A microbial grouting treatment soft foundation construction structure and construction method thereof

Abstract

The present application relates to a microbial grouting treatment soft foundation construction structure and its construction method. The scheme includes the following steps: improving the shear strength and bearing capacity of the soft foundation and reducing the compressibility and permeability of the foundation soil by setting up heap loading, microbial high-pressure rotary jet piles and microbial tree root steel pipe piles; draining the moisture in the foundation and eliminating or weakening the liquefaction characteristics of the foundation soil by heap loading in conjunction with drainage steel pipes, mesh water collection pipes and pumps; and improving the cooperative working ability of the microbial high-pressure rotary jet piles and the soil between the piles by setting up a microbial sand solidification layer, ensuring deformation coordination and preventing uneven settlement. The grouting material adopts a two-component microbial grouting material, which is safe, clean and environmentally friendly. The microbial induced calcium carbonate precipitation material has the advantages of fast speed and high efficiency. The induced precipitation of calcium carbonate can be completed in about a few hours, which greatly shortens the construction period and will not cause sewage to flow across the land and pollute the environment.

Description

Technical Field

[0001] The present application relates to the technical field of foundation treatment, and in particular to a microbial grouting treatment soft foundation construction structure and a construction method thereof. Background Art

[0002] Foundation treatment refers to the engineering and technical measures taken to improve the bearing capacity of the foundation supporting a building or to improve its deformation or permeability properties. It plays a vital role in ensuring the smooth progress of subsequent construction projects. Through foundation treatment, one or more of the following goals need to be achieved:

[0003] 1) Improve the bearing capacity of the foundation soil. Shear failure can manifest itself in the following ways: insufficient bearing capacity of the building foundation, leading to structural instability due to eccentric loads or lateral earth pressure; uplift of adjacent foundations due to fill or building loads; and slope instability during excavation and uplift of the pit floor during excavation. Shear failure of foundation soil is primarily due to insufficient shear strength. Therefore, to prevent shear failure, measures must be taken to increase the foundation soil's shear strength.

[0004] 2) Reduce the compressibility of the foundation soil. The compressibility of the foundation is reflected in large building settlements and differential settlements. Soil compressibility is related to the soil's compression modulus. Therefore, measures must be taken to increase the compression modulus of the foundation soil to reduce foundation settlement and differential settlement.

[0005] 3) Improve the permeability of the foundation. During foundation pit excavation, thin layers of silt or silt in the soil can cause pipe bursts or sand flow. These are problems caused by the movement of groundwater in the soil. Therefore, measures must be taken to reduce the permeability of the foundation soil or its dynamic water pressure.

[0006] 4) Eliminate or reduce the liquefaction characteristics of the foundation soil. Saturated soil will liquefy under the action of earthquakes or dynamic forces, resulting in large deformations. Therefore, foundation treatment requires removing moisture from the foundation and eliminating or reducing the liquefaction characteristics of the foundation soil.

[0007] There is currently no systematic foundation treatment method that can comprehensively and efficiently solve the above problems.

[0008] For example, Chinese patent application number CN201410837193.6 proposes a method for treating soft soil foundations with microbial grouting drainage sand piles. However, the method first forms the pile and then pre-presses it, which may cause the pile body to be crushed or penetrate into the foundation. At the same time, the application requires special drilling and sand filling, which is relatively inconvenient, and the diameter of the sand pile is generally at least 0.5 to 1 meter, and the amount of sand and gravel consumed is huge. More importantly, the application forms drainage after forming the microbial grouting solidified sand pile, but after the sand pile is cemented by microorganisms, the permeability will be greatly reduced, which may lead to poor drainage and seriously affect the foundation treatment effect.

[0009] For example, Chinese patent application number CN201810614498.9 discloses a drainage board device and method with water-absorbing and expanding material under preload. However, it only improves the shear strength and bearing capacity of the foundation soil by absorbing water, and the reinforcement means are relatively insufficient. In addition, the moisture is always retained in the water-absorbing and expanding material and exists in the foundation, which is also a hidden danger.

