CN115710923A - Composite separation wall for soft soil area and construction method thereof - Google Patents

Abstract

The invention provides a composite barrier wall for soft soil areas and a construction method thereof. The method includes first constructing a cement-based wall layer in the target soft soil area; The waterproof blanket is vibrated into the cement-based wall layer in turn; the sealing barrier agent is poured into the overlapping parts of the adjacent waterproof blanket, and the end of the waterproof blanket exposed to the cement-based wall layer is fixed. After the body layer curing is completed, the composite barrier wall is obtained. The composite barrier wall obtained in this way solves practical engineering problems such as poor single anti-seepage performance of the existing cement-based wall body and failure of anti-seepage performance due to deformation and cracking, and improves the overall anti-seepage performance of the wall body. Moreover, the wall layer is constructed first, and then the waterproof blanket is built in, so the vibration resistance is smaller, and the position of the waterproof blanket can be quickly fixed by the extrusion of cement, so the construction is more convenient, and the manpower, material resources and time costs are all reduced.

Description

Composite barrier wall used in soft soil area and its construction method

technical field

The invention relates to the technical field of vertical anti-seepage, in particular to a composite barrier wall used in soft soil areas and a construction method thereof.

Background technique

At present, more and more pollution control problems of tailings ponds, slag yards, landfills and other polluted sites need to be solved urgently. For pollution problems, emergency measures can be taken for control and treatment. The vertical anti-seepage technology controls pollutants in the barrier circle by setting up barrier barriers, blocks the migration and diffusion path of pollutants to the surrounding area, and avoids environmental pollution caused by pollutant leakage.

The vertical anti-seepage technology commonly used in soft soil areas is mainly rigid barrier technology, such as cement-soil mixing pile anti-seepage wall. Rigid barrier walls have many disadvantages, such as poor anti-seepage performance, which is generally difficult to reach 1×10 ^-7 cm/s, and due to stress concentration and uneven deformation, cracks will occur on the wall, especially at the overlap of the wall Leakage hazards are more likely to occur.

Many traditional barrier walls are formed by slotting, such as soil-bentonite mud wall. This wall forming method will cause problems such as large amount of work, long construction period, high wall construction cost and poor anti-seepage effect. Although the use of a built-in waterproof blanket can improve the anti-seepage effect, most of the existing technologies use vibration equipment to first vibrate the waterproof blanket into the soil body, and at the same time make grooves on both sides, and then grout for maintenance. On the one hand, this method is difficult to groove , It takes a long time. On the other hand, the parts used to fix the waterproof blanket need to stay at the bottom of the waterproof blanket, and the construction convenience and stability are not good.

In view of this, it is necessary to design a composite barrier wall and its construction method for soft soil areas to solve the above problems.

Contents of the invention

The purpose of the present invention is to provide a composite barrier wall for soft soil areas and its construction method, which adopts the method of first constructing the cement-based wall layer, then building a waterproof blanket, and injecting a sealing barrier agent at the overlapping part of the waterproof blanket , so as to obtain excellent anti-seepage, not easy to crack, and convenient construction, which can significantly save time and energy consumption, and reduce construction costs.

In order to achieve the above object, the present invention provides a construction method for a composite barrier wall in soft soil areas, comprising the following steps:

First construct the cement-based wall layer in the target soft soil area;

Between the initial setting and final setting of the cement-based wall layer, vibration equipment is used to vibrate the waterproof blanket into the cement-based wall layer in sequence;

Pouring a sealing barrier agent at the overlapping parts of adjacent waterproof blankets, and fixing the waterproof blanket end exposed to the cement-based wall layer, and after the curing of the cement-based wall layer is completed, a composite barrier wall is obtained.

Further, the cement-based wall layer is constructed into a wall through a five-axis mixing pile process, and the stirring sinking speed of the five-axis mixing pile process is 0.5-1.5m/min, and the lifting speed is 1.0-1.5m/min, The grouting pressure is not higher than 1.5MPa.

Further, the material of the cement-based wall layer includes cement, bentonite, water reducing agent, sodium sulfate and gypsum, and the water-cement ratio is 0.6-0.8;

The mixing amount of the cement is 15% to 20% of the weight of the reinforced soil; the mixing amount of the bentonite is 5-10% of the cement weight; the mixing amount of the water reducer, sodium sulfate and gypsum is sequentially 0.3-0.5%, 0.6-1.3% and 1.5-2.5% by weight; the mixing amounts of sodium sulfate and gypsum are preferably 1% and 2% by weight of cement respectively.

