0010] Step 3: The main engine of the TRD pile driver returns to the positive position, and the curing liquid is injected into the bottom of the chain saw cutting box to mix the cut soil and the curing liquid to form a cement soil water-stop curtain;

[0011] S4. Construction plan of HDPE membrane:

[0012] After the cement soil water-stop curtain in step S3 is solidified, the TRD cement soil mixing wall construction plan is constructed on the side of the domestic waste landfill away from the river and lake. This construction plan requires the construction of two cement soil water-stop curtains in step S3. A gap is left between the two cement soil water-stop curtains for the construction of HDPE membranes. The construction steps of the two cement soil water-stop curtains are consistent with the construction steps of S3.

[0013] S5, forming bentonite composite wall: after the two cement soil water-stopping curtains in step S4 are solidified, the gap space left between the two cement soil water-stopping curtains is again taken out by the TRD pile driver, and then the anti-seepage geomembrane is vertically placed in the gap space by the geomembrane laying device, and after the placement, bentonite is backfilled and poured into shape by a double-duct construction method, and a bentonite composite wall is formed in the gap space and solidified, and together with the two cement soil water-stopping curtains, a supporting anti-seepage wall is formed;

[0014] S6. Construction completion: After the cement soil water-stop curtain and bentonite composite wall are solidified, a cement guide wall layer is made above the entire cement soil water-stop curtain and supporting anti-seepage wall. The cement guide wall layer is flush with the upper plane of the domestic waste landfill.

[0015] The beneficial effects of the present invention are as follows: by adopting the HDPE membrane construction scheme and the TRD cement soil mixing wall construction scheme in the application of landfill closure at the edge of a river or lake, the HDPE membrane construction scheme is adopted on the side of the landfill at the edge of a river or lake, and the TRD cement soil mixing wall construction scheme is adopted on the side of the landfill far away from the river or lake, which can play a role in organizing water seepage and providing support, and the landfill closure effect is more stable. In the process of cement soil water-stopping curtain construction, a long-arm excavator with an extended grille bucket is adopted to scoop out large-particle suspended garbage, which is not only convenient for scooping, but also makes the cement soil water-stopping curtain not affected by the suspended garbage after being formed, and its water seepage probability is greatly reduced, thereby improving the vertical barrier groove wall reinforcement effect. In the support and anti-seepage wall formed by the HDPE membrane construction scheme, the two cement soil water-stopping curtains play a role of support and water seepage prevention, and the bentonite composite wall plays a role of water seepage prevention, which makes the vertical barrier groove wall reinforcement effect on the side of the landfill at the edge of a river or lake better and more stable.

[0016] Preferably, the excavation depth of the long-arm excavator with an extended grille bucket is greater than the depth of the cement soil water-stop curtain, and the width of the grille bucket is 5 to 10 cm less than the design width of the cement soil water-stop curtain, and the grille mesh diameter of the bucket is 3-8 cm; through the setting of the above-mentioned grille bucket, while meeting the design width of the cement soil water-stop curtain, large particles of suspended garbage in the trench can also be retrieved, and the diameter is set at 3-8 cm. Since the width of the cement soil water-stop curtain is basically maintained at about 1 m, if the diameter of the large particles of suspended garbage is below 3-8 cm, it will not affect the water seepage problem of the cement soil water-stop curtain.

[0017] Preferably, the width of the gap space between the two cement soil water-stop curtains in step S4 is equal to the width of the cement soil water-stop curtain in step S3, and the two cement soil water-stop curtains in step S4 extend to both sides of the cement soil water-stop curtain in step S3, and the extension distance is 5 to 10m; in this way, a concave anti-seepage structure is formed between the cement soil water-stop curtain in step S3 and the supporting anti-seepage wall, which can greatly prevent water seepage between the two, and this structure is relatively easy to form, can be formed by on-site equipment, is easy to construct, and has low construction cost.

