Recycled micro-powder improved soil-bentonite vertical anti-fouling isolation wall and construction method thereof

Abstract

The present invention discloses a regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall and a construction method thereof, including an isolation wall body, a guide wall and a steel pipe frame, wherein the steel pipe is arranged at the bottom of the isolation wall body. The method comprises: a, preparation of bentonite slurry; b, preparation of regenerated micro-powder of construction waste; c, construction of the guide wall; d, digging and grooving; e, preparation of the wall material of the isolation wall; f, making a bottom support plate and an inner insert plate; g, making a steel pipe frame; h, welding a bottom support plate; i, welding an inner insert plate; j, hanging and placing the steel pipe frame; k, hot-melt connection of the anti-seepage plate; l, backfilling of the wall material of the isolation wall; m, forming of the vertical anti-fouling isolation wall. The present invention can enhance the stability of the groove during the construction of the vertical anti-fouling isolation wall, that is, ensure the integrity of the wall body after the wall is formed, enhance the anti-seepage and anti-fouling performance of the vertical anti-fouling isolation wall, and at the same time, utilize the regenerated micro-powder of construction waste as the wall improvement material, which can optimize the mechanical properties and anti-seepage and anti-fouling performance of the wall body.

Description

Technical Field

[0001] The invention belongs to the technical field of urban groundwater and soil pollution prevention and control, and specifically relates to a regenerated micro-powder improved soil-bentonite vertical anti-pollution isolation wall and a construction method thereof. Background Art

[0002] Urban groundwater and soil pollution is characterized by concealment, accumulation and irreversibility. Its management is difficult, costly and time-consuming, and its impact on human health and economic and social development is long-term.

[0003] Vertical anti-pollution isolation walls are currently the most widely used and basic groundwater and soil pollution prevention and control technology. In recent years, my country has gradually begun to use vertical isolation wall technology to control groundwater and soil pollution sources. Common isolation wall materials include plastic concrete, soil-bentonite, etc. Among them, plastic concrete vertical anti-pollution isolation walls are often found to have substandard permeability in engineering practice; and although the soil-bentonite vertical anti-pollution isolation wall has low permeability and good chemical compatibility, the wall strength is low and the compressibility is large. Therefore, it is necessary to conduct further in-depth research on the improvement method of isolation wall materials, so that the vertical anti-pollution isolation wall has good impermeability, barrier and durability, and fully play the role of controlling the diffusion of pollutants in groundwater and soil.

[0004] On October 31, 2017, China Patent disclosed an invention patent named Cement-Bentonite Vertical Anti-Fouling Isolation Wall Structure and Method (Application Number: CN201711047288.8). The structure includes a cement-bentonite wall and its material ratio, as well as guide walls arranged on both sides of the surface of the cement-bentonite wall. The cement-bentonite wall penetrates from the surface through the high permeability rock and soil layer to the relatively impermeable soil layer, forming a stable upstream water level surface and downstream water level surface in the high permeability rock and soil layer; the overlying structure on the top surface of the cement-bentonite wall and the guide wall and the surrounding ground. The above-mentioned vertical anti-pollution isolation wall structure has the following technical effects: the wall material has the advantages of high water content, low permeability, strong deformation resistance, high shear strength, etc., and adopts a one-step construction method in which the cement-bentonite slurry used for trench excavation wall protection is directly formed into the wall material through hydration and hardening. The method is simple and the working surface is small, which simplifies the construction process of the vertical anti-pollution isolation wall; the isolation wall is used for the centralized groundwater seepage regulation and control of pollutant diffusion from pollution sources, and is particularly suitable for working conditions with large overburden pressure or foundation lateral pressure.

[0005] The construction process of soil-bentonite vertical anti-pollution isolation wall usually includes three processes: trench excavation, backfilling of wall materials and consolidation of wall materials. The trenching machine excavates the trench according to the designed width on the site. Bentonite slurry needs to be poured into the trench to protect the wall to ensure the stability of the trench. After that, the wall material is backfilled into the trench to replace the slurry to initially form the wall. The wall material undergoes a consolidation process to achieve the target permeability. However, during the construction of the vertical anti-pollution isolation wall, the stability of the trench wall is not easy to ensure, and the formed soil-bentonite vertical anti-pollution isolation wall may be partially sandwiched with soil, resulting in a large local permeability and poor anti-pollution performance of the vertical anti-pollution isolation wall. Summary of the invention

[0006] The purpose of the present invention is to solve the above-mentioned deficiencies existing in the prior art and provide a vertical anti-fouling isolation wall of regenerated micro-powder improved soil-bentonite and a construction method thereof. The steel pipe frame of the vertical anti-fouling isolation wall can play a certain restraining role on the wall material of the isolation wall, increase the bearing capacity of the vertical anti-fouling isolation wall to a certain extent, and reduce the impact of the wall material of the isolation wall on the bottom of the groove when backfilling, which is conducive to maintaining the stability of the groove, thereby ensuring that the vertical anti-fouling isolation wall can achieve the target anti-seepage and anti-fouling performance after the wall is completed. In the construction method, recycled micro-powder from construction waste is used as a wall improvement material to make the vertical anti-fouling isolation wall have better anti-seepage and anti-fouling properties, which not only realizes the resource recycling of construction waste, but also reduces the secondary pollution of the environment by recycled micro-powder from construction waste; geogrids are laid on both sides of the trench wall, which can effectively prevent the trench wall from collapsing during the process of bentonite mud wall protection, thereby ensuring the stability of the trench, that is, ensuring the integrity of the vertical anti-fouling isolation wall after the wall is completed, and thus ensuring the anti-seepage and anti-fouling properties of the vertical anti-fouling isolation wall; a bottom support plate is set in the steel pipe frame for integrally welding the inner insert plate , and sufficient space is reserved between two adjacent bottom support plates to facilitate the flow and backfilling of the isolation wall material with a large slump. By installing an inner plug-in plate on the bottom support plate, the bottom of the anti-seepage plate inserted in the isolation wall material is limited in the inner plug-in plate to avoid the anti-seepage plate deviating from the installation position when the isolation wall material with a large slump flows. By arranging the anti-seepage plate in the isolation wall body, the anti-seepage plate and the soil-bentonite vertical anti-fouling isolation wall are combined into a composite vertical anti-fouling isolation system, which can not only improve the anti-seepage and anti-fouling performance of the isolation wall, but also improve the service life of the vertical anti-fouling isolation wall.

