A cofferdam structure suitable for seawall construction

Abstract

The utility model relates to a cofferdam structure suitable for sea embankment construction, comprising: rubble base layer, block stone weir body, gravel filter layer, composite anti -infiltration earthwork membrane layer, closed gas earth layer, straw bag earth protection layer, riprapping slope protection, the rubble base layer is thrown and is arranged in the foundation pit, the block stone weir body is filled in the rubble base layer top, the gravel filter layer is laid in the block stone weir body water side one side, the composite anti -infiltration earthwork membrane layer is laid in the block stone weir body and the gravel filter layer top, the closed gas earth layer is laid in the backwater slope one side, the straw bag earth protection layer is set on it, the riprapping slope protection is set in the cofferdam water side slope toe place. Utilize block stone vibration to roll compaction or is double low concrete net case filling to replace earthwork filling, and the weir body shaping speed is fast in the construction process, and the compressive strength is high, solves the problem that unconsolidated fill is easy to be washed away by water flow when tidal level rises rapidly, leads to the construction interruption.

Description

Technical Field

[0001] This utility model relates to the field of cofferdam structure technology, and in particular to a cofferdam structure suitable for seawall construction. Background Technology

[0002] In water conservancy and hydropower projects, cofferdams are generally used to solve the problem of water diversion during construction. Currently, one commonly used type of cofferdam in my country's water conservancy projects is the earth-rock cofferdam. This method has different production methods depending on the technology used, one of which involves alternating between rubble placement at the cofferdam base and earthwork filling. In coastal areas, cofferdam diversion design must consider not only normal water inflow but also the influence of sea tides. During construction according to the above-mentioned plan, it was found that due to the short tidal period, the high tide would carry away all the newly filled earthwork before the backfilling was completed, causing delays in the earthwork filling project and even halting cofferdam construction. Therefore, a cofferdam structure that can be constructed efficiently and effectively under tidal influences is needed. Utility Model Content

[0003] This invention aims to address the shortcomings of existing technologies by providing a cofferdam structure suitable for seawall construction.

[0004] To achieve the above objectives, this utility model adopts the following technical solution: a cofferdam structure suitable for seawall construction, comprising: a rubble base layer, a riprap dam body, a crushed stone filter layer, a composite impermeable geomembrane layer, a closed-soil layer, a straw bag soil protective layer, and a riprap slope protection. The rubble base layer is placed in the foundation pit, the riprap dam body is filled on top of the rubble base layer, the crushed stone filter layer is laid on the water-facing slope side of the riprap dam body, the composite impermeable geomembrane layer is laid on top of the riprap dam body and the crushed stone filter layer, the closed-soil layer is laid on the water-repellent slope side of the composite impermeable geomembrane layer, the straw bag soil protective layer is stacked on the composite impermeable geomembrane layer and the closed-soil layer, and the riprap slope protection is located at the toe of the water-facing slope of the cofferdam.

[0005] Furthermore, it also includes: steel sheet piles, which are installed on the inner side of the back slope of the cofferdam, with the lower end of the steel sheet piles inserted into the foundation.

[0006] Furthermore, the rubble base layer is formed by replacing the silt layer with rubble with a diameter greater than 30cm, and has a thickness greater than 2m.

[0007] Furthermore, the riprap embankment is constructed by filling it with riprap and compacting it with a 15t self-propelled vibratory roller.

[0008] Furthermore, the riprap dam body is constructed using a metal mesh frame and is made of double-low-density concrete wet material sprayed in.

[0009] Furthermore, the crushed stone filter layer is laid with crushed stone filter material with a particle size of less than 15mm.

[0010] Furthermore, the composite impermeable geomembrane layer has a unit mass greater than 550 g / m³. 2 The geomembrane is composed of overlapping sections, with a horizontal overlap length greater than 1.0m, and is connected by composite welding.

[0011] Furthermore, the airtight soil layer is laid with low-permeability loess and has a thickness greater than 0.8m.

[0012] The beneficial effects of this utility model are as follows: This utility model designs a collaborative structure of riprap siltation base, riprap weir, crushed stone filter material, composite geomembrane, airtight loess, straw bag soil, and riprap slope protection. It uses riprap vibratory compaction or double-low concrete gabion filling to replace earthwork filling. During construction, the weir body forms quickly and has high compressive strength. It solves the problem that when the tidal water level rises rapidly, the unconsolidated fill is easily washed away by the water flow, causing construction interruption. Attached Figure Description

[0013] Figure 1 This is a schematic cross-sectional view of the structure of this utility model;

[0014] In the diagram: 1-Rubber base layer; 2-Rubber weir; 3-Crushed stone filter layer; 4-Composite impermeable geomembrane layer; 5-Air-tight soil layer; 6-Straw bag soil protection layer; 7-Rubber revetment; 8-Sheet pile;

[0015] The accompanying drawings in this utility model are all schematic diagrams and their sizes do not represent actual dimensions.

