高庙子膨润土已被确定为我国高放废物地质处置的首选缓冲/回填材料，进行其力学特性及应用模拟研究对合理设计处置库具有十分重要的意义。考虑膨胀效应的UH模型是在超固结非饱和土本构模型（非饱和土UH模型）的基础上提出的，因引入了土体团粒的吸水膨胀作用，使其适用于非饱和膨润土。基于有限元软件ABAQUS的二次开发平台，利用Fortran语言编制模型的UMAT（user-difined material）材料子程序，进行了考虑膨胀效应UH模型的有限元实现。然后针对高放废物处置概念模型，利用编制的模型子程序对高放废物处置系统进行了三维有限元模拟，并对渗流场和应力场的演化规律进行了初步探究。模拟结果显示处置系统中膨润土的内应力增加，土体的稳定性较好，说明选择高庙子膨润土作为缓冲/回填材料的合理性，也同时验证了程序的正确性。

Gaomiaozi bentonite has been identified as the proper buffer/backfill materials of the high-level radioactive waste geological disposal in China. It’s significant to study its mechanical properties and applications to design the repository more reasonable. UH model for bentonite is proposed based on the UH model for unsaturated soils. By considering the expansion of the soil aggregate, the model is suitable for unsaturated bentonite. Based on the user subroutines, UH model considering the expansion of the bentonite has been developed in finite element software using the semi-implicit algorithm. 3D numerical simulations of the deep geological disposal are carried out with ABAQUS using the proposed model. The analysis of the seepage field and stress field are made preliminarily. The results show that the inner stress of the bentonite in the repository is increasing. Also, a good stability of the disposal repository can be noticed from the simulation results when using the Gaomiaozi bentonite as buffer/backfill material. Based on the above analysis. The Gaomiaozi bentonite is proved to be a reasonable buffer/backfill material; and the subroutine is proved to be valid by the numerical simulation.