预应力锚杆复合土钉墙支护体系增量解析方法

Incremental analytical method for prestressed anchor and soil nail wall composite support system

以预应力锚杆复合土钉支护体系受力变形为分析对象,假定潜在滑裂面为平面,并考虑土体分层开挖过程,将施加预应力作为一个施工工况,建立了预应力锚杆复合土钉支护体系受力变形的增量解析方法。锚杆预应力和设置位置影响分析表明,随着锚杆预应力值的增加,潜在滑裂面的倾角逐渐减小,对基坑整体稳定性的贡献先增大后减小;锚杆设置越低,增加预应力对基坑整体稳定性的贡献越大。通过实际基坑支护工程的数值模拟分析与施工过程监测结果的对比分析,验证了考虑预应力锚杆施工过程特点的复合土钉支护体系增量解析方法的合理性。

An incremental method is proposed for analyzing the load transfer mechanism and deformation of pre-stressed anchor and soil nailing composite supporting system in the layered excavation process by considering the application of pre-stress as a loading step as well as assuming that the potential slip surface is a plane.Analysis of the influence of anchor pre-stress and setting position shows that with the increase of anchor pre-stress,the inclination of potential slip surface decreases gradually,and the contribution to the overall stability of foundation pit increases first and then decreases.Further,the contribution of the pre-stress becomes more significant as the position of the anchor becomes lower.The validity of proposed method is verified through comparisons among predictions using proposed method,numerical simulations and field investigations.