Tough flow state filling type refuse landfill composite diaphragm wall structure and construction method thereof

Abstract

The invention discloses a tough flow state filling type refuse landfill composite anti-seepage wall structure and a construction method thereof, and belongs to the technical field of underground engineering of household refuse disposal and pollution control, and the anti-seepage wall structure comprises an inner side main anti-seepage layer, a middle secondary anti-seepage layer and an outer side rigid supporting layer which are sequentially arranged from inside to outside; the inner side main impermeable layer is made of low-strength tough flow state solidified soil; the middle secondary impermeable layer adopts a geotextile composite thermoplastic polyolefin TPO impermeable geomembrane; the outer side rigid supporting layer is provided with a plurality of all-solid-waste regenerated gel high-pressure jet grouting secant piles which are distributed in the length direction of the diaphragm wall at intervals, and a plurality of piles of the all-solid-waste regenerated gel high-pressure jet grouting secant piles are meshed with one another. According to the anti-seepage wall structure and the construction method thereof, the anti-seepage performance is excellent, the structure is stable, and construction is easy and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of underground engineering for domestic waste disposal and pollution prevention and control, and specifically relates to a composite anti-seepage wall structure of a toughness flow filling type landfill and a construction method thereof. Background Art

[0002] With the acceleration of urbanization, the amount of domestic waste is increasing day by day, and landfills have become one of the main ways to deal with urban solid waste. However, the leakage problem of landfills has always been a major challenge in the field of environmental engineering. The leakage of leachate not only pollutes groundwater resources, but also causes serious damage to the surrounding ecological environment. Therefore, the anti-seepage design of landfills is very important.

[0003] Chinese utility model CN221052648U proposes a new type of composite anti-seepage wall, which is a trench section excavated by professional trenching equipment, with guide walls on both sides of the trench section, HDPE membrane laid on the outer side of the trench section, adhesive tape pasted on the HDPE membrane, and magnetic connection between adjacent HDPE membranes with adhesive tape, and cement-bentonite mixed filler is filled behind the HDPE membrane to form a new type of composite anti-seepage wall. Although the patent mentions saving drainage costs, HDPE anti-seepage membrane and adhesive tape may be expensive, especially when constructing a large area, which may increase the total cost of the project.

[0004] Chinese invention patent CN110984238A discloses a HDPE membrane-bentonite composite vertical barrier wall system that can be constructed quickly without excavation. The patent introduces a composite anti-seepage wall system constructed using HDPE membrane and bentonite. The HDPE membrane is placed underground through ground drilling and vertical vibration technology to form an effective vertical anti-seepage barrier. A wedge-shaped steel head is used at the bottom of the system to increase stability, and the HDPE membrane is sandwiched and vibrated at the top by steel plates. Finally, a gap filled with bentonite is formed by pulling out the steel plates to enhance the anti-seepage effect. Although the amount of work has been reduced, the skills required of the construction workers are relatively high, and the HDPE membrane is prone to aging under ultraviolet radiation and microbial action, resulting in a decrease in anti-seepage performance.

[0005] Chinese invention patent CN108930293A provides a GCL composite vertical mud anti-seepage barrier and its construction method, wherein the GCL composite component is laid along the wall of one side of the anti-seepage trench, and the bottom ends are extended to the bottom of the anti-seepage trench, and the composite mud anti-seepage structure is arranged in the anti-seepage trench where the GCL composite component is laid against the wall. Although the GCL composite component has good anti-seepage performance, it may be affected by chemical corrosion, physical wear, etc. during long-term use, resulting in a decrease in its performance. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a composite anti-seepage wall structure of a tough flow filling type landfill and a construction method thereof, which has a stable structure, strong durability, convenient construction, and achieves multiple anti-seepage effects.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a composite anti-seepage wall structure of a tough flow-filled landfill, comprising an inner main anti-seepage layer, an intermediate secondary anti-seepage layer and an outer rigid support layer arranged in sequence from the inside to the outside; The inner main anti-seepage layer adopts low-strength and tough fluidized solidified soil; the middle secondary anti-seepage layer adopts geotextile composite thermoplastic polyolefin TPO anti-seepage geomembrane; the outer rigid support layer adopts a plurality of all-solid waste recycled gel high-pressure rotary spraying interlocking piles which are distributed at intervals along the length direction of the anti-seepage wall and multiple piles are interlocked with each other.