[0010] Cement jet grouting piles are also a commonly used foundation treatment method, but conventional cement slurry takes a long time to solidify, which is difficult to meet the urgency of the project. More importantly, cement consumes a lot of energy, and sewage often flows during the construction of cement jet grouting piles, which easily pollutes the environment.

[0011] Therefore, there is an urgent need for a microbial grouting treatment soft foundation construction structure and a construction method thereof to solve the above technical problems.

[0012] Application Contents

[0013] The purpose of this application is to address the above-mentioned problems existing in the prior art and to provide a microbial grouting treatment soft foundation construction structure and a construction method thereof.

[0014] In order to achieve the above application objectives, this application adopts the following technical solution: A microbial grouting method for treating soft foundation includes the following steps:

[0015] S00, clean the soft foundation surface and prepare the working platform;

[0016] S10. Install drainage steel pipes vertically on the working platform according to the designed formation and penetrate the soft base to be treated;

[0017] S20, sealing the drainage steel flower pipe and the drilled hole with a sealing ring sleeve, and pressing the sealing ring sleeve into the soft foundation;

[0018] S30. Lay a drainage sand cushion layer on the ground surface;

[0019] S40, heaping the material on the sand cushion layer, and avoiding the drainage steel pipe and the reserved pile position of the microbial high-pressure jet grouting pile in the subsequent step;

[0020] S50, connecting all drainage steel pipes through a mesh water supply pipe and converging them into a drainage main pipe, and the drainage main pipe is connected to a pump;

[0021] S60, arranging the microbial high-pressure jet grouting piles in a designed formation between the drainage steel pipes, and ensuring that the microbial high-pressure jet grouting piles are long enough to penetrate the soft base to be treated;

[0022] S70, using a microbial high-pressure rotary jet drilling rig, drilling and grouting operations of microbial high-pressure rotary jet piles are performed on the soft foundation through a dual-channel high-pressure grouting pipe, so that the two-component grouting material mixes and deposits with each other and cuts the surrounding soil, mixing with the soil to form a microbial high-pressure rotary jet pile, and stopping the grouting operation when the bottom elevation of the dual-channel high-pressure grouting pipe reaches the surface elevation, completing the construction of the microbial high-pressure rotary jet pile;

[0023] S80. Degas the drainage steel pipes, and in conjunction with the vertical squeezing of the pile load and the lateral squeezing of the surrounding soil by the microbial high-pressure jet grouting piles, further promote the seepage of water in the soft foundation from the drainage steel pipes, and improve the consolidation and bearing capacity of the soft foundation;

[0024] S90. After the soft foundation is drained and consolidated, the drainage steel pipe is used as a grouting pipe, and microbial high-pressure grouting is performed inside the pipe, so that the slurry penetrates into the surrounding soil through the holes of the drainage steel pipe, forming a root-like calcium carbonate reinforcement;

[0025] S100, filling the drainage steel pipe with sand and injecting microbial high-pressure grouting slurry, so that the sand particles in the drainage steel pipe are cemented together by the deposited calcium carbonate, and the calcium carbonate reinforcement in the shape of tree roots works in coordination to form a microbial tree root steel pipe pile;

[0026] S110. Cut the drainage steel pipe that is too high, and perform microbial grouting on the sand cushion layer to form a microbial sand solidification layer, and use the microbial sand solidification layer as the pile cap of the microbial high-pressure rotary jet pile.

[0027] Furthermore, the design formations in step S10 and step S60 are both square or plum blossom shaped.

[0028] Furthermore, in steps S10 and S60, the layout areas of the drainage steel pipes and the microbial high-pressure rotary jet piles are both greater than or equal to the area of ​​the soft foundation to be treated.

[0029] Furthermore, in step S70, the two-component grouting material is a urease-producing bacteria solution and a nutrient salt solution.