Further, the initial setting time of the cement-based wall layer is 3±0.5h, and the final setting time is 9±0.5h, that is, the waterproof blanket is vibrated in about 3-9 hours after grouting; the waterproof blanket It is a GCL bentonite waterproof blanket with a permeability coefficient of <5×10 ^-11 cm/s, and the height of the waterproof blanket exposing the cement-based wall layer is 0.3-0.6m, preferably 0.5m.

Further, by excavating a cement guide groove on one side of the cement-based wall layer, anchoring the exposed part of the waterproof blanket into the guide groove, and then pouring cement grout, the exposed end of the waterproof blanket is fixed.

Further, the vibration device includes a fixed motherboard for supporting the waterproof blanket and a jar connected with the fixed template, and the fixed motherboard is provided with an automatic lock for fixing the waterproof blanket Buckle, so that the waterproof blanket is close to the fixed mother board and vibrates downward into the cement-based wall layer; the fixed mother board is preferably one, and the thickness is 5-10cm, preferably 6-8cm, In order to prevent the steel plate from bending due to deflection during the vibration-in process, resulting in unevenness of the waterproof blanket.

Further, the bottom end of the fixed motherboard is also provided with a conical impact head with a length of 20-40cm.

Further, the sealing and blocking agent is injected through the grouting pipes buried on both sides of the overlapping parts of the waterproof blanket; the sealing and blocking agent includes 50% cement, 10% bentonite, 3% hydroxypropyl acrylate, chlorinated Calcium 2.5% and carboxymethyl cellulose 2.5%, the water-cement ratio is 1-1.5.

A composite barrier wall, obtained by the above-mentioned construction method, comprising a cement-based wall layer and a waterproof blanket arranged inside the cement-based wall layer, and a sealing barrier layer is provided at the overlapping part of the waterproof blanket .

Further, the cement-based wall layer is a cement-soil mixing pile wall layer with a thickness of 60-100cm; the waterproof blanket is a granular sodium-based bentonite waterproof blanket with a grammage of 4000-5500g/m ² , preferably 5000g/m ² ; the length of the overlapping part of the waterproof blanket is not less than 300mm.

The beneficial effects of the present invention are as follows:

1. The construction method of the composite barrier wall used in soft soil areas provided by the present invention firstly constructs a cement-based wall layer, then builds a waterproof blanket by vibrating, and injects a sealing barrier agent into the overlapping parts of the waterproof blanket. In this way, there is no need to make grooves, and the waterproof blanket is vibrated into the wall by using the fluidity and plasticity of the cement paste before final setting, and then integrated maintenance and molding, which can not only reduce the vibration resistance, but also use the flow of the paste The extrusion effect fixes the waterproof blanket to the wall, breaking the inherent thinking of the existing technology that the waterproof blanket is built first and then grouted, the construction convenience and stability are significantly improved, and the construction time and energy consumption are significantly saved.

2. The composite barrier wall obtained by the present invention solves practical engineering problems such as poor single anti-seepage performance of the cement-based wall body in the prior art, deformation and cracking, and failure of the anti-seepage performance due to loose joints, and improves the overall anti-seepage performance of the wall body.

Description of drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are the present invention. For some embodiments of the invention, those skilled in the art can also obtain other drawings based on these drawings without creative effort.

Fig. 1 is the schematic diagram of the cross-sectional structure of the composite barrier wall of the present invention;

Fig. 2 is a structural schematic diagram of the vibration equipment of the waterproof blanket;

Figure 3 is a schematic diagram of the longitudinal section structure of the composite barrier wall;

Figure 4 is a schematic diagram of the clamping side structure for fixing the motherboard and the waterproof blanket;

Fig. 5 is a schematic structural diagram of the process of lifting the fixed motherboard upward.