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

[0008] The regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall comprises an isolation wall body and guide walls arranged on both sides of the surface part of the isolation wall body, and is characterized in that it also comprises a steel pipe frame, and the steel pipe frame is arranged at the bottom of the isolation wall body.

[0009] During the construction of the vertical anti-pollution isolation wall, a steel pipe rack is suspended in the trench. The steel pipe rack is set at the bottom of the isolation wall. The steel pipe rack can play a certain restraining role on the wall materials of the isolation wall, which increases the bearing capacity of the vertical anti-pollution isolation wall to a certain extent, and can reduce the impact of the wall materials of the isolation wall on the bottom of the trench when backfilling, which is beneficial to maintaining the stability of the trench, thereby ensuring that the vertical anti-pollution isolation wall can achieve the target anti-seepage and anti-pollution performance after the wall is completed.

[0010] Furthermore, the wall of the isolation wall is a structure made of recycled micro-powder from construction waste, bentonite and in-situ foundation soil. With the continuous acceleration of my country's urbanization process, a series of infrastructure projects continue to generate a large amount of construction waste. The waste concrete, waste mortar and brick and tile fragments in these construction wastes can be processed into recycled coarse and fine aggregates of a certain particle size through crushing, screening, impurity removal and other processes. In the process of preparing recycled aggregates from construction waste, a large amount of recycled micro-powder materials with a particle size of less than 0.075mm will inevitably be produced at the same time, accounting for about 15% to 20% of the total mass of construction waste. The recycled micro-powder has fine particles and low activity, and has the function of an inert mineral admixture. It can be added to the wall material to effectively fill the pores of the wall material, improve the strength of the wall, optimize the mechanical properties and anti-seepage properties of the wall, and reduce the deformation of the wall during use. In addition, the recycled micro-powder is a loose and porous powder with a large specific surface area and good ability to adsorb pollutants, which can effectively improve the anti-fouling performance of the vertical isolation wall. Moreover, it can realize the resource recycling of construction waste and reduce the secondary pollution of the environment caused by the recycled micro powder of construction waste.

[0011] Furthermore, it also includes geogrids, which are fixedly connected to the steel pipe frame and the guide wall, and are arranged on both sides of the isolation wall. The geogrid can effectively prevent the trench wall from collapsing during the bentonite slurry wall protection process, ensuring the stability of the trench, that is, ensuring the integrity of the vertical anti-fouling isolation wall after the wall is completed, thereby ensuring the anti-seepage and anti-fouling performance of the vertical anti-fouling isolation wall.

[0012] Furthermore, an anti-seepage plate is included, which is inserted at the center of the upper part of the isolation wall. By arranging the anti-seepage plate in the isolation wall, the anti-seepage plate and the soil-bentonite vertical anti-fouling isolation wall are combined into a composite vertical anti-fouling isolation system, which can improve the anti-seepage and anti-fouling performance of the isolation wall and improve the service life of the vertical anti-fouling isolation wall.

[0013] Furthermore, a bottom support plate is welded on the top of a single steel pipe rack, and an inner insert plate is welded between the bottom support plates. The bottom support plate is provided with a slot, and the bottom end of the inner insert plate is matched and welded in the slot. A groove is provided at the center of the inner insert plate, and the width of the groove is slightly greater than the thickness of the anti-seepage plate, and the bottom end of the anti-seepage plate is inserted into the groove. By arranging a bottom support plate in the steel pipe rack, the inner insert plate is used for integral welding, and sufficient space is reserved between two adjacent bottom support plates, so that the wall material of the isolation wall with a large slump can flow backfill. By installing the inner insert plate on the bottom support plate, the bottom of the anti-seepage plate inserted in the wall material of the isolation wall is limited in the inner insert plate, so as to avoid the anti-seepage plate from deviating from the installation position when the wall material of the isolation wall with a large slump flows.

[0014] Furthermore, a lifting lug is welded on the top of the bottom support plate, which is convenient for hoisting the steel pipe rack as a whole, so that the steel pipe rack can be manufactured on the ground, increasing the manufacturing space of the steel pipe rack.

[0015] Furthermore, the bottom ends of the card slot and the inner plug-in board are both trapezoidal in shape, so that the card slot is small at the top and large at the bottom. In this way, when welding the inner plug-in board, the inner plug-in board can only move horizontally along the length direction of the card slot of the bottom support plate, and cannot move up and down, so that the bottom end of the inner plug-in board can be completely welded to the bottom support plate, reducing the difficulty of welding and improving the welding quality.

[0016] Furthermore, the steel pipe rack includes vertical steel pipes and horizontal steel pipes, and the horizontal steel pipe is welded between two adjacent vertical steel pipes arranged in parallel, so that the entire steel pipe rack has a strong anti-deformation ability. A connecting steel pipe is welded between the vertical steel pipes of two adjacent steel pipe racks, so that multiple steel pipe racks are connected into a whole, which is convenient for hanging and placing the steel pipe racks, and a certain space is reserved between two adjacent steel pipe racks, so that sufficient space is reserved between two adjacent bottom support plates, which is convenient for the flow backfill of the wall material of the isolation wall with a large slump.

[0017] The construction method of the regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall is characterized by comprising the following steps:

[0018] a. Preparation of bentonite slurry:

[0019] Bentonite slurry is mainly used for mud wall protection after the isolation wall is grooved and as a component of the isolation wall material. After being fully stirred, the bentonite slurry needs to be left to stand for 24 hours to ensure that the bentonite is fully hydrated. The main control indicators of bentonite slurry quality are: specific gravity 1.1~1.3, viscosity 18~25s, sand content ≤5%, colloid rate 95%, etc.