[0018] Preferably, the bottom of the cement-soil water-stop curtain and the bottom of the bentonite composite wall both enter the relative impermeable layer of clay or rock under the domestic waste landfill site; this makes the cement-soil water-stop curtain and the bentonite composite wall more effective in preventing water seepage, and serves as a vertical barrier to isolate pollutants during construction to reinforce the trench wall.

[0019] Preferably, during the process of mixing and stirring the cement soil water-stop curtain with the solidifying liquid in steps S4 and S5, bentonite is added in an amount of 2.5% to 5%, and the mass percentage of bentonite particles with a particle size less than 0.075 mm should not be less than 95%, and the mass percentage of particles with a particle size less than 0.002 mm should not be less than 35%; this makes the cement soil water-stop curtain stronger and has a better anti-water seepage effect.

[0020] Preferably, the cement guide wall layer includes an anchoring ditch and a guide wall layer, the anchoring ditch is arranged above the cement soil water-stop curtain and the supporting anti-seepage wall, the guide wall layer is located on both sides of the anchoring ditch, and the guide wall layer and the anchoring ditch are formed by an L-shaped steel bar bracket and concrete pouring, and the upper plane of the guide wall layer is flush with the upper plane of the domestic waste landfill; through the design of the cement guide wall layer, it not only plays the role of the roadbed after the construction is completed, but also can protect the cement soil water-stop curtain and the supporting anti-seepage wall from damage, especially the setting of the guide wall layer, so that when it is used as a roadbed, part of the force is transferred to the landfill layer other than the cement soil water-stop curtain and the supporting anti-seepage wall through the guide wall layer, and the force is effectively decomposed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the construction area structure of the construction method of the present invention.

[0022] Figure 2 It is a schematic diagram of the construction structure between the long-arm excavator and the TRD pile driver of the present invention.

[0023] Figure 3 It is a schematic diagram of the cement guide wall layer structure of the present invention.

[0024] The numbers in the attached drawings are: 1. long-arm excavator; 2. TRD pile driver; 3. cement-soil water-stop curtain; 4. grid bucket; 5. heavy-duty roadbed box; 6. relative water-proof layer; 7. bentonite composite wall; 8. support and anti-seepage wall; 9. cement guide wall layer; 10. domestic waste landfill; 91. anchor ditch; 92. guide wall layer. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings: Figures 1 to 3 As shown, the cement soil water-stop curtain construction method of the present invention comprises the following steps:

[0026] S1. Construction preparation: According to the distribution of the domestic waste landfill, survey and stake out and determine the construction process. The domestic waste landfill located near the river and lake adopts the HDPE membrane construction plan, and the domestic waste landfill far from the river and lake adopts the TRD cement soil mixing wall construction plan. The TRD cement soil mixing wall construction plan is constructed first, and then the HDPE membrane construction plan is constructed after completion, and the area to be constructed is staked out on the domestic waste landfill;

[0027] S2. Construction equipment enters the site: the long-arm excavator 1 with an extended grille bucket and the TRD pile driver 2 enter the site, and the TRD pile driver 2 is located on the side of the cement soil water-stop curtain 3 to be constructed, and the long-arm excavator 1 is located directly above the cement soil water-stop curtain 3 to be constructed. During the construction process, the long-arm excavator 1 moves forward in the construction direction along with the TRD pile driver 2, and the two are distributed vertically on the cement soil water-stop curtain 3 to be constructed;

[0028] S3, Construction of TRD cement soil mixing wall construction plan, that is, three-step construction:

[0029] Step 1: The TRD pile driver 2 moves forward along the length direction of the cement soil waterproof curtain 3 to be constructed. When moving forward, cutting fluid is injected for cutting. The long-arm excavator 1 follows the TRD pile driver 2. When the TRD pile driver 2 is cut by the chain saw-type cutting box, when the projection of the swing arm of the long-arm excavator 1 on the horizontal plane coincides with the designed cement soil waterproof curtain 2, the long-arm excavator 1 scoops up large suspended particles through the grille bucket 4, and pours the garbage out of the grille bucket 4 after scooping it out. When no suspended garbage appears in the trench after the grille bucket 4 is lifted out, the scooping can be stopped. During the moving process, the long-arm excavator 1 sets up a heavy roadbed box 5 above the trench after scooping up the large suspended particles. The scooping process of the long-arm excavator 1 ends until the construction of the TRD pile driver 2 is completed;