[0008] Furthermore, the low-strength and tough fluidized solidified soil of the inner main anti-seepage layer includes attapulgite, bentonite, epoxy resin EP, basalt fiber and water reducer, and the mass ratio of each component is: attapulgite is 15%-30%, bentonite is 15%-30%, epoxy resin is 5%-10%, fatty amine is 1%-3%, basalt fiber is 1%-3%, water reducer is 0.5%-2%, and water is 30%-50%.

[0009] Furthermore, the thickness of the low-strength and tough fluidized solidified soil of the inner main anti-seepage layer is 300 mm to 500 mm.

[0010] Furthermore, the anti-seepage geomembrane is made of geotextiles tightly compounded on the upper and lower surfaces of the heated and molten thermoplastic polyolefin TPO material, and three 10m wide double-sided butyl tapes are used to adhesively overlap two adjacent anti-seepage geomembranes along the length direction of the anti-seepage wall.

[0011] Furthermore, the thickness of the intermediate secondary anti-seepage layer is 0.5 mm to 1 mm.

[0012] Furthermore, the all-solid waste regenerated gel high-pressure rotary grouting interlocking piles include at least three interlocking high-pressure rotary grouting piles, and the spacing between adjacent interlocking piles is not less than three times the diameter of the high-pressure rotary grouting piles; The all-solid waste recycled gel high-pressure jet grouting bite pile is provided with a reinforced concrete cap beam on the pile head along the length direction of the anti-seepage wall, and the width of the cap beam is not less than the pile diameter of the high-pressure jet grouting pile, and the height is not less than 0.6 times the pile diameter of the high-pressure jet grouting pile; A bamboo reinforcement sleeved with a thin-walled steel pipe is inserted along the central axis of the high-pressure jet grouting pile. The surface of the bamboo reinforcement is coated with raw tung oil once a day for three consecutive days, and asphalt is applied on the surface of the steel pipe.

[0013] Furthermore, the all-solid waste regenerated gel high-pressure rotary jet interlocking piles adopt all-solid waste alkali-activated cementitious materials, and the all-solid waste alkali-activated cementitious materials are prepared using papermaking wastewater as an alkali activator, slag as a volcanic ash material and silicate cement clinker, wherein the slag accounts for 60%-80%, the papermaking wastewater accounts for 10%-15%, and the silicate cement clinker accounts for 10%-20%.

[0014] Furthermore, the diameter of the high-pressure jet-jet pile is 400mm~600mm; the bamboo reinforcement is made of straight bamboo with a diameter of 70mm~90mm.

