Method for surrounding water by combination of steel cofferdam and heavy-pressure rotary-spraying pile in deep-water low-pile cap construction

Abstract

The invention discloses a construction method using a steel cofferdam to be combined with a high-pressure rotary jet grouting pile to surround water in the deep-water low-pile cap construction. A steel boxed cofferdam is conveyed to the position of a pier and is located through a location system; the water is filled between double walls to cause the steel cofferdam to go down below the riverbed surface under the action of self-weight; the top surface of the cofferdam is provided with a rotary jet grouting pile construction platform for placing a single-tube high-pressure rotary jetting jig and a high-pressure grouting pump; a rotary jet grouting pile is formed through guide-hole, blocking of vertical nozzles, mortar stirring and rotary jetting construction of the rotary jetting jig; the rotary jet grouting pile is constructed in a sequence from inner layers to outer layers around the cofferdam; a pile cap foundation pit in the cofferdam is made a water extraction and dug, then the pile cap is constructed. The invention has the advantages that: the steel cofferdam is settled to the soil layer of the riverbed and is used for the water surrounding structure in deep water, a vertical curtain is established in the soil layer by using the high-pressure rotary jet grouting pile and is mainly used for water stop and support excavation below the riverbed surface, the steel cofferdam is organically combined with the high-pressure rotary jet grouting pile, the settlement difficulty that the cofferdam runs through the thicker hard clay layer is solved, also the problems of water stop and support when the underwater pile cap digs to the sand layer and the sandy loam layer are overcome.

Description

technical field [0001] The invention relates to a method for completing the construction of low pile caps in deep water by using steel casing cofferdams combined with high-pressure rotary grouting piles. It belongs to the technical field of bridge construction. Background technique [0002] The conventional method of deep-water low-pile cap construction generally adopts the steel casing cofferdam to sink to the elevation, remove the soil layer above the bottom elevation of the bottom sealing concrete in the cofferdam, pour the underwater bottom sealing concrete, pump water, and carry out cap construction. However, for the surface geology of the deep-water low pile cap riverbed is hard clay, and the bottom of the cap is located in the sand layer and sub-sand soil permeable layer, if only steel box cofferdams are used, in order to pass through smoothly when sinking For the hard clay layer on the surface of the river bed, a double-wall structure can be adopted at the full heig...

AI Technical Summary

Problems solved by technology

Since the geology of the pile cap at the pier site is a sand layer and a permeable layer of sub-sand soil, the depth of the cofferdam sinking will increase, and the overall steel consumption of the cofferdam will increase. It can be seen that the above methods all make the construction It is very complicated, the investment is increased, and the operation is difficult

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