[0030] Step 2: The main engine of the TRD pile driver 2 reverses along the trench after the long-arm excavator 1 has scooped up the soil, so that the cut soil is further mixed and stirred. During the reverse cutting process, the heavy roadbed box 5 is lifted out of the trench, and the long-arm excavator 1 moves away from the original position and chooses whether to scoop up the large suspended garbage in the trench again according to the on-site conditions. If necessary, the long-arm excavator 1 moves to the other side of the TRD pile driver 2 and follows it, and continues the operation using the first step;

[0031] Step 3: The main engine of the TRD pile driver 2 is returned to the positive position, and the curing liquid is injected into the bottom of the chain saw cutting box to mix the cut soil and the curing liquid to form a cement soil water-stop curtain 3;

[0032] S4. Construction plan of HDPE membrane:

[0033] After the cement soil water-stop curtain 3 in step S3 is solidified, a TRD cement soil mixing wall construction plan is constructed on the side of the domestic waste landfill away from the river and lake. The construction plan requires the construction of two cement soil water-stop curtains 3 in step S3. A gap space is left between the two cement soil water-stop curtains 3 and is used to construct the HDPE membrane. The construction steps used for the two cement soil water-stop curtains 3 are consistent with the construction steps of S3.

[0034] S5, forming of bentonite composite wall: after the two cement soil water-stopping curtains 3 in step S4 are solidified, the gap space left between the two cement soil water-stopping curtains 3 is again taken out by the TRD pile driver 2, and then the anti-seepage geomembrane is vertically placed in the gap space by the geomembrane laying device, and after being placed, bentonite is backfilled and poured into shape by a double-duct construction method, forming a bentonite composite wall 7 in the gap space and solidifying it, and forming a supporting anti-seepage wall 8 together with the two cement soil water-stopping curtains 3;

[0035] S6, construction completed: after the cement soil water stop curtain 3 and the bentonite composite wall 7 are solidified, a cement guide wall layer 9 is made above the entire cement soil water stop curtain 3 and the supporting anti-seepage wall 8, and the cement guide wall layer 9 is flush with the upper plane of the domestic waste landfill.

[0036] Note the following points in step S3:

[0037] 1. During construction, the chassis of the TRD pile driver should be kept horizontal and the guide rod should be kept vertical. Before construction, use measuring instruments to measure the axis to ensure that the TRD pile driver is correctly positioned and verify that the verticality deviation of the pile driver column guide frame is less than 1 / 250.

[0038] 2. During the construction process, the vertical accuracy of the wall can be managed by installing an inclinometer inside the cutting box. The verticality of the wall is no more than 1 / 250.

[0039] 3. After the wall mixing of the TRD method is completed or stopped for some reason, the cutting box should be at least 3.4m away from the wall forming area, and high-concentration excavation fluid should be injected for temporary retreat and curing operations to prevent the cutting box from being locked.

[0040] 4. After a section of the working surface is completed, the cutting box is pulled out one by one using the TRD main engine. The time should be controlled within 4 hours. At the same time, an equal volume of mixed mud is injected into the bottom of the cutting box.

[0041] 5. When pulling out the cutting box, negative pressure should not be generated in the hole to cause settlement of the surrounding foundation. The working flow of the grouting pump should be adjusted according to the speed of pulling out the cutting box.

[0042] The excavation depth of the long-arm excavator 1 with the extended grid bucket is greater than the depth of the cement soil water-stop curtain 3. The maximum excavation depth, the depth of the cement soil water-stop curtain, and the forward distance of the first step of cutting are in a right triangle relationship, which can be calculated using the Pythagorean theorem. The width of the grid bucket 4 is 5 to 10 cm less than the design width of the cement soil water-stop curtain 3. The grid mesh diameter of the grid bucket 4 is 3-8 cm according to the on-site conditions.

