基于时空概率的公路崩塌灾害危险性评价

Hazard Assessment of Highway Rockfall Based on Spatial and Temporal Probability

崩塌灾害是山区公路主要的地质灾害风险源,崩塌灾害危险性评价是地质灾害防控与治理规划的重要依据。以318国道湖北谋道-重庆龙驹段为研究区,综合考虑公路崩塌灾害发生的空间、时间概率以及崩塌灾害作用强度,开展研究区公路崩塌灾害危险性定量评价研究。在资料收集、现场调查和数据统计分析的基础上,首先采用信息量模型对原始地形条件下研究区公路原生崩塌灾害的易发性进行分区;然后,考虑公路开挖工程的影响,针对公路切坡路段采用岩性组合、优势节理组合、节理密度以及地表汇流累积量等关键因素,对研究区切坡单元的崩塌灾害易发性进行评价,并对初步的公路崩塌灾害易发性评价结果进行修正;最后,综合考虑不同重现期下公路崩塌灾害的时间概率、崩塌灾害规模超越概率以及高易发区潜在崩塌源对于临近公路的到达概率,对研究区公路崩塌灾害危险性进行定量化求解,得到不同重现期下研究区主要道路沿线崩塌灾害的危险性空间分布。该研究结果可为该区段崩塌灾害的风险控制与管理提供科学依据。

Rockfall is a significant risk source of geo-hazard in mountain highway.Hazard assessment of rockfall is an important support for hazard prevention and risk control.Taking the section from Hubei Moudao to Chongqing Longju of National Highway 318 as the study area,based on the spatial and temporal probabilities and impact intensity of the rockfall,a quantitative assessment study on the highway rockfall is conducted in this paper.Based on data collection,field investigation and statistical analysis,the Information Model is used to carry out the susceptibility of protosomatic rockfall with the original topography.Then,considering the influence of highway excavation,the causal factors,including lithology,dominant joint com-bination,joint density and surface flow accumulation,are applied to evaluate the rockfall susceptibility of the cutting-slope units,which is used to revise the preliminary susceptibility map of highway rookfall.Fi-nally,considering the temporal probability in different return periods,the volume exceeding probability,and the arrival probability to adjacent highways of potential rockfalls in high-prone areas,the rockfall hazard is quantitatively estimated in the study area.The spatial distribution of rockfall hazard under different return periods along the major highways are obtained.The hazard maps can provide scientific support for the risk control and management of highway rockfall in the study area.