为合理反映膨胀岩湿度应力场对围岩变形与次生应力状态的影响,首先,根据增量理论和膨胀变形机制,建立膨胀岩湿度应力场弹塑性本构模型,并推导其差分格式。其次,基于FLAC3D提供的二次开发程序接口,实现本构模型的二次开发,给出该模型的程序流程图和代码编写中的关键问题。最后,结合工程实例,将湿度应力场模型与传统的莫尔–库仑模型对比研究,验证自定义本构模型的正确性,研究表明所开发的湿度应力场本构模型能更好地反映膨胀力对巷道围岩变形与次生应力状态的影响。 In order to reasonably reflect the influence of the stress field of the expansive rock on the deformation and the secondary stress state of the surrounding rock, the elastic-plastic constitutive model of the stress field of the expansive rock is established based on the incremental theory and the expansion deformation mechanism, and the difference scheme is derived. Secondly, based on the secondary development program interface provided by FLAC3D, the secondary development of the constitutive model is realized, and the program flow chart and the key problems in the code writing are given. Finally, with the engineering example, the humidity stress field model is compared with the traditional Mohr-Coulomb model to verify the correctness of the self-defined constitutive model. The results show that the developed constitutive model of moisture stress field can better reflect the expansion force Influence of Surrounding Rock Deformation and Secondary Stress State in Roadway.