群桩非线性工作机理的研究

The Study of the Nonlinear Working Mechanism of Pile Group

通过群桩基础的室内模型试验和数值模拟对比研究对群桩受荷的非线性过程进行了深入分析,研究结果表明群桩受荷时,桩间土体会发生绕桩流动,桩的遮拦作用使承台底土体受到极限滑动阻力,从而使土体极限承载力有一个增加值Δfu;在大桩距群桩的情况下,桩较早地发挥到极限状态,随后承台下土体才充分参加工作,承担后续加荷的主要部分,进入以土体承载为主要表现的极限状态,同时在大桩距的情况下桩土的荷载分担是明确的。

The nonlinear working progress of group pile foundation is studied by means of model tests and numerical simulations. The results are just as follows： on the one hand, when the group pile foundation is working to the critical state, the soil between the piles will slide around the pile, and the counteraction of the pile will heighten the limit bearing capability of soil-the △fu is acquired ; on the other hand, in the condition of large pile space, the pile bearing capability reaches limit earlier. Then, the soil under cap takes part in working, adequately and bears the following load, and the whole group pile foundation indicates a limit state of soil bearing. In the mean time, soil and pile bearing capability is definite.