[0020] b. Preparation of recycled micro powder from construction waste:

[0021] The waste concrete is first crushed as a whole from large to small, and the large pieces of waste concrete are crushed into small test pieces below 40mm, and then crushed for the second time by a crusher. The small pieces of concrete with a particle size less than 10mm after crushing are screened by screening equipment, and finally the recycled micro powder of construction waste with a particle size of less than 0.16mm is obtained.

[0022] Waste concrete, waste mortar, brick and tile fragments and other materials in construction waste can be processed into recycled coarse and fine aggregates of a certain particle size through crushing, screening, impurity removal and other processes. In the process of preparing recycled aggregates from construction waste, a large amount of recycled micro-powder materials with a particle size of less than 0.075mm will inevitably be produced at the same time, accounting for about 15% to 20% of the total mass of construction waste. These recycled micro-powders have certain activity. Using recycled micro-powders as isolation wall improvement materials has a good anti-seepage effect, which can not only realize the resource reuse of construction waste, but also reduce the secondary pollution of recycled micro-powders to the environment.

[0023] c. Guide wall construction:

[0024] Before the construction of the isolation wall, you can choose whether to build a guide wall according to the site conditions. Generally, when the shallow surface of the site is filled with soil or silty sand, a guide wall needs to be built to avoid soil collapse during the trenching process. The guide wall can also guide the direction of the trenching equipment to ensure the stability of the mud liquid level. During the construction of the guide wall, gantry columns are set along the axis in sections to control the axis of the guide wall, the excavator digs the trench, the slope is repaired manually, the guide wall formwork is erected, the steel mesh is placed in the formwork, and the symmetrical pouring is carried out. When the strength reaches 70%, the formwork is removed and a safety mesh is laid on the top of the guide wall.

[0025] d. Digging trenches:

[0026] The trench for the vertical anti-pollution isolation wall is excavated in the soil layer between the guide walls on both sides using the hydraulic grab method. The trenching machinery is usually required to be equipped with a verticality display instrument and an automatic deviation correction device to ensure that the trenching process is corrected at any time.

[0027] Bentonite slurry is injected into the trench during excavation to form a slurry wall. Since the mud cake at the joint of the trench wall will affect the quality of the joint and cause water leakage, a forced wall brushing machine should be used to brush the joint after the trench is excavated. Then a hydraulic grab is used to sweep away the residual sediment at the bottom of the trench, and a reverse circulation method is used to remove the sediment at the bottom of the trench. When cleaning the bottom, the mud suction pipe sucks the soil and silt at the bottom of the trench from shallow to deep. After the sediment at the bottom of the trench is removed, the slurry is replaced, and sampling is taken to test whether the bottom cleaning and slurry replacement are qualified.

[0028] e. Preparation of isolation wall materials:

[0029] The recycled micro powder of construction waste, bentonite and in-situ foundation soil are mixed, and the wall materials of the isolation wall are directly rolled and shoveled repeatedly on the open ground with a bulldozer, or mixed with a mixer.

[0030] The prepared wall materials must pass the slump test and permeability test before they can be used. Usually the slump can be in the range of 100-150mm, and the permeability coefficient must be less than 1×10 -9 ~5×10 -9 m / s.

[0031] f. Make the bottom support plate and inner insert plate in the processing plant according to the design drawings.

[0032] g. Steel pipe frame is made and assembled into a whole:

[0033] On the ground at the construction site, a horizontal steel pipe is welded between two adjacent vertical steel pipes arranged in parallel to form a single steel pipe rack, and then a connecting steel pipe is welded between the vertical steel pipes of the two adjacent steel pipe racks.

[0034] h. Weld the bottom support plate on the top of each steel pipe frame.

[0035] i. Match and weld the bottom end of the inner plug-in board into the slot of the bottom support board.

[0036] j. Steel pipe rack hanging:

[0037] The lower part of the geogrid is fixedly connected to the vertical steel pipe of the steel pipe rack with iron wire, and then the steel pipe rack connected as a whole is hoisted to the bottom of the vertical anti-pollution isolation wall trench by a crane, and the geogrid is laid on both sides of the trench wall, and then the upper part of the geogrid is fixed to the side of the guide wall by U-shaped nails.

[0038] k. On the ground at the construction site, hot-melt the anti-seepage plates together.

[0039] 1. Backfill of isolation wall materials:

[0040] At one end of the trench, a conduit is inserted into the bottom of the trench, and the wall materials of the isolation wall are allowed to flow down along the conduit under the action of their own weight, gradually replacing the mud in the trench from the bottom to the top, and gradually forming a slope. During pouring, the depth of the wall materials of the isolation wall needs to be monitored so that the conduit can be lifted up at the same time. When the height of the wall materials of the isolation wall at the conduit exceeds the mud liquid level, the subsequent wall materials of the isolation wall can be directly piled on the top of the trench and allowed to flow down along the slope, thereby pushing the slope forward as a whole.

[0041] m. Forming of vertical anti-fouling isolation wall:

[0042] An anti-seepage plate connected as a whole is inserted downward into the unconsolidated isolation wall material, the bottom end of the anti-seepage plate is inserted into the groove of the inner insert plate, and the top surface of the anti-seepage plate is flush with the top surface of the wall. After the isolation wall material is consolidated, a vertical anti-fouling isolation wall is formed.