[0030] Furthermore, in step S70, the dual-channel high-pressure grouting pipe includes a drill rod and two independent nozzles arranged in the drill rod, and each nozzle extends from a side of the drill rod.

[0031] Furthermore, in step S70, the drill bit of the microbial high-pressure rotary jet drilling rig rotates and drills downward to the designed depth, then rises at a predetermined speed and keeps rotating, while the dual-channel high-pressure grouting pipes respectively spray out urease-producing bacteria solution and nutrient salt solution at high speed.

[0032] Furthermore, in step S20, the sealing ring sleeve is mounted on the outer ring of the drainage steel flower pipe, the protruding portion of the bottom of the sealing ring sleeve is inserted into the soft base, and the downward flat portion is in close contact with the surface of the soft base.

[0033] Furthermore, in step S10, the top of the drainage steel pipe exceeds the ground elevation by a certain height.

[0034] A microbial grouting soft foundation treatment construction structure is used to reinforce the soft foundation, comprising:

[0035] The working platform is set up on the soft ground surface and is used for construction work;

[0036] The sand cushion layer is laid on the surface of the soft foundation and is used for drainage. It is also used to form a microbial sand solidification layer through microbial grouting in the final stage of construction, serving as the pile cap for the microbial high-pressure jet grouting piles.

[0037] The pile load is placed on the sand cushion layer and avoids the drainage steel pipe and microbial high-pressure jet grouting pile positions to provide vertical pressure;

[0038] Drainage steel pipes are evenly spaced and laid on the soft foundation, with the bottom penetrating the soft base and the top exceeding the ground elevation by a certain height. The layout area is larger than the soft foundation area to be treated. They are used for drainage and grouting to form microbial root steel pipe piles after drainage is completed.

[0039] Microbial high-pressure jet grouting piles are evenly spaced on the soft foundation and located between the drainage steel pipes. The bottom of the microbial high-pressure jet grouting piles penetrates the soft base, and the layout area is larger than the soft foundation area to be treated. They are used for grouting to form microbial high-pressure jet grouting piles.

[0040] A water pump is used to pump water from the drainage steel pipe;

[0041] A vacuum pump is used to evacuate the soft base covered with the vacuum film;

[0042] The drainage main pipe is connected to the top of each drainage steel pipe and is connected to the pump for pumping operation;

[0043] Sealing ring sleeve, used to seal drainage steel pipes and soft foundation.

[0044] Compared with the prior art, this application has the following beneficial effects:

[0045] 1. Compared with the existing technology (CN201410837193.6), this application first pre-compresses the foundation and then forms piles, which can effectively prevent the pile body from being crushed or pierced into the foundation. In addition, the pile loading and overburdening can also improve the construction quality of microbial high-pressure rotary jet piles and prevent the soil from rising and being damaged under high-pressure grouting.

[0046] 2. Compared with the existing technology (CN201410837193.6 requires special drilling and sand filling, which is relatively inconvenient, and the diameter of the sand pile is generally at least 0.5 to 1m, and the amount of sand and gravel consumed is huge), this application uses microbial high-pressure rotary jet piles, which can make full use of the original soil of the soft foundation to form a reinforced body without the need for additional sand and gravel filling.

[0047] 3. Compared with the prior art (the sand piles in CN201410837193.6, after being cemented by microorganisms, have greatly reduced permeability, and thus the effect of "the pore water in the soil between the piles 2 being discharged along the drainage channel formed by the sand piles and the sand cushion layer" may be very poor, seriously affecting the foundation treatment effect), the present application, by installing steel flower pipes, can produce different effects as the construction progresses: first, it is used specifically for drainage, then as a microbial high-pressure grouting pipe, and finally it can form microbial root steel pipe piles to improve the bearing capacity of the foundation. The function of the steel flower pipe can be fully utilized under various working conditions, without causing idleness and waste of materials. By simply increasing the appropriate amount of material, multiple purposes can be achieved, achieving twice the result with half the effort and achieving multiple goals at one stroke.

