应用激光扫描技术对深基坑施工过程形态监测与分析

The Laser Scanning Technique is used to Monitor and Analyze The Construction Process of Deep Foundation pit

针对海淀区某工程项目25 m深基坑、邻近三环主路、紧邻住宅区、多阶梯挖土等特点,采用三维激光扫描法对5 m、10 m、15 m、20 m、25 m时深基坑侧壁及桩位偏差和形态、垫层完成后筏形完成后进行变形监测。通过统计图表的方法,对深基坑开挖过程的变形进行了分析,从分析结果可知,利用三维激光扫描技术法对深基坑施工过程变形监测是行之有效的。此技术既保证了施工质量,又为工程结构施工提供了形态依据。三维激光扫描技术可以提供快速准确的基坑点云信息,它能够准确地捕捉基坑侧壁和桩位的细微差别,并且能够创建出三维模型来分析支护结构的变形情况。通过利用影像几何校正技术,可以从多期基坑分级图中提取出具有一致性和相似性的变化点,从而有效地计算出基坑施工过程中的形变量。

In view of the 25m deep foundation pit of a project in Haidian District,its proximity to the main road of the Third Ring Road,its proximity to residential areas and the multi-step excavation,three-dimensional laser scanning method was used to monitor the deformation of pit sidewall,pile position deviation and form,raft after cushion layer was completed at 5,10,15,20 and 25 meters.The deformation of deep foundation pit during excavation is analyzed by means of statistical chart.The result shows that it is effective to monitor the deformation of deep foundation pit during construction by means of 3D laser scanning technology.This technology not only ensures the construction quality,but also provides the morphological basis for the construction of engineering structures.3D laser scanning technology can provide fast and accurate information of pit point cloud,it can accurately capture the subtle differences between pit sidewall and pile position,and can create a 3D model to analyze the deformation of retaining structure.By using the image geometric correction technique,we can extract the consistent and similar change points from the multi-stage pit classification map,and effectively calculate the deformation in the process of pit construction.