Drainage structure of aquitard of foundation pit

Abstract

The foundation pit aquitard drainage structure is characterized in that the foundation pit aquitard drainage structure comprises a gravel tiling layer, a waterproof cloth and a concrete base layer which are sequentially laid on the bottom face of a foundation pit, a sand-pipe-free dewatering well is inserted into the gravel tiling layer and extends out of the concrete base layer, and a gravel filling layer, a bagged cement piling layer and a brick body covering outer layer are arranged on the side wall of the foundation pit from inside to outside; the bagged water layer piling layer is piled on the gravel tiling layer, and the gravel filling layer is communicated with the gravel tiling layer. According to the utility model, favorable waterproof construction conditions are provided for the concrete base layer, moistureproof protection is formed for the concrete base layer, and the gravel filling layer is communicated with the gravel tiling layer, so that seepage water of the aquitard on the foundation pit slope is converged into the sand pipe dewatering well through the gravel filling layer and the gravel tiling layer; the device is suitable for the situation that the aquitard extends to the foundation pit slope from the base, the phenomenon that collapse occurs on the local slope of the foundation pit is avoided, centralized drainage of underground water of the aquitard of the foundation pit is effectively achieved, and the device is simple in structure, easy to construct and high in practicability.

Description

Technical Field

[0001] The utility model relates to a drainage structure for a foundation pit with a weakly permeable layer, and belongs to the technical field of drainage for foundation pit excavation with a weakly permeable layer. Background Art

[0002] In the foundation construction of the construction engineering field, due to the influence of groundwater, well point dewatering is required before construction, and the groundwater level is lowered to 0.5 meters below the construction working surface before construction. However, no matter what dewatering method is used, the base elevation of the elevator shaft, sump, etc. is often lower than the base elevation of the foundation, and the earthwork needs to be excavated deeper. At this time, the excavation may reach unforeseen local permeable layers, quicksand and other complex geological conditions, causing groundwater in the local weak permeable layer to seep outward, and after the foundation concrete cushion layer is poured, it will seep to the surface of the foundation, resulting in the surface being too high in water content to be able to carry out waterproofing membrane construction; or because the seepage part has not been treated for a long time, or because the water flow is too large to be treated, the soil particles inside the soil layer flow out with the water flow, and "holes" are formed inside the soil, causing the slope earthwork of the elevator shaft and sump to collapse, and the foundation cushion layer and waterproofing membrane cannot be constructed.

[0003] Commonly used anti-seepage methods include grouting, anti-seepage walls, high-pressure spraying, etc. At present, cement, water glass and polymer organic materials are generally used for grouting treatment, among which cement is the most commonly used grouting reinforcement material. For high-standard anti-seepage treatment of weakly permeable strata, anti-seepage wall construction technology, chemical slurry grouting technology, high-pressure pulsating grouting technology, silica sol slurry injection technology, etc. are generally used. However, the above treatment methods have complex construction processes, slow construction speed, high standards, and high costs. Moreover, they are only applicable when a weakly permeable layer (quicksand layer) appears on the base. It is not applicable when the weakly permeable layer extends from the base to the slope of the foundation pit, causing landslides on the local slope of the foundation pit. Utility Model Content

[0004] The utility model provides a drainage structure for the weak permeable layer of the foundation pit, which provides favorable waterproof construction conditions for the concrete base layer, forms moisture-proof protection for the concrete base layer, connects the crushed stone filling layer with the crushed stone paving layer, and allows the infiltrated water of the weak permeable layer on the slope of the foundation pit to be gathered into the sand pipe precipitation well through the crushed stone filling layer and the crushed stone paving layer. It is suitable for the situation where the weak permeable layer extends from the base to the slope of the foundation pit, avoids landslides in the local slope of the foundation pit, and effectively realizes the centralized discharge of groundwater in the weak permeable layer of the foundation pit. The utility model has the advantages of simple structure, easy construction and high practicability.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] The weakly permeable layer drainage structure of the foundation pit is characterized by: it includes a crushed stone paving layer, a rainproof cloth and a concrete base layer laid in sequence on the bottom surface of the foundation pit, a sand-free pipe precipitation well is inserted into the crushed stone paving layer and extends out from the concrete base layer, a crushed stone filling layer, a bagged cement masonry layer and a brick covering outer layer are arranged on the side walls of the foundation pit from the inside to the outside, the bagged water layer masonry layer is stacked on the crushed stone paving layer, and the crushed stone filling layer is connected to the crushed stone paving layer.

