关键词: 扩底桩, 离心模型试验, 岩体破坏模式, 极限抗拔承载力, 简化计算方法

Abstract: With the rapid development of the transmission line project in western China, the problems of the tower foundation uplift become prominent. It is necessary to solve the failure model of rock and the calculation method of ultimate uplift bearing capacity urgently. The centrifuge model test results are used to analyze the failure model of rock, load-displacement curve, axial force distribution and friction resistance curve of piles. According to the test results, after the failure shape of rock is non-dimensionally processed and fitted, a unified function description form is obtained. On this basis, the limit equilibrium method is used to derive the calculation method of ultimate uplift bearing capacity of the rock-socketed pedestal pile overburden soil, and the calculation method is simplified. The integral calculation value and the simplified calculation value are compared with the results of the centrifugal model test. The results show that the failure model of the soft rock is trumpet-shaped surface, which can be described by a unified power function. The results of the simplified calculation method are in good agreement with the results of the centrifugal model test. Therefore, the method proposed in this paper provides a reference for the uplift design of tower foundation in the western mountainous area.

Key words: pedestal pile, centrifugal model test, failure model of rock, ultimate uplift bearing capacity, simplified calculation method