基于多样本容量近景摄影测量的基坑稳定性评价  

Evaluation for the foundation pit stability based on the multi-sample capacity close-range photogrammetry

作　　者：何乐平[1] 钟林[1] 胡启军[1] 梅健 蔡其杰 谭杰 HE Le-ping;ZHONG Lin;HU Qi-jun;MEI Jian;CAI Qi-jie;TAN Jie(School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu 610500,China;Liangshan Statc Transportation Emergency Command Center,Xichang 615000,Sichuan,China;School of Transportation and Logistics,Southwest Jiatonug Universily,Chengdu 611756,China)

机构地区：[1]西南石油大学土木工程与测绘学院,成都610500 [2]凉山州交通运输应急指挥中心,四川西昌615000 [3]西南交通大学交通运输与物流学院,成都611756

出　　处：《安全与环境学报》2020年第6期2180-2186,共7页Journal of Safety and Environment

基　　金：国家自然科学基金项目(51574201);四川省杰出青年项目(2019JDJQ0037);四川省教育厅科研创新团队项目(8TD0014)。

摘　　要：基坑变形监测对评价基坑稳定性具有重要意义。针对基坑监测过程中控制点与监测点难以在同一测区内构像的问题,首先,通过分析图片数量、光照强度、棋盘格尺寸3个外界影响因素确定靶标视场范围影响下的相机标定结果的可靠性;然后,通过非量测数码相机采集多测区基坑图像,运用灰度矩亚像素边缘定位算法,对得到照片标志点像点坐标进行亚像素级定位;最后,通过3种近景摄影测量解析方法对基坑多测区坐标的解算实现基坑的多样本容量变形监测。结果表明:当靶标所占像幅比例介于0.2~0.8时,标定结果更可靠;直接线性变换算法(DLT)实现多样本容量(多测点、多测区)基坑变形监测的精度更高;通过测量精度试验及工程实例验证了该方法的可行性与合理性。Aiming at the problem that the control point and the monitoring point are difficult to form in the same measurement area during the monitoring process of the foundation pit,the basis of the influence of the 3 external influential factors of the picture’s number,the light intensity and checker board size on the calibration accuracy of the camera has to be analyzed through the room-in experiments,so as to determine the optimal field of the target view.For the sub-pixel edge positioning problem of the top corner landmarks has to be solved based on the digital image processing technology and that of the sub-pixel positioning.Moreover,the sub-pixel image point coordinates of the landmarks have to be determined and solved through the straight line fitting so as to find the intersections,so as for the DLT algorithm to be dealt with and solved by using the rear-front intersection method,the relative orientation and absolute orientation method.What is more,since the control point and the monitoring point are not lying in the same measuring areas during the monitoring process of the foundation pit,it would be necessary for us to realize the multi-sample volume deformation monitoring by the virtue of the feasibility and rationality of the digital close-range photogrammetry application to the foundation pit through the measuring accuracy analysis tests and the on-the-spot authentic tests.Thus,starting from such a stand point,the research results can prove that the calibration results turns to be more reliable on the condition if the number of the target image is greater than 20,whereas the accuracy of the calibration results can be effectively improved with its uniformly high light intensity.In addition,when the ratio of the target’s image frame is between 0.2-0.8,the calibration results can be made more reliable.Besides,in the process of measuring the coordinates of the landmark points,the contour marks of the corners instead of the square marks of the corners can be made much more convenient for the Hough transform so

关 键 词：安全工程 建筑施工安全 基坑 多样本容量 近景摄影测量 变形监测 

分 类 号：X947[环境科学与工程—安全科学]