[0007] Preferably, the thickness of the gravel paving layer is not less than 500 mm, and the height of the sand-free pipe drainage well extending out of the concrete base is not less than 500 mm.

[0008] Preferably, the bagged cement masonry layer includes an outer masonry layer formed by bagged cement, a steel pipe pile support arranged on the inner surface of the outer masonry layer, and an inner masonry layer formed by bagged cement on the inner side of the steel pipe pile support, and the height of the outer masonry layer is less than the height of the inner masonry layer.

[0009] Preferably, the steel pipe pile support includes a steel pipe column which is evenly spaced along the inner surface of the outer layer of the masonry and extends through the gravel flat layer into the foundation pit stratum, and a horizontal steel pipe fastened to the steel pipe column with fasteners, and a plurality of horizontal steel pipes are evenly spaced from top to bottom on the steel pipe column.

[0010] Preferably, the brick body covering outer layer comprises an autoclaved lime sand brick layer, a plaster layer, a rolled waterproof layer and a mortar waterproof protective layer sequentially covering the bagged cement masonry layer, and the autoclaved lime sand brick layer extends to the top surface of the outer masonry layer and the top surface of the inner masonry layer.

[0011] Preferably, the rainproof cloth extends onto the autoclaved lime sand brick layer, and the extension length is not less than 300 mm.

[0012] The beneficial effects of the utility model are:

[0013] The utility model discloses a drainage structure for a weakly permeable layer of a foundation pit. A crushed stone paving layer, a rainproof cloth and a concrete base layer are laid on the bottom surface of the foundation pit. Groundwater seeping from the weakly permeable layer at the bottom of the base is collected into a sand-free pipe precipitation well through the gaps in the crushed stone paving layer. The water in the sand-free pipe precipitation well is then pumped out by a water pump. The rainproof cloth prevents the infiltrated water in the crushed stone paving layer from gushing upward, thereby providing a working surface that meets the moisture content requirements for the pouring of the concrete base layer, providing favorable waterproof construction conditions for the concrete base layer, preventing the groundwater vapor from causing moisture in the concrete base layer, and forming moisture-proof protection for the concrete base layer. A crushed stone filling layer, a bagged cement masonry layer and a brick covering outer layer are arranged on the side wall of the foundation pit from the inside to the outside, a filling space for the crushed stone filling layer is formed between the bagged cement masonry layer and the side wall of the foundation pit, and the crushed stone filling layer is connected with the crushed stone paving layer, so that the infiltration water of the weak permeable layer on the slope of the foundation pit is gathered into the sand pipe precipitation well through the crushed stone filling layer and the crushed stone paving layer. It is suitable for the situation that the weak permeable layer extends from the base to the slope of the foundation pit, avoids the collapse of the local slope of the foundation pit, and effectively realizes the centralized discharge of groundwater in the weak permeable layer of the foundation pit. It has simple structure, is easy to construct and is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the drainage structure of the weak permeable layer of the foundation pit in a specific implementation method.

[0015] Figure 2 for Figure 1 A partial enlarged schematic diagram of .

[0016] Figure 3 for Figure 1 Another partial enlarged schematic diagram of .

[0017] Figure 4 Schematic diagram of steel pipe pile support. DETAILED DESCRIPTION

[0018] Combine the following Figures 1 to 4 The embodiments of the utility model are described in detail.