[0048] 4. Generally, high-pressure grouting is relatively random, and the reinforcement range and quality are relatively uncontrollable. Therefore, in addition to randomly high-pressure grouting microbial bacterial liquid through the holes of the steel flower pipe to generate microbial tree root steel pipe piles as auxiliary reinforcement bodies, this application also generates microbial high-pressure rotary jet piles through high-pressure rotary jetting. The pile quality is more controllable, the strength and reinforcement range are more uniform, and the reinforcement effect is better than the general high-pressure grouting with greater randomness.

[0049] 5. Previous cement grouting materials were highly polluting and energy-intensive, while microbial grouting materials are green, environmentally friendly, efficient, and pollution-free. Microbial-induced calcium carbonate precipitation materials have the advantages of fast speed and high efficiency, and can complete the induced precipitation of calcium carbonate in about a few hours, greatly shortening the construction period and making them suitable for large-scale promotion and application.

[0050] 6. In addition to using a vacuum pump to increase the vacuum degree of the soft foundation, this application also uses a water pump to directly evacuate the mesh water collection pipes and steel flower pipes, which can more directly discharge the moisture in the soft foundation without the problem of vacuum pressure loss.

[0051] 7. Based on the above advantages, this application has the advantages of simple process, light equipment, easy operation, short construction period and good effect. It is very suitable for working conditions with tight construction period and high environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the construction structure of this application;

[0053] Figure 2 It is a schematic diagram of the construction process of this application;

[0054] Figure 3 This is a schematic diagram of the installation of the sealing ring sleeve of this application;

[0055] Figure 4 It is a flow chart of the construction method of this application;

[0056] Figure 5 It is a structural diagram of a dual-channel high-pressure grouting pipe.

[0057] In the figure, 1. Sand cushion layer; 2. Dual-channel high-pressure grouting pipe; 3. Heap load; 4. Drainage steel pipe; 5. Soft foundation; 6. Microbial high-pressure rotary jet pile position; 7. Water pump; 8. Vacuum pump; 9. Drainage main pipe; 11. Microbial sand solidification layer; 41. Sealing ring; 42. Microbial tree root steel pipe pile; 61. Microbial high-pressure rotary jet pile; 21. Drill rod; 22. Drill bit; 23. Nozzle. DETAILED DESCRIPTION

[0058] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0059] Those skilled in the art should understand that, in the disclosure of this application, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms cannot be understood as limiting this application.

[0060] Example 1

[0061] like Figure 1-Figure 2 As shown, the microbial grouting soft foundation treatment construction structure is used to reinforce the soft foundation 5, including:

[0062] The working platform is set on the surface of the soft foundation 5 and is used for construction work;

[0063] The sand cushion layer 1 is laid on the surface of the soft foundation 5 and is used for drainage and to form a microbial sand solidification layer 11 through microbial grouting in the final stage of construction, which serves as the pile cap of the microbial high-pressure jet grouting pile 61;

[0064] The pile load 3 is set on the sand cushion layer 1 and the vacuum membrane 2 and avoids the drainage steel flower pipe 4 and the microbial high-pressure rotary jet pile position 6 to provide vertical pressure;

[0065] Drainage steel pipes 4 are evenly spaced and laid on the soft foundation 5, with the bottom penetrating the soft foundation 5 layer and the top exceeding the ground elevation by a certain height. The layout area is larger than the area of ​​the soft foundation 5 to be treated. They are used for drainage and grouting to form microbial root steel pipe piles 42 after drainage is completed.

