土钉墙施工阶段土体剪切破坏分析与加固处理

Shear Failure Model and Reinforcement Analysis of Soil Nail Wall on the Constructing Phase

详细介绍了某土钉墙的设计情况和某开挖工况下的失稳现象,并对这种现象进行了分析。通过分析提出,在土钉墙施工阶段不仅要按圆弧滑动的简单条分法进行内部稳定性分析,同时还要进行每个工况的土体剪切分析。采用材料力学和土体极限平衡的理论提出了剪切破坏分析方法,分析了剪切破坏产生的机理,指出剪切破坏失稳的主要原因是由于土体抗剪强度不满足局部压力要求,这类失稳与每个工况的开挖深度无关,但与土体抗剪强度、开挖时间以及上一工况的土钉长度有关。剪切破坏失稳后,最佳的处理措施是采用预应力锚索加固,提出了加固锚索所需拉力的计算方法。

The design of a soil nail wall and its instability about the excavtaion phase are introduced in detail. Internal stability by slice method of circular and soil shear failure should be both analyzed for every condition on constructing pahse of soil nail wall by analyzing unstability phenomena. Through analyzing mechanism of shear failure, calculating and analysis methods are presented by material mechanics and theory of soil ultimate balance, the mian reason for shear instability is that soil shear strength dissatisfy local stress, shear instability is independent of excavation depth of every condition, but soil parameters and excavation time and length of soil nail of last condition do. The best reinforcement method to treat shear failure is adding pre-stressed anchor rope, and the calculating method of anchorage force is present.