Reference signs:

1-cement-soil mixing pile wall; 2-wall lap joint; 3-waterproof blanket; 4-grouting pipe; 5-vibration equipment; 6-vibrator; 7-automatic lock; 8-fixed motherboard ; 9-impact head; 10-sleeve valve; 11-sealing barrier.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention are clearly and completely described below. Apparently, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Please refer to Figures 1-3, a composite barrier wall for soft soil areas, including a cement-based wall layer and a waterproof blanket 3 arranged inside the cement-based wall layer, and the overlapping parts of the waterproof blanket 3 A sealing barrier layer 11 is provided. The composite barrier wall obtained in this way can effectively solve practical engineering problems such as poor anti-seepage performance of the cement-based wall in the prior art and failure of anti-seepage performance caused by deformation and cracking through the built-in waterproof blanket and barrier agent, and significantly improve the overall performance of the wall. Anti-seepage performance.

Among them, the cement-based wall layer is preferably a cement-soil mixing pile wall 1, and the waterproof blanket 3 is preferably a GCL bentonite waterproof blanket 3. The GCL bentonite waterproof blanket 3 is vibrated into the cement-soil mixing pile wall 1 through the vibrating equipment 5. The GCL bentonite waterproof blanket 3 is a lap connection, and the sealant 11 is poured through the grouting pipe 4 on both sides of the lap joint to form an overall composite barrier. wall. With this configuration, the cement-soil mixing pile wall 1 does not need to be slotted, and the cement slurry is mixed with the soil directly during the mixing process of the mixing pile to form a reinforced barrier layer, so that the amount of cement slurry and the construction time can be saved. At the same time, utilizing the fluidity and plasticity of the slurry, between the initial setting and the final setting, the waterproof blanket 3 is vibrated into the wall, preferably in the middle of the wall, compared with the prior art (built-in waterproof blanket first) , re-grouting, the flexibility of the waterproof blanket makes it inconvenient to fix, especially the overlapping parts are difficult to stabilize), which can not only reduce the vibration resistance, but also use the flow and extrusion of the slurry to fix the waterproof blanket 3 to the wall In vivo, and then maintenance to achieve integrated molding, the construction convenience and stability are significantly improved. Therefore, the present invention breaks the technical prejudice of the existing barrier wall construction, and provides an effective idea for the rapid construction of the anti-seepage barrier wall.

Before the initial setting, the slurry is in a flow-plastic state, and the wall has no strength and cannot be formed. At this time, the vibration of the waterproof blanket will cause the waterproof blanket to sink and fold more; and the present invention chooses 1 after the initial setting, the slurry has a certain plastic strength and It is in a soft plastic state without losing fluidity, which is beneficial to the flatness and tightness of the waterproof blanket.

In particular, the cement-soil mixing pile wall 1 is arranged linearly, and is constructed in the soft soil area through a five-axis mixing process. The thickness of the cement-soil mixing pile wall 1 is 60-100 cm, for example, 85 cm. Adjacent wall sections are lapped, and the length of the lapped end of the wall is 200±20mm. In this way, when the position of the five-axis stirring pile is moved, there will be a gap between the two piles, which will affect the uniformity of the cavity.

The main material of the cement-soil mixing pile wall 1 is cement, such as PO42.5 ordinary Portland cement, and the amount of cement added is 15%-20% of the weight of the reinforced soil, and bentonite with 5-10% of the weight of cement is required in addition. To improve the anti-seepage performance of the wall. In order to increase fluidity, 0.3-0.5% polycarboxylate superplasticizer by weight of cement, 0.6-1.3% sodium sulfate and 1.5-2.5% gypsum are added, and the water-cement ratio is 0.6-0.8. The mixing amounts of sodium sulfate and gypsum are preferably 1% and 2% by weight of cement respectively. The slurry obtained in this way has good fluidity, which is convenient for the waterproof blanket 31 to vibrate into.

GCL bentonite waterproof blanket 3 is granular sodium bentonite waterproof blanket, the product type of sodium bentonite waterproof blanket is GCL-NP, the weight is 4000-5500g/m ² , for example 5000g/m ² , the thickness is 5-8mm, the penetration Coefficient <5×10 ^-11 cm/s.

GCL bentonite waterproof blanket 3 is connected by lap joints to improve the sealing of the joints and improve the impermeability. The top of GCL bentonite waterproof blanket 3 is exposed to the ground for about 0.5m, and the top is fixed by cement guide grooves. The purpose is to prevent the waterproof blanket from sinking or folding and stacking during the wall solidification process, which will affect the uniformity and strength of the composite barrier wall. .

As shown in FIG. 3 , the grouting pipe 4 includes an outer pipe, an inner pipe, a sleeve valve 10 and casing material.

