Sand-bag and steel sheet pile combined cofferdam for hard formation and construction method of cofferdam

Abstract

The invention discloses a sand-bag and steel sheet pile combined cofferdam for hard formation and a construction method of the cofferdam. The sand-bag and steel sheet pile combined cofferdam comprises an inner cofferdam body and an outer cofferdam body which are disposed on the hard formation. Clay is disposed in the clearance between the inner cofferdam body and the outer cofferdam body, sand is then filled, and a steel sheet pile is then driven to penetrate through the sand and clay and into the hard formation deeply. The clay is disposed at the bottom of the clearance between the inner cofferdam body and the outer cofferdam body, the sand is disposed above the clay, and the steel sheet pile penetrates through the sand and the clay into the hard formation deeply to form a water stopping core wall. Due to the fact that the clay is high in viscosity, poor in water permeability and the like, when the steel sheet pile penetrates through the clay, the clay is adhered to the bottom of steel sheet pile and penetrates into the hard formation deeply, tight combination of the clay with the hard formation is achieved, water is prevented from permeating from the bottom of the steel sheet pile, and the water stopping core wall has good water stopping performance.

Description

technical field [0001] The invention relates to a water retaining cofferdam and a construction method thereof, in particular to a mold bag sand and steel sheet pile combined cofferdam and a construction method thereof on a hard ground. Background technique [0002] For water conservancy and hydropower, water transport and port projects, municipal engineering and civil construction projects built near the water, construction cofferdams for retaining water need to be installed before construction to form foundation pits for dry construction. Commonly used cofferdams include gravity sand molds Bag cofferdam, double-row steel sheet pile embedded cofferdam and double-row steel sheet pile sand mold bag bottom-locking foot cofferdam, etc. [0003] Most of the bottom surface of the general water area is covered by weak soil layer, and mold bag sand can be used to make a water-retaining cofferdam with a large width. Concrete anti-seepage walls, geotechnical vertical curtains, rotary ...

AI Technical Summary

Problems solved by technology

[0004] However, if it is necessary to set mold bag sand cofferdams on the surface of hard ground in shallow waters, the draft of piling boats in shallow waters is not enough to construct concrete cut-off walls; instead, multiple rows of mixing piles that can stop water, It is difficult for rotary grouted piles or steel sheet piles to enter the hard ground at the bottom of the cofferdam to the required depth, especially for steel sheet piles, which will puncture the mold bag when driven in, and seepage is prone to occur at the junction with the hard ground, making it difficult to reach the bottom of the cofferdam. water effect

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