Novel subway foundation pit anti-seepage structure

Abstract

The utility model relates to the technical field of foundation pit engineering, in particular to a novel subway foundation pit anti-seepage structure which comprises a foundation pit side wall support and anti-seepage cushion layer, an earth surface combined anti-seepage cushion layer, an earth surface drainage channel and a fixing device, and the foundation pit side wall support and earth surface combined anti-seepage cushion layer comprises an underground diaphragm wall and anti-seepage geotechnical cloth; the earth surface combined anti-seepage cushion layer comprises an anti-seepage geotechnical cloth layer, a bentonite waterproof blanket layer and an anti-seepage geomembrane layer; the earth surface drainage channel is composed of a base layer and an internally-laid polymer plate. According to the utility model, the structure arrangement is clear, the function of each component is clear, the layout is simple, and the practicability is strong; various anti-seepage structures or materials are comprehensively utilized, and the anti-seepage effect is good; blocking and dredging are combined, drainage is guided while an infiltration channel is cut off, and the situation that water is accumulated due to the fact that leaking stoppage is excessively paid attention to is avoided; and the material hardly causes pollution to the environment and conforms to the development concept of green and environment-friendly.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation pit engineering, in particular to a new anti-seepage structure for subway foundation pits. Background Technique

[0002] As a large-capacity and high-density urban rail transit mode that often does not require a large amount of ground space and can also take into account civil air defense projects, the subway has received increasing attention, and subway projects have gradually emerged.

[0003] The construction of the subway is inseparable from foundation pit engineering. Foundation pit engineering has the characteristics of relatively high risk, strong temporariness, small safety reserves in terms of deformation, strength, durability, load, anti-seepage, etc., being greatly affected by the environment and also having a greater impact on the environment. Among them, the change of the water environment around the foundation pit is an important factor affecting the safety of the foundation pit. There are numerous cases where the change of the water environment caused by rainfall and other factors leads to the instability or even destruction of the foundation pit. Therefore, anti-seepage is an important issue that foundation pit engineering needs to face.

[0004] At present, a large amount of research and engineering applications have been carried out on the layout of vertical water-stop curtains for foundation pits. However, the vertical water-stop curtain is more helpful for maintaining the stability of the groundwater environment of the rock and soil mass at the bottom of the foundation pit, and there is still a lack in maintaining the stability of the groundwater environment of the rock and soil mass around the foundation pit. In addition, the change of the water environment around the foundation pit may also cause the overturning of the side wall support of the foundation pit. In addition, foundation pits in subway construction often have the characteristics of narrow strips, which are different from general foundation pit engineering. In view of this, it is necessary to study the comprehensive anti-seepage system for the ground surface and the side wall of the foundation pit in view of factors such as rainfall. Content of the Utility Model

[0005] To achieve the above technical purpose, in view of the deficiencies of the prior art, the utility model provides an anti-seepage structure for subway foundation pits. This structure can take into account maintaining the stability of the groundwater environment of the rock and soil mass at the bottom of the subway foundation pit and around the foundation pit, and better ensure the safety of subway foundation pit construction.

[0006] To achieve the above purpose, the utility model adopts the following technical scheme: a new anti-seepage structure for subway foundation pits, including foundation pit side wall support and anti-seepage cushion, surface combined anti-seepage cushion, surface drainage channel and fixing device.

[0007] The foundation pit side wall support and surface combined anti-seepage cushion include diaphragm wall and anti-seepage geotextile.

[0008] The surface combined anti-seepage cushion includes three layers: anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane.

[0009] The surface drainage channel is composed of a base layer and an inner-laid high-molecular plate. The high-molecular plate is fixed to the surface combined anti-seepage cushion through a fixing device.

[0010] Preferably, the diaphragm wall serves as both the support structure and the anti-seepage structure of the foundation pit, and an anti-seepage geotextile is vertically attached to the outside of the diaphragm wall as a combined anti-seepage measure.

[0011] Preferably, the anti-seepage geotextile is made of polyester fiber non-woven geotextile.

[0012] Preferably, the anti-seepage geomembrane is made of high-density polyethylene membrane.

[0013] Preferably, the fixing device includes a conical cylinder which penetrates through the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane. A convex ring is fixedly installed at the upper port of the conical cylinder, a connecting rod is fixedly installed inside the conical cylinder, two support frames are slidably connected to the side wall of the connecting rod, four pointed protrusions are fixedly connected to the side wall of the support frame, and through holes are formed in the side wall of the conical cylinder.

