Underneath King’s Cross redevelopment

作者：Lidijašpiranec和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栋建筑物，1,900栋新房屋，20个新街道，26个新公园和正方形以及26英亩的开放空间。

该主要铁路枢纽的更新工作始于2010年。该项目的主要限制之一是该地点下面有四个铁路隧道，这是与King Cross站的主要连接的一部分。这些连接每天被数十万通勤者使用。

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- 自信地衡量和报告
可重复- 获得一致的观察
自动化- 在没有载人访问的环境中运行
连续的- 24/7操作
无障碍——阿尔l stakeholders

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调查设备有限公司，六边形的一部分亚搏苹果app, 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亚搏彩票手机版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

该项目使用的设备包括以下传感器：

徕卡TM30/50监测总站提供亚博5分钟快三ed the ability to narrow the measuring laser beam detector sensitivity, eliminating the risk of interference from adjacent targets in these long linear sites, which is a unique ability of Leica Geosystems’ instrumentation. This enabled the system to be configured with fewer total stations while still maintaining the target frequency required by Network Rail. The monitoring instrumentation automatically measures:

• 3D隧道位移，通过测量五个横截面的五个棱镜阵列

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

Outside of the tunnels, a permanent network of stable control points was measured to eliminate the movements of the total stations.

无线倾斜节点安装在冠棱镜附近的隧道衬里上，并以3m的间隔轨道床/卧铺，以镜像铁路棱镜。无线倾斜和距离节点位于每个10米横截面的隧道衬里上，以测量隧道的收敛和卵形化。

安装了所有内容后，使用扫描仪及其专用软件的轨道几何测量设备用于测量/验证隧道，并确保监视设备清除过往的火车和运动式信封。

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 Geosystems现在！。

Due to the complex environment and long linear nature of the project with only stable areas at each end, the total station data required correction to a homogeneous model rather than each unit working independently. Thus, a fully-integrated and automated least square adjustment of the control network was computed real time during the observation cycles using Star*Net software by MicroSurvey Software Inc., part of Hexagon. The GeoMoS system was then automatically updated with live network adjustment coordinates for the entire network prior to each monitoring array observation.

“现在使用Geomos！使我们能够为该项目建立简单，清晰的仪表板。在任何时候，有多个承包商现场，他们只对监视计划的各个部分感兴趣。Geomos监视器允许为每个承包商建立特定的警报制度，现在在Geomos！中开发了单独的仪表板，该仪表板特定于该承包商。”，Weekes解释说。

克服监控挑战

佩尔·弗里施曼（Pell Frischmann）团队在监视期间必须克服一些复杂的挑战。在Thameslink隧道中，火车每五分钟以50 mph的速度通过，导致振动和空气运动，从而影响仪器的方向和水平。每三个月限制对隧道的访问限制为两个四个小时的班次，因此通过安装Geolaser AD-12自动拖动Tribrach找到了永久解决方案。这是通过Geomos Monitor完全控制的。

在Gasworks隧道中，要克服的挑战有所不同 - 一种油性烟灰残基。隧道中的砖砌层厚，从蒸汽和柴油火车在隧道中运行的几年开始。这导致在整个监测期间持续构建残留物。因此，作为主动维护计划的一部分，需要每隔几个月清洁每隔几个月的总站光学和棱镜才能保持信号强度。

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.

设备的可靠性和准确性确保了隧道附近开发的所有作品都可以在2010年以后的十年后继续进行。这种灌输了网络铁路对系统的信心，并且无需停止或慢速火车，避免避免任何经济罚款延误都将产生。”

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。

“The client and all stakeholders were very happy with the system and its performance. They particularly liked the real time unlimited access to the data, which enabled them to check any minor triggers and see trending without the need for any specialist knowledge or training on the system. We plan on sharing our level of satisfaction with this product within this collaborative network of companies, so it can be utilised on a wide range of projects,” concluded Weekes.

“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.