Abstract：Shuibuya concrete faced rock-fill dam(CFRD) with a height of 233 m on Qingjiang River is the highest CFRD in the world at present. The foundation rock under toe-slab has complicated lithological condition，and the rock masses are soft layers alternating with hard layers. It is worth to study that how to establish the utilizable and acceptable criteria of foundation rock with consideration of economy and engineering safety. In the past，the weathering degree or sonic wave velocity of rock mass was often used as the acceptance criterion for the utilization and caving of the rock foundation of hydraulic structure；but these criteria cann¢t reflect the comprehensive characteristics of rock masses，such as the compressive strength，deformation properties and anti-permeability of rock mass. The engineering classification of rock masses is used for evaluating the quality of foundation rock under toe-slab；and the corresponding criteria of rock utilization and acceptance are established，which are applied to the acceptance of foundation rock under toe-slab. The quality of foundation rock under toe-slab is evaluated and divided by using elastic wave and compression tests in laboratory；and the distribution of rock masses with poor quality is pointed out，which can be remedied timely during construction process.
