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传统强度折减法通常对整个边坡区域进行折减,因而只能得到最小安全系数及对应的最危险临界滑动面。但在工程实践中,边坡的治理范围不能局限于最危险滑动面所包围的区域,不满足规范要求的次级滑动面范围内的坡体亦应得到治理。为了克服传统强度折减法在搜索次级滑动面方面的缺陷,提出了一种新的强度折减法。一般而言,边坡的屈服区域主要集中在滑动面两侧附近,形成一个沿滑动面分布的剪切破坏带,因此,在用强度折减法进行边坡稳定性分析时,只需对剪切破坏带范围内的局部坡体进行折减,则可得到该滑动面的安全系数和滑动面。基于以上认识,假设剪切破坏带沿对数螺旋曲线分布,不断调整对数螺旋曲线的形状以得到不同范围的剪切破坏带,对各种不同的剪切破坏带范围内的坡体进行局部折减计算,即可得到不同的安全系数及对应的滑动面。通过两个边坡算例(单台阶、双台阶)验证了该方法的可行性,并最后讨论了剪切破坏带的宽度对结果的影响。两个算例的计算结果表明,该方法不仅可以得到最危险临界滑动面,亦可得到任意安全系数对应的滑动面。
The traditional strength reduction method generally reduces the entire slope area, so only the minimum safety factor and the corresponding critical dangerous sliding surface can be obtained. However, in engineering practice, the scope of slope treatment can not be limited to the area surrounded by the most dangerous sliding surface, and the slope within the range of secondary sliding surface that does not meet the standard requirements should be governed. In order to overcome the shortcomings of the traditional strength reduction method in search of secondary sliding surface, a new strength reduction method is proposed. Generally speaking, the yielding area of the slope mainly concentrates on both sides of the sliding surface to form a shear failure zone distributed along the sliding surface. Therefore, when analyzing the slope stability by strength reduction method, The local slopes within the range of the damage zone are reduced, the safety factor and the sliding surface of the sliding surface can be obtained. Based on the above understanding, it is assumed that the shear failure zone distributes along the logarithmic spiral curve, and the shape of the logarithmic spiral curve is continuously adjusted to obtain different ranges of shear failure zones, and the slopes within the range of various shear failure zones are locally Reduce the calculation, you can get a different safety factor and the corresponding sliding surface. The feasibility of this method is verified by two slope examples (single step and double step). Finally, the effect of the width of the shear failure zone on the result is discussed. The calculation results of two examples show that this method can not only get the most critical critical slip surface, but also obtain the sliding surface corresponding to any safety factor.