摘要:
传统光学及雷达遥感技术在地震灾害损失评估中无法获取建筑物立面破坏信息,对结构已遭破坏,但顶面基本完好的建筑物识别能力较差.三维激光扫描技术(terrestrial laser scanning,TLS)可以获取建筑物结构破坏状况的高精度三维信息.利用2013年10月23日RIEGL VZ-1000三维激光扫描仪采集到的汶川地震震后彭州市白鹿中学的精细点云数据,通过不规则三角网建模和纹理贴图等处理进行三维建模分析,在此基础上对建筑物的典型破坏特征及地表破裂情况进行了详细建模研究,真实再现了白鹿中学破坏场景,实现了震害信息的永久保存.研究结果表明:位于断层上盘的勤学楼整体无明显破损;位于下盘的求知楼损毁相对严重,普遍出现“X”形的共轭剪切裂缝、构造柱断裂及露筋等现象;地震陡坎沉降量不大,高程剖面显示现今该陡坎最低高度为205 cm,最高为231 cm,与GPS测量结果大致吻合.
Abstract:
Traditional optical and Radar remote sensing technology fails to acquire the building facade damage in the case of earthquake damage assessment.The capability of identifying the buildings whose structure has been destroyed and whose roof top is basically complete is poor.This reduces the assessment accuracy.However,terrestrial laser scanning could acquire the high precision 3D information of the damaged structure.Using RIEGL VZ-1000 laser scanner,the authors collected laser point clouds data of Bailu middle school on October 23,2013.The point clouds were used to conduct 3 D modeling and analysis through triangular irregular network modeling and texture mapping.On such a basis,a detailed modeling study was carried out on the typical architectural damage characteristics and surface rupture destruction.The authors achieved damaged buildings surface observation at any angle and quantitative measurement of the sudace rupture through point clouds 3D modeling.The results truly reproduced the current scene of Bailu middle school after earthquake and permanently preserved the damage information.The results showed that the Qinxue building located on the hanging wall had no significant damage,whereas the Qiuzhi building located on the heading wall was seriously damaged."X"-shaped conjugate shear fracture,structural column fracture,rebar exposure and other phenomena were widespread.The earthquake scarp settlement was small and the scarp elevation profile showed that the minimum and maximum height was 205cm and 231 cm respectively.This was consistent with the GPS measurements.
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