柱下筏板基础冲切承载力的试验研究

Punching failure test study on raft foundation under column load

通过大比例室内模型试验,对天然地基土上两块完全相同的筏板分别进行了单独加荷和同步加荷破坏试验,对表现出来的冲切性状进行了研究,得出了集中柱荷载作用下角柱、边柱下筏板冲切破坏实测承载力值,并与规范计算值做了对比。试验表明,类似试验条件下的筏板破坏,验算时的控制截面是冲切破坏截面。增加上部结构刚度和基础刚度及减少筏板差异沉降可使筏板冲切破坏荷载大大提高,从而提高筏板冲切设计安全度。

The punching failure of comer columns and border columns under vertical concentrated columns load is studied through large-scale model tests in the laboratory. On the basis of crude soil, two identical raft foundations are tested under different loads. Different punching failure values of the comer columns, border columns are obtained under the vertical concentrated column load, and these values are compared with the code＇s values. The study shows the control failure section of the raft foundation is the punching failure section, and that the increase of the rigidity of foundation and upper structure and the reduction of the differential settlement of the raft foundation can greatly improve its carrying capacity and enhance the degree of safety in designing raft foundation.