[0043] Since the unconsolidated isolation wall material has a large slump, in order to make the insertion of the anti-seepage plate more accurate, the present invention designs step m, which specifically includes: installing an anti-seepage plate positioning device on the guide wall, the anti-seepage plate positioning device includes a positioning plate and a mounting plate, the positioning plate is in a W shape, a fixed plate is welded to the bottom of the mounting plate, an auxiliary flat plate is welded to the outer side of the positioning plate, a movable plate is welded to the outer side of the auxiliary flat plate, and the movable plate is arranged in the through hole of the fixed plate, firstly a pressing plate is used to flatten the inner side of the positioning plate so that the contact surfaces of the positioning plate and the pressing plate are on the same plane, then the movable plate of the positioning plate is moved in the through hole of the fixed plate, the positioning plate is extended a sufficient distance from the mounting plate, and then the fasteners are tightened to fix the movable plate in the through hole, and then Place the installation plate on the guide wall, and insert the positioning plate into the wall material of the isolation wall. Then control the distance between the two positioning plates so that the distance between the two positioning plates allows the anti-seepage plate to pass through. Then fix the installation plate on the guide wall with bolts. Insert the anti-seepage plate connected as a whole downward along the space between the two positioning plates in the unconsolidated wall material of the isolation wall. Insert the bottom end of the anti-seepage plate into the groove of the inner insert plate. When the top surface of the anti-seepage plate is flush with the top surface of the wall, lightly press the positioning plate so that the two positioning plates limit the top of the anti-seepage plate. When the consolidation degree of the isolation wall material reaches 80% or more, remove the anti-seepage plate positioning device from the guide wall as a whole. After the consolidation of the isolation wall material is completed, a vertical anti-fouling isolation wall is formed.

[0044] The positioning plates of the two anti-seepage plate positioning devices are symmetrically arranged, which can play a positioning and guiding role for the inserted anti-seepage plates, and prevent the anti-seepage plates from deviating from the installation position when the wall materials of the isolation wall with a large slump flow. The positioning plates are designed to be W-shaped, which is convenient for using a pressure plate to flatten the inner side of the positioning plates, so that the contact surfaces of the positioning plates and the pressure plate are on the same plane, while minimizing the contact area between the positioning plates and the anti-seepage plates to avoid damage to the anti-seepage plates. By lightly pressing the positioning plates, the two positioning plates limit the top of the anti-seepage plates, and the technical effect of the top surface of the anti-seepage plates being flush with the top surface of the wall can be achieved. In addition, the anti-seepage plate positioning device can be removed as a whole to avoid the influence of the anti-seepage plate positioning device on the vertical anti-fouling isolation wall structure.

[0045] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0046] 1. During the construction of the vertical anti-pollution isolation wall, a steel pipe rack is suspended in the trench. The steel pipe rack is set at the bottom of the isolation wall. The steel pipe rack can play a certain restraining role on the wall materials of the isolation wall, which increases the bearing capacity of the vertical anti-pollution isolation wall to a certain extent, and can reduce the impact of the wall materials of the isolation wall on the bottom of the trench when backfilling, which is beneficial to maintaining the stability of the trench, thereby ensuring that the vertical anti-pollution isolation wall can achieve the target anti-seepage and anti-pollution performance after the wall is completed.

[0047] 2. The wall of the isolation wall is a structure made of a mixture of recycled micro-powder from construction waste, bentonite and in-situ foundation soil. Among them, in-situ foundation soil refers to the uncontaminated foundation soil in the site where groundwater and soil pollution prevention and control is required. The wall materials of the isolation wall should make maximum use of the in-situ soil resources of the site to save earthwork costs. If the in-situ foundation soil is clay soil, the permeability is relatively small, and it itself has a certain blocking function on the diffusion of pollutants; if the in-situ foundation soil is silty sand, the permeability is relatively large. The in-situ foundation soil usually cannot meet the permeability coefficient requirements of the vertical anti-pollution isolation wall, so it is necessary to add bentonite to form a soil-bentonite isolation wall to reduce the permeability of the wall so that it can isolate the diffusion of underground pollutants to the greatest extent during use. However, the isolation wall formed by the in-situ foundation soil and bentonite has low strength, so it is necessary to add improved materials to increase its strength.

[0048] Recycled micropowder from construction waste is used as a material for improving the isolation wall. The recycled micropowder has fine particles and low activity. It has the function of an inert mineral admixture. When added to the wall material, it can effectively fill the pores of the wall material, improve the strength of the wall, optimize the mechanical properties and anti-seepage performance of the wall, and reduce the deformation of the wall during use. The recycled micropowder is a loose and porous powder with a large specific surface area and good ability to absorb pollutants. It can effectively improve the anti-fouling performance of the vertical isolation wall. It can also realize the resource reuse of construction waste and reduce the secondary pollution of the environment caused by the recycled micropowder from construction waste.

[0049] 3. The thickness of the vertical anti-pollution isolation wall in the prior art is 0.6 to 1.5 m. Therefore, the excavated trench is narrow and it is not suitable for technicians to enter the trench for construction operations.

[0050] In order to solve the technical problem that the trench is narrow and it is difficult to lay the geogrid, the lower part of the geogrid is fixedly connected to the vertical steel pipe of the steel pipe rack with iron wire, and then the steel pipe rack connected as a whole is hoisted to the bottom of the vertical anti-pollution isolation wall trench by a crane, and the geogrid is laid on both sides of the trench wall, and then the upper part of the geogrid is fixed to the side of the guide wall by U-shaped nails. In this way, the geogrid can be laid on both sides of the trench wall of the trench by hanging the steel pipe rack and the guide wall set on the surface. The geogrid can effectively prevent the trench wall from collapsing during the bentonite mud wall protection process, thereby ensuring the stability of the trench, that is, ensuring the integrity of the vertical anti-pollution isolation wall after the wall is completed, and then ensuring the anti-seepage and anti-pollution performance of the vertical anti-pollution isolation wall.

[0051] 4. By setting a bottom support plate in the steel pipe frame for integrally welding the inner insert plate, and welding a connecting steel pipe between two adjacent steel pipe frames, sufficient space is reserved between two adjacent bottom support plates to facilitate the flow and backfilling of the wall material of the isolation wall with a large slump.

[0052] By installing an inner insert plate on the bottom support plate, the bottom of the anti-seepage plate inserted in the isolation wall material is limited in the inner insert plate, thereby preventing the anti-seepage plate from deviating from the installation position when the isolation wall material with a large slump flows, thereby improving the installation quality of the anti-seepage plate.

[0053] By setting an anti-seepage plate in the isolation wall, the anti-seepage plate and the soil-bentonite vertical anti-fouling isolation wall are combined into a composite vertical anti-fouling isolation system, which can not only improve the anti-seepage and anti-fouling performance of the isolation wall, but also improve the service life of the vertical anti-fouling isolation wall.