[0043] The width of the gap space between the two cement soil water-stopping curtains 3 in step S4 is equal to the width of the cement soil water-stopping curtains 3 in step S3, and the two cement soil water-stopping curtains 3 in step S4 extend to both sides of the cement soil water-stopping curtains 3 in step S3, and the extension distance is 5 to 10m.

[0044] The bottom of the cement soil waterproof curtain 3 and the bottom of the bentonite composite wall 7 both enter the relative water-proof layer 6 of the clay or rock layer under the domestic waste landfill site.

[0045] During the process of mixing and stirring the cement soil water-stop curtain 3 with the solidifying liquid in steps S4 and S5, bentonite is added in an amount of 2.5% to 5%. The mass percentage of bentonite particles with a particle size less than 0.075 mm should not be less than 95%, and the mass percentage of particles with a particle size less than 0.002 mm should not be less than 35%.

[0046] The cement guide wall layer 9 includes an anchoring ditch 91 and a guide wall layer 92. The anchoring ditch 91 is arranged above the cement soil water-stop curtain 3 and the supporting anti-seepage wall 8. The guide wall layer 92 is located on both sides of the anchoring ditch 91. The guide wall layer 92 and the anchoring ditch 91 are formed by L-shaped steel support brackets and concrete pouring. The upper plane of the guide wall layer 92 is flush with the upper plane of the domestic waste landfill.

[0047] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A cement soil water-stop curtain construction method for a domestic waste landfill, characterized in that: The construction method of cement soil water-stop curtain includes the following steps: S1. Construction preparation: According to the distribution of the domestic waste landfill, survey and stake out and determine the construction process. The domestic waste landfill located near the river and lake adopts the HDPE membrane construction plan, and the domestic waste landfill far from the river and lake adopts the TRD cement soil mixing wall construction plan. The TRD cement soil mixing wall construction plan is constructed first, and then the HDPE membrane construction plan is constructed after completion, and the area to be constructed is staked out on the domestic waste landfill; S2. Construction equipment enters the site: a long-arm excavator (1) with an extended grille bucket and a TRD pile driver (2) enter the site, and the TRD pile driver (2) is located on the side of the cement soil water-stop curtain (3) to be constructed, and the long-arm excavator (1) is located directly above the cement soil water-stop curtain (3) to be constructed. During the construction process, the long-arm excavator (1) moves forward in the same construction direction as the TRD pile driver (2), and the two are arranged vertically on the cement soil water-stop curtain (3) to be constructed; S3, Construction of TRD cement soil mixing wall construction plan, that is, three-step construction: Step 1: The TRD pile driver (2) moves forward along the length direction of the cement soil waterproof curtain (3) to be constructed. When moving forward, cutting fluid is injected for cutting. The long-arm excavator (1) follows the TRD pile driver (2). When the TRD pile driver (2) is cut by the chain saw-type cutting box, when the projection of the swing arm of the long-arm excavator (1) on the horizontal plane coincides with the designed cement soil waterproof curtain (2), the long-arm excavator (1) scoops up large suspended particles through the grille bucket (4). After scooping out, the garbage is poured out from the grille bucket (4). After the grille bucket (4) is lifted out of the groove and no more suspended garbage appears, the scooping can be stopped. During the moving process, the long-arm excavator (1) sets up a heavy roadbed box (5) above the groove after scooping out the large suspended particles. The scooping process of the long-arm excavator (1) ends until the construction of the TRD pile driver (2) is completed; Step 2: The main engine of the TRD pile driver (2) cuts back along the trench after the long-arm excavator (1) has scooped up the soil, so that the cut soil is further mixed and agitated. During the cutting back process, the heavy roadbed box (5) is lifted out of the trench, and the long-arm excavator (1) moves away from the original position and chooses whether to scoop up the large suspended garbage particles in the trench again according to the on-site conditions. If necessary, the long-arm excavator (1) moves to the other side of the TRD pile driver (2) and follows it, and continues the operation according to the first step; Step 3: The main engine of the TRD pile driver (2) returns to the forward position, and the bottom end of the chain saw-type cutting box is injected with solidifying liquid, so that the cut soil and the solidifying liquid are mixed and stirred to form a cement soil waterproof curtain (3); S4. Construction plan of HDPE membrane: After the cement soil water-stop curtain (3) in step S3 is solidified, a TRD cement soil mixing wall construction plan is constructed on the side of the domestic waste landfill away from the river bank. The construction plan requires the construction of two cement soil water-stop curtains (3) in step S3. A gap space is left between the two cement soil water-stop curtains (3) for the construction of the HDPE membrane. The construction steps of the two cement soil water-stop curtains (3) are consistent with the construction steps of S3. S5, forming a bentonite composite wall: after the two cement soil water-stopping curtains (3) in step S4 are solidified, the gap space between the two cement soil water-stopping curtains (3) is again used to remove all the soil in the gap space by the TRD pile driver (2), and then the anti-seepage geomembrane is vertically placed in the gap space by the geomembrane laying device. After the placement, the bentonite is backfilled and poured into shape by the double-duct construction method, and a bentonite composite wall (7) is formed in the gap space and solidified, and together with the two cement soil water-stopping curtains (3), a supporting anti-seepage wall (8) is formed; S6, construction completed: after the cement soil water stop curtain (3) and the bentonite composite wall (7) are solidified, a cement guide wall layer (9) is made on the entire cement soil water stop curtain (3) and the supporting anti-seepage wall (8), and the cement guide wall layer (9) is flush with the upper plane of the domestic waste landfill.

