Study and Engineering Practice on Cracks Control Measures for Concrete Face Slab of High Cfrd

摘要

Being the face slabs of high concrete faced rockfill dams (CFRD) are under complex stress state, the slabs are relative vulnerable. And crack is easy to form on slab, which can influence durability and integrity, then weaken impermeable ability and safety of dam. The factors that contribute to the structural cracks, non-structural cracks and extruding cracks of concrete face-slab are analyzed in detail. The result shows that the structural crack is mainly due to differential settlement, the extruding crack in riverbed position is mainly caused by rockfill body over-settlement of dam beyond 150m high and the non-structural crack is mainly caused by temperature shrinkage and air shrinkage. Therefore, crack control of CFRD face slab should be regulated by the three means coming from structural design, construction control and concrete material. It is proved by the practices in Shuibuya CFRD that face slab cracks on CFRD beyond 200m high can be reduced effectually by the present technique means.