Analysis And Treatment Of Cracking Along Water Current Direction On The Double-hole Water-conveyance Tunnel In Ship Lock Of Three-Gorge Project

The concrete lining of water-conveyance tunnel of ship lock in Three-Gorge Project was cracked in the direction of water current during construction and regulation. In the paper, the cause and harmfulness of the cracks are discussed in detail by RCFEM and the crack investigation. Through analysis of the crack investigation data, check of the reinforcement arrangement, and numerical analysis of stress and cracks of the structure during normal operation, construction, regulation under thermal effect and water pressure, following conclusions are derived.1 .The reinforcement arrangement design of the structure meets the needs of the Design Code for Hydraulic Concrete Structure.2.Only concrete cover of the structure would be cracked under the design water level.3. There are two main factors causing concrete cracking, a) the thermal stress is bigger than the expecting value during construction; b) the water filled regulation was carried on in winter and the displacement difference between the structure and rock was produced by air temperature drop, and it enlarges the stress of structure under water pressure.4.The resistance capability of the structure is not harmed when it is cracked.5.The cracks should be grouted and sealed for seepage prevention.