明晰水合物沉积物（gas hydrate-bearing sediments, GHBS）的应力-应变特征，是实现海域天然气水合物安全开采的重要前提。为定量探究水合物的生成对GHBS力学特性的影响，通过室内试验测试了不同围压和不同水合物饱和度的影响，结果表明，水合物主要增大了GHBS的黏聚强度，而内摩擦角大致不变。为表征GHBS复杂的力学特性，通过前期建立的弹塑性本构模型进行预测，对比发现本构模型具有一定的适用性。在此基础上，基于ABAQUS提供的UMAT用户材料子程序接口，利用FORTRAN语言编写了本构模型的计算机程序，植入ABAQUS中，实现了对本构模型的开发。对GHBS的单个单元和三轴试样进行有限元仿真，结果表明开发的本构模型是有效和稳定的。

The stress-strain characteristics of gas hydrate-bearing sediments (GHBS) are essential for achieving safe and secure extraction of marine natural gas hydrate. To quantitatively investigate the influence of hydrate formation on the mechanical properties of GHBS, laboratory tests were conducted under different confining pressures and various hydrate saturations, and it was found that hydrate primarily enhanced the cohesive strength of GHBS, while the internal friction angle remained relatively unchanged. To comprehensively describe the intricate mechanical properties of GHBS, the previously established elastic-plastic constitutive model was employed for predictive purposes. A comparative analysis revealed that the constitutive model exhibited a certain level of applicability. Subsequently, a computer program was developed for the constitutive model by leveraging the UMAT user material subroutine interface provided by ABAQUS. The program was written in FORTRAN language and integrated into ABAQUS, facilitating the implementation of the constitutive model. To validate the effectiveness and stability of the developed model, finite element simulations were conducted on single elements as well as triaxial specimens of GHBS. The results of these simulations confirm the efficacy and reliability of the developed model.