[0054] 5. The positioning plates of the two anti-seepage plate positioning devices are symmetrically arranged. With the use of the inner insert plate, the inserted anti-seepage plates can be positioned and guided to avoid the anti-seepage plates from deviating from the installation position when the wall materials of the isolation wall with a large slump flow, thereby improving the installation accuracy of the anti-seepage plates. The positioning plates are designed to be W-shaped, which is convenient for using a pressure plate to flatten the inner side of the positioning plates, so that the contact surfaces of the positioning plates and the pressure plate are on the same plane, while minimizing the contact area between the positioning plates and the anti-seepage plates to avoid damage to the anti-seepage plates. By lightly pressing the positioning plates, the two positioning plates limit the top of the anti-seepage plates, and the technical effect of the top surface of the anti-seepage plates being flush with the top surface of the wall can be achieved. In addition, the anti-seepage plate positioning device can be removed as a whole to avoid the influence of the anti-seepage plate positioning device on the vertical anti-fouling isolation wall structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present invention will be further described below in conjunction with the accompanying drawings:

[0056] Figure 1 This is a schematic diagram of the structure of the present invention when the steel pipe frame is being manufactured;

[0057] Figure 2It is a schematic diagram of the structure of the present invention when the bottom support plate is welded;

[0058] Figure 3 It is a schematic diagram of the structure of the bottom support plate in the present invention;

[0059] Figure 4 This is a schematic diagram of the structure of the present invention when the inner insert plate is welded;

[0060] Figure 5 It is a structural schematic diagram of the inner plug-in board in the present invention;

[0061] Figure 6 This is a schematic diagram of the structure of the present invention when an anti-seepage plate is inserted;

[0062] Figure 7 It is a structural schematic diagram of the anti-seepage plate positioning device in the present invention;

[0063] Figure 8 It is a schematic diagram of the structure of the connection between the mounting plate and the fixing plate in the present invention;

[0064] Fig. 9 It is a schematic structural diagram of the regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall in the present invention.

[0065] In the figure, 1-isolation wall; 2-guide wall; 3-steel pipe rack; 4-geogrid; 5-anti-seepage plate; 6-bottom support plate; 7-slot; 8-insertion plate; 9-groove; 10-lifting ear; 11-vertical steel pipe; 12-horizontal steel pipe; 13-connecting steel pipe; 14-mounting plate; 15-fixed plate; 16-through hole; 17-fastener; 18-movable plate; 19-positioning plate; 20-bolt; 21-auxiliary plate. DETAILED DESCRIPTION

[0066] like Figures 1 to 9 As shown, the regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall of the present invention includes an isolation wall body 1 and guide walls 2 arranged on both sides of the surface part of the isolation wall body 1. It also includes a steel pipe frame 3, which is arranged at the bottom of the isolation wall body 1. The steel pipe frame 3 includes a vertical steel pipe 11 and a horizontal steel pipe 12. The length of the vertical steel pipe 11 shall be based on the design drawings to meet the height requirements of the bottom support plate installed later. The horizontal steel pipe 12 is welded between two adjacent parallel vertical steel pipes 11. A plurality of mutually parallel horizontal steel pipes 12 can be arranged between the two adjacent vertical steel pipes 11, so that the entire steel pipe frame 3 has a strong anti-deformation ability. A connecting steel pipe 13 is welded between the vertical steel pipes 11 of two adjacent steel pipe racks 3. The length of the connecting steel pipe 13 is based on the design drawings to ensure that there is enough space between the two adjacent steel pipe racks 3 to facilitate the flow and backfill of the wall materials of the isolation wall with a large slump. The connecting steel pipe 13 connects multiple steel pipe racks 3 into a whole, which is convenient for hanging the steel pipe racks 3.

[0067] The vertical anti-pollution isolation wall is hoisted into the groove of the vertical anti-pollution isolation wall, so that the steel pipe frame 3 is arranged at the bottom of the isolation wall body 1. The steel pipe frame 3 can play a certain restraining role on the wall material of the isolation wall, increase the bearing capacity of the vertical anti-pollution isolation wall to a certain extent, and reduce the impact of the wall material of the isolation wall on the bottom of the groove when backfilling, which is beneficial to maintaining the stability of the groove, and further ensure that the vertical anti-pollution isolation wall can achieve the target anti-seepage and anti-pollution performance after the wall is completed.

[0068] The wall body 1 of the isolation wall is a structure made of recycled micro-powder of construction waste, bentonite and in-situ foundation soil. With the continuous acceleration of my country's urbanization process, a series of infrastructure projects continue to generate a large amount of construction waste. The waste concrete, waste mortar and brick and tile fragments in these construction wastes can be processed into recycled coarse and fine aggregates of a certain particle size through crushing, screening, impurity removal and other processes. In the process of preparing recycled aggregates from construction waste, a large amount of recycled micro-powder materials of construction waste with a particle size less than 0.075mm will inevitably be produced at the same time, accounting for about 15% to 20% of the total mass of construction waste. The recycled micro-powder has fine particles and low activity, and has the function of inert mineral admixture. It can effectively fill the pores of the wall material when added to the wall material, improve the strength of the wall, optimize the mechanical properties and anti-seepage performance of the wall, and reduce the deformation of the wall during use. The recycled micro-powder of construction waste is a loose and porous powder with a large specific surface area and good ability to adsorb pollutants, which can effectively improve the anti-fouling performance of the vertical isolation wall. Moreover, it can realize the resource recycling of construction waste and reduce the secondary pollution of the environment caused by the recycled micro powder of construction waste.

[0069] It also includes a geogrid 4, which is fixedly connected to the steel pipe frame 3 and the guide wall 2, and is arranged on both sides of the isolation wall 1. By hanging the steel pipe frame 3 and the guide wall 2 arranged on the surface, the technical problem that the trench is narrow and it is difficult to lay the geogrid 4 is solved. The geogrid 4 can effectively prevent the trench wall from collapsing during the bentonite mud wall protection process, ensuring the stability of the trench, that is, ensuring the integrity of the vertical anti-fouling isolation wall after the wall is completed, and then ensuring the anti-seepage and anti-fouling performance of the vertical anti-fouling isolation wall.

