Construction of the First Cut-Off Wall by a Low Headroom Cutter inside a Dam Tunnel in China

In the South of Sichuan province a 240 MW Yeleh hydroelectric plant was under construction by Sichuan Nanya River Basin Hydraulic Power Development Company Limited, a stateowned enterprise, and China Gezhou Ba Water & Power Group Company Limited. This project sets out to develop the mountain cascade of the Nanya river, a tributary of the Dadu river, provide superior electricity and adjust flood peak & frequency. The specialist contractor Foundation Engineering Company of China Water Resource and Hydropower (FEC) was awarded the contract for foundation treatment at right bank, which included the construction of 75 m deep concrete Cut-Off Wall (COW) inside a 6.0m x 6.5m tunnel. The requirement for 19,317 m3 COW to be constructed in permeable and very dense gravel/cobble formations and a demanding project programme led FEC to adopt Bauer Low Headroom Cutter CBC25/MBC30 in conjunction with Overlap Cutter Joint (OCJ).

Keywords:

Dam , earth-fill dam , cut-off wall , trench cutter , low headroom cutter