隧道震害和地表变形相关性的实例分析

A case study of correlation between seismic damages of mountain tunnel and ground deformation

考察地震作用下的地表运动特征,是一种直接有效观测地震作用机制的方法.为此,结合2016年日本熊本地震俵山隧道震害案例,探讨地表变形运动与地下结构震害之间的相关性.基于高精度机载激光测量技术(LiDAR),获取地震前后俵山隧道周边地形的变形数据;建立隧道周边地形的数字高程模型.借助组合分类迭代最近点(CCICP)算法,得到俵山隧道周边地表变形特征.在此基础上,探讨隧道震害与周边地表变形特征的相关性.结果表明,强烈的地面运动能够在一定程度上反映地下结构震害的真实情况,如衬砌、路面和施工缝等各种结构的破坏;另一方面,地表变形运动方向在一定条件下(如排除地震断层等特定地质构造的影响等条件)反映地震波的传播方向,可用于验证地震波对俵山隧道的破坏机理.

The study of seismic deformation of ground is an effective and intuitive way to analyze the influence of earthquake.The Tawarayama tunnel subjected to the 2016 Kumamoto earthquake in Kumamoto City in Japan was taken as an example to investigate the correlation between the seismic deformation of ground and the seismic damages of underground structures.Data of the ground surface above the Tawarayama tunnel before and after the earthquake were collected by the technology of airborne light detection and ranging(LiDAR),and digital elevation models were obtained from the LiDAR data.Combination and Classification Iteratively Closest Point algorithm was introduced to detect the deformation field of the ground.Based on the detected results,spatial comparison of the ground deformation with the seismic damages of Tawarayama tunnel was analyzed to find their correlation.Results show that strong ground horizontal motion can reflect the damage conditions of underground structures to some extent(such as failure of tunnel lining,pavement,or construction joints)when subject to earthquake force.Moreover,the direction of the ground horizontal deformation can provide an insight into the propagation direction of the seismic wave,such as excluding the influence of some special geological conditions(e.g.,fault).The finding can also be used to verify the failure mechanism of Tawarayama tunnel by seismic wave.