在国王的十字架重建下

Authors: Lidija Špiranec & Steven Thurgood

国王十字架是英国伦敦最重要的重建项目之一。国王十字架周围的地区有67英亩的未使用土地，该土地于2008年被指定为开发。总体规划包括50座建筑物，1,900栋新房屋，20个新街道，26个新的公园和正方形以及26英亩的开放空间。

Renewal work for this major rail hub began in 2010. One of the key constraints of the project was the presence of four railway tunnels beneath the site, which were part of the main connections with King’s Cross Station. These connections are utilised by hundreds of thousands of commuters every day.

For the development project to proceed, it was necessary to build adjacent to and over the top of these tunnels. In conjunction with Network Rail, the asset owner, it was agreed this could take place, provided any movement of the tunnels and track was analysed and a real-time monitoring scheme installed. The monitoring scheme was required to confirm predicted movements, and measure any exceedances, so work could be stopped before any damage to the infrastructure occurred, minimising risks to travellers and trains.

由于项目的规模，其价值和影响，监视系统的要求是严格的：

Robust- 持续12年的合同持续时间
可扩展- 适应扩展
Accurate / Precise- to measure and report with confidence
Repeatable- 获得一致的观察
Automated- 在没有载人访问的环境中运行
Continuous- 24/7操作
无障碍- 对所有利益相关者

佩尔·弗里奇曼（Pell Frischmann）, one of the UK’s leading consulting engineering companies with almost 100 years of experience, accepted this monitoring challenge. Having used various Leica Geosystems’ instruments and equipment for over 30 years, the company knew thatLeica Geosystems’ monitoring solutions由于可靠性，技术卓越，备份和支持，这是正确的方法。因此，公司与SCCS Survey Equipment Ltd, part of Hexagon, the UK leading distributor of Leica Geosystems Surveying Equipment, to deliver the required monitoring system.

“ Leica Geosystems开发新产品的悠久历史，同时完全保持向后兼容性，确保可以在该项目的bob综合app下载延长期间使用最新设备扩展该系统。同时，Leica Geosystems的维护和支持网络意味着在整个项目生命周期内，所有购买的设备（无论其年龄如何）都可以使用备件和维修，” Pell Frischmann的资产管理总监Gary Weekes说。“ SCC在帮助指定合适的设备并协助设置系统方面的支持也是为项目选择Leica GeoSystems设备的关键驱动力。”

There were two independent monitoring systems installed at King’s Cross Station – the primary one was geodetic monitoring with automatic total stations (ATS) and the backup one was geotechnical monitoring, providing redundancy in measurements, delivering additional information and increasing certainty and reliability of results.

Tailored solution for London’s tunnels

The equipment used for the project consisted of following sensors:

Leica TM30/50监视总站提供了缩小测量激光束检测bob apple器灵敏度的能力，从而消除了这些长线性位点中相邻目标干扰的风险，这是Leica Geosystems仪器的独特能力。这使系统能够使用较少的总站配置，同时仍保持网络导轨所需的目标频率。bob apple监视仪器自动衡量：

• 3 d隧道displacement by measuring five prism arrays attached to the tunnel lining at 10m cross sections

• Rail geometry for cant, twist, gauge and alignment by measuring prism pairs attached to each rail of the track

外的隧道,一个permanent network of stable control points was measured to eliminate the movements of the total stations.

The wireless tilt nodes were installed on the tunnel lining adjacent to the crown prism and track bed/sleepers at 3m intervals to mirror rail prisms. The wireless tilt and distance nodes were located on the tunnel lining at each 10-m cross section to measure convergence and ovalisation of the tunnel.

Once everything was installed, a track geometry measuring device with scanner and its dedicated software was used to measure/verify the tunnels and ensure the monitoring equipment was clear of passing trains and kinematic envelope.

Data acquisition and processing of all geodetic and geotechnical measurements were facilitated using Leica Geosystems地球仪监视器. The software allowed for assigning priorities and control of observations, whereas the frequency of observations was remotely adjustable to match dynamic events. The computed results of prism measurements were further used for computation of virtual observation points for mathematically derived values, enabling complex calculations from a variety of data sources into a single computation model. Deformation movement limits, alarms and actions were defined with bespoke variables depending on activity and instrumentation. Data visualisation and reporting were seamlessly integrated using the cloud-based service from Leica GeosystemsGeoMoS Now!.

由于项目的复杂环境和长线性性质，两端仅稳定区域，总站数据需要对均匀模型的校正，而不是独立工作的每个单元。因此，在观察周期期间，使用Star*Net Software由Microsurvey Software Inc.进行了实时计算对照网络的完全集成和自动化的最小二平方调整，这是Hexagon的一部分。bob体育报道然后，在每个监视阵列观察之前，将对整个网络的实时网络调整坐标自动更新地球系统。

“The use of GeoMoS Now! enabled us to establish simple, clear dashboards for the project. At any time, there were multiple contractors onsite, who were only interested in individual sections of the monitoring scheme. GeoMoS Monitor allowed specific alert regimes to be established for each contractor, with individual dashboards developed in GeoMoS Now!, which were login specific to that contractor.“, explained Weekes.

克服监控挑战

There were several complex challenges that the Pell Frischmann team had to overcome during the monitoring period. In the Thameslink Tunnels, trains were passing at 50 mph every five minutes, causing vibration and air movement, affecting instrument orientation and level. The access to the tunnels was limited to two four-hour shifts every three months, so a permanent solution was found by installing GeoLaser AD-12 self-levelling tribrach to enable remote users to correct the total station back to the horizontal plane without requiring access. This was fully controlled via GeoMoS Monitor.

In the Gasworks Tunnels there was a different challenge to be overcome – an oily soot residue. The brickwork in the tunnels had thick layers of it built up over time from the years of steam and diesel trains operating in the tunnels. This caused constant residue built up throughout the monitoring period. Therefore, the total station optics and prisms needed to be cleaned every couple of months to maintain signal strength, as part of the active maintenance plan.

Over the life of the installation, the monitoring scheme operator with continued support from SCCS found innovative solutions to increase system reliability and reduce operational costs. This also included anti-corrosive fittings and prism covers which made them resistant to constant exposure to previously unknown environmental conditions discovered in the tunnel.

“The equipment delivered accurate and repeatable results 24/7 for extended periods of time without the need for manual intervention between the standard bi-monthly maintenance visits. This was particularly important in the Gasworks tunnels, where diesel residue and water leakage caused a particularly harsh working environment, in which the instrumentation had to operate faultlessly for 12 months between servicing,” said Weekes.

The reliability and accuracy of the equipment ensured that all work on the development near the tunnels could continue without any delays a decade later from 2010. This instilled confidence in the system from Network Rail and there has been no need to stop or slow trains, avoiding any financial penalties delays would have incurred.”

未来的防止监控数据

一旦国王十字架的再生完成，对隧道的监视将继续。该数据集的重要性在于记录隧道的自然运动和状况。这可能成为工程师确定隧道生命周期延长并计划预防性维护的重要资产。

“客户和所有利益相关者对系统及其性能都很满意。他们特别喜欢实时对数据的无限访问，这使他们能够检查任何次要的触发器，并看到趋势，而无需在系统上进行任何专业知识或培训。我们计划在公司的协作网络中分享对该产品的满意度，因此可以在各种项目中使用。”

“Pell Frischmann provides innovative solutions working closely with Leica Geosystems and wider Hexagon team. They have responded promptly to any issues, including out of hours and have saved the project from the costs of any delays to trains”, added Alastair Mitchell, project director of Kings Cross Partnership.