Abstract:The advantages and disadvantages of single-line method and double-line method for determining wetting deformation of coarse-grained materials are analyzed. The idea of combining single-line method test with double-line method to solve wetting deformation problem is presented. The wetting deformation tests of coarse- grained materials are carried out on the single-line method and double-line method by use of large triaxial test apparatus. Some laws of the test results between the single-line method and the double-line method are found by studying the wetting deformation characteristics. The test results by other scholars also verify these laws. The mechanism of these laws is discussed. Based on these laws,an improvement analysis method for determining wetting deformation is presented. Finally using improvement method and double-line method to predict the result of the experiment;the predicative results show that the improvement method is much better than the double-line method. The calculated results of the improvement method are quite agree with the test results.