Abstract: During the triaxial drainage shear tests on coarse-grained soil, the rubber film embedded in the particle gap affects the accuracy of measuring the volume deformation of specimens, especially under loading conditions such as isotropic compression and equal stress ratio. In response to this problem, the K₀ consolidation tests are carried out on the coarse-grained shell material of the Shuangjiangkou earth-rock dam using the new static lateral pressure coefficient tester for rigid walls and the conventional triaxial tester for flexible walls. The effects of the effective net pressure p, the initial void ratio e₀ and the average particle size d₅₀ on the amount of rubber film embedded per unit area are studied. A new method can be used to accurately measure the embedding amount of rubber film. The test results show that the embedding amount of rubber film per unit area has a good hyperbolic relationship with the effective net pressure p/p_a, and the effective net pressure p, the initial void ratio e₀ and the average particle size d₅₀ all have a greater impact on the embedding amount of rubber film. Based on the test results, an empirical formula for predicting the amount of rubber film embedded per unit area in the triaxial tests on coarse-grained soil is proposed and verified. Compared with the previous test results, the proposed empirical formula can better predict the amount of rubber film embedded in the triaxial tests on coarse-grained soil.