关键词: 岩土工程；高速铁路；串珠状溶洞；数值计算；群桩基础；承载特性

Abstract: Based on Nanyu high-speed railway in Guangxi, combined with physical model test and finite element numerical simulation, the influence of different cave height and cave radius on load transfer and bearing capacity of foundation piles in karst area was analyzed. The research results show that the axial force and lateral friction resistance of pile groups in karst area is affected by the radius and height of karst cave. Under the same load, the variation of cave radius has a greater impact on axial force and lateral friction resistance. The axial force and lateral friction resistance of each foundation pile is as follows: corner pile>edge pile>center pile. The corner pile bears the most force. After the pile top load is applied step by step, the effect of group pile is more obvious. The axial force of each foundation pile is increasing continuously, the difference in axial force between the center pile and the corner pile continues to increase, and the load sharing at the pile top becomes more uneven. Under the same load, the lower the height of the karst cave, the larger the radius of the karst cave, the greater the settlement of the pile foundation, the smaller the lateral friction resistance of the pile body, the poorer the overall bearing capacity of the pile foundation, and the more likely the karst cave roof is to be damaged under external loads.

Key words: geotechnical engineering; high-speed railway; beaded karst cave; numerical calculation; pile group foundation; bearing characteristics