Channel Tunnel Rail Link Contractors

Contract 310

The C310 civil engineering contractor was required to construct a large piled slab across the Rainham marshes to provide a structurally robust platform for the new high speed railway as well as other structures and earthworks. Southdowns was involved in the initial negotiations with the local authorities on, and the development of, Section 61 applications for the works and the provision of advice on monitoring protocols.

Other issues involved concerns over vibration induced damage as a result of vibratory and percussively driven piling activities. An empirically derived prediction model was developed to enable the prediction of vibration from vibratory driven sheet piles for both disturbance and damage purposes. Elsewhere both Transco and Thames Water required strict monitoring of vibration during the percussive driving of large diameter pre-cast concrete piles across the marshes. Southdowns undertook the measurements and were able to assess the risk of damage to the pipelines and direct the piling operations accordingly in real-time as each pile was inserted.

Contract 576

C576 was responsible for the main track and overhead catenary system (OCS) installation for Section 2 of the Channel Tunnel Rail Link running from Pepper Hill in North Kent to St Pancras Station in London.

C576 operations involved constructing and operating major temporary railheads and material transfer sites in potentially sensitive areas, to service the track and OCS installation works along the CTRL trace.

closely with C576 engineers, Southdowns developed detailed noise calculation procedures for construction activities and for assessing the movement of engineering trains along the trace during sensitive periods of the day and night. The models were used to optimise the contractors' construction methodologies and sequencing. Southdowns was responsible for generating construction noise and vibration management documentation for all the proposed works as well as developing the Section 61 consent applications. Noise and vibration monitoring was undertaken on this project.

Contract 588

C588 was responsible for the mechanical and electrical fit out for Section 2 of CTRL. This included the installation of in-tunnel ventilation equipment, ventilation shaft equipment, shaft headhouse structures, signalling rooms, control and communications rooms and various lineside works such as cable laying and the installation of signalling equipment.

The majority of the main C588 worksites were situated in predominantly high density residential areas with sensitive receivers in close proximity. Southdowns was responsible for developing Section 61 consent applications, advising on BPM measures including screening requirements and appropriate measures to remain within the Projects noise commitments. Southdowns also provided expert training for the contractor's staff on noise monitoring and assisted in the procurement of monitoring equipment on its behalf.

Contract 105

Contract 105 was responsible for the refurbishment of the St Pancras station concourse and undercroft areas, and also for the new extension to the station required to accommodate the Eurostar trains. Southdowns undertook Section 61 calculations during the main civils work stages.