[0016] The following will describe in detail the embodiments of this utility model with reference to the accompanying drawings. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0018] like Figure 1As shown, a cofferdam structure suitable for seawall construction includes: a rubble base layer 1, a riprap dam body 2, a crushed stone filter layer 3, a composite impermeable geomembrane layer 4, a closed-soil layer 5, a straw bag soil protective layer 6, and a riprap slope protection 7. The rubble base layer 1 is placed in the foundation pit. The riprap dam body 2 is built on top of the rubble base layer 1. The crushed stone filter layer 3 is laid on the upstream slope of the riprap dam body 2. The composite impermeable geomembrane layer 4 is laid on top of the riprap dam body 2 and the crushed stone filter layer 3. The closed-soil layer 5 is laid on the downstream slope of the composite impermeable geomembrane layer 4. The straw bag soil protective layer 6 is stacked on top of the composite impermeable geomembrane layer 4 and the closed-soil layer 5. The riprap slope protection 7 is located at the toe of the upstream slope of the cofferdam. This seven-layer synergistic structure solves the problems of soil loss and impermeability failure in tidal zones, while the riprap slope protection 7 resists tidal erosion.

[0019] It also includes: steel sheet piles 8, which are installed on the inner side of the back slope of the cofferdam, and the lower end of the steel sheet piles 8 is inserted into the foundation.

[0020] The rubble base layer 1 is formed by replacing the silt layer with rubble with a diameter greater than 30 cm, and has a thickness greater than 2 m. The rubble-silt replacement method quickly forms a stable foundation and shortens the tidal operation window.

[0021] The riprap weir 2 is constructed with riprap and compacted using a 15t self-propelled vibratory roller. The vibratory roller travels parallel to the weir axis, and the compaction method is a staggered forward and backward method. The overlap width between adjacent working surfaces is no less than 50cm parallel to the weir axis and no less than 1.5m perpendicular to the weir axis. The overlap width of the compacted edges is greater than 10cm. For areas that are difficult to reach with the vibratory roller, small rammers are used to compact them.

[0022] The riprap dam 2 is constructed using a metal mesh frame and wet-mixed double-low concrete. The wet-mixed double-low concrete is obtained by mixing double-low concrete, deactivated fly ash, lithium salt, and seawater, and it can solidify within 20 minutes after spraying.

[0023] The gravel filter layer 3 is laid with gravel filter media with a particle size of less than 15 mm. The gravel filter layer 3 can reduce the osmotic pressure.

[0024] The composite impermeable geomembrane layer 4 has a unit mass greater than 550g / m³. 2 The geomembrane is composed of overlapping sections, with a horizontal overlap length greater than 1.0m, and is connected by composite welding.

[0025] The airtight soil layer 5 is laid with low-permeability loess and has a thickness greater than 0.8m. The composite impermeable geomembrane layer 4 and the airtight soil layer 5 form a double water-blocking effect.

[0026] The construction steps of this utility model are as follows: First, the silt nearly 2m deep in the foundation pit is squeezed out by throwing boulders; second, the boulder dam 2 is filled; third, crushed stone filter material is laid on the water-facing slope; then a composite impermeable geomembrane is laid on it; next, airtight soil is laid; then straw bags are stacked on it and filled with soil for protection; the boulder slope protection 7 is constructed to prevent erosion by tides and ensure the stability of the cofferdam; finally, steel sheet piles 8 are driven in.

[0027] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or direct application to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A cofferdam structure suitable for seawall construction, characterized in that, include: The cofferdam consists of a rubble base layer (1), a boulders (2), a crushed stone filter layer (3), a composite impermeable geomembrane layer (4), a closed soil layer (5), a straw bag soil protection layer (6), and a riprap slope protection layer (7). The rubble base layer (1) is placed in the foundation pit. The boulders (2) are filled on top of the rubble base layer (1). The crushed stone filter layer (3) is laid on the water-facing slope of the boulders (2). The composite impermeable geomembrane layer (4) is laid on top of the boulders (2) and the crushed stone filter layer (3). The closed soil layer (5) is laid on the back slope of the composite impermeable geomembrane layer (4). The straw bag soil protection layer (6) is stacked on the composite impermeable geomembrane layer (4) and the closed soil layer (5). The riprap slope protection layer (7) is set at the toe of the water-facing slope of the cofferdam.

2. The cofferdam structure suitable for seawall construction according to claim 1, characterized in that, Also includes: Sheet piles (8) are installed on the inner side of the back slope of the cofferdam, and the lower end of the sheet piles (8) is inserted into the foundation.

3. A cofferdam structure suitable for seawall construction according to claim 2, characterized in that, The rubble base layer (1) is formed by replacing the silt layer with rubble with a diameter greater than 30cm, and has a thickness greater than 2m.

4. A cofferdam structure suitable for seawall construction according to claim 2, characterized in that, The riprap dam (2) is constructed by filling with riprap and compacted with a 15t self-propelled vibratory roller.

5. A cofferdam structure suitable for seawall construction according to claim 2, characterized in that, The riprap dam (2) is constructed with a metal mesh frame and wet concrete sprayed onto it.

6. A cofferdam structure suitable for seawall construction according to claim 2, characterized in that, The crushed stone filter layer (3) is laid with crushed stone filter material with a particle size of less than 15 mm.

7. A cofferdam structure suitable for seawall construction according to claim 2, characterized in that, The composite impermeable geomembrane layer (4) has a unit mass greater than 550g / m 2 The geomembrane is composed of overlapping sections, with a horizontal overlap length greater than 1.0m, and is connected by composite welding.

8. A cofferdam structure suitable for seawall construction according to claim 2, characterized in that, The airtight soil layer (5) is laid with low-permeability loess and has a thickness of more than 0.8m.

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