Secondary processing method of collapsibility foundation in loess region and composite foundation structure

Abstract

The invention discloses a secondary processing method of collapsibility foundation in loess region and a composite foundation structure. The method comprises the following steps: a foundation is dug on an area, and the depth of the foundation is the thickness of collapsibility loess under foundation and the depth which can be processed by a lime-soil compacted column; the first-time lime-soil compacted column construction is carried out with a land extrusion method; after construction is finished and qualified by tests, original soil dug out is backfilled on the lime-soil compacted column foundation on the lower layer and is tamped, and the backfilling height is 0.6-1.6 meters below building foundation base elevation; then, the second-time lime-soil compacted column construction is carried out on the backfilled soil with the land extrusion method; after second construction is finished and qualified by tests, the lime-soil subcrust construction is carried out on the second-time lime-soil compacted column foundation, the thickness is 0.5-1.5 meters, and a complete composite foundation is formed. Under the condition of ensuring foundation bearing capacity, the invention can finish foundation processing construction by sections, and solves the problems that the existing construction machines can not finish foundation processing in which the construction depth is beyond mechanical construction ability thereof.

Description

technical field [0001] The invention relates to a secondary treatment method for foundations in collapsible loess areas and a composite foundation structure, belonging to the field of civil engineering foundations. Background technique [0002] In Northwest my country, we often carry out engineering construction on sites in collapsible loess areas. Since the use function of the building has strict restrictions on the settlement of the foundation, it is necessary to carry out foundation treatment according to relevant specifications to completely or partially eliminate the collapsibility of the foundation to improve its bearing capacity. The usual method is to use lime-soil compaction piles to The foundation is reinforced. [0003] At present, the treatment depth of lime-soil compaction piles is not more than 15 meters, and due to mechanical limitations, it can only be processed to a depth of about 10 meters. In actual engineering, the depth to be treated for the foundation ...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a secondary treatment method and composite foundation structure for foundations in collapsible loess areas, so as to solve the problem that the foundation treatment depth required by the specifications cannot be completed at one time due to the limitation of engineering machinery, and eliminate the wetness of foundations in collapsible loess areas. Sinkability, improve the bearing capacity of the foundation, and make up for the deficiencies of existing technologies

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