In some embodiments, the material of the outer pipe of the grouting pipe 4 is a PVC pipe with a diameter of 52 mm, and the material of the inner pipe is a galvanized pipe with a diameter of 25 mm. The body of the grouting pipe 4 is provided with a sleeve valve 10, and the material of the sleeve valve 10 is rubber, and the setting distance is 0.5m. A shell material is arranged between the inner and outer tubes of the grouting pipe 4, and the weight ratio of the shell material is cement:bentonite:water=1:1.5:2. After grouting, the grouting pipe 4 does not need to be pulled out. Specifically, the sealing barrier 11 contains the following dry powder raw material mass fractions: 50% cement, 10% bentonite, 3% hydroxypropyl acrylate, 2.5% calcium chloride, 2.5% carboxymethyl cellulose, and the water-cement ratio is 1-1.5 .

As shown in Figure 1, the sealing barrier agent 11 is poured on both sides of the overlap of the GCL bentonite waterproof blanket 3 through the grouting pipe 4, and the grouting pressure is 1.0-1.5 MPa. The impermeability of the overlapping ends of the GCL bentonite waterproof blanket 3 is improved by pouring the sealing barrier agent.

As shown in Figures 2 and 4-5, the vibrating device 5 includes a fixed motherboard 8 for supporting the waterproof blanket 3 and a vibrator 6 connected to the fixed template 8. The fixed motherboard 8 is provided with a 3's automatic lock 7. The automatic lock 7 has the function of automatic locking. When the GCL bentonite waterproof blanket 3 is vibrated in place, it will automatically lock, so that the GCL bentonite waterproof blanket 3 and the fixed mother board 8 are separated.

When vibrating, put the waterproof blanket 3 close to the fixed mother board 8, and lock it with the automatic lock 7, so that the waterproof blanket 3 vibrates downward with the fixed mother board 8 into the cement-soil mixing pile wall 1. After the vibration is in place, , turn on the automatic locking function, separate the GCL bentonite waterproof blanket 3 from the fixed mother board 8, and then slowly lift the fixed mother board 8 to the surface; during the lifting process, the cement slurry gradually flows to fill the space left by the fixed mother board 8, thereby The GCL bentonite waterproof blanket 3 is fixed in the cement-soil mixing pile wall 1 . The vibrating time period needs to be kept between the initial setting (about 3 hours) and the final setting (about 9 hours) of the cement-soil mixing pile wall. In a specific embodiment, the power of the jar 6 is 100kW, and the length is 0.8m.

Because the invention vibrates into the cement slurry, the resistance is significantly reduced compared with the original soft soil, so the difficulty of vibrating is significantly reduced, the speed is increased, and time, cost and energy consumption are saved. Among them, clamping the waterproof blanket 3 close to the fixed motherboard 8 can prevent the vibration resistance from increasing due to the gap between the waterproof blanket 3 and the fixed motherboard 8, and at the same time prevent the edge of the waterproof blanket 3 (especially the lower edge) from being The resistance curls.

In particular, there is preferably one fixed motherboard 8 with a thickness of 5-10 cm, preferably 6-8 cm. Since the resistance of the cement slurry is relatively small, the fixed formwork 8 can only be set on one side of the GCL bentonite waterproof blanket 3, and the rigidity of the fixed formwork 8 can be used to improve the vibration strength, and at the same time, the GCL bentonite waterproof blanket 3 can always be in a flat state , to prevent folding and curling during the vibration-in process, which will affect the spreading effect of the waterproof blanket 3 . It can also be set as two thin splints under the condition that the total thickness of the fixed motherboard 8 remains unchanged, and the waterproof blanket 3 is clamped in the middle. When lifting, the two splints are released and then lifted. This method can utilize the smooth structure of the steel plates on both sides to reduce the frictional resistance on one side of the waterproof blanket 3 .

In particular, the jarring device 5 includes a jar 6, an automatic lock 7, a fixed motherboard 8 and a "V"-shaped impact head 9, and the length of the impact head 9 is 20-40 cm, preferably 30 cm. Utilize the tip structure of the impact head 9 to reduce the vibration difficulty of the fixed mother board 8; moreover, when it is lifted up, the impact head 9 moves upward together with the fixed mother board 8, and a gap is formed between it and the waterproof blanket 3, which is convenient for cement slurry Flow to the waterproof blanket 3 to form extrusion positioning.

