Abstract

The study of ultimate bearing capacity (UBC) of uplift piles in combined soil and rock mass is of great significance in engineering. In order to study the UBC of uplift piles in combined soil and rock mass, in situ uplift tests in practical engineering were conducted, and a suitable Flac^3D numerical simulation model was established by combining with geological conditions in engineering and in situ test data. And a combined inverted cone failure model was modified for the calculation of UBC. The normal stress and shear stress on the failure surface of soil and rock mass were solved based on zero-tension truncation modified, small and non-zero tensile truncation modified Mohr–Cloumb criterion. Finally, the UBC of uplift pile was solved according to the upper bound method of limit analysis. Although the obtained calculation formula can reflect the change of the UBC of uplift pile with different rock-socketed depths, the calculation accuracy was not high enough and the error was relatively large. Consequently, the proposed analytical formula was further modified. The results showed that the proposed UBC formula can be used to predict the UBC of uplift pile in combined soil and rock mass.

摘要

土岩结合体中抗拔桩的极限承载力(UBC)研究具有重要的工程意义。为研究土石结合体中隆起桩的UBC，在实际工程中进行了原位隆起试验，并结合工程地质条件和原位条件，建立了合适的Flac ^{3D数值模拟模型。}测试数据。并修改了组合倒锥破坏模型用于计算UBC。土岩体破坏面的正应力和剪应力基于零张力截断修正、小和非零张力截断修正的Mohr-Cloumb准则求解。最后，根据极限分析的上界法求解抗拔桩UBC。得到的计算公式虽然能反映不同嵌岩深度的顶升桩UBC的变化，但计算精度不够高，误差较大。因此，进一步修改了所提出的分析公式。结果表明，所提出的UBC公式可用于预测土岩组合中隆起桩的UBC。