Analysis On Vertical Load-bearing Characteristics Of Large Diameter Pile Foundation Influenced By Pile Side Cave Through Numerical Simulation In Karst Areas

Due to the complexity and uncertainty of geological condition in karst area, there appearmany difficulties in pile foundation design and construction, but home and aboard research onpile foundation in karst area is mainly centered on the stability of karst carve roof at pilebottom, research on pile foundation bearing capacity is fewer when karst carve is aside pilelateral, and research on large diameter pile in karst area is few reported.Based on the careful analysis of home and aboard research literature about pilefoundation in karst area, combined with the loading features of pile foundation in non-karstarea, this paper deep analyzed the large diameter pile vertical bearing characteristic underdifferent condition of pile length, pile diameter, karve carve size and distance between pileand carve by finite element method, and on the basis of above research results, made anevaluation on the large pile foundation design and construction technology in karst area. Themain results are as follows:(1) When pile length increased5m for the large diameter pile foundation in karst carve,pile foundation vertical characteristic increased6%(taking15m long pile foundation verticalbearing capacity as reference), but the increase range of pile foundation bearing capacitygradually decreased with pile length increasing.(2) When pile diameter was not less than1.5m, pile resistance of the large diameter pilefoundation rock-socketed section took a proportion of above70%in pile foundation verticalbearing capacity.(3) The size affect of pile lateral karst carve on large diameter pile foundation bearingcapacity was smaller, when karst carve side length increased2m, pile foundation verticalbearing capacity decreased1~2%.(4) Under a certain condition of pile length, pile diameter and karst carve size, with theincrease of distance between pile and carve, pile foundation vertical bearing capacitygradually increased, and when the distance between pile and carve was not less than4timespile diameter, pile foundation vertical bearing capacity was more than90%that when therewas no karst carve aside pile lateral.