Quality and Risk Management Considerations for Very Shallow Soft Ground Conventional Tunnelling in Urban Settings

Synopsis:

The construction of shallow mined tunnels in urban settings is frequently undertaken by use of conventional tunneling methods.  In soft ground under shallow cover the construction techniques rely largely on the use of pre-support measures and ground improvement to limit the deformations of affected facilities and underground utilities to a permissible level.  Initial location and assessment of all underground structures and conditions is vital in designing the tunnel and evaluating excavation methods.

This is of particular importance when pre-support consists of long, drilled steel pipes that could potentially damage underground utilities.  A key element of risk management in urban tunneling is ground stabilization and with it minimizing the impact of the excavation and construction activities on adjacent infrastructure. Another key element of risk mitigation is assembling a skilled and experienced tunneling crew that will be able to execute the project meticulously according to design and effectively manage any unanticipated events.  A detailed approach to the project from design to execution is key in obtaining owner, third party, and insurer’s approvals.

2011 World Tunnel Congress and 37th ITA General Assembly Proceedings
World Tunnel Congress 2011
May 20-25, 2011
Helsinki, Finland