[0015] In a second aspect, the present invention provides a construction method of a composite anti-seepage wall structure of a landfill in a ductile flow filling type as described in any one of the first aspects, comprising the following steps: Step S1: Ground treatment: clean and level the landfill foundation; set up cast-in-place reinforced concrete guide walls with a net width of 700 mm and a depth of 1500 mm. After the guide walls reach the specified strength and are removed from the formwork, two upper and lower supports are added along the longitudinal direction of the guide walls. Step S2: Positioning and drilling of the high-pressure rotary grouting bite piles of the outer rigid support layer, calibrating from two mutually perpendicular directions to ensure that the verticality deviation of the pile body does not exceed 1%, moving the full hydraulic anchor drilling rig to the pile position for positioning and centering, starting the drilling rig while rotating and drilling to the designed elevation; Step S3: insert the rotary jet grouting pipe, and when the nozzle reaches the bottom of the hole, perform the jetting operation from bottom to top, control the lifting speed between 6 and 8 cm / min, and stop lifting when it reaches 0.5 m from the pile top, and perform rotary jetting for 30 seconds, and then slowly lift and jet upward for 0.5 m to ensure the quality and density of the pile top; Step S4: After each pile is jetted, the residual liquid in the circulation pipe is cleaned with clean water to ensure normal use of the next pile construction; Step S5: Before the high-pressure jet grouting pile is cured, the bamboo reinforcement sleeved with steel pipe and coated with raw tung oil is inserted into the high-pressure jet grouting pile. If the insertion resistance is large, a vibration hammer can be used to assist in pile sinking; Step S6: breaking and chiseling the high-pressure jet grouting pile head slurry to the designed elevation, constructing the cushion layer, tying the crown beam steel bars, supporting the crown beam side formwork, and pouring the crown beam concrete; Step S7: excavate trenches according to the pre-divided sections, with the length of one trench section not exceeding 4m; after trench excavation is completed, use a grab bucket to remove the residue at the bottom of the trench; hang and place the joint pipe, and a circular lock joint pipe needs to be placed on the outside of the unit trench section, with the center line of the joint pipe coinciding with the framing line, and the bottom of the joint pipe flush with the bottom of the trench; Step S8: Lower the TPO anti-seepage geomembrane to the bottom of the trench. Before lowering it, stick one side of three double-sided butyl adhesives (4) to the anti-seepage geomembrane on an open ground. Do not tear off the adhesive strip on the back first. Insert a 5mm thick iron wire into the double-sided adhesive strip at the bottom of the geomembrane. Insert one iron wire into the two edge corners and the middle position of each double-sided butyl adhesive. Lower the geomembrane and fix the upper part. The overlapping width of two adjacent TPO anti-seepage geomembranes is not less than 0.3m. When the later-placed membrane is lowered to the bottom of the trench, tear off the adhesive strip of 10-15cm on the upper end of the previously-placed membrane. Then align the tops of the two membranes and press and stick them together. Then lift up the iron wire and tear off the adhesive strip on the back so that the two membranes are stuck together. Step S9: lowering a conduit into the trench at the inner main anti-seepage layer, placing a water-blocking ball into the conduit, pouring low-strength and tough fluidized solidified soil, lifting the conduit in due time during the pouring process, keeping the buried depth of the conduit at 2.5 to 6 m, and the average rising speed of the low-strength and tough fluidized solidified soil poured into the trench is not less than 2 m / h; Step S10: After a section of trench is constructed, the joint pipe is promptly pulled out, and the anti-seepage wall trench section is excavated, and construction is performed at intervals; the above process is repeated to complete the construction of other trench sections; Step S11: Quality inspection: Perform quality inspection on the completed anti-seepage wall to ensure that the anti-seepage performance meets the design requirements.

[0016] Furthermore, step S8 also includes: placing an uninflated airbag with a length approximately the same as the width of the groove and a width of approximately 0.5m into the bottom of the groove; before lowering it, tying a loose knot with wire on both sides of the long side of the airbag to allow the airbag to expand freely; after the airbag is lowered to the bottom, inflating the airbag so that the expansion of the airbag creates pressure on the groove; finally, slowly pulling the airbag up in parallel so that the airbag squeezes the overlap during the pulling process, so that the overlap is tightly adhered.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the composite anti-seepage wall structure of the toughness flow filling type landfill and the construction method thereof provided by the present invention are provided with an inner main anti-seepage layer, a middle secondary anti-seepage layer and an outer rigid support layer arranged in sequence from the inside to the outside; By combining attapulgite, bentonite, epoxy resin (EP), fatty amine, basalt fiber and water reducer to form the inner anti-seepage layer, it provides the main anti-seepage performance, prevents the landfill leachate from entering the groundwater and the surrounding environment, and prevents the groundwater from entering the landfill area, reducing the amount of leachate generated; The middle secondary anti-seepage layer uses geotextile composite TPO anti-seepage geomembrane to enhance the overall anti-seepage effect, further isolate the leachate, and extend the service life of the anti-seepage system; The outer rigid support layer adopts a number of all-solid waste recycled gel high-pressure rotary spray interlocking piles that are distributed at intervals along the length of the anti-seepage wall and multiple piles are interlocked with each other, providing structural stability and support, ensuring the stability and durability of the anti-seepage wall; the tough flow filling type landfill composite anti-seepage wall structure has a stable structure, strong durability and easy construction, so as to achieve multiple anti-seepage effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A front cross-sectional view of a multi-layer tough flow filling type landfill anti-seepage wall provided in an embodiment of the present invention.

[0019] Figure 2 A top view of a cross-sectional view of a multi-layer tough flow filling type landfill anti-seepage wall provided in an embodiment of the present invention.

[0020] Figure 3 The invention provides a TPO anti-seepage geomembrane overlapping method.

[0021] Figure 4 A three-dimensional schematic diagram of an anti-seepage wall provided in an embodiment of the present invention.

