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未来地震的发生具有一定的随机性,以研究区遭受一定超越概率水平地震动作用所开展的滑坡危险性区划,忽视了部分潜在发生的地震的影响,是一种条件概率下的危险性区划。基于概率地震危险性分析及Newmark累积位移评估模型,以滑坡概率为危险性指标,提出一种考虑潜在地震影响的概率性地震滑坡危险性区划新方法,并可对震源机制、场地类型及地形高度的影响进行修正。以天水研究区为例,采用第五代地震动参数区划图的潜在震源区划分方案,结合研究区工程地质岩性分组及地形高程数据,对研究区未来50 a内地震滑坡危险性进行区划,结果表明地震滑坡中、高危险区主要集中于黄土覆盖或泥岩出露且斜坡坡度大于30°的地区,其中又以渭河及其支流藉河、牛头河两岸部分地区的地震滑坡危险性较高,对天水市区周边及陇海铁路线构成威胁。
The occurrence of future earthquakes has a certain degree of randomness. It is a dangerous zoning under the conditional probability that the landslide hazard zoning delineated by some seismic activity beyond the probabilistic level of the study area ignores the impact of some potential earthquakes. Based on the probabilistic seismic hazard analysis and the Newmark cumulative displacement assessment model, a new method of zoning of the probabilistic seismic landslide risk considering the potential earthquake impact is proposed based on the landslide probability as a hazard index. Based on the focal mechanism, site types and topographical height The impact of the amendment. Taking the Tianshui study area as an example, the potential hypocenter zone division scheme of the fifth generation of ground motion parameter zoning map is adopted. Based on the engineering geologic lithology grouping and topographic elevation data of the study area, the landslide risk in the study area within the next 50 years is zoned, The results show that the high and middle risk areas in the earthquake landslide are mainly concentrated in areas where the loess cover or mudstone is exposed and the slope gradient is greater than 30 °. Among these, the Weihe River and its tributaries are inundated with landslides in parts of both sides of the Nintou River, Tianshui around the city and the Longhai Railway threaten.