Abstract
Water tightness of rock mass has been evaluated by the exceeding probability of Lugeon values. While constructing a darn, a curtain wall is often constructed to ensure the water tightness and the tightness is measured by the Lugeon values. This paper proposes a modeling of new Lugeon values distribution and evaluates the effectiveness of curtain wall from the exceeding probability of Lugeon values distribution proposed herein. The evaluation method described above is utilized to two target sites and successful results are obtained.