[0022] In the figure: 1. Main anti-seepage layer; 2. Secondary anti-seepage layer; 3. Rigid support layer; 4. Double-sided butyl rubber; 5. Bamboo reinforcement; 6. Steel pipe; 7. Crown beam. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention. Example

[0024] like Figure 1 and Figure 4 As shown, an embodiment of the present invention provides a composite anti-seepage wall structure of a tough flow filling type landfill, comprising an inner main anti-seepage layer 1, a middle secondary anti-seepage layer 2 and an outer rigid support layer 3 arranged in sequence from the inside to the outside.

[0025] The inner main anti-seepage layer 1 adopts low-strength toughness fluidized solidified soil; the middle secondary anti-seepage layer 2 adopts geotextile composite thermoplastic polyolefin TPO anti-seepage geomembrane; the outer rigid support layer 3 adopts a number of all-solid waste recycled gel high-pressure rotary spraying interlocking piles that are distributed at intervals along the length direction of the anti-seepage wall and multiple piles are interlocked with each other.

[0026] In this embodiment, the low-strength and tough fluidized solidified soil of the inner main anti-seepage layer 1 includes attapulgite, bentonite, epoxy resin EP, basalt fiber and water reducer, and the mass ratio of each component is: 15%-30% of attapulgite, 15%-30% of bentonite, 5%-10% of epoxy resin, 1%-3% of fatty amine, 1%-3% of basalt fiber, 0.5%-2% of water reducer, and 30%-50% of water. Among them, attapulgite and bentonite have strong adsorption and are dense, and the epoxy resin forms a solidified body, and the basalt fiber enhances toughness to achieve a low-strength and tough fluidized solidified soil form.

[0027] Table 1 Low-strength and ductile fluidized soil

[0028] In order to verify the anti-seepage effect of this fluidized solidified soil, the variable head permeability test method was used in the laboratory. The GYC-1 variable head permeameter, L140 soil pressure sensor, and FT8000 tensile strength testing machine were used to measure the permeability coefficient, compressive strength, and tensile strength of the materials under different material ratios. When the ratio of attapulgite to bentonite was 10%, the permeability coefficient increased to 10⁻ 9 m / s or even higher, the anti-seepage effect is reduced. When the content is 20%, the permeability coefficient is 10 -11 m / s, and when the ratio is 40%, the permeability coefficient will rise to 10 -8 m / s, the anti-seepage effect will also be reduced. Secondly, when the epoxy resin ratio is 2%, it will lead to incomplete curing, compressive strength of 3 MPa, and the permeability coefficient will increase to 10⁻ 6 m / s, when the content is 8%, the compressive strength is 15MPa and the permeability coefficient is 10 -9 When the content is 20%, it will lead to over-curing, the compressive strength is 19MPa, but the brittleness increases, and the permeability coefficient increases to 10⁻ 6 m / s. When the proportion of fatty amine is 0.5%, the curing time will be too long, the compressive strength will be 1.5 MPa, and the permeability coefficient will increase to 10⁻ 6 m / s, when the content is 2%, the compressive strength is 10MPa and the permeability coefficient is 10 -9 , and when the ratio is 6%, it will cause too fast curing, the compressive strength is 13 MPa, and the permeability coefficient increases to 10⁻ 6m / s, brittleness increases. Then, when the basalt fiber content is 0.5%, the tensile strength is 2MPa, the toughness is low and it is easy to crack. When the content is 2%, the compressive strength is 5MPa, and when the content exceeds 6%, the tensile strength of the solidified soil will reach 6 MPa, but the brittleness of the material will increase. When the water reducer content is 0.1%, the fluidity is poor, the mixture is difficult to stir evenly, the fluidity is 15 cm, when the content is 1%, the fluidity is 35cm, and when the water reducer ratio is 5%, the fluidity is 45cm, the fluidity is too strong, the looseness increases, and the strength decreases. When the water content is 20%, the fluidity will deteriorate and the fluidity will be 17cm. Due to insufficient water, the strength of the solidified soil is weak, and the anti-seepage effect is poor during long-term use. When the water content is 40%, the fluidity is 42cm, and when the water content is 60%, the fluidity is too high and the fluidity is 56cm. Excessive water causes the mixture to be too thin, and the compressive strength after solidification decreases.

[0029] The thickness of the low-strength and tough fluidized solidified soil of the inner main anti-seepage layer 1 is 300 mm to 500 mm.

[0030] In this embodiment, the thickness of the intermediate secondary anti-seepage layer 2 is 0.5 mm to 1 mm.

