Abstract

The paper presents the monitoring and corresponding monitoring data management that is currently executed at the Cityringen project in Copenhagen, Denmark. In particular, it informs on the layout of the implemented monitoring programs, the different geotechnical and geodetic monitoring sensors and measuring systems used, how the monitoring data is acquired, transferred and further processed and, finally, the layout of the installed tunnel information system applied for monitoring data management. Examples of monitoring data, their acquisition, processing, visualization, alarming and reporting are described along with the experience of managing a huge amount of monitoring data.

1 Project Overview

The new Cityringen is part of the metro system in Copenhagen, Denmark. The Project comprises the construction of 17 new stations, five other underground structures as well as a 16.5 km twin-tube tunnel. The Client Metroselskabet IS has awarded the contract in 2011 to the Italian joint venture CMT led by Salini-Impregilio. SMT Denmark, a company owned by Angermeier Ingenieure (Germany) and Geodata Group (Austria) is responsible for the implementation and maintenance of the geodetic and geotechnical monitoring. The stations and shafts are constructed using secant pile walls or, for the deepest structures, diaphragm walls. In the inner city, many buildings have been founded either on wooden piles or soft layers. In the western part of the project area, groundwater abstraction for domestic water supply is taking place. At a few sites, extensive groundwater contamination has been found. Therefore, minimum 95% of the abstracted groundwater has to be re-infiltrated. The groundwater control system in place is performed by pumping in abstraction wells at the bottom of the deep excavation, treating the abstracted groundwater and recharging all of the pumped groundwater in recharge wells surrounding the box. A comprehensive monitoring system has been established. The central part of the monitoring system is the state of the art monitoring database system (Kronos, provided by Geodata), where real time data from the tunnel boring machines, the groundwater management system and all data from geodetic and geotechnical monitoring of buildings and structures within the zone of influence of the works, is collected. In order to perform the monitoring of possible movements of the ground and structures a very extensive 3D monitoring system with more than 100 robotic total stations, along with extensometers, inclinometers and piezometers, and strain gauges have been installed.

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