Construction method for excavating mucky soil body area foundation provided with PHC pipe pile

Abstract

The invention discloses a construction method for excavating a mucky soil body area foundation provided with a PHC pipe pile. The construction method comprises the following steps that geological condition supplementary survey is carried out on a deep foundation pit foundation in a design drawing and a foundation with a shallow distribution sludge layer in a geological survey report or a foundation of a geological abnormal area in pile foundation construction, and the like, the condition of the sludge layer below is found out, a single-shaft jet grouting drilling machine is adopted for performing jet grouting on a mud layer on a foundation meeting the mud layer in the foundation excavation process to perform mud layer consolidation, after consolidation strength is achieved, layered excavation of foundation earthwork is carried out, and by means of the technology, when the foundation is excavated, the construction problem that the pile body of the PHC pipe pile is inclined or the joint welding seam between the PHC pipe piles is cracked due to the fact that the bond stress of the pile top of the PHC pipe pile is not enough is solved, the engineering construction period is ensured, and the situation that the engineering cost is increased due to the quality problem of the PHC pipe pile is avoided.

Description

technical field [0001] The invention belongs to the technical field of building construction, and relates to pile foundation construction, in particular to a construction method for foundation excavation in a muddy soil area provided with PHC pipe piles. Background technique [0002] During construction, it is often encountered that new factories or buildings are built on coastal beaches, and the foundation in such projects is often backfilled with materials such as block stones. The bearing capacity of the foundation formed by backfilling block stones cannot reach the foundation of factories or buildings. For the design value of the required bearing capacity, one of the pile foundation forms—PHC pipe pile is often used to realize the design bearing capacity requirement. However, before the construction of PHC pipe piles, the rocks must be excavated to the underground soft soil layer, and replaced with granular gravel soil or silt, so as to reduce the phenomenon of large-are...

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Problems solved by technology

However, before the construction of PHC pipe piles, the rocks must be excavated to the underground soft soil layer, and replaced with granular gravel soil or silt, so as to reduce the phenomenon of large-area broken piles caused by PHC pipe piles. After the backfill stones are excavated and gradually cleared, the relatively stable silt layer originally formed in the backfill stones will also be disturbed with the cleaning of the stones. The elevation of the actual block after excavation is inconsistent. For example, after the pile foundation construction is completed, the shallow silt in the excavation area is not technically treated before the foundation excavation. When the silt layer is encountered during the foundation excavation, the PHC pipe pile Due to the absence of the gripping force of the backfill material on the top of the pile, and the PHC pipe pile in the mud layer is subjected to the disturbance force of the mud layer and the additional lateral force of the construction machinery during foundation excavation, the inclination of the PHC pipe pile body or the PHC pipe pile body will appear. The joint welds between piles are cracked, so that the pile quality of PHC pipe piles cannot meet the design requirements of the foundation bearing capacity. Subsequent quality treatment or re-compensation must be carried out for the quality defects of pile body inclination or joint weld cracks between piles. Pile, will inevitably lead to delays in the construction period and an increase in construction costs

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