[0031] The anti-seepage geomembrane is made of geotextiles tightly compounded on the upper and lower surfaces of the heated and molten thermoplastic polyolefin TPO material, and three 10m wide double-sided butyl adhesive 4 tapes are used to adhesively overlap two adjacent anti-seepage geomembranes along the length direction of the anti-seepage wall.

[0032] Specifically, it is produced through a hot melt extrusion process, wherein the TPO material is heated and melted, and then extruded through an extruder, and during the extrusion process, the geotextile is compounded on the upper and lower surfaces of the TPO material to ensure a tight bond between the TPO and the fabric. Three double-sided butyl tapes with a width of about 10m are used to stick two adjacent TPO anti-seepage geomembranes. Before laying the membrane, the double-sided butyl tape is adhered to the overlapping part of the membrane that is laid first, and the membrane that is laid later will overlap together due to the stickiness of the tape, ensuring the connection at the joint.

[0033] In this embodiment, the all-solid waste recycled gel high-pressure rotary jet interlocking piles include at least three interlocking high-pressure rotary jet piles, and the spacing between adjacent interlocking piles is not less than three times the diameter of the high-pressure rotary jet piles, that is, after every three high-pressure rotary jet piles are interlocked, the next group of three mutually interlocking high-pressure rotary jet piles are arranged at a distance not exceeding three times the diameter of the high-pressure rotary jet piles.

[0034] A reinforced concrete cap beam is added to the pile head of the all-solid waste recycled gel high-pressure jet grouting interlocking pile along the length direction of the anti-seepage wall, and the width of the cap beam is not less than the diameter of the high-pressure jet grouting pile, and the height is not less than 0.6 times the diameter of the high-pressure jet grouting pile.

[0035] A bamboo reinforcement 5 sleeved with a thin-walled steel pipe 6 is inserted along the central axis of the high-pressure jet grouting pile. The surface of the bamboo reinforcement 5 is coated with raw tung oil once a day for three consecutive days, and asphalt is applied on the surface of the steel pipe 6.

[0036] The diameter of the high-pressure jet-jet pile is 400mm~600mm; the bamboo reinforcement 5 is made of straight bamboo with a diameter of 70mm~90mm.

[0037] All-solid waste recycled gel high-pressure rotary jet interlocking piles use all-solid waste alkali-activated cementitious materials. The all-solid waste alkali-activated cementitious materials are prepared using papermaking wastewater as an alkali activator, slag as a volcanic ash material and silicate cement clinker, among which slag accounts for 60%-80%, papermaking wastewater accounts for 10%-15%, and silicate cement clinker accounts for 10%-20%.

[0038] Table 2 All-solid waste alkali-activated cementitious materials slag Papermaking wastewater Portland cement clinker Example 1 50% 5% 5% Example 2 70% 12% 15% Example 3 90% 20% 30% The compressive strength of the pile side was measured using a WDW-50E electronic universal testing machine and a JSM-5900 scanning electron microscope. When the slag content was 50%, the compressive strength of the pile side was 35 MPa, when the slag content was 70%, the compressive strength of the pile side was 56 MPa, and when the slag content was 90%, the compressive strength increased from 56 MPa to 59 MPa. However, the SEM scanning results showed that the unreacted slag particles gathered around the pores, reducing the uniformity of the system. At this time, the amount of gel generated was close to saturation, and the marginal contribution of increasing the slag ratio to the strength was weakened; when the papermaking wastewater content was 5%, the compressive strength was 36M pa, when the papermaking wastewater content is 12%, the compressive strength is 46Mpa, when the papermaking wastewater content is 20%, the compressive strength is 40Mpa; when the silicate cement clinker content is 5%, the compressive strength is 37Mpa, when the silicate cement clinker content is 15%, the compressive strength is 58Mpa, when the silicate cement clinker content is 30%, the compressive strength is 60Mpa. This is because high clinker content will lead to reduced fluidity of the material, increase the difficulty in the mixing process, may lead to an increase in the internal porosity of the material, reduce the slag excitation efficiency, and the long-term strength and durability may be affected.

[0039] The embodiment of the present invention further provides a construction method of the above-mentioned ductile flow filling type landfill composite anti-seepage wall structure, comprising the following steps.

