Construction method for large-area pit support structure in deep-sludge type soft soil area

Abstract

The invention discloses a construction method for a large-area pit support structure in a deep-sludge type soft soil area and relates to the technical field of geotechnical engineering. The construction method solves the problems that for a soil layer with distribution of deep sludge and a construction site large in area and small in dredging depth, an existing pit support structure construction method is large in influence to surrounding environments, high in engineering cost and long in construction period. The construction method includes: 1, separating an area within a foundation pit excavation sideline into at least four subareas; 2, constructing piles along the excavation sideline by a construction method and fixing concrete ring beams on the piles; 3, constructing within one subarea and laying light well point pipes before earth excavation; 4, excavating earth in the current subarea, pouring a baseplate and brackets and erecting steel tube diagonal bracings on the brackets; 5, removing the steel tube diagonal bracings in the construction subarea after construction meets requirements, pulling out H-shaped steels, and circularly applying the steel tube diagonal bracings and the H-shaped steels to construction for the next subarea; 6, repeating the steps from step 3 to step 5 until constructions for all the subareas are completely sequentially, and thereby finishing the construction for the integral foundation pit support structure.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering design and construction, in particular to a construction method suitable for a foundation pit enclosure structure with a large area and a small excavation depth under complex geological conditions of deep and thick muddy soft soil. Background technique [0002] In soft soil areas, it is often encountered that the project site is distributed with deep muddy soil layers, sometimes as deep as 20 to 30 meters. Such as figure 1 As shown, the profile of a typical deep silty soft soil stratum can be summarized into three layers. The upper layer I is mainly miscellaneous fill soil, containing a large amount of construction waste, pond mud, plant rhizomes and concrete ground, etc. The soil is loose and its cohesion is about 8kPa. , the internal friction angle is about 8°, and the permeability coefficient is large, about 3.0×10 -4 (cm / s); the middle layer II is silty clay, the soil proper...

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Problems solved by technology

[0013] In view of the above-mentioned engineering site with deep silty soil layer, large area and small excavation depth, the existing foundation pit enclosure structure construction method has a great impact on the surrounding environment of the foundation pit, high project cost and long construction period. The purpose of the present invention is to provide a large-area foundation pit enclosure structure and its construction method in the deep muddy soft soil area, which can realize the maximum economic benefit under the premise of satisfying the safety of the foundation pit and protecting the surrounding environment

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