The Contribution of Computer Systems to the Management of Geotechnical and Construction Risk on the Klang Valley MRT SBK Line Underground Works
Dr. Angus Maxwell, Maxwell Geosystems SDN BHD S. Vasagavijayan, MMC Gamuda KVMRT SDN BHD S. Satkunaseelan, MMC Gamuda KVMRT SDN BHD
Abstract:
The recommendation of the joint code of practice for tunnel works promulgated by the International Tunnelling Societies and Insurers requires that active risk management form an integral part of every tunnel project. Tunnelling hazards and risks should be constantly viewed during the course of a project with effective systems put in place to do so. These systems should ensure effective communication of risk mitigation actions. Where the response values are reached or abnormal response is observed, then the pre-defined contingency or remedial action needs to be taken in a timely manner.
Geotechnical risk management process should not be isolated from other project activities. The communication of risk information and consultation with the project participants are two-way processes that should be proactively undertaken and should continue throughout the duration of the project. Projects are embracing this approach but are finding in practice that that this is somewhat harder to achieve due in part to geographical and functional separation of teams, short time span and the sheer volume of information to be processed.
This paper demonstrates how intelligent flexible computer systems were used to assist this process on the highly sensitive Klang Valley Metro in Kuala Lumpur.
Keywords
Data system, risk, tunnel, best tunnelling process control
1. Introduction
The underground portion of the Klang Valley Metro in Kuala Lumpur extends from North Semantan Portal to South Maluri Portal. The tunnels start in the meta-sediments of the Kenny Hill formation and transitions into the karstic Kuala Lumpur Limestone in front of Pavillion in Bukit Bintang. Compared with the SMART tunnel the KVMRT tunnels are much deeper. The tunnels have either a stacked or parallel configuration with cover of about 20m and 30m respectively Both slurry and earth pressure balance TBMs have been used with slurry preferred in the limestone and EPBM in the Kenny Hill.
2.1 Organisation
The project owner MRT Corporation of Malaysia awarded the USD 3.27 Billion contract to MMC-Gamuda KVMRT-T SDN BHD in April 2012 on a design and build basis. Whilst the main works were contractors design, the owner’s engineer had specified strict control criteria for the works and procedures to be followed should tolerance levels be exceeded. The Gamuda technical organisation comprised divisions looking after geotechnical works, design planning and programming and production. Instrumentation contracts were let under Gamuda and looked after by the geotechnical team which also implemented the IDMS system.
2.2 Key Drivers
IDMS systems had been successfully implemented on the SMART tunnel and in view the heavy levels of instrumentation a similar approach was considered imperative and thus the services of the Maxwell GeoSystems’ MissionOS system were procured to draw in both manual and automatic real time data and communicate changes in the data to the various project teams.
2.2.1 Data Volumes
As of the 2014 some 9500 instruments have been logged and of these almost 1200 instruments are real time resulting in 15 million records of data amounting to 100GB of data. Such a volume would be impossible to manage without IDMS especially as the protection of surrounding infrastructure is one of the key factors.
2.2.2 Feedback
At the inception of the project the planning and production team considered the need for proper feedback of ground and groundwater movement data to the designers and tunnel and station managers so that the effect of ground conditions on tunneling processes and station box excavations be better understood. For this to be effective audited data had to be presented to the user quickly. It was also hoped that the IDMS would become a back bone to the risk management process.
2.2.3 Timeliness
During the tunneling works the TBMs could advance as much as ten rings in a day therefore it was vitally important that data could be delivered to the IDMS within one day of being recorded. This too was crucial during the station box excavation. Uploading processes in the IDMS were automated and data could be filtered processed review, audited and published within one hour of receipt.
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