[0066] Microbial high-pressure rotary jet grouting pile positions 6 are evenly spaced on the soft foundation 5 and located between the drainage steel flower pipes 4. The bottom of the microbial high-pressure rotary jet grouting pile position 6 penetrates the soft foundation 5 layer, and the layout area is larger than the area of ​​the soft foundation 5 to be treated; grouting is used to form microbial high-pressure rotary jet grouting piles 61;

[0067] A water pump 7 is used to pump water from the drainage steel pipe 4;

[0068] A vacuum pump 8 is used to evacuate the soft base 5 covered by the vacuum film 2;

[0069] The drainage main pipe 9 is connected to the top of each drainage steel pipe 4 and is connected to the pump 7 for pumping operation;

[0070] The sealing ring 41 is used to seal the drainage steel flower pipe 4 and the soft foundation 5.

[0071] Example 2

[0072] Based on Example 1, Figure 4 As shown, the microbial grouting method for treating soft foundation includes the following steps:

[0073] S00, clean the surface of the soft foundation 5 and prepare the working platform;

[0074] S10, vertically install the drainage steel pipe 4 according to the designed formation on the working platform and penetrate the soft foundation layer 5 to be treated;

[0075] In this embodiment, a drainage steel flower pipe 4 is vertically installed on the working platform. The length penetrates the soft foundation 5 layer to be treated and is arranged in a square or plum blossom shape. The top of the drainage steel flower pipe 4 needs to exceed the ground elevation by a certain height to facilitate the connection of the mesh water collection pipe (drainage main pipe 9) and the pump 7. The layout area needs to be larger than the area of ​​the soft foundation 5 to be treated to fully drain the excess water in the soft foundation 5 and eliminate the liquefaction characteristics; the soil strength of the soft foundation 5 is relatively low, which is convenient for the installation of the drainage steel flower pipe 4.

[0076] S20, sealing the drainage steel flower pipe 4 and the drill hole through the sealing ring 41, and pressing the sealing ring 41 into the soft foundation 5;

[0077] In this embodiment, if Figure 3As shown, the rubber ring (sealing ring sleeve 41) is inserted into the drainage steel flower pipe 4 (the protruding part of the bottom of the sealing ring sleeve 41 is inserted into the soft base 5, and the downward flat part is close to the surface of the soft base 5), and is pressed into the soft base 5, fitting the surface of the soft base 5, and trying to prevent air leakage between the drainage steel flower pipe 4 and the drilled hole.

[0078] S30, laying a drainage sand cushion layer 1 on the ground surface;

[0079] In this embodiment, a drainage sand cushion layer 1 is laid on the ground surface, and the water seeping from the surface of the soft foundation 5 can be drained away in the horizontal direction through the sand cushion layer 1.

[0080] S40, performing heap loading 3 on the sand cushion layer 1, and avoiding the reserved pile position of the drainage steel pipe 4 and the subsequent microbial high-pressure rotary jet pile 61;

[0081] In this embodiment, a load 3 is applied on the sand cushion layer 1. The load size is determined according to the design load, soil quality and the required bearing capacity of the foundation. At the same time, the load must avoid the positions of the drainage steel pipe 4 and the microbial high-pressure jet grouting pile 61. The reserved gap is preferably slightly larger than the diameter of the jet grouting pile borehole. At this time, under the action of the load 3, the foundation gradually begins to consolidate and settle.

[0082] S50, connecting all the drainage steel pipes 4 through a mesh water supply pipe and converging them into a drainage main pipe 9, which is connected to the pump 7;

[0083] In this embodiment, the top ends of the drainage steel flower pipes 4 are interconnected by a mesh water supply pipe, and finally merged into one pipe, which is then connected to a water pump 7 .

[0084] S60, arrange the microbial high-pressure rotary grouting piles 61 between the drainage steel pipes 4 according to the designed formation, and make the pile body length of the microbial high-pressure rotary grouting piles 61 penetrate the soft foundation 5 layers to be treated;

[0085] In this embodiment, the microbial high-pressure rotary jet piles 61 are arranged between the drainage steel pipes 4. The length of the pile body penetrates the soft foundation 5 layers to be treated, and is arranged in a square or plum blossom shape. The arrangement area must be no less than the area of ​​the soft foundation 5 to be treated to fully reinforce the soft foundation 5.

