Designed and manufactured by China Railway Engineering Equipment Group CO., LTD. (hereinafter referred to as “CREG”), the Tunnel Boring Machine (TBM) CR-51 and CR-50 have successfully completed two 2.814 m long tunnels. CR-51&50’s breakthrough were celebrated during the morning of October 21^stand October 29, 2014 respectively at Parsar Seni Station part of the Klang Valley Mass Rapid Transit (KVMRT) Project - Kuala Lumpur, Malaysia. 

celebrating  CR51 TBM-Breakthrough in front of the cutter head
CR50 and CR51TBM-Breakthrough

The excavation diameter for the tunnel was 6670mm and the tunnel has been bored through Kenny Hill Formation which features residual soil with highly and moderately weathered rock as well as a short zone of quartzite with strengths up to 294Mpa. Tight radius curves and complicated surface conditions have been experienced along the route of the tunnel, with several sensitive high rise buildings in close proximity to the tunnel alignment posing a big challenge. In order to successfully overcome such challenges, the CREG EPB-TBM featured a specially designed cutter-head for mixed ground conditions, as well as a very powerful cutter-head drive, A-B (two component) liquid grouting system, active articulation and effective soil conditioning system.

CR-50 was officially launched at SEMANTAN North Portal on June 13, 2013 while another TBM CR-51 commencd the excavation one month later. The initial tunnel drive which were completed on December 24, 2013 and January 16, 2014 in success was to KL Sentral Station which had already been partially constructed, the TBM were then pushed through the station so as to continue the final drive to Pasar Seni Station. During boring of the 2^nd drive, challenges such as the passing under traffic sensitive flyover-bridges, the Kuala Lumpur Central Railway Station as well as the Klang River were overcome successfully.

Despite the described challenges, CR-50 achieved a daily progress record of 21 m and a monthly progress record of 345 m and CR-
51 a daily record of 21m also and 330m a month progress.

A very minimal ground-settlement has let project owner, contractor and building owners more than to be satisfied. The availability of the TBM was confirmed to have achieved an availability of 98% over the whole tunnel length.

The achievement of both TBMs have encouraged the TBM supplier CREG with its ambition to enlarge the TBM-business share in the overseas market. CREG will ambitiously continue with the company`s commitment to improving tunneling operation by making it faster and safer!