In the present invention, after the cement-soil mixing pile wall 1 is constructed in the soft soil area, the GCL bentonite waterproof blanket 3 is vibrated into the cement-soil mixing pile wall 1 by the vibration method, and the GCL bentonite waterproof blanket 3 is connected by lap joints, and the lap joints are buried The sleeve valve pipe is poured with the sealing barrier agent 11, and the cement-soil mixing pile wall 1, the GCL bentonite waterproof blanket 3 and the sealing barrier agent 11 are combined to form a composite barrier wall. The permeability coefficient of the finally obtained composite barrier wall is less than 1×10 ^-7 cm/s.

To sum up, the composite barrier wall combined with cement-soil mixing pile wall 1, GCL bentonite waterproof blanket 3, and lap seal barrier agent 11 solves the problem of poor anti-seepage performance, deformation and cracking, and loose joints of cement-based walls in the prior art. Practical engineering problems such as the failure of anti-seepage performance have improved the overall anti-seepage performance of the wall. At the same time, the GCL bentonite waterproof blanket-cement soil mixing pile composite barrier wall constructed by the vibration technology has a short construction period and low cost.

Specifically, the construction method of the composite barrier wall of the present invention includes the following processes:

Stirring into the wall: The five-axis mixing process is used to construct the wall.

Material fixing: Install the GCL bentonite waterproof blanket 3 on the fixed motherboard 8 through the automatic lock 7 .

Vibrating in place: During the period from the initial setting to the final setting of the pile body, the GCL bentonite waterproof blanket 3 is vibrated into the cement-soil mixing pile wall 1 by using the vibrating equipment 5 . After the vibration is in place, turn on the automatic locking function, separate the GCL bentonite waterproof blanket 3 from the fixed mother board 8, then lift the fixed mother board 8 to the ground surface, clean it with water, and install the next GCL bentonite waterproof blanket 3.

Infusion of sealing and blocking agent: Embed grouting pipes 4 on both sides of the overlapping section of GCL bentonite waterproof blanket 3 for sealing and blocking agent injection.

Top fixing: The exposed section of GCL bentonite waterproof blanket 3 is anchored into the cement guide groove, and the cement slurry is poured. After the cement slurry finally sets, the top fixing process is completed.

More specifically, during construction, the following steps are included:

Step 1. Level the site: remove sundries and surface loose soil.

Step 2. Measurement and stakeout: Mark the cement-soil mixing pile wall 1, the GCL bentonite waterproof blanket 3 dimension line and the grouting pipe 4 position.

Step 3. Stir to form a wall: Use a five-axis mixing pile machine to construct a wall. The mixing sinking speed is 0.5-1.5m/min, the lifting speed is 1.0-1.5m/min, the grouting pressure is not higher than 1.5MPa, and the cement-soil mixing pile The 28-day unconfined compressive strength of wall 1 is 0.5-0.8 MPa. The lap length of the cement-soil mixing pile wall 1 is 200mm.

Step 4, material fixing: install the GCL bentonite waterproof blanket 3 on the fixed mother board 8 through the automatic lock 7 .

Step 5: Vibrating in place: During the period from the initial setting to the final setting of the pile body, vibrate the GCL bentonite waterproof blanket 3 into the cement-soil mixing pile wall 1 by using the vibrating equipment 5 . After the vibration is in place, turn on the automatic locking function, separate the GCL bentonite waterproof blanket 3 from the fixed mother board 8, then lift the fixed mother board 8 to the surface, clean it with water, and install the next GCL bentonite waterproof blanket 3, so Construct the next section of cement-soil mixing pile wall 1 and GCL bentonite waterproof blanket 3 in sequence. The lap length of GCL bentonite waterproof blanket is not less than 300mm.

Step 6. Injecting sealing and blocking agent: Embedding grouting pipes 4 on both sides of the overlapping section of the GCL bentonite waterproof blanket 3 for sealing and blocking agent injection, and the grouting pressure is 1.0-1.5 MPa.

Step 7. Fix the top: Finally, excavate a cement channel on one side of the wall, the size of the channel is 30×20×30cm (make sure that each piece of GCL bentonite waterproof blanket 3 is partially anchored, and each waterproof blanket can be fixed. ), anchor the exposed section of the GCL bentonite waterproof blanket 3 into the guide groove, and then pour cement slurry, and after the cement slurry finally sets, the top of the GCL bentonite waterproof blanket 3 is fixed.

