Method for bracing foundation pit by using steel box piles

Abstract

The invention discloses a method for bracing a foundation pit by using steel box piles. The method comprises the following steps of: (1) making the steel box piles: welding profile steels or steel plates into a steel box pile box, and arranging transverse connecting members among the piles at two sides of the steel box pile box; (2) arranging a ground guiding structure: pouring reinforced concrete to form a foundation pit bracing guiding wall or arranging steel members to form the ground guiding structure; (3) positioning: sequentially positioning a plurality of steel box piles along the guiding structure respectively; (4) sinking the piles: driving the steel box piles into soil; (5) lengthening the piles: when the foundation pit is relatively deep and the prefabricated steel box piles are not long enough, lengthening the steel box piles through pile body lengthening members; and (6) digging and supporting: digging layer by layer, arranging enclosing purlins and erecting supports in the foundation pit of the steel box piles, and completing the construction. The method has the advantages of high construction efficiency, short construction period, reliable pile forming quality, low engineering cost, resource economization and the like, and is particularly suitable for weak strata in which holes and grooves are not easily formed such as silt soil, peat soil, saturated water-containing sand layers, powdery clay, soil sand and the like.

Description

technical field [0001] The invention relates to the technical field of foundation pit enclosure protection for underground engineering in the field of construction, and is particularly suitable for silty soil, peaty soil, saturated water-bearing sand layer, silty clay, and soil-sand interbeds, etc., which are not easy to form holes and grooves. Ground pit protection method. Background technique [0002] There are many open-cut deep foundation pits in underground railways, urban roads and high-rise building projects. Existing retaining structures for foundation pits usually adopt a variety of retaining forms such as underground diaphragm walls, bored piles, driven piles, and rigid cement jet grouting (SMW) piles. [0003] For silty soil, peaty soil, saturated water-bearing sand layer, silty clay, and soil-sand interbedded weak strata that are not easy to form holes and troughs, such as: soft soil strata along the Yangtze River Delta, Pearl River Delta and Bohai Bay and other...

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Problems solved by technology

[0003] For silty soil, peaty soil, saturated water-bearing sand layer, silty clay, and soil-sand interbedded weak strata that are not easy to form holes and troughs, such as: soft soil strata along the Yangtze River Delta, Pearl River Delta and Bohai Bay and other coastal areas. The alluvial terraces along the Yangtze River and the Pearl River and other rivers adopt the existing foundation pit enclosure technology, which has obvious defects: the common disadvantages of underground diaphragm walls and bored piles are high cost, long construction period, and great impact on the environment ; There are certain difficulties in the recovery of section steel of rigid cement jet grouting (SMW) piles, and the construction quality is not easy to guarantee, which inevitably pollutes the environment, and is not suitable for deep foundation pits; steel sheet piles are only suitable for shallow foundation pits

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