[0086] S70, using a microbial high-pressure rotary jet drilling rig, the soft foundation 5 is subjected to the drilling and grouting operation of the microbial high-pressure rotary jet pile 61 through the dual-channel high-pressure grouting pipe 2, so that the two-component grouting material is mixed and deposited with each other and cuts the surrounding soil, and is mixed with the soil to form the microbial high-pressure rotary jet pile 61. When the bottom elevation of the dual-channel high-pressure grouting pipe 2 reaches the surface elevation, the grouting operation is stopped, and the construction of the microbial high-pressure rotary jet pile 61 is completed;

[0087] The two-component grouting materials are urease-producing bacteria solution and nutrient salt solution (containing urea and calcium chloride);

[0088] Among them, the drilling tool of the high-pressure rotary jet drilling rig consists of a drill bit 22, a drill rod 21, a dual-channel high-pressure grouting pipe 2 in the drill rod 21 and a nozzle 23. The drilling tool rotates at high speed and drills downward (no grouting is performed at this time). After reaching the designed depth, it is lifted at a predetermined speed and keeps rotating. At the same time, the dual-channel high-pressure grouting pipe 2 sprays urease-producing bacteria liquid and nutrient salt solution at high speed respectively.

[0089] Among them, through the dual-channel high-pressure grouting pipe 2, the urease-producing bacteria liquid and the nutrient salt solution are respectively sprayed out from two nozzles at high speed, cutting the surrounding soil and mixing with the soil. At the same time, after the urease-producing bacteria liquid and the nutrient salt solution are mixed, the microorganisms begin to continuously deposit calcium carbonate cementing material, which is mixed with the soil to form a microbial high-pressure rotary jet pile 61 with a certain strength (the principle is: urease-producing bacteria release urease during metabolism; urease hydrolyzes urea in the nutrient salt solution to generate carbonate ions; calcium carbonate ions then react with calcium ions of calcium chloride in the nutrient salt solution to generate calcium carbonate cementing material, thereby reinforcing the soil).

[0090] Among them, the dual-channel high-pressure grouting pipe 2 is lifted at a set speed, and grouting is carried out continuously. The soft foundation 5 soil cut by the high-speed slurry can be better combined with the microbial slurry, and the reinforcement effect is better. Due to the existence of the heap load, the microbial high-pressure rotary jet pile 61 is formed under axial pressure. On the one hand, this improves the density and strength of the pile body, and on the other hand, it is more conducive to the discharge of excess moisture in the pile body after the microbial reaction, and the moisture in the pile body and the soil around the pile is more fully squeezed into the drainage steel pipe 4, and then smoothly discharged.

[0091] S80, evacuating the drainage steel pipe 4, in conjunction with the vertical squeezing of the heap load 3 and the lateral squeezing of the surrounding soil by the microbial high-pressure jet grouting pile 61, further promotes the water in the soft foundation 5 to seep out of the drainage steel pipe 4, thereby improving the consolidation degree and bearing capacity of the soft foundation 5;

[0092] In this embodiment, the drainage steel flower pipe 4 is evacuated to increase the vacuum degree inside the pipe. Combined with the vertical extrusion generated by the pile load 3 and the lateral extrusion of the surrounding soil by the expansive microbial high-pressure rotary jet pile 61, the moisture deep in the soft foundation 5 can fully seep out from the drainage steel flower pipe 4, further improving the consolidation degree and bearing capacity of the soft foundation 5 soil and eliminating the liquefaction characteristics.