[0014] Preferably, a connecting block is fixedly connected to the inside of the conical cylinder, an inserting bar is slidably connected inside the connecting block, the lower end side cross-section of the inserting bar is an isosceles triangle, a connecting pin is fixedly connected to the upper surface of the convex ring, and a rotating block is rotatably connected to the upper end of the connecting pin.

[0015] Preferably, a spring is sleeved on the surface of the connecting rod, and both ends of the spring are fixedly connected to the inside of the support frame and the conical cylinder respectively.

[0016] In summary:

[0017] 1. In the present utility model, the structure is clearly arranged, the functions of each component are clear, the layout is simple, and the practicability is strong; a variety of anti-seepage structures or materials are comprehensively used, and the anti-seepage effect is good; blocking and drainage are combined, while paying attention to intercepting the infiltration channel, guiding drainage is also considered, avoiding the situation of water accumulation caused by overemphasis on plugging; the materials have almost no pollution to the environment, meeting the development concept of green environmental protection.

[0018] 2. In the present utility model, when it is necessary to fix the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane, insert the conical cylinder into the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane, and the convex ring is pressed above the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane, which can realize the preliminary fixing of the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane. By setting the fixing device, it is convenient to stabilize the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane on the base, thereby improving the stability of the anti-seepage geotextile, bentonite waterproof blanket and anti-seepage geomembrane after laying. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overall structural schematic diagram of the present utility model;

[0020] Figure 2 It is a schematic structural diagram of the fixing device in the present utility model;

[0021] Figure 3 In the present utility model Figure 2 is a schematic cross-sectional structural diagram;

[0022] Figure 4 In the present utility model Figure 3 is an enlarged view of part A.

[0023] Legend: 1. Foundation pit body; 2. Diaphragm wall; 3. Surface drainage channel; 4. Geotextile; 5. Bentonite waterproof blanket; 6. Geomembrane; 7. Fixing device; 701. Cone; 702. Convex ring; 703. Insert bar; 704. Connecting block; 705. Connecting pin; 706. Rotating block; 707. Support frame; 708. Sharp projection; 709. Through hole; 710. Connecting rod; 711. Spring. Specific implementation manner

[0024] Referring to Figures 1-4 as shown, the present utility model provides a technical solution: a new type of anti-seepage structure for subway foundation pit, including foundation pit side wall support and anti-seepage cushion layer, surface combined anti-seepage cushion layer, surface drainage channel 3 and fixing device 7.

[0025] Next, specifically describe its overall specific settings and functions.

[0026] Referring to Figure 1 as shown, in this implementation: the foundation pit side wall support and surface combined anti-seepage cushion layer include diaphragm wall 2 and geotextile 4, the surface combined anti-seepage cushion layer includes three layers of geotextile 4, bentonite waterproof blanket 5 and geomembrane 6, the surface drainage channel 3 is composed of a base layer and an inner-laid polymer sheet, the polymer sheet is fixed to the surface combined anti-seepage cushion layer through the fixing device 7, the diaphragm wall 2 serves as both the support structure and anti-seepage structure of the foundation pit, and a geotextile 4 is vertically attached to the outside of the diaphragm wall 2 as a combined anti-seepage measure, the geotextile 4 is made of polyester fiber non-woven geotextile, and the geomembrane 6 is made of high-density polyethylene film.

[0027] Referring to Figures 1-4As shown in the figure, specifically, the fixing device 7 includes a conical cylinder 701. The conical cylinder 701 penetrates through the anti-seepage geotextile 4, the bentonite waterproof blanket 5, and the anti-seepage geomembrane 6. A convex ring 702 is fixedly installed at the upper port of the conical cylinder 701. A connecting rod 710 is fixedly installed inside the conical cylinder 701. Two support frames 707 are slidably connected to the side wall of the connecting rod 710. Four pointed protrusions 708 are fixedly connected to the side wall of the support frame 707. A through hole 709 is formed in the side wall of the conical cylinder 701. A connecting block 704 is fixedly connected to the inside of the conical cylinder 701. An insertion bar 703 is slidably connected inside the connecting block 704. The lower end side cross-section of the insertion bar 703 is an isosceles triangle. A connecting pin 705 is fixedly connected to the upper surface of the convex ring 702. The upper end of the connecting pin 705 is rotatably connected to a rotating block 706. A spring 711 is sleeved on the surface of the connecting rod 710. The two ends of the spring 711 are respectively fixedly connected to the support frame 707 and the inside of the conical cylinder 701.

