铁道建筑

强度折减法通过对强度参数进行等比例折减使边坡渐进发生失稳破坏，但等比例强度折减计算结果存在失稳边坡体内部塑性区域过大、参数弱化路径比例不变等缺点，与客观现象不符。本文提出一种新的强度折减思路，首先以全局失稳状态下边坡体内部贯通的剪切塑性应变为基础，利用自编程序语言提取出失稳单元作为参数折减对象，然后在折减的过程中反映参数的动态劣化路径，最终以强度储备面积计算边坡稳定性系数。计算结果表明：基于Drucker-Prager(D-P)准则的局部非等比例强度折减计算结果较传统强度折减法效果更好，误差更小。由于真实考虑到折减区域、参数路径，边坡失稳过程中塑性区域最早出现在坡脚，随着折减参数的不断增大，塑性区域逐渐向上发展最终贯通整个模型，边坡变形较传统方法偏小，局部非等比例强度折减思路避免了折减范围过大导致的塑性破坏区失真现象，为强度折减法更有效地应用于边坡稳定性分析提供了有效途径。

The strength reduction method simulates the progressive instability and failure of slopes by proportionally reducing strength parameters. However, the equal-proportional strength reduction method has shortcomings such as excessively large plastic zones within the unstable slope and constant parameter weakening paths, which do not align with objective phenomena. This paper proposed a novel strength reduction approach. Firstly, based on the shear plastic strain that penetrates the slope body under a global instability state, a self-programmed language was used to extract unstable elements as the objects of parameter reduction. Secondly, dynamic deterioration paths of parameters were reflected during the reduction process. Finally, the slope stability factor was calculated using the strength reserve area.Numerical examples demonstrate that the local non-proportional strength reduction method based on the Drucker-Prager(D-P) criterion yields better results and smaller errors compared to the traditional strength reduction method. By realistically considering the reduction area and parameter paths, plastic zones first appear at the slope toe during the slope failure process. As the reduction parameters continuously increase, the plastic zones gradually develop upward and eventually penetrate the entire model. The slope deformation is smaller than that in traditional methods. The local non-proportional strength reduction approach avoids the distortion of plastic failure zones caused by excessive reduction scopes, providing an effective way to apply the strength reduction method more efficiently in slope stability analysis.