Combined type double-steel-sheet-pile cofferdam structure for water taking pump room deep foundation pit construction
By adopting a combined double steel sheet pile cofferdam structure and spray anchor support combination technology in the deep foundation pit construction of the water intake pump room, the problem of insufficient safety and permeability in the deep water foundation pit is solved, and a more efficient and safe construction effect is achieved.
Patent Information
- Application Number
- CN202421563648.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-04
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2034-07-04
AI Technical Summary
In the construction of deep foundation pits of water intake pump room, traditional cofferdam structures cannot effectively deal with the safety and permeability of underwater cofferdams in deep water large foundation pits, resulting in high construction costs and high safety risks.
A combined double steel sheet pile cofferdam structure is adopted, which includes two steel sheet piles in the cofferdam foot and foundation pit, and a combination structure is formed by spray anchor support and net drainage pipes to form a stable foundation pit.
It improves the anti-slip force and permeability of the cofferdam and foundation pit, enhances the stability of the soil around the foundation pit, reduces the construction scope and soil source demand, and reduces construction costs.
Smart Images
Figure CN222745085U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of cofferdam design and construction, in particular to a combined double steel sheet pile cofferdam structure for the construction of a deep foundation pit for a water intake pump house. Background Art
[0002] Cofferdam refers to a temporary enclosure structure built in water conservancy project construction to meet the construction conditions of building facilities. Its function is to prevent seepage and ensure the stability of the foundation pit, drainage and construction of buildings. In large-scale water conservancy projects such as water intake projects, it is necessary to face the difficulty of building cofferdams in deep water large foundation pits under restricted conditions.
[0003] Traditional cofferdams mainly include earthwork cofferdams, sack cofferdams, pinewood pile cofferdams, etc. Among these mature traditional cofferdam methods, earthwork cofferdams are suitable for shallow water areas, low water flow rates, and low riverbed soil permeability. If earthwork cofferdams and sack cofferdams are used in deep water large foundation pit cofferdams, they will not only consume a large amount of earthwork, but also affect the normal operation of the construction site and the river, thereby significantly increasing construction costs. Pinewood pile cofferdams cannot be driven into deeper strata, and the safety of underwater cofferdams cannot be guaranteed in deep and large foundation pits, posing a major safety hazard.
[0004] In the construction of the weir of the water intake pump house, there are high requirements on the construction scope and soil source of the cofferdam and foundation pit. The project cost is too high when the construction scope and soil source are limited. At the same time, due to the deep and large foundation pit of the water intake pump house and the weak soil, it is necessary to consider the pile body entering the bearing layer to resist the soil and water flow pressure outside the foundation pit, and also to ensure the stability and anti-seepage capacity of the foundation pit. Therefore, the traditional single cofferdam structure cannot be applied to the deep water large foundation pit cofferdam project of the water intake pump house. Utility Model Content
[0005] In order to solve the technical problems raised in the above background technology, the utility model provides a combined double steel sheet pile cofferdam structure for the construction of a deep foundation pit of a water intake pump house.
[0006] The utility model is implemented by the following technical scheme: a combined double steel sheet pile cofferdam structure for the construction of a deep foundation pit of a water intake pump house, characterized in that it comprises an earth cofferdam of a water intake pump house, a first row of steel sheet piles is arranged at the weir foot of the earth cofferdam of the water intake pump house, a foundation pit is provided in the earth cofferdam of the water intake pump house, a second row of steel sheet piles is arranged in the foundation pit, and a sprayed anchor support located in the foundation pit is arranged between the first row of steel sheet piles and the second row of steel sheet piles.
[0007] As a further improvement of the above solution, all of the first steel sheet piles are connected end to end to form an annular cofferdam structure.
[0008] As a further improvement of the above scheme, a steel reinforcement plate is added to the second steel sheet pile at the corner in the foundation pit, and the second steel sheet pile located at the corner in the foundation pit is overlapped and fixed to the adjacent second steel sheet pile with corner angle steel.
[0009] As a further improvement of the above solution, all of the second-row steel sheet piles are connected end to end to form a rectangular cofferdam structure.
[0010] As a further improvement of the above solution, two adjacent steel sheet piles are connected by locking steel pipe piles to form a closed loop.
[0011] As a further improvement of the above solution, steel purlins, transverse braces, diagonal braces and short brace reinforcement connecting plates are added to the steel sheet piles.
[0012] As a further improvement of the above solution, the relative deflection angles of all the first steel sheet piles are the same.
