Measuring construction and post-construction deformations of mechanically-stabilized earth walls using terrestrial laser scanning

TREK Geotechnical Inc.是一家位于马尼托巴省温尼伯的岩土工程咨询公司，专门从事基础和土方结构的设计。他们目前的项目是萨斯喀彻温省萨斯卡通的mccommand - college Drive交汇处，使用机械稳定土（MSE）挡土墙作为桥台。MSE墙具有成本效益和技术效率，因为它可以在最小的结构破坏下处理大变形。但是，变形应在可容忍的范围内，并应在墙体施工期间和施工后进行监测。常用的监测方法，如沉降板和全站仪，不测量整个墙，只在几个离散点。在未被调查的地点可能发生多少移动是不确定的。本研究将评估地面激光扫描（TLS）在测量这些MSE壁中的适用性。TLS是一种非破坏性的方法，可以在一小时内完成整个墙壁的扫描，而无需在现场进行永久设置。扫描将在施工完成期间和之后进行。扫描数据将被分析，以确定墙体首次安装时的水平和垂直运动。这些数据将与从沉降盘和现场测量的全站仪收集的数据进行比较。将开发一个数值模型来预测MSE壁的变形。数值模型的校准和激光扫描仪数据的充分性可以帮助MSE墙和其他岩土基础设施的未来设计、施工和维护操作。随着结构监测效率的提高和对土体沉降行为的了解，本研究将有助于设计师和承包商减少工期延误的财务风险、设计的保守性以及结构变形超容限的安全风险。

TREK Geotechnical Inc. is a geotechnical consulting firm in Winnipeg, Manitoba that specializes in the design of foundations and earth structures. Their current project, the McOrmand-College Drive Interchange in Saskatoon, Saskatchewan uses Mechanically-Stabilized-Earth (MSE) retaining walls for abutments. MSE walls are cost-effective and technically-efficient because it can handle large deformations with minimal structural distress. However, deformations should be within tolerable limits and should be monitored during and after construction of the walls. Common monitoring practices, like settlement plates and total station, do not survey the entire wall, only at few discrete points. There is uncertainty about how much movements in the non-surveyed locations can occur.This research will assess the applicability of Terrestrial Laser Scanning (TLS) in surveying these MSE walls. The TLS is a non-destructive method that can complete its scanning of the entire wall in an hour's time without the need for permanent setup at site. Scanning will be done during and after construction is completed. The data from the scans will be analyzed to determine the horizontal and vertical movements from when the wall was first installed. This data will be compared to data collected from the settlement plates and total station that are surveyed at site. A numerical model will be developed to predict deformations of MSE walls. Calibration of the numerical model and laser scanner data adequacy can aid in future design, construction, and maintenance operations of MSE walls and other geotechnical infrastructure. With the increased efficiency of structure monitoring and knowledge of soil settlement behaviour, this research will help designers and contractors in reducing financial risks of schedule delays, conservatism in design, and safety risks of structure deformation exceeding tolerance limits.