[0070] It also includes an anti-seepage plate 5, which is inserted at the center of the upper part of the isolation wall body 1. The setting depth of the anti-seepage plate 5 is set according to the requirements for the prevention and control of groundwater and soil pollution on site. By setting the anti-seepage plate 5 in the isolation wall body 1, the anti-seepage plate 5 and the soil-bentonite vertical anti-fouling isolation wall are combined into a composite vertical anti-fouling isolation system, which can improve the anti-seepage and anti-fouling performance of the isolation wall and improve the service life of the vertical anti-fouling isolation wall.

[0071] A bottom support plate 6 is welded to the top of a single steel pipe frame 3, and an inner insert plate 8 is welded between the bottom support plates 6. The bottom support plate 6 is provided with a slot 7, and the bottom end of the inner insert plate 8 matches and is welded in the slot 7. A groove 9 is provided at the center of the inner insert plate 8, and the width of the groove 9 is slightly greater than the thickness of the anti-seepage plate 5, and the bottom end of the anti-seepage plate 5 is inserted into the groove 9. By arranging the bottom support plate 6 in the steel pipe frame 3, the inner insert plate 8 is used for integral welding, and sufficient space is reserved between two adjacent bottom support plates 6, which is convenient for the flow and backfilling of the wall material of the isolation wall with a large slump. By installing the inner insert plate 8 on the bottom support plate 6, the bottom of the anti-seepage plate 5 inserted in the wall material of the isolation wall is limited in the inner insert plate 8, so as to avoid the anti-seepage plate 5 from deviating from the installation position when the wall material of the isolation wall with a large slump flows. A lifting lug 10 is welded on the top of the bottom support plate 6, which is convenient for the overall lifting of the steel pipe frame 3, so that the steel pipe frame 3 can be manufactured on the ground, and the manufacturing space of the steel pipe frame 3 is increased. The bottom ends of the card slot 7 and the inner insert plate 8 are both trapezoidal in shape, so that the card slot 7 is small at the top and large at the bottom. In this way, when welding the inner insert plate 8, the inner insert plate 8 can only move horizontally along the length direction of the card slot 7 of the bottom support plate 6, and cannot move up and down, so that the bottom end of the inner insert plate 8 can be completely welded to the bottom support plate 6, reducing the difficulty of welding and improving the welding quality.

[0072] The construction method of the regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall comprises the following steps:

[0073] a. Preparation of bentonite slurry:

[0074] Bentonite slurry is mainly used for mud wall protection after the isolation wall is grooved and as a component of the isolation wall material. After being fully stirred, the bentonite slurry needs to be left to stand for 24 hours to ensure that the bentonite is fully hydrated. The main control indicators of bentonite slurry quality are: specific gravity 1.1~1.3, viscosity 18~25s, sand content ≤5%, colloid rate 95%, etc.

[0075] b. Preparation of recycled micro powder from construction waste:

[0076] The waste concrete is first crushed as a whole from large to small, and the large pieces of waste concrete are crushed into small test pieces below 40mm, and then crushed for the second time by a crusher. The small pieces of concrete with a particle size less than 10mm after crushing are screened by screening equipment, and finally the recycled micro powder of construction waste with a particle size of less than 0.16mm is obtained.

[0077] Waste concrete, waste mortar, brick and tile fragments and other materials in construction waste can be processed into recycled coarse and fine aggregates of a certain particle size through crushing, screening, impurity removal and other processes. In the process of preparing recycled aggregates from construction waste, a large amount of recycled micro-powder materials with a particle size of less than 0.075mm will inevitably be produced at the same time, accounting for about 15% to 20% of the total mass of construction waste. These recycled micro-powders have certain activity. Using recycled micro-powders as isolation wall improvement materials has a good anti-seepage effect, which can not only realize the resource reuse of construction waste, but also reduce the secondary pollution of recycled micro-powders to the environment.

[0078] c. Construction of guide wall 2:

[0079] Before the construction of the isolation wall, it is possible to choose whether to build the guide wall 2 according to the site conditions. Generally, the guide wall 2 needs to be built when the shallow surface of the site is filled with soil or silty sand to avoid soil collapse during the trenching process. The construction of the guide wall 2 can also guide the direction of the trenching equipment to ensure the stability of the mud liquid level. During the construction of the guide wall 2, gantry columns are set along the axis in sections to control the axis of the guide wall 2, the excavator digs the trench, the slope is repaired manually, the template of the guide wall 2 is erected, the steel mesh is placed in the template, and the casting is symmetrical. When the strength reaches 70%, the template is removed, and the top surface of the guide wall 2 is laid with a safety mesh to improve the strength of the guide wall.

[0080] d. Digging trenches:

[0081] The trench for the vertical anti-pollution isolation wall is excavated in the soil layer between the guide walls 2 on both sides by using a hydraulic grab method. The trenching machine is usually required to be equipped with a verticality display instrument and an automatic deviation correction device to ensure deviation correction at any time during the trenching process.

[0082] Bentonite slurry is injected into the trench during excavation to form a slurry wall. Since the mud cake at the joint of the trench wall will affect the quality of the joint and cause water leakage, a forced wall brushing machine should be used to brush the joint after the trench is excavated. Then a hydraulic grab is used to sweep away the residual sediment at the bottom of the trench, and a reverse circulation method is used to remove the sediment at the bottom of the trench. When cleaning the bottom, the mud suction pipe sucks the soil and silt at the bottom of the trench from shallow to deep. After the sediment at the bottom of the trench is removed, the slurry is replaced, and sampling is taken to test whether the bottom cleaning and slurry replacement are qualified.

[0083] e. Preparation of isolation wall materials:

[0084] The recycled micro powder of construction waste, bentonite and in-situ foundation soil are mixed, and the wall materials of the isolation wall are directly rolled and shoveled repeatedly on the open ground with a bulldozer, or mixed with a mixer.