[0013] As a further improvement of the above solution, the slope foot of the earth cofferdam of the water intake pump house is compacted and fixed with bagged soil.
[0014] As a further improvement of the above scheme, the sprayed anchor support includes a hanging net and a drainage pipe laid on the slope of the foundation pit, and a concrete layer is sprayed in the steel mesh segments of the hanging net.
[0015] Compared with the prior art, the beneficial effects of the present invention are:
[0016] 1. The combined double steel sheet pile cofferdam structure for the deep foundation pit construction of the water intake pump house of the utility model forms a double steel sheet pile cofferdam and support structure by arranging two steel sheet piles at the cofferdam foot and in the foundation pit, thereby increasing the anti-sliding force and anti-seepage property of the cofferdam and the foundation pit and enhancing the stability of the soil around the foundation pit.
[0017] 2. The combined double steel sheet pile cofferdam structure for the deep foundation pit construction of the water intake pump house of the utility model gives full play to the good performance of several different construction techniques, and solves the problems of insufficient space required for the construction of traditional earth-rock cofferdams, insufficient soil source and insufficient rigidity of the cofferdam under the action of high water level.
[0018] 3. The combined double steel sheet pile cofferdam structure for the deep foundation pit construction of the water intake pump house of the utility model effectively reduces the construction scope of the cofferdam and the foundation pit, and forms a stable foundation pit in the second rectangular structure steel sheet pile by combining double steel sheet piles and traditional earth cofferdam and mesh spraying anchor. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of the overall plan view of the combined double steel sheet pile cofferdam provided in Example 1 of the utility model;
[0020] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the combined double steel sheet pile cofferdam and support;
[0021] Figure 3 This is a schematic diagram of the installation of the first and second steel sheet piles in conjunction with the guide frame;
[0022] Figure 4 This is a schematic diagram of the overlap at the corner of Larsen steel sheet pile;
[0023] Figure 5 This is a schematic diagram of shotcrete support;
[0024] Figure 6 This is a schematic diagram of the slope drainage hole;
[0025] Figure 7 This is a flow chart of a combined double steel sheet pile cofferdam construction method for deep foundation pit construction of a water intake pump house provided in Example 2 of the utility model.
[0026] Description of main symbols:
[0027] 1. The first row of steel sheet piles; 2. The second row of steel sheet piles; 3. Earth cofferdam of water intake pump house; 4. Hanging net; 5. Foundation pit; 6. Guide frame; 7. Positioning piles; 8. Corner angle steel; 9. Steel mesh; 10. Concrete surface layer; 11. Inserted rebar; 12. Drain pipe; 13. Drain hole. DETAILED DESCRIPTION
[0028] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.
[0029] Example 1
[0030] Please combine Figures 1 to 6 The combined double steel sheet pile cofferdam structure for the deep foundation pit construction of the water intake pump house comprises an earth cofferdam 3 for the water intake pump house, a first steel sheet pile 1 is arranged at the weir foot of the earth cofferdam 3 for the water intake pump house, a foundation pit 5 is arranged in the earth cofferdam 3 for the water intake pump house, a second steel sheet pile 2 is arranged in the foundation pit 5, and a sprayed anchor support located in the foundation pit 5 is arranged between the first steel sheet pile 1 and the second steel sheet pile 2.
[0031] In this embodiment, the first steel sheet pile 1 and the second steel sheet pile 2 are both Larsen IV hot-rolled steel sheet piles, and the pile length can be 12m. The first steel sheet pile 1 and the second steel sheet pile 2 are built on the basis of the earth cofferdam 3 of the water intake pump house. After the double steel sheet piles are completed, the earth between the first steel sheet pile 1 and the second steel sheet pile 2 is excavated and sloped, and sprayed anchor support is set to ensure the stability of the slope. Finally, the foundation pit 5 is excavated in the middle of the second steel sheet pile 2. The excavation and slope are carried out by backhoe digging, digging one layer and spraying one layer, and excavating in layers.
[0032] All the first steel sheet piles 1 are connected end to end to form a circular cofferdam structure.
[0033] All the second steel sheet piles 2 are connected end to end to form a rectangular cofferdam structure.
[0034] In this embodiment, the corresponding steel sheet piles of the annular cofferdam structure and the rectangular cofferdam structure are extended by adding fishplate welding or split butt welding; the pile body joints in the same section are less than 50%, and the welds of adjacent successive piles should be staggered by more than 1.0m and set at intervals.