[0093] S90, after the soft foundation 5 is drained and consolidated, the drainage steel pipe 4 is used as a grouting pipe, and microbial high-pressure grouting is performed inside the pipe, so that the slurry penetrates into the surrounding soil through the holes of the drainage steel pipe 4, forming a root-like calcium carbonate reinforcement;

[0094] S100, filling the drainage steel pipe 4 with sand, and injecting urease-producing bacteria solution and nutrient salt solution. The deposited calcium carbonate cements the sand particles in the drainage steel pipe 4 together, and works in conjunction with the aforementioned root-like calcium carbonate reinforcement to form microbial root steel pipe piles 61, which can be used to further improve the bearing capacity of the foundation.

[0095] S110, cutting the excessively high drainage steel pipe 4, and performing microbial grouting on the sand cushion layer 1 to form a microbial sand solidification layer 11, and using the microbial sand solidification layer 11 as the pile cap of the microbial high-pressure jet grouting pile 61;

[0096] In this embodiment, the excessively high drainage steel pipe 4 is cut off, and urease-producing bacteria solution and nutrient salt solution are sprayed onto the sand cushion layer 1 to cement the originally loose sand particles together to form a microbial sand solidification layer 11 with certain strength and flexibility, which can be directly used as the pile cap of the microbial high-pressure rotary jet pile 61, thereby improving the collaborative working ability of the microbial high-pressure rotary jet pile 61 and the soil between the piles, ensuring deformation coordination, and preventing uneven settlement.

[0097] S120. Dismantle construction equipment, clean up the site and complete the construction.

[0098] The parts not described in detail in this application are prior art, so this application does not describe them in detail.

[0099] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0100] Although this document frequently uses terms such as sand cushion layer 1, dual-channel high-pressure grouting pipe 2, heap load 3, drainage steel pipe 4, soft foundation 5, microbial high-pressure rotary jet grouting pile position 6, pump 7, vacuum pump 8, drainage main 9, microbial sand and soil solidification layer 11, sealing ring 41, microbial tree root steel pipe pile 42, microbial high-pressure rotary jet grouting pile 61, drill rod 21, drill bit 22, and nozzle 23, the use of other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of this application; interpreting them as any additional limitations is contrary to the spirit of this application.

[0101] This application is not limited to the above-mentioned optimal implementation method. Anyone can derive various other forms of products based on the inspiration of this application. However, no matter what changes are made in their shape or structure, any technical solution that is the same or similar to that of this application falls within the scope of protection of this application.

Claims

1. A microbial grouting method for treating soft foundation, characterized in that: The following steps are involved: S00, clean the soft foundation surface and prepare the working platform; S10, vertically installing drainage steel pipes on the working platform according to the designed formation and penetrating the soft base to be treated; S20, sealing the drainage steel flower pipe and the drilled hole with a sealing ring sleeve, and pressing the sealing ring sleeve into the soft foundation; the sealing ring sleeve is mounted on the outer ring of the drainage steel flower pipe, the bottom protruding portion of the sealing ring sleeve is inserted into the soft foundation, and the downward flat portion is in close contact with the surface of the soft foundation; S30. Lay a drainage sand cushion layer on the ground surface; S40, heaping on the sand cushion layer, and avoiding the drainage steel pipe and the reserved pile position of the microbial high-pressure jet grouting pile in the subsequent step; S50, connecting all drainage steel pipes through a mesh water supply pipe and converging them into a drainage main pipe, and the drainage main pipe is connected to a pump; S60, arranging the microbial high-pressure rotary grouting piles in a designed formation between the drainage steel pipes, and ensuring that the pile bodies of the microbial high-pressure rotary grouting piles are long enough to penetrate the soft base to be treated; S70, using a microbial high-pressure rotary jet drilling rig, drilling and grouting the microbial high-pressure rotary jet pile on a soft foundation through a dual-channel high-pressure grouting pipe, so that the two-component grouting material mixes and deposits with each other and cuts the surrounding soil, and mixes with the soil to form the microbial high-pressure rotary jet pile, and when the bottom elevation of the dual-channel high-pressure grouting pipe reaches the surface elevation, the grouting operation is stopped, and the construction of the microbial high-pressure rotary jet pile is completed; wherein the two-component grouting material is a urease-producing bacteria liquid and a nutrient salt solution; the dual-channel high-pressure grouting pipe includes a drill pipe and two independent nozzles disposed in the drill pipe, each of the nozzles extending from a side of the drill pipe; S80, evacuating the drainage steel pipe, coordinating with the vertical extrusion of the heap load and the lateral extrusion of the surrounding soil by the microbial high-pressure rotary jet grouting pile, further promotes the seepage of water in the soft foundation from the drainage steel pipe, and improves the consolidation degree and bearing capacity of the soft foundation; S90, after the soft foundation is drained and consolidated, the drainage steel pipe is used as a grouting pipe, and microbial high-pressure grouting is performed into the pipe, so that the slurry penetrates into the surrounding soil through the holes of the drainage steel pipe, forming a root-like calcium carbonate reinforcement; S100, filling the drainage steel pipe with sand and injecting a microbial high-pressure grouting slurry, so that the sand particles in the drainage steel pipe are cemented together by the deposited calcium carbonate, and the calcium carbonate reinforcement in the shape of tree roots works in coordination to form a microbial tree root steel pipe pile; S110, cutting the excessively high drainage steel pipe, and performing microbial grouting on the sand cushion layer to form a microbial sand solidification layer, and using the microbial sand solidification layer as the pile cap of the microbial high-pressure rotary jet pile.