[0085] The prepared wall materials must pass the slump test and permeability test before they can be used. Usually the slump can be in the range of 100-150mm, and the permeability coefficient must be less than 1×10 -9 ~5×10 -9 m / s.

[0086] f. Make the bottom support plate 6 and the inner insert plate 8 in the processing plant according to the design drawings.

[0087] g. Steel pipe frame 3 is manufactured and assembled into a whole:

[0088] On the ground of the construction site, a horizontal steel pipe 12 is welded between two adjacent vertical steel pipes 11 arranged in parallel to form a single steel pipe rack 3 , and then a connecting steel pipe 13 is welded between the vertical steel pipes 11 of the two adjacent steel pipe racks 3 .

[0089] h. Weld a bottom support plate 6 on the top of each steel pipe frame 3.

[0090] i. Match and weld the bottom end of the inner plug-in board 8 into the slot 7 of the bottom support board 6 .

[0091] j. Hanging of steel pipe rack 3:

[0092] The lower part of the geogrid 4 is fixedly connected to the vertical steel pipe 11 of the steel pipe frame 3 by iron wire, and then the steel pipe frame 3 connected as a whole is hoisted to the bottom of the vertical anti-fouling isolation wall trench by a crane, and the geogrid 4 is laid on both sides of the trench wall, and then the upper part of the geogrid 4 is fixed to the side of the guide wall 2 by U-shaped nails.

[0093] k. On the ground at the construction site, the anti-seepage plates 5 are connected to each other by hot-melt connection. The present invention accelerates the connection speed between the anti-seepage plates 5 by directly hot-melt connection between the anti-seepage plates 5.

[0094] 1. Backfill of isolation wall materials:

[0095] At one end of the trench, a conduit is inserted into the bottom of the trench, and the wall materials of the isolation wall are allowed to flow down along the conduit under the action of their own weight, gradually replacing the mud in the trench from the bottom to the top, and gradually forming a slope. During pouring, the depth of the wall materials of the isolation wall needs to be monitored so that the conduit can be lifted up at the same time. When the height of the wall materials of the isolation wall at the conduit exceeds the mud liquid level, the subsequent wall materials of the isolation wall can be directly piled on the top of the trench and allowed to flow down along the slope, thereby pushing the slope forward as a whole.

[0096] m. Forming of vertical anti-fouling isolation wall:

[0097] An anti-seepage plate 5 connected as a whole is inserted downward into the unconsolidated wall material of the isolation wall, the bottom end of the anti-seepage plate 5 is inserted into the groove 9 of the inner insert plate 8, and the top surface of the anti-seepage plate 5 is flush with the top surface of the wall. After the wall material of the isolation wall is consolidated, a vertical anti-fouling isolation wall is formed.

[0098] Since the unconsolidated wall material of the isolation wall has a large slump, in order to make the insertion of the anti-seepage plate 5 more accurate, the present invention designs step m, which specifically includes: installing an anti-seepage plate positioning device on the guide wall 2, the anti-seepage plate positioning device includes a positioning plate 19 and a mounting plate 14, the positioning plate 19 is in a W shape, a fixed plate 15 is welded to the bottom of the mounting plate 14, an auxiliary flat plate 21 is welded to the outside of the positioning plate 19, and a movable plate 18 is welded to the outside of the auxiliary flat plate 21, and the movable plate 18 is arranged in the through hole 16 of the fixed plate 15, and a pressing plate is first used to flatten the inner side of the positioning plate 19 so that the contact surface of the positioning plate 19 and the pressing plate are on the same plane. Then, the movable plate 18 of the positioning plate 19 is moved in the through hole 16 of the fixed plate 15, and the positioning plate 19 is extended out of the mounting plate 14 by a sufficient distance, and then the fasteners 17 are tightened to fix the movable plate 18 in the through hole 16. Then, the mounting plate 14 is placed on the guide wall 2, and the positioning plate 19 is inserted into the wall material of the isolation wall. The distance between the two positioning plates 19 is controlled so that the distance between the two positioning plates 19 allows the anti-seepage plate 5 to pass through. Then, the mounting plate 14 is fixed to the guide wall 2 by bolts 20. The anti-seepage plate 5 connected as a whole is inserted downward along the space between the two positioning plates 19 in the unconsolidated wall material of the isolation wall. The bottom end of the anti-seepage plate 5 is inserted into the groove 9 of the inner insert plate 8. When the top surface of the anti-seepage plate 5 is flush with the top surface of the wall, the positioning plate 19 is lightly pressed so that the two positioning plates 19 limit the top of the anti-seepage plate 5. When the consolidation degree of the wall material of the isolation wall reaches 80% or more, the anti-seepage plate positioning device is removed from the guide wall 2 as a whole. After the consolidation of the wall material of the isolation wall is completed, a vertical anti-fouling isolation wall is formed.

[0099] The positioning plates 19 of the two anti-seepage plate positioning devices are symmetrically arranged, which can play a positioning and guiding role for the inserted anti-seepage plate 5, and prevent the anti-seepage plate from deviating from the installation position when the wall material of the isolation wall with a large slump flows. The positioning plate 19 is designed to be in a W shape, which is convenient for using a pressure plate to flatten the inner side of the positioning plate 19, so that the contact surface of the positioning plate 19 and the pressure plate are in the same plane, and at the same time, the contact area between the positioning plate 19 and the anti-seepage plate 5 is minimized to avoid the damage of the anti-seepage plate 5. By lightly pressing the positioning plate 19, the two positioning plates 19 limit the top of the anti-seepage plate 5, and the technical effect of the top surface of the anti-seepage plate 5 and the top surface of the wall body can be achieved. In addition, the anti-seepage plate positioning device can be removed as a whole to avoid the influence of the anti-seepage plate positioning device on the vertical anti-fouling isolation wall structure.

