Larsen steel sheet pile cofferdam has an important role in the construction of water-tight cofferdam bridge, but Larsen steel sheet pile cofferdam is required for river cofferdam, which includes river environment requirements and steel sheet pile cofferdam construction requirements. Respectively.
First, the river Environmental requirements:
1、steel sheet pile coffers for water depth of 4m or more;
2、deep water or deep foundation pit, the larger flow of sand soil, cohesive soil, gravel soil and weathered rock and other hard river bed.
Second, Larsen steel sheet pile cofferdam construction requirements:
1、there are large boulders and hard rock bed should not use Larsen steel sheet pile cofferdam.
2、Larsen steel sheet pile of mechanical properties and size should meet the requirements.
3、before the Larsen steel sheet pile, should be in the cofferdam upstream and downstream of the measured observation points, control cofferdam long, short side of the direction of positioning. When playing, you must have guided equipment to ensure that the Larsen steel sheet pile in the correct position.
4、playing Larsen steel sheet pile before the steel sheet pile should be used to lock the mouth with a waterproof material to prevent leakage.
5、hit the order from the upstream to the downstream joint dragon.
6、steel piles can be thumped, vibration, water and other methods to sink, but the clay should not use water sinking method.
7、after the renovation or welding steel sheet pile application of the same type of steel sheet pile lock test, inspection. The length of the joints of the adjacent steel sheet pile should be staggered.
8、playing Larsen steel sheet pile process, should always check the location of the pile is correct, the pile is vertical, or should immediately correct or pull out the re-hit.
9、in the general bridge engineering foundation pit construction, shallow base with rectangular and wooden frame, deep foundation pit and more round and steel.
10、waterproof performance, and more single-layer cofferdam, with double-layer cofferdam, in the middle of the double-layer cofferdam generally filled with clay.
11、in the lower part of the sandwich underwater concrete to improve the anti-seepage capacity, in the construction of steel sheet pile cofferdam, multi-purpose groove steel sheet pile.
12、cofferdam inside the face of the size, to meet the top edge of the pit between the retention of not less than 1.0m distance.
13、cofferdam top surface than the construction may occur during the highest water level higher than 0.5m.
14、when the foundation is deeper, the pit wall is poor, the seepage is large, the slope (pit) is easy to collapse, then the inside of the cofferdam to the edge of the top of the pit, the appropriate increase to ensure safety.