Step 8. Maintenance: After 28 days of maintenance, the construction of the composite barrier wall is completed.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A composite barrier wall construction method for soft soil area, is characterized in that, comprises the steps: First construct the cement-based wall layer in the target soft soil area; Between the initial setting and final setting of the cement-based wall layer, vibration equipment is used to vibrate the waterproof blanket into the cement-based wall layer in sequence; Pouring a sealing barrier agent at the overlapping parts of adjacent waterproof blankets, and fixing the waterproof blanket end exposed to the cement-based wall layer, and after the curing of the cement-based wall layer is completed, a composite barrier wall is obtained. 2. the composite barrier wall construction method that is used for soft soil area according to claim 1, it is characterized in that, described cement-based wall body layer is constructed into wall by five-axis mixing pile technology, and the five-axis mixing pile technology The stirring sinking speed is 0.5-1.5m/min, the lifting speed is 1.0-1.5m/min, and the grouting pressure is not higher than 1.5MPa. 3. The composite barrier wall construction method for soft soil areas according to claim 1, wherein the material of the cement-based wall layer comprises cement, bentonite, water reducer, sodium sulfate and gypsum, and water ash The ratio is 0.6-0.8; The mixing amount of the cement is 15% to 20% of the weight of the reinforced soil; the mixing amount of the bentonite is 5-10% of the cement weight; the mixing amount of the water reducer, sodium sulfate and gypsum is sequentially 0.3-0.5%, 0.6-1.3% and 1.5-2.5% by weight; the mixing amounts of sodium sulfate and gypsum are preferably 1% and 2% by weight of cement respectively. 4. The construction method for composite barrier walls in soft soil areas according to claim 1, wherein the initial setting time of the cement-based wall layer is 3 ± 0.5h, and the final setting time is 9 ± 0.5h The waterproof blanket is a GCL bentonite waterproof blanket with a permeability coefficient of <5×10 ^-11 cm/s, and the height of the waterproof blanket exposing the cement-based wall layer is 0.3-0.6m, preferably 0.5m. 5. The construction method for composite barrier walls in soft soil areas according to claim 1 or 4, characterized in that, by excavating cement guide grooves on one side of the cement-based wall layer, the waterproof blanket The exposed part of the waterproof blanket is anchored into the guide groove, and then the cement grout is poured to realize the fixing of the exposed end of the waterproof blanket. 6. The construction method for composite barrier walls in soft soil areas according to any one of claims 1-4, characterized in that, the vibrating equipment includes a fixed mother board for supporting the waterproof blanket and is connected with the The vibrator connected to the fixed template, the fixed motherboard is provided with an automatic lock for fixing the waterproof blanket, so that the waterproof blanket is close to the fixed motherboard and vibrates downward into the cement base In the wall layer; there is preferably one fixed motherboard with a thickness of 5-10cm, preferably 6-8cm. 7. The construction method for the composite barrier wall used in soft soil areas according to claim 6, characterized in that, the bottom end of the fixed mother plate is also provided with a conical impact head with a length of 20-40cm. 8. The construction method for a composite barrier wall in soft soil areas according to claim 1, wherein the sealing barrier agent is injected through grouting pipes embedded in both sides of the lap joint of the waterproof blanket; The sealing barrier agent includes 50% of cement, 10% of bentonite, 3% of hydroxypropyl acrylate, 2.5% of calcium chloride and 2.5% of carboxymethyl cellulose, and the water-cement ratio is 1-1.5. 9. A composite barrier wall, characterized in that it is obtained by the construction method described in any one of claims 1-8, comprising a cement-based wall layer and a waterproof blanket arranged inside the cement-based wall layer, The overlapping part of the waterproof blanket is provided with a sealing barrier agent layer. 10. The composite barrier wall according to claim 9, wherein the cement-based wall layer is a cement-soil mixing pile wall layer with a thickness of 60-100 cm; the waterproof blanket is a granular sodium-based bentonite waterproof The weight of the blanket is 4000-5500g/m ² , preferably 5000g/m ² ; the length of the overlapping part of the waterproof blanket is not less than 300mm.

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