[0040] Step S1: Ground treatment: clean and level the landfill foundation; set up a cast-in-place reinforced concrete guide wall with a net width of 700 mm and a depth of 1500 mm. After the guide wall reaches the specified strength and is removed from the formwork, two upper and lower supports are added along the longitudinal direction of the guide wall.

[0041] Step S2: Positioning and drilling of the high-pressure rotary grouting interlocking piles of the outer rigid support layer 3, correction from two mutually perpendicular directions, ensuring that the verticality deviation of the pile body does not exceed 1%, moving the full hydraulic anchor drilling rig to the pile position for positioning and centering, starting the drilling rig while rotating and drilling to the designed elevation. In the embodiment of the present invention, more general construction equipment is used, for example: the full hydraulic anchor (drilling) drilling rig reduces the dependence on high-specification construction equipment, thereby reducing construction costs.

[0042] Step S3: insert the rotary jet grouting pipe, and when the nozzle reaches the bottom of the hole, perform the jetting operation from bottom to top, control the lifting speed between 6 and 8 cm / min, and stop lifting when it reaches 0.5 m from the top of the pile, and perform rotary jetting for 30 seconds in situ, and then slowly lift and jet upward for 0.5 m to ensure the quality and density of the pile top. In the embodiment of the present invention, by using low-cost materials such as attapulgite and bentonite, combined with all-solid waste recycled high-pressure rotary jetting interlocking piles, the material cost can be greatly reduced, the construction process is simplified, and the labor cost is reduced.

[0043] Step S4: After each pile is jetted, the residual liquid in the circulation pipe is cleaned with clean water to ensure normal use of the next pile construction.

[0044] Step S5: Before the high-pressure jet grouting pile is cured, the bamboo reinforcement 5 which is sheathed with the steel pipe 6 and coated with raw tung oil is inserted into the high-pressure jet grouting pile. If the insertion resistance is large, a vibration hammer can be used to assist in sinking the pile.

[0045] Step S6: breaking and chiseling the floating slurry at the head of the high-pressure jet grouting pile to the designed elevation, constructing the cushion layer, tying the steel bars of the crown beam 7, supporting the side formwork of the crown beam 7, and pouring the concrete of the crown beam 7.

[0046] In the embodiment of the present invention, the fully solid waste regeneration high-pressure rotary grouting bite piles of the outer rigid support layer in steps S2 to S6 can reduce the demand for construction space, so that the anti-seepage wall can be constructed in a smaller space, which is suitable for environments with limited space. In addition, the use of fully solid waste regeneration high-pressure rotary grouting bite piles reflects the resource utilization of solid waste, reduces the demand for new resources, and conforms to the concept of sustainable development.

[0047] Step S7: excavate trenches according to the pre-divided sections, with the length of one trench section not exceeding 4m; after trench excavation is completed, use a grab bucket to remove the residue at the bottom of the trench; hang and place the joint pipe, and a circular lock joint pipe needs to be placed on the outside of the unit trench section, with the center line of the joint pipe coinciding with the dividing line, and the bottom of the joint pipe flush with the bottom of the trench.

[0048] Step S8: Lower the TPO anti-seepage geomembrane to the bottom of the trench. Before lowering it, stick one side of three double-sided butyl rubbers 4 (4) to the anti-seepage geomembrane on the open ground. Do not tear off the adhesive strip on the back first, and insert a 5mm thick iron wire into the double-sided adhesive strip at the lower end of the geomembrane. Insert one iron wire into the two edge corners and the middle position of each double-sided butyl rubber 4. Lower the geomembrane and fix the upper part. The overlapping width of two adjacent TPO anti-seepage geomembranes is not less than 0.3m. When the later membrane is lowered to the bottom of the trench, tear off the adhesive strip 10-15cm above the previously lowered membrane, and then align the positions of the two membranes and compact and stick them together. Then lift up the iron wire and tear off the adhesive strip on the back to make the two membranes stick together.

[0049] In addition, an uninflated airbag with a length approximately the same as the width of the groove and a width of about 0.5m is placed at the bottom of the groove. Before lowering, a loose knot is tied with wire on both sides of the long side of the airbag to allow the airbag to expand freely. After the airbag is lowered to the bottom, it is inflated to allow the expansion of the airbag to create pressure on the groove. Finally, the airbag is slowly pulled up in parallel so that the airbag squeezes the overlap during the pulling process, making the overlap tightly sticky.