2. A microbial grouting soft foundation treatment construction method according to claim 1, characterized in that: The design formations in steps S10 and S60 are both square or plum blossom shaped.

3. A microbial grouting soft foundation treatment construction method according to claim 1, characterized in that: In steps S10 and S60, the arrangement areas of the drainage steel pipes and the microbial high-pressure rotary jet grouting piles are both greater than or equal to the area of ​​the soft foundation to be treated.

4. A microbial grouting soft foundation treatment construction method according to claim 1, characterized in that: In step S70, the drill bit of the microbial high-pressure rotary jet drilling rig rotates and drills downward to the designed depth, then rises at a predetermined speed and keeps rotating, while the dual-channel high-pressure grouting pipes respectively spray out urease-producing bacteria solution and nutrient salt solution at high speed.

5. A microbial grouting method for treating soft foundation according to any one of claims 1 to 4, characterized in that: In step S10, the top of the drainage steel pipe exceeds the ground elevation by a certain height.

6. A microbial grouting treatment soft foundation construction structure, used for a microbial grouting treatment soft foundation construction method according to any one of claims 1 to 5, characterized in that: include: The working platform is set up on the soft ground surface and is used for construction work; The sand cushion layer is laid on the surface of the soft foundation and is used for drainage. It is also used to form a microbial sand solidification layer through microbial grouting in the final stage of construction, serving as the pile cap for the microbial high-pressure jet grouting piles. The heap load is placed on the sand cushion layer and avoids the drainage steel pipe and the microbial high-pressure jet grouting pile position to provide vertical pressure; Drainage steel pipes are evenly spaced and laid on the soft foundation, with the bottom penetrating the soft base and the top exceeding the ground elevation by a certain height. The layout area is larger than the soft foundation area to be treated. They are used for drainage and grouting to form microbial root steel pipe piles after drainage is completed. The microbial high-pressure rotary jet piles are evenly spaced and placed on the soft foundation and between the drainage steel pipes. The bottoms of the microbial high-pressure rotary jet piles penetrate the soft base layer, and the layout area is larger than the soft foundation area to be treated. The microbial high-pressure rotary jet piles are used for grouting to form the microbial high-pressure rotary jet piles. A water pump is used to pump water from the drainage steel pipe; A vacuum pump is used to evacuate the soft base covered with the vacuum film; A drainage main pipe is connected to the top of each drainage steel pipe and is connected to the pumping machine for pumping operation; Sealing ring sleeve, used to seal drainage steel pipes and soft foundation.

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