基于强度储备的边坡非等比例双安全系数研究

Research on non-proportional double safety factors of slope based on strength reserve

边坡的失稳过程是一个渐进性的累积破坏过程。在破坏过程中抗剪强度参数黏聚力c、内摩擦角?的发挥程度是不同的,对应的安全储备也就不同,那么基于强度储备的双安全系数确定及其基于双安全系数的边坡稳定性评价就值得深入探讨。首先从岩土材料的软化规律出发,在强度参数服从线性分布假定的基础上,推导了黏聚力折减系数和内摩擦角折减系数之间的数学关系;其次将此数学表达式引入到传统的Bishop条分法中,提出了非等比例双安全系数Bishop条分法;然后以强度参数对抗滑力的贡献为权重,提出了综合安全系数来评价边坡的稳定性;此方法不仅克服了传统双安全系数法确定双安全系数的盲目性,而且为双安全系数法应用于工程实践提供了新途径;最后结合算例通过与传统方法的计算结果进行对比分析,验证了该方法的合理性。

Failure of slope is progressive process. The shear strength parameters c、？ have different exerting extents during the destroy process, so the strength reserve is different. Thus, the determining of double safety factors based on the strength reserve and the slope stability evaluation based on double safety factors are worthy of investigation. On the basis of softening regularities of geo-material and assumption of linear distribution of strength parameters, the correlation between the reduction factor of cohesion and the reduction factor of inner friction angle is deduced in this article. Then the correlation is introduced into Bishop＇s slice method, the non-proportional double safety factors Bishop＇s slice method is developed. The slope stability can be evaluated with comprehensive safety factor based on weight of strength parameters contributing to the resistant shear force. This method not only overcomes the blindness of the existing double safety factors method to determine the double safety factors but also provides a new approach to applying the double safety factors method to engineering practice. Finally, the proposed and traditional methods are both applied in an example and the resemblance of their output validates the suggested method.