基于拟静力法的不同地震工况斜坡单元危险性评价方法研究

RISK ASSESSMENT METHOD OF SLOPE UNIT IN GENERAL SURVEY AREAS OF DIFFERENT SEISMIC CONDITIONS BASED ON QUASI-STATIC METHOD

地震造成斜坡失稳是其引起的最为显著的次生灾害,在小震频发,大震多发的现实背景下,开展不同等级地震作用条件下斜坡危险性评价对区域防灾减灾、地质灾害风险管控及国土空间规划的现实意义日渐凸显。基于拟静力法,根据斜坡所处场地类别和不同超越概率水平地震作用,对其地震动峰值加速度进行调整,确定斜坡不同等级地震作用下的综合水平地震系数,计算不同等级地震作用引起的作用于斜坡重心处的水平和竖向惯性力,以极限平衡法为理论基础,计算不同等级地震作用下斜坡稳定性系数,结合危险性指数法,计算不同等级地震作用下斜坡失稳概率和危险性指数,据此对斜坡不同等级地震作用下的危险性进行划分。结果表明斜坡稳定性系数随地震作用的增强逐渐减小,斜坡失稳概率随地震作用的增强逐渐增大,斜坡危险性指数随地震作用的增强逐渐增大,斜坡危险性亦随地震作用的增强逐渐增大。

The slope instability caused by earthquakes is the most significant secondary disaster caused by earthquakes.Under the realistic background of frequent small earthquakes and frequent large earthquakes,the practical significance of slope risk assessment under different earthquake action conditions for regional disaster prevention and mitigation,geological disaster risk control and territorial space planning has become increasingly prominent.Based on the pseudo-static method,according to the slope site category and exceeding probability of different seismic action,to adjust the peak ground motion acceleration,determination of slope under seismic action of different levels,a comprehensive coefficient of horizontal seismic calculation of different level earthquake effect caused by the horizontal and vertical inertial force ACTS on the slope of center of gravity,based on the theory of limit equilibrium method,The slope stability coefficient under the action of earthquake of different grades was calculated,and the slope instability probability and risk index under the action of earthquake of different grades were calculated based on the risk index method.The results show that the slope stability coefficient decreases with the increase of earthquake,the slope instability probability increases with the increase of earthquake,the slope risk index increases with the increase of earthquake,and the slope risk increases with the increase of earthquake.