Urban tunnel projects, like the Cityringen or Crossrail in London, are related with special geotechnical risks. Most typically they are caused by poor geological conditions, very low overburden and existing structures in the influence zone of the construction. To manage these risks, an early detection and warning of unexpected behaviour of the affected geotechnical objects (ground, structures like tunnel and buildings) is mandatory. To accomplish this detection and warning, the design and execution of a suitable geotechnical monitoring program is necessary. This can only be achieved by implementing a monitoring database system capable of collecting monitoring results according to the monitoring program from different sources in near real time and to use the data after importing to the database to check different alarm levels and the monitoring frequency. In more detail, this means specifying and performing a systematic and continuous acquisition, processing and analysis of monitoring data and information.
In order to handle this huge amount of data, tunnel information systems and geo-databases have been developed and already installed and run on various projects. In contrast to most of these systems, the KRONOS system developed by GEODATA has the capability to connect to the different theme-specific databases used by subcontractors and, thus, to serve as a central data management system through which can be accessed any kind of digital data produced in the tunnel project. This makes possible the implementation of further useful functions and services supporting tunnelling tasks such as machine control, tunnel simulation, geological prediction, process optimization, etc. where data from different engineering disciplines must be combined and processed in an integrated way.
We run one integrated database system which is the single source of truth for all monitoring data.
The KRONOS system has been successfully up and running since 2007 on several major infrastructure projects like metro Thessaloniki, Cityringen Copenhagen and Crossrail Farringdon Station and has delivered reliable results to the Client and the Contractor.
KRONOS major benefits
KRONOS has provided several major benefits to the Contractors and the Clients. KRONOS provides functionalities to check if all monitoring works are carried out in compliance with the monitoring design by setting monitor plans for the different construction activities.
The monitor plans are working with monitor point groups. A monitor group can consist of the monitor points inside the zone of influence for example.
Dynamic Zone of Influence
KRONOS is adjusting the monitor point groups according to the construction progress of a TBM, where the zone of influence is following the progress of the TBM. You know exactly which monitor points have to be measured and this allows an effective and economic planning of resources.
KRONOS has implemented filters and routines to verify the monitoring results and to avoid false alarm generation. Reliable early warnings through KRONOS have already helped so for example in adjusting the low pressure grouting of micro piles and to control dewatering activities.
Results fully traceable
In KRONOS database not only the values of the monitor points are stored, also the raw data, calculation protocols and quality data from automatic monitoring systems are stored and linked to the results and every result can be reproduced.