[0035] The axis of the steel sheet pile cofferdam uses steel sheet piles as positioning piles 7. When driving the piles, the intersection measurement and guide frame 6 are used to control the driving route and verticality (axis) of the steel sheet piles. The steel sheet pile driving method adopts the single driving method, starting from one corner and driving the single piles one by one.
[0036] Two adjacent steel sheet piles are connected to form a closed loop through the steel pipe pile lock. The lock mouth of the steel sheet pile is processed to make it a shape that can be connected to each other (such as a rectangular slot and block structure that can be plugged into each other), and then fixed by welding to achieve a more secure docking purpose.
[0037] Steel purlins, horizontal braces, diagonal braces, and short brace reinforcement connection plates are added to the steel sheet piles. The steel sheet piles and steel purlins are fixed by welding. The joints between two adjacent steel purlins can be connected by bolts and reinforcement plates.
[0038] The relative deflection angles of all the first-row steel sheet piles 1 are the same, so that after all the first-row steel sheet piles 1 are connected end to end, they are closer to a circle, thereby improving the anti-sliding force and anti-seepage property of the cofferdam system.
[0039] A steel reinforcement plate is added to the corner of the second steel sheet pile 2 in the foundation pit 5 to increase the strength and stability of the structure, and the second steel sheet pile 2 located at the corner in the foundation pit 5 is overlapped and fixed to the adjacent second steel sheet pile 2 by a corner angle steel 8, and the corner angle steel 8 is welded and fixed to the corresponding steel sheet pile.
[0040] The slope foot of the earth cofferdam 3 of the water intake pump house is compacted and fixed with bagged soil.
[0041] The spray anchor support includes a hanging net 4 and a drainage pipe 12 laid on the slope of the foundation pit 5.
[0042] In this embodiment, the hanging net 4 is mainly composed of a steel mesh 9 and a dowel 11, and a concrete surface layer 10 is sprayed on the steel mesh 9, that is, a concrete layer is sprayed into the segment of the steel mesh 9 of the hanging net 4. When the hanging net 4 is overlapped, the steel mesh 9 and the dowel 11 are bent and tied into a whole.
[0043] The drain pipe 12 can be made of PVC material. A plurality of drain holes 13 are evenly and evenly opened on the axial outer wall of the drain pipe 12 at equal intervals, and a mung bean sand layer is filled near the drain holes 13 .
[0044] Example 2
[0045] Please combine Figure 7 This embodiment provides a combined double steel sheet pile cofferdam construction method for deep foundation pit construction of a water intake pump house applied to the double steel sheet pile cofferdam structure of embodiment 1, comprising the following steps:
[0046] S1: Cofferdam filling construction: The earth cofferdam 3 of the water intake pump house is constructed with clay. The filling clay required for the earth cofferdam 3 of the water intake pump house is made of the excavated material of the water plant's single structure. The two sides are gradually pushed into the river. When the weir body is raised and thickened above the water surface, dump trucks are used to dump soil, and bulldozers are used to assist in layered paving and compacting to ensure the density of the earth cofferdam. The height, width and slope ratio must meet the requirements.
[0047] S2: Prefabricate the first steel sheet pile 1, the second steel sheet pile 2 and the guide device.
[0048] S3: Construction of the first steel sheet pile 1: Use the single driving method to continuously drive a single pile from one corner. At the same time, pay attention to the corresponding angle when driving each steel sheet pile, so that all the first steel sheet piles 1 are connected end to end to form a circular cofferdam structure.
[0049] S4: Earthwork excavation: After the first steel sheet pile 1 is completed, the slope is excavated from top to bottom in layers and sections, with each layer excavation depth less than 3.0m, and each layer is sprayed after excavation. The lower earthwork excavation can be carried out only after the sprayed concrete surface reaches the strength requirement.
[0050] S5: Spray anchor support construction: Install the hanging net 4 on the slope of the foundation pit 5, and then spray the concrete surface layer 10 into the steel mesh 9, and the steel mesh 9 and the inserted steel bar 11 are bent and tied into a whole. After the steel mesh 9 is tied and the inserted steel bar 11 is fixed, the air compressor spray device should be used to spray the concrete surface layer 10 in time, and a drainage pipe 12 is set on the slope (the drainage hole 13 on the drainage pipe 12 is kept outwardly inclined by 5%, in a plum blossom shape), and the drainage hole 13 is filled with a mung bean sand layer, and 500mm is buried in the soil.
