A multi-step decompression and dewatering control method for deep and large foundation pits in highly confined water formations

Abstract

The invention discloses a multi-step pressure reducing and dewatering control method for a high confined water stratum deep and large foundation ditch. Multiple waterproof curtains are additionally arranged outside the foundation ditch, the first waterproof curtain is also taken as a foundation ditch retaining structure, modes such as an underground diaphragm wall, a bored secant cast-in-place pile, a plain concrete wall, double-row mixing piles and a high-pressure jet grouting pile can be adopted by the waterproof curtains, meanwhile a certain number of dewatering wells are arranged between waterproof walls, the dewatering wells are opened according to the needs, water head differences on the two sides of the waterproof walls are distributed in a stepped mode, the purposes that the numberof seepage paths is increased, the water pressure difference borne by the foundation ditch retaining structure is reduced, and the bursting risk of the bottom of the foundation ditch is lowered are achieved, and the destructive influence on surrounding important buildings is avoided.

Description

technical field [0001] The invention belongs to the technical field of civil engineering and traffic engineering, and in particular relates to a multi-step decompression and dewatering control method for deep and large foundation pits in high confined water formations. Background technique [0002] In areas along rivers, seas and lakes in cities, the groundwater level is relatively high, and the lithology of the strata is mostly muddy soil and clayey soil in newly deposited river floodplains. . Excavation of deep and large foundation pits in such areas often faces the problem of uncontrollable construction quality caused by the deep and thick confined aquifer, the enclosure structure cannot be completely cut off, or the continuous wall is too deep, which affects the safety of the foundation pit structure itself. And the surrounding important structures pose a major threat. [0003] Taking the typical binary geological structure of the floodplain of the Yangtze River as an ...

AI Technical Summary

Problems solved by technology

The middle and lower parts often form a confined aquifer with a thickness of 40-60m, and the confined water head is relatively large. At the same time, it receives the water supply from the Yangtze River, and the construction risk of the foundation pit is high.

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