基于激光点云的预制混凝土箱梁外观尺寸检测方法研究  

Research on Appearance and Dimension Detection Method Based on Laser Point Clouds for Precast Concrete Box Girder

作　　者：吴文清[1] 王新雅 刘泓佚 周小燚 WU Wenqing;WANG Xinya;LIU Hongyi;ZHOU Xiaoyi(School of Transportation,Southeast University,Nanjing 211189,China)

机构地区：[1]东南大学交通学院,江苏南京211189

出　　处：《桥梁建设》2023年第4期25-32,共8页Bridge Construction

基　　金：国家自然科学基金项目(52278149);江苏省重点研发计划项目(BE2018120)。

摘　　要：为精确评估复杂施工环境下具有弯扭变形的预制混凝土箱梁的外观尺寸制作精度,基于三维激光点云提出预制混凝土箱梁的外观尺寸和整体变形全流程检测方法。该方法针对扫描点云的非均匀性,提出了点云混合压缩算法,较好地保护了曲率特征和低密度区点云。通过点云边界识别、点云面域分割提取特征线和特征面;对实际扫描中点云缺失面进行填充;采用切片投影法提取构件局部断面点云以进行尺寸计算。以某单跨高架桥8片预制混凝土箱梁为检测对象,针对7个典型尺寸检测项目,计算分析了其点云计算值和现场测量值的绝对差值,依据《公路工程质量检验评定标准第一册土建工程》(JTG F80/1—2017)评估了箱梁整体尺寸的制作精度,运用统计学方法评估整体变形形态。结果表明:箱梁7个尺寸检测项目共132组对比数据中80.3%的绝对差值保持在10 mm以内,验证了本文点云特征提取及尺寸计算方法具有较高精度;箱梁整体尺寸制作质量基本合格;箱梁上拱线形更接近三次多项式曲线,腹板相对扭转角保持在2°以内,表明箱梁并未产生过大的扭转变形。A method based on 3D laser point clouds to detect appearance and integral deformation process of precast concrete box girders is presented,aiming to accurately evaluate the appearance,dimension and fabrication quality of precast concrete box girders that are of likelihood to undergo bending and torsional deformation in complicated construction environment.To address the non-uniformity of scanning point clouds,a hybrid point cloud compression algorithm is proposed,to effectively protect the curvature property and point clouds in low density area.Feature lines and feature surfaces are extracted via point cloud boundary identification and plane area segmentation,respectively.The missing points in planes of actual scanning points are filled and repaired.The slice projection method is applied to extract point clouds on local cross-sections.The method was used to detect dimensions of 8 precast concrete box girders in a one-span viaduct,and the absolute differences between calculated values from point clouds and the field measured values of 7 typical detection items were computed to evaluate the integral fabrication quality and deformation.The integral fabrication accuracy and deformation behavior of the box girder were assessed in accordance with the Inspection and Evaluation Quality Standards for Highway Engineering(JTG F80/1-2017)and using statistical methods,respectively.The results show that 80.3%of the absolute differences in 132 sets of comparative data for the 7 detection items of box girders were within 10 mm,proving the high accuracy of the point clouds feature extraction algorithm and dimension calculation method proposed in this paper.The integral fabrication dimension of box girders basically meets the quality requirements,the camber of the box girder is closer to a 3.0 power parabola,and the relative twist angle of the web is kept within 2°,indicating that no excessive torsional deformation of box girders was observed.

关 键 词：预制混凝土箱梁 外观尺寸 整体变形 三维激光扫描点云 点云混合压缩 现场测量 

分 类 号：U448.213[建筑科学—桥梁与隧道工程] U446[交通运输工程—道路与铁道工程]