[0051] S6: Construction of the second steel sheet piles 2: The construction method is the same as step S3, and all the second steel sheet piles 2 are connected end to end to form a rectangular cofferdam structure. In order to ensure that the steel sheet piles are connected in a regular shape at the corners, the planar layout of the wall steel sheet piles of the foundation pit 5 should be as straight and neat as possible.
[0052] S7: Excavation of earthwork inside the second steel sheet pile 2: The excavation of earthwork inside the second steel sheet pile 2 is carried out in layers from the side where the steel sheet piles are first driven to the side where they are driven later. After the upper surface of the foundation pit 5 is excavated to 80cm below the surrounding purlin, the surrounding purlin and internal support are installed, and over-excavation is not allowed. After the excavation is completed, the structural concrete cushion layer is poured. For the corner support part where the excavator cannot be constructed, manual cooperation is used for excavation. At the same time, before the excavation of the foundation pit 5, a water collection pit is set around the foundation pit 5 for centralized drainage.
[0053] Furthermore, in order to prevent rainwater erosion and the influence of wind and waves, the earth cofferdam 3 of the water intake pump house in S1 is covered with a geomembrane after the weir body is filled, and the slope foot is compacted with bagged soil. At the same time, water collection pits are set at the slope foot on both sides of the longitudinal direction of the back water surface of the cofferdam.
[0054] Furthermore, the guide frame in S2 is mainly assembled and welded by No. 36 channel steel to form a frame-type guide device. In order to ensure the accurate insertion position, the intersection measurement method is used to control its plane coordinates and verticality.
[0055] Furthermore, before each steel sheet pile is driven in, the guide frame 6 is fixed with a limit frame 1 cm larger than each side of the steel sheet pile, so that the steel sheet pile and the guide frame 6 are closely fitted during driving, and the steel sheet pile is constructed along the route determined by the guide frame.
[0056] Furthermore, a 25 mm gap is set between the steel mesh 9 and the slope soil of the foundation pit 5 in S5 as a protective layer. When overlapping, one by one is overlapped up and down, left and right, and more than three points are tied. The inserted reinforcement 11 is bent and tied and fixed with iron wire to the steel mesh 9.
[0057] Furthermore, all the second steel sheet piles 2 in S6 are connected end to end to form a rectangular cofferdam structure, and the corresponding steel sheet piles at the corners are reinforced to increase the stability of the structure. The main method of reinforcement is to add reinforcement connectors at the corners, and the reinforcement connectors can be connected to the steel sheet piles by welding or bolts.
[0058] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.
Claims
1. A combined double steel sheet pile cofferdam structure for deep foundation pit construction of a water intake pump house, characterized in that: It comprises an earth cofferdam of a water intake pump house, wherein a first row of steel sheet piles is arranged at the weir foot of the earth cofferdam of the water intake pump house, a foundation pit is provided in the earth cofferdam of the water intake pump house, a second row of steel sheet piles is arranged in the foundation pit, and a sprayed anchor support located in the foundation pit is arranged between the first row of steel sheet piles and the second row of steel sheet piles.
2. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of a water intake pump house as claimed in claim 1, characterized in that: All of the first-row steel sheet piles are connected end to end to form a circular cofferdam structure.
3. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of water intake pump house according to claim 1, characterized in that: All of the second-row steel sheet piles are connected end to end to form a rectangular cofferdam structure.
4. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of a water intake pump house as claimed in claim 1, characterized in that: Two adjacent steel sheet piles are connected by locking the steel pipe piles to form a closed loop.
5. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of water intake pump house according to claim 1, characterized in that: Steel purlins, transverse braces, diagonal braces and short brace reinforcement connecting plates are added to the steel sheet piles.
6. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of water intake pump house according to claim 1, characterized in that: All of the first-row steel sheet piles have the same relative deflection angle.
7. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of water intake pump house as claimed in claim 2, characterized in that: A steel reinforcement plate is added to the second steel sheet pile at the corner in the foundation pit, and the second steel sheet pile located at the corner in the foundation pit is overlapped and fixed to the adjacent second steel sheet pile by using corner angle steel.
8. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of a water intake pump house as claimed in claim 1, characterized in that: The slope foot of the earth cofferdam of the water intake pump house is compacted and fixed with bagged soil.
9. The combined double steel sheet pile cofferdam structure for deep foundation pit construction of water intake pump house according to claim 1, characterized in that: The sprayed anchor support comprises a hanging net and a drainage pipe laid on the slope of the foundation pit, and a concrete layer is sprayed in sections of the steel mesh of the hanging net.