[0050] In the embodiment of the present invention, the middle secondary anti-seepage layer uses TPO anti-seepage geomembrane, which is well-known for its excellent chemical resistance and aging resistance and can maintain its waterproof performance for a long time, thereby improving the durability of the anti-seepage wall.

[0051] Step S9: lower the conduit into the trench at the inner main anti-seepage layer 1, put the water-blocking ball into the conduit, and pour low-strength and tough fluid-solidified soil. During the pouring process, lift the conduit in time to keep the buried depth of the conduit at 2.5 to 6 m. The average rising speed of the low-strength and tough fluid-solidified soil poured in the trench shall not be less than 2 m / h.

[0052] Step S10: After the construction of one section of trench is completed, the joint pipe is pulled out in time, and the anti-seepage wall trench section is excavated, and the construction is carried out at intervals; the above process is repeated to complete the construction of other trench sections.

[0053] Step S11: Quality inspection: Perform quality inspection on the completed anti-seepage wall to ensure that the anti-seepage performance meets the design requirements.

[0054] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A composite anti-seepage wall structure of a ductile flow filling type landfill, characterized in that: It includes an inner main anti-seepage layer, an intermediate secondary anti-seepage layer and an outer rigid support layer which are arranged in sequence from the inside to the outside; The inner main anti-seepage layer adopts low-strength and tough fluidized solidified soil; the middle secondary anti-seepage layer adopts geotextile composite thermoplastic polyolefin TPO anti-seepage geomembrane; the outer rigid support layer adopts a plurality of all-solid waste recycled gel high-pressure rotary spraying interlocking piles which are distributed at intervals along the length direction of the anti-seepage wall and multiple piles are interlocked with each other.

2. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 1 is characterized in that: The low-strength and tough fluidized solidified soil of the inner main anti-seepage layer includes attapulgite, bentonite, epoxy resin EP, fatty amine, basalt fiber and water reducer, and the mass ratio of each component is: attapulgite is 15%-30%, bentonite is 15%-30%, epoxy resin is 5%-10%, fatty amine is 1%-3%, basalt fiber is 1%-3%, water reducer is 0.5%-2%, and water is 30%-50%.

3. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 2 is characterized in that: The thickness of the low-strength and tough fluidized solidified soil of the inner main anti-seepage layer is 300 mm to 500 mm.

4. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 1 is characterized in that: The anti-seepage geomembrane is made of geotextiles tightly compounded on the upper and lower surfaces of the heated and molten thermoplastic polyolefin TPO material, and three 10m wide double-sided butyl tapes are used to adhesively overlap two adjacent anti-seepage geomembranes along the length direction of the anti-seepage wall.

5. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 4 is characterized in that: The thickness of the intermediate secondary anti-seepage layer is 0.5 mm to 1 mm.

6. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 1 is characterized in that: The all-solid waste regenerated gel high-pressure rotary grouting interlocking piles include at least three interlocking high-pressure rotary grouting piles, and the spacing between adjacent interlocking piles is not less than three times the diameter of the high-pressure rotary grouting piles; The all-solid waste recycled gel high-pressure jet grouting bite pile is provided with a reinforced concrete cap beam on the pile head along the length direction of the anti-seepage wall, and the width of the cap beam is not less than the pile diameter of the high-pressure jet grouting pile, and the height is not less than 0.6 times the pile diameter of the high-pressure jet grouting pile; A bamboo reinforcement sleeved with a thin-walled steel pipe is inserted along the central axis of the high-pressure jet grouting pile. The surface of the bamboo reinforcement is coated with raw tung oil once a day for three consecutive days, and asphalt is applied on the surface of the steel pipe.

7. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 6 is characterized in that: The all-solid waste recycled gel high-pressure rotary jet interlocking piles adopt all-solid waste alkali-activated cementitious materials, and the all-solid waste alkali-activated cementitious materials are prepared using papermaking wastewater as an alkali activator, slag as a volcanic ash material and silicate cement clinker, wherein the slag accounts for 60%-80%, the papermaking wastewater accounts for 10%-15%, and the silicate cement clinker accounts for 10%-20%.

8. The composite anti-seepage wall structure of the tough flow filling type landfill according to claim 7 is characterized in that: The diameter of the high-pressure jet-jet pile is 400mm-600mm; the bamboo reinforcement is made of straight bamboo with a diameter of 70mm-90mm.