[0028] Working principle: The foundation pit is 8 m deep. First, the construction of the diaphragm wall is carried out. The grooving machine is used to excavate rectangular grooves around the foundation pit. The steel reinforcement cage is hoisted into the grooves, and underwater concrete is poured until it is formed, that is, the diaphragm wall 2 is formed. The grooving machine is used to groove on the outside of the diaphragm wall 2 (i.e., the other side of the foundation pit 1), and the non-woven geotextile 4 made of polyester fiber is vertically laid, backfilled. A surface drainage channel 3 is excavated parallel to the direction of the diaphragm wall 1 m outside the diaphragm wall 2. The cross-section of the drainage channel 3 is rectangular. After lining with cement, it is 0.65 m wide and 0.4 m deep. 10 mm thick PE plates are additionally laid on both sides. After laying, the net width of the surface drainage channel 3 is 0.45 m. The non-woven geotextile 4 made of polyester fiber is laid on the surface. The surface drainage channel 4 and the diaphragm wall 2 are closely laid, and are bonded to the vertically arranged non-woven geotextile on the outside of the diaphragm wall, and the lap width is 60 mm ± 10 mm. The surface drainage channel 4 extends 5 m outside, so as to ensure that the width of the horizontally laid anti-seepage cushion on the surface is greater than 75% of the depth of the foundation pit. The above non-woven geotextiles made of polyester fiber are all above 500 g / ㎡. The bentonite waterproof blanket 5 is laid on the surface. The surface drainage channel 4 and the diaphragm wall 2 are closely laid, and the surface drainage channel 4 extends 5 m outside, so as to ensure that the width of the horizontally laid anti-seepage cushion on the surface is greater than 75% of the depth of the foundation pit. The total mass per unit area of the bentonite waterproof blanket should not be less than 4200 g / ㎡, of which the mass of bentonite per unit area should not be less than 4000 g / ㎡, and the permeability coefficient should be less than 6× cm / s. The high-density polyethylene film 6 is laid on the surface. The surface drainage channel 4 and the diaphragm wall 2 are closely laid, and the surface drainage channel 4 extends 5 m outside, so as to ensure that the width of the horizontally laid anti-seepage cushion on the surface is greater than 75% of the depth of the foundation pit.The thickness of the high-density polyethylene film is 1 mm, and the permeability coefficient is ≤ 2.0× cm / s. The polyester fiber non-woven geotextile 4, bentonite waterproof blanket 5, and high-density polyethylene film 6 are fixed together with the PE material board laid in the surface drainage channel 4 by rivets, and leak-proof glue is used to fill the leak at the edge. The diaphragm wall 2 serves as both the retaining structure and the anti-seepage structure of the foundation pit, and the anti-seepage geotextile 4 is vertically attached to the outside of the diaphragm wall 2 as a combined anti-seepage measure. The surface is provided with three anti-seepage materials, namely, the anti-seepage geotextile 4, bentonite waterproof blanket 5, and anti-seepage geomembrane 6, as a combined anti-seepage cushion layer. At the same time, drainage channels are arranged in parallel with the surface along the four walls of the foundation pit, and polymer sheets are laid on the inner walls of the drainage channels and fixed together with the combined anti-seepage cushion layer laid on the surface by fixing devices 7 such as rivets to achieve the effect of combining blocking and drainage. The side wall of the subway foundation pit adopts the diaphragm wall 2. This structural form has better integrity, anti-seepage performance, and retaining strength, and is widely used especially in soft soil areas. The anti-seepage geotextile 4 is made of polyester fiber non-woven geotextile, which has better waterproofness, water absorption, crack resistance, etc. In the present utility model, the anti-seepage geomembrane 6 adopts a high-density polyethylene film. This material is an environmentally friendly material with excellent properties of being non-toxic and odorless. At the same time, it also has the characteristics of being stable under temperature changes, not easily cracking under environmental stress, good chemical stability, good moisture-proof and anti-seepage performance, etc. It is a plastic coil widely used in various projects at present. The structure is clearly arranged, the functions of each component are clear, the layout is simple, and the practicability is strong; a variety of anti-seepage structures or materials are comprehensively used, and the anti-seepage effect is good; the combination of blocking and drainage is adopted, while paying attention to cutting off the downward seepage channel, guiding drainage is also considered, avoiding the situation of water accumulation caused by overemphasis on leak prevention; the material hardly pollutes the environment, meeting the development concept of green environmental protection.

