土钉墙内部稳定性分析方法改进

现有土钉墙滑动面的确定方法大多假定圆弧滑动面通过坡脚，但事实并非如此。文中总结了实际中可能出现的圆弧滑动面的4种类型，利用圆弧滑动面圆心坐标与圆弧上3个位置参数的关系建立了不通过坡脚的土钉墙最危险滑动面的搜索方法。根据土钉墙滑动面的类型，讨论和完善了建筑基坑支护技术规程中土钉墙整体稳定安全系数计算公式。在3个算例中将不同方法得到的滑动面和整体稳定安全系数进行对比分析，结果表明文中方法得到的滑动面与其他方法结果接近，说明文中方法的可行性；部分情况下文中得到的滑动面不通过坡脚，而传统方法假定滑动面通过坡脚，二者计算偏差较大；对于除传统方法得到的滑动面之外的3种滑动面类型，在相同滑动面条件下完善后的公式由于考虑了部分土体重力沿滑动面切向的抗滑力作用，计算出的整体稳定安全系数稍大。

Improvement of internal stability analysis method of soil nailing wall

Most methods to determine sliding surface of soil nailing wall are based on the assumption that all circular sliding surfaces pass the foot of slope; but the assumption is not always true. In this paper, four kinds of circular sliding surfaces that may appear in reality are summarized and an approach to search the most dangerous sliding surface that does not pass through the foot of slope is put forward using the relationship between the center coordinate and three location parameters of this circular sliding surface. In addition, the calculation formula for the factor of safety of soil nailing wall in Technical specification for retaining and protection of building foundation excavations is discussed and improved. Through comparing and analyzing sliding surfaces and the factors of safety obtained by different methods in three examples, the results show that sliding surfaces and the factors of safety got by the method established in this paper is quite close to those obtained by other methods, so as to verity the feasibility of the method established in this paper. In some cases, sliding surface got by the method established in this paper is very different from traditional method because of the assumption that the all circular sliding surfaces pass the foot of slope. The improved formula which takes the anti-sliding force produced by soil weight along the tangential direction of sliding surface into account can get a slightly greater safety factors under the same sliding surface for other three kinds of sliding surface except for the sliding surface got by traditional method.