The engineered slopes along transportation routes in the Himalayan region are manifested by multiple sets of discontinuities and are vulnerable to structurally controlled failures. The hazard potential along one such route was assessed by an empirical Q-slope method. The investigated engineered slopes along the route are unstable, and the Q-slope value ranges from 0.0023 to 0.7701. By considering the ongoing road development and excavation works, optimal angles without any requirements of reinforcement measures ( β ) were determined for the probability of failure (PoF) as 1%, 15%, 30%, and 50%. The outcomes obtained by Q-slope were also correlated with the continuous slope mass rating (CSMR) values. A linear relationship was obtained between Q-slope and CSMR values, having the coefficient of determination as 0.67. The study also aims to assess the applicability of the existing Q-slope method for toppling mode of failure. A modified Q-slope method for toppling failure is proposed by considering the basic principles of toppling failure. The role of joint roughness parameter in topple mechanism is highlighted. Consequently, chart based modifications along with proper guidelines for the newly introduced parameter has also been proposed. It is also pointed out that the Q-slope chart is slightly conservative in nature particularly for β corresponding to low Q-slope values. The optimal slope angle for the PoF 1% was correlated with the slope angle at factor of safety as 2, and an extended stable zone is proposed with further scope of development. The modifications and suggestions for the refinement of the system will enhance the applicability of the method for a much broader range of initial ground conditions. The outcomes may be advantageous for the progressing road widening and development work along a section of the transportation route in Uttarakhand Himalaya.

中文翻译：

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Q-slope方法在喜马拉雅公路切割岩石边坡中的适用性及其与CSMR的比较

喜马拉雅地区运输路线沿线的工程斜坡表现出多组不连续性，并且容易受到结构控制故障的影响。沿着一条这样的路线的潜在危险是通过经验 Q 斜率方法评估的。沿线调查的工程边坡不稳定，Q-slope值范围为0.0023～0.7701。通过考虑正在进行的道路开发和开挖工程，将失效概率 (PoF) 确定为 1%、15%、30% 和 50% 的没有任何加固措施 (β) 要求的最佳角度。通过 Q 斜率获得的结果也与连续斜率质量评级 (CSMR) 值相关。在 Q 斜率和 CSMR 值之间获得线性关系，确定系数为 0.67。该研究还旨在评估现有 Q 斜率方法对倾覆失效模式的适用性。考虑到倾覆破坏的基本原理，提出了一种改进的Q-slope倾倒破坏方法。突出了关节粗糙度参数在倾覆机制中的作用。因此，还提出了基于图表的修改以及新引入参数的适当指导方针。还指出，Q 斜率图本质上稍微保守，特别是对于对应于低 Q 斜率值的 β。PoF 1% 的最佳倾斜角与安全系数为 2 时的倾斜角相关，并提出了具有进一步开发范围的扩展稳定区。改进系统的修改和建议将增强该方法在更广泛的初始地面条件范围内的适用性。这些成果可能有利于北阿坎德邦喜马拉雅地区一段运输路线沿线的道路拓宽和开发工作。