Scanning high-traffic roads unmanned

作者：Kiew Tian Lim

The Singapore Land Transport Authority’s (LTA) motto isWe Keep Your World Moving. The organisation had committed to it with the construction of Mass Rapid Transit (MRT) System – Thomson-East Coast Line (TEL), which enhances rail connectivity cutting across from North to South corridors of the city. The new MRT line will greatly enhance the accessibility to the Central Business District and Marina Bay area.

TEL的建设大大改善了通勤者的旅行时间，其中包括从伍德兰兹北站到垫脚的43公里地下隧道。在双三车道重型交通电路（SLE）下方的4.5公里的隧道（SLE）下方，监视至关重要，在承包商以确保会影响交通流量的情况下可忽略不计的道路变形或干扰。

The engineering firm Tritech Engineering & Testing (S) Pte Ltd was contracted to monitor the road surface with a fully automated monitoring system on a real-time basis. To provide this service, due to critical circumstances and high stringent monitoring requirement, Tritech initiated with Leica Geosystems’ monitoring solutions.

Laser scanning and total station in one

使用徕卡新星MS60 MultiStation plus Leica GeoMoS monitoring software v6 and later, Tritech was able to set up an Automatic Road Monitoring System (ARMS) covering a two-kilometres critical stretch of the SLE affected by drilling of the Tunnel Boring Machines (TBM) underneath. The essential laser scanning functionality of the Leica Geosystems MultiStation combined with reflectorless and prism measurements came to the rescue, as prisms installation on the road, which is prone to destruction by passing vehicles, was not an option for this project.

“With the MS60 MulitStation, we were able to setup the ARMS, enhancing productivity as an unmanned measuring system,”said Dr. Tor Yam Khoon, registered surveyor with Tritech Engineering & Testing (S) Pte. Ltd.“The system also serves as an effective measuring system delivering the results wirelessly soon after the completion of a measurement epoch.”

The automatic scanning ability of the system enabled quick delivery of deformation information. With GeoMoS image-assisted scan area definition feature, the firm was able to add the defined areas to the measurement cycle. For the firm, this combined solution helped enhance:

• 准确性和可靠性；
• Quick interpretation of monitoring data; and
• Correct remedial decision making.

“Leica Nova MS60 is a good hybrid of total station and laser scanner useful in deformation monitoring of points using glass prisms and surfaces using new Leica GeoMoS n.Vec Technology. In this project of road surface monitoring, successful application of the n.Vec Technology to horizontal surfaces is well demonstrated,”托尔博士说。“It is definitely better to derive the vector of deformation from a scan patch of at least 500 readings rather than from a single reflectorless reading.”

在Tritech的专有自动化的结构化监控系统中，整理了该项目中使用的八个多阶段​​的数据。自动监测系统，具有四个小时周期的测量，每周7天的多阶段和地奇异的能力转化为减轻人工成本的主要成本。

Data was collected from MultiStations set up at the road shoulder on a 4-m-high observation platform at the middle of four rows of patches of road surface at 25 m apart. These four scan patches were defined in rows crossing the road over the white lane markings. These 16 regular scan patches are monitored at regular intervals. Between each 25-m regular monitoring zone there were also defined with “standby” scan patches at 5 m apart. These standby scan patches will be added to the monitoring scheme for automatic monitoring cycles whenever there is a planned or unplanned cutter head intervention. While the above MultiStation is in active monitoring, another one will be setup ahead and ready to go when the TBM enters its monitoring zone.

Support from abroad

For such a precise setup, there were initial challenges. Leica Geosystems staff in Singapore worked diligently with support staff in Switzerland to quickly diagnose the setup issues and effectively resolve them.

“当需要在监测活动中改变多个阶级时，由于Leica Geosystems技术支持的及时有效响应，该项目不会对该项目产生不利影响，”托尔博士说。

Monitoring solutions by Leica Geosystems support LTA to fulfill its promise and keep the world moving wherever heavy construction projects are underway.