9. A construction method for a composite anti-seepage wall structure of a landfill in a tough flow state as claimed in any one of claims 1 to 8, characterized in that: The steps include: Step S1: Ground treatment: clean and level the landfill foundation; set up cast-in-place reinforced concrete guide walls with a net width of 700 mm and a depth of 1500 mm. After the guide walls reach the specified strength and are removed from the formwork, two upper and lower supports are added along the longitudinal direction of the guide walls. Step S2: Positioning and drilling of the high-pressure rotary grouting bite piles of the outer rigid support layer, calibrating from two mutually perpendicular directions to ensure that the verticality deviation of the pile body does not exceed 1%, moving the full hydraulic anchor drilling rig to the pile position for positioning and centering, starting the drilling rig while rotating and drilling to the designed elevation; Step S3: insert the rotary jet grouting pipe, and when the nozzle reaches the bottom of the hole, perform the jetting operation from bottom to top, control the lifting speed between 6 and 8 cm / min, and stop lifting when it reaches 0.5 m from the pile top, and perform rotary jetting for 30 seconds, and then slowly lift and jet upward for 0.5 m to ensure the quality and density of the pile top; Step S4: After each pile is jetted, the residual liquid in the circulation pipe is cleaned with clean water to ensure normal use of the next pile construction; Step S5: Before the high-pressure jet grouting pile is cured, the bamboo reinforcement sleeved with steel pipe and coated with raw tung oil is inserted into the high-pressure jet grouting pile. If the insertion resistance is large, a vibration hammer can be used to assist in pile sinking; Step S6: breaking and chiseling the high-pressure jet grouting pile head slurry to the designed elevation, constructing the cushion layer, tying the crown beam steel bars, supporting the crown beam side formwork, and pouring the crown beam concrete; Step S7: excavate trenches according to the pre-divided sections, with the length of one trench section not exceeding 4m; after trench excavation is completed, use a grab bucket to remove the residue at the bottom of the trench; hang and place the joint pipe, and a circular lock joint pipe needs to be placed on the outside of the unit trench section, with the center line of the joint pipe coinciding with the framing line, and the bottom of the joint pipe flush with the bottom of the trench; Step S8: Lower the TPO anti-seepage geomembrane to the bottom of the trench. Before lowering it, stick one side of three double-sided butyl adhesives (4) to the anti-seepage geomembrane on an open ground. Do not tear off the adhesive strip on the back first. Insert a 5mm thick iron wire into the double-sided adhesive strip at the bottom of the geomembrane. Insert one iron wire into the two edge corners and the middle position of each double-sided butyl adhesive. Lower the geomembrane and fix the upper part. The overlapping width of two adjacent TPO anti-seepage geomembranes is not less than 0.3m. When the later-placed membrane is lowered to the bottom of the trench, tear off the adhesive strip of 10-15cm on the upper end of the previously-placed membrane. Then align the tops of the two membranes and press and stick them together. Then lift up the iron wire and tear off the adhesive strip on the back so that the two membranes are stuck together. Step S9: lowering a conduit into the trench at the inner main anti-seepage layer, placing a water-blocking ball into the conduit, pouring low-strength and tough fluidized solidified soil, lifting the conduit in due time during the pouring process, keeping the buried depth of the conduit at 2.5 to 6 m, and the average rising speed of the low-strength and tough fluidized solidified soil poured into the trench is not less than 2 m / h; Step S10: After a section of trench is constructed, the joint pipe is promptly pulled out, and the anti-seepage wall trench section is excavated, and construction is performed at intervals; the above process is repeated to complete the construction of other trench sections; Step S11: Quality inspection: Perform quality inspection on the completed anti-seepage wall to ensure that the anti-seepage performance meets the design requirements.

10. The construction method of the composite anti-seepage wall structure of the ductile flow filling type landfill according to claim 9 is characterized in that: Step S8 also includes: placing an uninflated airbag with a length approximately the same as the width of the groove and a width of approximately 0.5m into the bottom of the groove; before lowering it, tying a loose knot with wire on both sides of the long side of the airbag to allow the airbag to expand freely; after the airbag is lowered to the bottom, inflating the airbag so that the expansion of the airbag creates pressure on the groove; finally, slowly pulling the airbag up in parallel so that the airbag squeezes the overlapping part during the pulling process, so that the overlapping part sticks tightly.

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