考虑滑带土剪切强度空间变异性的滑坡危险性评价

Landslide risk assessment considering spatial variability of shear strength in slip zone

【目的】滑带土剪切强度控制着滑坡的变形演化和稳定性,滑坡危险性评价应考虑其不确定性的影响。当前滑坡危险性评价普遍采用随机场来模拟滑带土剪切强度的空间变异性,并没有纳入已知采样点数据,浪费了地质勘察工作。为了更加准确地评价滑坡的危险性,【方法】在Monte Carlo模拟的框架下,给出了滑坡危险性的概率评价方法以及详细的计算流程。该评价方法依据划分地土条形式,采用条件随机场模拟技术模拟滑带土剪切强度参数的空间变异性,并在每次Monte Carlo模拟时采用Morgenstern-Price条分法来计算滑坡安全系数。【结果】滑坡实例研究结果显示,随着滑带土剪切强度的相关距离增加,条件随机场与非条件随机场计算结果相差增大;传统采用随机场滑坡危险性评价会高估滑坡的破坏概率。【结论】实例研究证明了此方法的有效性,表明条件随机场能有效减小分析中的不确定性,从而更加真实地评价滑坡的危险性,为滑坡危险性评价提供理论指导和技术参考。

[Objective]The stability and deformation progression of a landslide are controlled by the shear strength of the slide zone,and the impact of uncertainty should be taken into account while assessing landslide risk.In landslide risk assessment,random field is now utilized to replicate the variability of shear strength of sliding zone soil.However,the data from sampling points is not included,which is a waste of geological exploration.[Methods]In this research,a probability assessment approach is provided within the context of Monte Carlo simulation in conjunction with a conditional random field.[Results]The outcomes of a case study on landslides show that the difference between conditional random field and unconditional random field increases as the correlation distance of the shear strength of the slide zone increases.The research findings also indicate that the traditional random field will overestimate the failure probability of the landslide.[Conclusion]The conditional random field may more accurately assess the danger of the landslide.The analysis of a landslide case study demonstrates the viability of this proposed approach,which provides a theoretical guidance and technical reference for landslide risk assessment.