Abstract: The valley shrinkage deformation caused by reservoir impoundment has a direct influence on the safety of high arch dam structure.The safety state of arch dam under the condition of valley shrinkage deformation is evaluated with a high arch dam in southwest China as an example.First,the monitoring model of dam deformation is established to study the relation between dam deformation and valley shrinkage deformation.On this basis,an evaluation model is constructed for dam safety based on multi-source information fusion in consideration of valley shrinkage deformation indices;the Cloud Model and D-S Model are combined to evaluate the safety of the dam.The basic probability distribution of evaluation indices is determined according to the membership degree obtained by Cloud Model of monitoring data,which overcomes the disadvantage of strong subjectivity of traditional method;furthermore,the dam safety can be evaluated comprehensively in association with basic credibility of each monitoring index acquired from the D-S Model.Results suggest that the compression load caused by valley shrinkage deformation could be the main reason of dam deformation towards the upstream;the studied dam is in a basically normal state,which is consistent with the actual situation of the high arch dam.The results demonstrate that the membership degree obtained by Cloud Model is reasonable and feasible to determine the basic credibility allocation of evaluation indices.

Key words: arch dam, valley shrinkage deformation, Cloud Model, D-S Model, safety evaluation