ABSTRACT
This paper describes the decision-making process and implementation of a value engineering alternative that allowed a shallow launch of TBM on Route2020 Metro program in Dubai. This replaces a 300m long cut and cover tunnel included in the reference design. The TBM launch was originally targeted at the end of the cut and cover tunnel with 12m cover to the tunnel alignment. After award of the construction works, the client, contractor and designer investigated a value engineering alternative to launch the TBM from the open cut section, hence, replacing the cut and cover tunnel with a bored tunnel. The intent of the shallow launch was to de-risk the challenging construction program by reducing the construction works required prior to TBM delivery. Ultimately, the TBM was successfully launched with only 2.0m of cover. The paper will present an outline on the risk management, engineered mitigation measures together with a review of performance during construction.
