桩间土拱效应离心模型试验及数值模拟研究

抗滑桩的设计理念是采用非连续结构，利用土体自身强度形成的拱效应来达到支挡的目的。通过离心模型试验，对抗滑桩加固滑坡形成土拱效应的现象进行研究，再现了桩间土拱形成的现象及其破坏模式。根据试验现象提出两种典型的土拱破坏模式，即拱顶发生破坏和拱脚发生破坏，并提出改善拱脚受力，防止土拱拱脚发生破坏的工程措施。基于离心模型试验，采用二维颗粒流方法对桩间水平土拱的应力分布和破坏过程进行数值模拟分析，提出土拱破坏的判别标准为抗滑桩所承担的荷载发生急剧变化，此时土拱传递荷载的功能部分失效，并研究了桩间土拱承载力与桩间净距的关系。随着桩间净距的增大，土拱承载力变化的趋势并非线性的减小，当桩间净距增大到一定程度后，土拱承载力会急剧减小，由此可合理确定桩间距的范围。

Study of centrifuge model tests and numerical simulation on soil arching in space of piles

The concept of designing anti-slide pile is using discontinuous structure and the soil arching effect to support the sliding force. By the centrifuge model tests, studying the phenomenon of soil arching effect when anti-slide pile is used to reinforce the landslide, reproducing the soil arching in space of piles and its failure mode. Two typical failure modes are put forward; i.e. soil arching crown failure and soil arching springer failure; and the engineering measure preventing soil arching springer from failure is put forward. Based on the centrifuge model tests, using 2D particle flow method to analyse the distribution of stress and failure process of horizontal soil arching in space of piles, and then that the failure criterion of soil arching is the sharp change of load of the anti-slide piles, is proposed; i.e. the function of soil arching transfering load is lapsing partially; and this may lead to that the load of one or another pile sharply raises. The relationship of load and pile space of soil arching is also studied. The load of soil arching changes with the increasing of pile space nonlinearly. When pile space increases to a certain extent, the load of soil arching will decrease sharply; so the area of reasonable pile space can be confirmed.