Abstract:In order to study the tensile deformation characteristics of soil, and then better to analyze and solve the engineering problems of cracks and surface subsidence caused by the tensile failure of soil. In this paper, the experimental research about compacted clay was carried out based on the independently developed uniaxial tensile test device, and the failure modes and factors of compacted clay, also with the variation and fitting formula of peak displacement were discussed. The results show that the failure mode of compacted clay is not fixed, including the shape of tensile fracture surface is not fixed, the fracture surface is the weak surface of specimen, and the fracture is unique but the weak surface is not always unique, the position of fracture surface is impacted by the specimen size and stretching rate, failure mode is not pure brittle failure, but there is a softening phrase. In addition, the peak displacement of compacted soil is significantly affected by the test conditions, the specific features include the following aspects: with the increase of the length of stretching section, the peak displacement increases logarithmically; with the increase of the stretching rate, the peak displacement increases linearly; with the increase of compactness, the peak displacement increases linearly; with the increase of moisture content, the peak displacement increases linearly.