2. The method for constructing a cement soil water-stop curtain on a domestic waste landfill according to claim 1, characterized in that: The excavation depth of the long-arm excavator (1) with the extended grid bucket is greater than the depth of the cement soil waterproof curtain (3), and the width of the grid bucket (4) is 5 to 10 cm less than the designed width of the cement soil waterproof curtain (3), and the grid mesh diameter of the grid bucket (4) is 3 to 8 cm.

3. The method for constructing a cement soil water-stop curtain on a domestic waste landfill according to claim 1, characterized in that: The width of the gap space between the two cement soil water-stopping curtains (3) in step S4 is equal to the width of the cement soil water-stopping curtain (3) in step S3, and the two cement soil water-stopping curtains (3) in step S4 extend to both sides of the cement soil water-stopping curtain (3) in step S3, and the extension distance is 5 to 10m.

4. The cement soil water-stop curtain construction method for domestic waste landfill according to claim 1, characterized in that: The bottom of the cement soil waterproof curtain (3) and the bottom of the bentonite composite wall (7) both enter the relative water-proof layer (6) of clay or rock layer under the domestic waste landfill site.

5. The method for constructing a cement soil water-stop curtain on a domestic waste landfill according to claim 1, characterized in that: During the process of mixing and stirring the cement soil water-stop curtain (3) with the solidifying liquid in step S4 and step S5, bentonite is added in an amount of 2.5% to 5%. The mass percentage of bentonite particles with a particle size of less than 0.075 mm should not be less than 95%, and the mass percentage of particles with a particle size of less than 0.002 mm should not be less than 35%.

6. The method for constructing a cement soil water-stop curtain on a domestic waste landfill according to claim 1, characterized in that: The cement guide wall layer (9) comprises an anchoring groove (91) and a guide wall layer (92); the anchoring groove (91) is arranged above the cement soil water-stop curtain (3) and the supporting anti-seepage wall (8); the guide wall layer (92) is located on both sides of the anchoring groove (91); and the guide wall layer (92) and the anchoring groove (91) are formed by L-shaped steel bar brackets and concrete pouring, and the upper plane of the guide wall layer (92) is flush with the upper plane of the domestic waste landfill.

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