地震滑坡灾害下输电杆塔灾损评估研究

Research on Transmission Tower Damage Assessment Caused by Earthquake and Landslide

为快速评估地震与滑坡灾害对输电杆塔的损毁作用,辅助风险防控措施制定与应急指挥人员决策,研究输电杆塔在地震与滑坡灾害中的损失概率模型。使用蒙特卡洛方法模拟地震震级与震源点坐标,结合峰值地面加速度与脆弱性曲线构建输电杆塔震损概率模型。基于Newmark理论与材料力学原理,构建地震诱发滑坡概率模型及杆塔滑坡冲击损毁概率模型。对我国西南部某区域输电杆塔进行地震与滑坡灾损分析,得到研究区域内各输电杆塔震损概率及滑坡冲击损毁概率。研究结果表明,输电杆塔损毁概率随震级的增大而增大,震级相同时输电杆塔损毁概率主要取决于震中距。滑坡体高度及杆塔与坡脚距离是影响杆塔损毁概率的主要因素,较高处的滑坡体下落时将重力势能转化为动能,进而冲击作用于杆塔,而较小的杆塔与坡脚距离将导致摩擦损耗较小。对于损毁概率较高的杆塔,应采取避让、迁移等措施,降低滑坡灾害的影响。

In order to evaluate the damage effect of earthquake and landslide disasters on transmission towers,assisting in the formulation of risk prevention and control measures and the decision-making of emergency commanders,this paper studies the loss probability model of transmission towers in earthquake and landslide disasters.The Monte Carlo method is used to simulate the earthquake magnitude and focal point coordinates,and combined with the peak ground acceleration(PGA)and vulnerability curve,the seismic loss probability model of transmission tower is constructed;Based on Newmark theory and the principle of material mechanics,the probability model of earthquake induced landslide and the impact damage probability model of tower landslide are constructed.The earthquake and landslide disaster damage analysis of transmission towers in a region in Southwest China is carried out,and the earthquake damage probability and landslide impact damage probability of transmission towers in the study area are obtained.The results show that the damage probability of transmission tower increases obviously with the increase of earthquake magnitude,and the damage probability of transmission tower mainly depends on the epicenter distance.The height of the landslide mass and the distance between the tower and the slope toe are the main factors affecting the damage probability of the tower.The falling of the landslide mass at a higher height will convert the greater gravitational potential energy into kinetic energy and then impact the tower,while the shorter distance between the tower and the slope toe will also lead to less friction loss.For the towers with high damage probability,effective planning such as avoidance and relocation should be adopted to reduce the impact of landslide disaster on the transmission grid.