[0019] The weakly permeable layer drainage structure of the foundation pit is characterized by: it includes a crushed stone paving layer 1, a rainproof cloth 2 and a concrete base layer 3 laid in sequence on the bottom surface of the foundation pit, a sand-free pipe precipitation well 4 is inserted into the crushed stone paving layer 1 and extends out from the concrete base layer 3, a crushed stone filling layer 5, a bagged cement masonry layer 6 and a brick covering outer layer 7 are arranged on the side wall of the foundation pit from the inside to the outside, the bagged water layer masonry layer 6 is stacked on the crushed stone paving layer 1, and the crushed stone filling layer 5 is connected to the crushed stone paving layer 1.

[0020] The above-mentioned foundation pit aquitard drainage structure has a crushed stone paving layer 1, a rainproof cloth 2 and a concrete base 3 laid on the bottom of the foundation pit. The groundwater seeping from the aquitard 100 at the bottom of the base is collected into the sand-free pipe precipitation well 4 through the gap in the crushed stone paving layer 1, and then the water in the sand-free pipe precipitation well 4 is pumped out by a water pump. The rainproof cloth prevents the infiltrated water in the crushed stone paving layer 1 from gushing upward, providing a working surface that meets the moisture content requirements for the pouring of the concrete base 3, providing favorable waterproof construction conditions for the concrete base 3, and preventing the groundwater vapor from causing the moisture of the concrete base, thus forming moisture-proof protection for the concrete base 3. A gravel filling layer 5, a bagged cement stacking layer 6 and a brick covering outer layer 7 are arranged from the inside to the outside on the side wall of the foundation pit, and a filling space of the gravel filling layer 5 is formed between the bagged cement stacking layer 6 and the side wall of the foundation pit. The gravel filling layer 6 is connected with the gravel paving layer 1, so that the infiltration water of the weak permeable layer on the slope of the foundation pit is gathered into the sand pipe precipitation well 4 through the gravel filling layer 6 and the gravel paving layer 1. It is suitable for the situation where the weak permeable layer extends from the base to the slope of the foundation pit, avoiding the collapse of the local slope of the foundation pit, and effectively realizing the centralized discharge of groundwater from the weak permeable layer of the foundation pit. The structure is simple, easy to construct, and highly practical. In the actual structure, the concrete base 3 includes a concrete cushion layer, a roll waterproof layer and a concrete waterproof protective layer from bottom to top, forming a basic concrete cushion layer on the bottom of the foundation pit, and a concrete base 3 is also required to be laid on the top of the foundation pit.

[0021] Among them, the thickness of the gravel paving layer 1 is not less than 500mm, and the height of the sand-free pipe dewatering well 4 extending out of the concrete base is not less than 500mm. The gaps between the gravels in the gravel paving layer 1 form a water channel to guide the infiltrated water to the sand-free pipe dewatering well 4. The thickness of the gravel paving layer 1 is not less than 500mm to ensure the reliability of water guidance and reduce the probability of infiltrated water penetrating upward. The sand-free pipe dewatering well 4 extends out for not less than 500mm, which can store a certain amount of water and facilitate the centralized pumping and discharge of water by the water pump.

[0022] The bagged cement masonry layer 6 includes an outer masonry layer 61 formed by bagged cement, a steel pipe pile support 62 arranged on the inner surface of the outer masonry layer 61, and an inner masonry layer 63 formed by bagged cement on the inner side of the steel pipe pile support 62. The height of the outer masonry layer 61 is less than the height of the inner masonry layer 63. A filling space of the crushed stone filling layer 5 is formed between the bagged cement masonry layer 6 and the side of the foundation pit, which supports and protects the crushed stone filling layer 5. The bagged cement masonry layer 6 solidifies after contacting water, has a high bearing capacity, and is simple to stack and easy to construct. The steel pipe pile support 62 is arranged between the outer masonry layer 61 and the outer masonry layer 63 to improve the lateral pressure bearing capacity of the bagged cement masonry layer 6.