[0100] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. The construction method of the vertical anti-fouling isolation wall of regenerated micro-powder improved soil-bentonite is characterized by: The regenerated micro-powder improved soil-bentonite vertical anti-fouling isolation wall comprises an isolation wall body, guide walls arranged on both sides of the surface part of the isolation wall body, a steel pipe frame, a geogrid and an anti-seepage plate, wherein the steel pipe frame is arranged at the bottom of the isolation wall body, the isolation wall body is a structure formed by mixing the regenerated micro-powder of construction waste, bentonite and in-situ foundation soil, the geogrid is fixedly connected to the steel pipe frame and the guide wall, the geogrid is arranged on both sides of the isolation wall, the anti-seepage plate is inserted at the center position of the upper part of the isolation wall, the top of the single steel pipe frame is welded with a bottom support plate, and the An inner insert plate is welded between the bottom support plates, the bottom support plate is provided with a slot, the bottom end of the inner insert plate is matched and welded in the slot, a groove is provided at the center of the inner insert plate, the width of the groove is greater than the thickness of the anti-seepage plate, the bottom end of the anti-seepage plate is inserted into the groove, a lifting ear is welded at the top of the bottom support plate, the slot and the bottom end of the inner insert plate are both trapezoidal, the steel pipe rack includes a vertical steel pipe and a horizontal steel pipe, the horizontal steel pipe is welded between two adjacent parallel vertical steel pipes, and a connecting steel pipe is welded between the vertical steel pipes of two adjacent steel pipe racks; The construction method comprises the following steps: a. Preparation of bentonite slurry; b. Preparation of recycled micro powder from construction waste: The waste concrete is crushed from large to small, and the large waste concrete is crushed into small test pieces below 40mm, and then crushed by a crusher for secondary crushing. The small concrete pieces with a particle size of less than 10mm after crushing are screened by a screening device, and finally the recycled micro powder of construction waste with a particle size of less than 0.16mm is obtained; c. Guide wall construction: The gantry columns are set up along the axis in sections, and then the trench is excavated by an excavator. Then the slope is repaired manually, the guide wall formwork is erected, and the steel mesh is placed in the guide wall formwork. Then the concrete is poured symmetrically. When the strength reaches 70%, the formwork is removed, and then a safety mesh is laid on the top surface of the guide wall. d. Digging trenches: The trench of the vertical anti-pollution isolation wall is excavated in the soil layer between the guide walls on both sides by using the hydraulic grab method. Bentonite slurry is injected into the trench during excavation to form a slurry wall, and then the wall is brushed. The residual sediment at the bottom of the trench is then swept away by using the hydraulic grab, and the sediment at the bottom of the trench is removed by using the reverse circulation method. When cleaning the bottom, the mud suction pipe sucks the soil and silt at the bottom of the trench from shallow to deep. After the sediment at the bottom of the trench is removed, the slurry is replaced, and sampling is taken to test whether the bottom cleaning and slurry replacement are qualified. e. Preparation of isolation wall materials: Mix the recycled micro powder of construction waste, bentonite and in-situ foundation soil, and use a bulldozer to repeatedly roll and shovel the wall materials on the open ground, or use a mixer to mix them; f. Make the bottom support plate and inner insert plate in the processing plant according to the design drawings; g. Steel pipe frame is made and assembled into a whole: On the ground of the construction site, a horizontal steel pipe is welded between two adjacent vertical steel pipes arranged in parallel to form a single steel pipe rack, and then a connecting steel pipe is welded between the vertical steel pipes of the two adjacent steel pipe racks; h. Weld the bottom support plate on the top of each steel pipe frame; i. Match and weld the bottom end of the inner plug-in board into the slot of the bottom support board; j. Steel pipe rack hanging: The lower part of the geogrid is fixedly connected to the vertical steel pipe of the steel pipe rack with iron wire, and then the steel pipe rack connected as a whole is hoisted to the bottom of the vertical anti-fouling isolation wall trench by a crane, and the geogrid is laid on both sides of the trench wall, and then the upper part of the geogrid is fixed to the side of the guide wall by U-shaped nails; k. On the ground at the construction site, hot-melt the anti-seepage plates together; 1. Backfill of isolation wall materials: At one end of the trench, a conduit is inserted into the bottom of the trench, and the wall materials of the isolation wall flow down along the conduit under the action of their own weight, gradually replacing the mud in the trench from the bottom to the top, and gradually forming a slope. During pouring, the depth of the wall materials of the isolation wall needs to be monitored so that the conduit can be lifted up at the same time. When the height of the wall materials of the isolation wall at the conduit exceeds the mud liquid level, the subsequent wall materials of the isolation wall can be directly piled on the top of the trench and allowed to flow down along the slope, so that the slope as a whole can be pushed forward; m. Forming of vertical anti-fouling isolation wall: An anti-seepage plate positioning device is installed on the guide wall, and the anti-seepage plate positioning device includes a positioning plate and a mounting plate. The positioning plate is in a W shape, a fixed plate is welded at the bottom of the mounting plate, an auxiliary flat plate is welded on the outer side of the positioning plate, a movable plate is welded on the outer side of the auxiliary flat plate, and the movable plate is arranged in the through hole of the fixed plate. First, a pressing plate is used to flatten the inner side of the positioning plate so that the contact surfaces of the positioning plate and the pressing plate are on the same plane, and then the movable plate of the positioning plate is moved in the through hole of the fixed plate, and the positioning plate is extended out of the mounting plate by a sufficient distance, and then the fasteners are tightened to fix the movable plate in the through hole, and then the mounting plate is placed on the guide wall, and at the same time, the positioning plate is inserted into the wall material of the isolation wall. The material is then adjusted, and the distance between the two positioning plates is controlled so that the distance between the two positioning plates allows the anti-seepage plate to pass through. The mounting plate is then fixed to the guide wall by bolts. The anti-seepage plate connected as a whole is inserted downward along the space between the two positioning plates in the unconsolidated isolation wall material. The bottom end of the anti-seepage plate is inserted into the groove of the inner insert plate. When the top surface of the anti-seepage plate is flush with the top surface of the wall, the positioning plate is lightly pressed so that the two positioning plates limit the top of the anti-seepage plate. When the consolidation degree of the isolation wall material reaches 80% or above, the anti-seepage plate positioning device is removed from the guide wall as a whole. After the consolidation of the isolation wall material is completed, a vertical anti-fouling isolation wall is formed.

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