Construction method for composite foundation on soft soil stratum

Abstract

The invention discloses a construction method for a composite foundation on a soft soil stratum. The main equipments relating to the construction method are a pile machine, a column hammer (2) and a pile casing (1), wherein feeding openings (3) are formed in the casing wall of the pile casing (1). Besides the preparatory processes such as staking, layout, and placing the pile machine in a proper place, the construction method further comprises the following steps: dropping the hammer repeatedly to beat a soft soil layer until the column hammer (2) is in contact with a bearing stratum (9) to form a pile hole (4); feeding and tamping repeatedly to form a single discrete pile (6); constructing corresponding multi-single discrete piles on multi-pile positions to form discrete cluster piles; treating the discrete cluster piles according to a post process to form the complete composite foundation; the solid material is an artificial compound composed by the inorganic solid material and original soil. Under the action of tamping energy, the dropped solid material not only is tamped, but also is extruded and expanded around; the soil mass intensity around the pile is also transformed when the pile is formed, and a pile-soil common stressing body is formed so as to form a composite foundation of which large area of the soft soil foundation is wholly strengthened and the displacement ratio is higher.

Description

technical field [0001] The invention relates to a soft soil foundation treatment technology for geotechnical engineering, in particular to a construction method for replacement treatment on soft soil layers such as construction of industrial or civil buildings and municipal engineering in areas along rivers, lakes and seas. The composite foundation construction method using loose piles as reinforcements on the stratum is suitable for the replacement treatment of large-area and deeply buried soft soil. Background technique [0002] To build a large area of ​​fixed facilities or ports, roads, etc. on silt or silt soft soil foundation, it is necessary to carry out large-scale foundation reinforcement treatment to prevent accidents such as foundation settlement and subsidence. At present, in the field of geotechnical engineering, for the construction technology of weak foundation replacement, the commonly used methods include vacuum compaction and compaction method, surcharge pr...

AI Technical Summary

Problems solved by technology

At present, in the field of geotechnical engineering, for the construction technology of weak foundation replacement, the commonly used methods include vacuum compaction and compaction method, surcharge preloading, deep mixing, dynamic compaction method, vibrating gravel pile, etc. However, these The method generally has low bearing capacity, large settlement, long construction period, large environmental impact, difficult construction quality control, high construction cost, unsatisfactory treatment effect, insufficient replacement depth and other related unfavorable factors

For example: Vacuum compaction compaction method and surcharge preloading method are passive treatment methods, and the construction period is very long, especially for soils with high saturation, low permeability, thixotropy, soft plastic or flow plastic state , the treatment effect of these construction methods is limited; the disadvantage of deep mixing piles is that they consume a large amount of cement and have low bearing capacity; the dynamic compaction replacement method is a direct and effective method in the case of soft soil layers with shallow burial depth and small thickness. However, when the weak soil layer to be reinforced is deeply buried, high water content, soft plastic or flow plastic soil, there are difficulties in entering the site, insufficient depth of ramming impact, and construction noise. In addition, when encountering soil with high moisture content, thixotropy, and cohesive soil with high clay content, this method is likely to cause rubbery soil; vibro-impacted gravel piles are loose piles, but the replacement rate Low construction noise, polluting the environment

Therefore, when large-area, deep-seated replacements are required to deal with weak formations, there are many technical problems that are difficult to overcome in the above-mentioned commonly used construction methods.

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