[0023] The steel pipe pile support 62 includes a steel pipe column 621 which is evenly spaced along the inner surface of the outer layer 61 and extends into the foundation pit through the gravel paving layer 1 and a horizontal steel pipe 622 which is tied to the steel pipe column 621 with fasteners. A plurality of horizontal steel pipes 622 are evenly spaced from top to bottom on the steel pipe column 611. The horizontal steel pipe 622 and the steel pipe column 621 are tied to form a grid-shaped steel pipe pile support 62. The steel pipe column support 62 is simple to form and easy to construct, and can effectively improve the lateral pressure bearing capacity of the bagged cement masonry layer 6. During construction, bagged cement is first piled to form the outer layer 61, and then the steel pipe column 621 is driven in and the horizontal steel pipe 622 is tied to form the steel pipe pile support 62. Then, bagged cement is piled inside the steel pipe support 62 to form the inner layer 63. During the process of piling the inner layer 63, gravel is filled in multiple times to gradually form the gravel filling layer 5.

[0024] The brick body covering outer layer 7 includes an autoclaved lime sand brick layer 71, a plaster layer 72, a roll waterproof layer 73 and a mortar waterproof protective layer 74 sequentially covering the bagged cement masonry layer 6, and the autoclaved lime sand brick layer 71 extends to the top surface of the masonry outer layer 61 and the top surface of the masonry inner layer 63. The brick body covering outer layer 7 covers the masonry outer layer 61 and the masonry inner layer 63 to form a waterproof slope of the foundation pit, and the autoclaved lime sand brick layer 71 has both good durability and high wall strength, ensuring the strength of the foundation pit slope.

[0025] The rainproof sheet 2 extends to the autoclaved lime sand brick layer 71 and the extension length is not less than 300 mm to prevent the edge of the rainproof sheet 2 from curling inwards and exposing the gravel paving layer 1 when the concrete base 3 is formed, thereby ensuring that the rainproof sheet 2 effectively covers the gravel paving layer 1.

[0026] The above is a complete description of the technical solutions of the embodiments of the utility model in combination with the accompanying drawings. It should be noted that the described embodiments are only part of the embodiments of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

Claims

1. The foundation pit aquitard drainage structure is characterized by: It includes a crushed stone paving layer, a rainproof cloth and a concrete base layer which are laid in sequence on the bottom surface of the foundation pit. A sand-free pipe precipitation well is inserted into the crushed stone paving layer and extends out from the concrete base layer. A crushed stone filling layer, a bagged cement masonry layer and a brick covering outer layer are arranged on the side wall of the foundation pit from the inside to the outside. The bagged water layer masonry layer is stacked on the crushed stone paving layer, and the crushed stone filling layer is connected to the crushed stone paving layer.

2. The foundation pit weak permeable layer drainage structure according to claim 1, characterized in that: The thickness of the gravel paving layer shall not be less than 500mm, and the height of the sand-free pipe drainage well extending out of the concrete base shall not be less than 500mm.

3. The foundation pit weak permeable layer drainage structure according to claim 2, characterized in that: The bagged cement masonry layer comprises an outer masonry layer formed by bagged cement, a steel pipe pile support arranged on the inner surface of the outer masonry layer, and an inner masonry layer formed by bagged cement on the inner side of the steel pipe pile support. The height of the outer masonry layer is less than that of the inner masonry layer.

4. The foundation pit weak permeable layer drainage structure according to claim 3, characterized in that: The steel pipe pile support includes a steel pipe column which is evenly spaced along the inner surface of the outer layer of the pile and extends through the gravel flat layer into the foundation pit stratum, and a horizontal steel pipe which is fastened to the steel pipe column with fasteners. A plurality of horizontal steel pipes are evenly spaced from top to bottom on the steel pipe column.

5. The foundation pit weak permeable layer drainage structure according to claim 4, characterized in that: The brick body outer layer includes an autoclaved lime sand brick layer, a plaster layer, a roll waterproof layer and a mortar waterproof protective layer sequentially covering the bagged cement masonry layer, and the autoclaved lime sand brick layer extends to the top surface of the outer masonry layer and the top surface of the inner masonry layer.

6. The foundation pit weak permeable layer drainage structure according to claim 5, characterized in that: The rainproof cloth extends to the autoclaved lime sand brick layer, and the extension length is not less than 300mm.

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