Comprehensive foundation pit support construction method for sandstone combined soil layer

Abstract

The invention provides a comprehensive foundation pit support construction method for a sandstone combined soil layer. The method comprises specific steps as follows: a, a clay layer on the upper layer is subjected to earth excavation, and a plurality of oblique inserting type well point dewatering pipes and a plurality of vertical type well point dewatering pipes are alternately mounted on a sand layer after excavation is performed to the sand layer; b, the oblique inserting type well point dewatering pipes and the vertical type well point dewatering pipes are operated simultaneously; c, excavation is continuously performed after water level of underground water in the sand layer is decreased to a reserved elevation, and dense steel screens are paved at the lower part of the sand layer and soil nails are adopted for anchoring after the excavation is performed to a rock layer; d, rocks of the rock layer are chiseled, and earth excavation is performed continuously; e, broken stones after chiseling are removed, and structural construction is performed. According to the method, a support mode of combination of light dewatering wells and dense steel screen anchoring is adopted, underground water in the sand layer can be drained in time, the safety of the foundation pit support process is improved, and the difficulty of foundation pit excavation is reduced. The support technology is simpler, the support cost is reduced, and the construction time is shortened.

Description

technical field [0001] The invention relates to a construction method for foundation pit support, in particular to a construction method for foundation pit comprehensive support with sandstone combined with soil layers. Background technique [0002] According to the actual project construction needs and the increasing shortage of construction land, the selected area for project construction land is gradually close to the areas along the river, coastal areas and tidal flats, and these areas are mostly sandstone-combined strata. Therefore, when excavating the foundation pit, it needs to pass through the clay layer, sand layer and rock layer in sequence from top to bottom. Since the middle sand layer has a high water content and sufficient water source, a large area of ​​quicksand will appear when the base excavation passes through the sand layer. , resulting in the inability to excavate the foundation pit smoothly. In the case of precipitation construction, because the rock l...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a comprehensive foundation pit support construction method with sandstone combined with soil layer, to solve the problems in the prior art that the foundation pit support construction is relatively complicated and the construction period is long in the environment of sandstone combined with soil layer

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