[0029] When it is necessary to fix the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6, the cone barrel 701 is inserted into the interiors of the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6, and the convex ring 702 is pressed above the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6, so as to realize the preliminary fixing work of the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6. At this time, continue to apply pressure to the inserting bar 703, and the inserting bar 703 will slide inside the connecting block 704. The lower end of the inserting bar 703 will pass through the inner sides of the two support frames 707. At this time, the support work for the two support frames 707 can be realized. The sliding of the support frame 707 on the surface of the connecting rod 710 plays a role in restricting the moving direction of the support frame 707. The support frame 707 will drive the pointed protrusion 708 to pass through the through hole 709 and insert into the foundation, improving the stability of the cone barrel 701 inserted into the foundation and avoiding the phenomenon that the cone rod is prone to looseness inside the foundation pit under the action of external forces, further improving the stability of fixing the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6. After the support frame 707 is opened, the rotating block 706 on the connecting pin 705 can be rotated, and the rotating block 706 is blocked above the inserting bar 703, which can avoid the phenomenon that the inserting bar 703 slides out between the two support frames 707, further improving the stability of using the inserting bar 703. When the inserting bar 703 is pulled out between the two support frames 707, at this time, the two support bars will respectively drive the pointed protrusion 708 to retract inside the through hole 709 under the elastic force of the springs 711 inside the two cone barrels 701, and the extraction work of the cone barrels 701 on the inner side of the foundation pit can be realized. By setting the fixing device 7, it is convenient to fix the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6 on the base, thereby improving the stability of the anti-seepage geotextile 4, bentonite waterproof blanket 5 and anti-seepage geomembrane 6 after laying and use.

[0030] This embodiment well maintains the stability of the groundwater environment around the foundation pit when external factors such as rainfall occur.

[0031] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood through specific situations.

Claims

1. A new type of anti-seepage structure for subway foundation pits, comprising a foundation pit side wall support and anti-seepage cushion layer, a surface combined anti-seepage cushion layer, a surface drainage channel (3) and a fixing device (7), characterized in that: The foundation pit side wall support and the surface combined anti-seepage cushion layer include a diaphragm wall (2) and an anti-seepage geotextile (4); The surface combined anti-seepage cushion layer includes three layers, namely an anti-seepage geotextile (4), a bentonite waterproof blanket (5) and an anti-seepage geomembrane (6); The surface drainage channel (3) is composed of a base layer and an inner-laid high molecular sheet material, and the high molecular sheet material is fixed to the surface combined anti-seepage cushion layer through the fixing device (7).

2. A novel anti-seepage structure for subway foundation pits according to claim 1, characterized in that: The diaphragm wall (2) serves as both a support structure and an anti-seepage structure for the foundation pit, and an anti-seepage geotextile (4) is vertically attached to the outer side of the diaphragm wall (2) as a combined anti-seepage measure.

3. A novel anti-seepage structure for subway foundation pits according to claim 1, characterized in that: The anti-seepage geotextile (4) is made of polyester fiber non-woven geotextile.

4. A novel anti-seepage structure for subway foundation pits according to claim 1, characterized in that: The anti-seepage geomembrane (6) is made of high-density polyethylene film.

5. A novel anti-seepage structure for subway foundation pits according to claim 1, characterized in that: The fixing device (7) includes a conical cylinder (701), the conical cylinder (701) penetrates through the anti-seepage geotextile (4), the bentonite waterproof blanket (5) and the anti-seepage geomembrane (6), a convex ring (702) is fixedly installed at the upper port of the conical cylinder (701), a connecting rod (710) is fixedly installed inside the conical cylinder (701), two support frames (707) are slidably connected to the side wall of the connecting rod (710), four pointed protrusions (708) are fixedly connected to the side wall of the support frame (707), and a through hole (709) is opened on the side wall of the conical cylinder (701).

6. A novel anti-seepage structure for a subway foundation pit according to claim 5, characterized in that: A connecting block (704) is fixedly connected to the inside of the conical cylinder (701), an insertion bar (703) is slidably connected to the inside of the connecting block (704), the lower end side cross-section of the insertion bar (703) is an isosceles triangle, a connecting pin (705) is fixedly connected to the upper surface of the convex ring (702), and a rotating block (706) is rotatably connected to the upper end of the connecting pin (705).

7. A novel anti-seepage structure for a subway foundation pit according to claim 5, characterized in that: A spring (711) is sleeved on the surface of the connecting rod (710), and both ends of the spring (711) are fixedly connected to the inner side of the support frame (707) and the conical cylinder (701) respectively.

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