This article is based on the YTHJ4 project of the Cen-Da Highway by China Railway 19th Bureau Group Co.,Ltd.,and a 3D geological model was built by Civil 3D.Two different failure modes of the cave under the action of pile foundation were introduced.Then,the single factor variable method based on FLAC 3D was used to analyze the effects of different cave roof thickness,roof span,cave height,and distance from the cave center from the pile axis on the bearing capacity characteris-tics of rock-socketed piles(ultimate bearing capacity,ultimate side friction resistance,relative slip distance of pile-soil,etc.).The results show that the thickness of cave roof is the most significant fac-tor to affect the pile bearing capacity.The failure mode in the ultimate limit state of the cave strongly depends on the roof thickness,the roof span and the mechanical properties of the rock mass.When the roof thickness reaches three times the pile diameter,the pile side friction resistance can be fully exerted.There is a stable point for the influence of the span and eccentricity distance of the cave roof on the bearing capacity characteristics of the pile foundation.The research conclusions provide a cer-tain reference basis for the design of rock-socketed piles in karst area,and enrich the design concept of pile foundation in karst area.
维普
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