Abstract:

In the study of gas hydrate-related Slipstream submarine slide, the finite element analysis software ANSYS is used to construct the 3D model with complicated submarine slump topography acquired by multibeam sounding system. The lower part of sliding surface buried by slump accumulation is estimated from the main scarp geometry, and the original ground surface before slump is reconstructed according to the morphological similarity of surrounding ridges. Then, the high precision 3D geological model is automatically completed by running Jscript file in ANSYS Workbench, which greatly improves the efficiency of complex geometric modeling and thus provides a key guarantee for the accuracy of subsequent finite element numerical analysis. The stability simulation of Slipstream Ridge under its self-weight condition showes that the maximum shear stress in sediments above a shallow gas hydrate concentration layer at about 100 meters below seafloor is distributed as a series of high value bands in wedge shape, which matches well with the stepped topography observed on the current slump surface and verifies the accuracy of the 3D geological model and the validity of the proposed modeling method.

Key words: 3D geological modeling, ANSYS Workbench, gas hydrate, submarine slide

摘要：

在采用有限元软件ANSYS分析水合物相关的Slipstream海底滑坡体时, 针对多波束测深获得的复杂滑塌区海底地貌, 首先通过滑坡陡壁的形态恢复滑塌面被掩埋的部分, 然后通过与周围海脊的形态相似性对比, 重建滑塌发生前的海脊地貌。在此基础上, 利用ANSYS Work- bench的Jscript脚本功能, 实现三维地质模型的高精度自动构建, 极大地提高了复杂坡体结构的建模效率, 可以为后续数值分析的准确性提供关键保障。对Slipstream海底滑塌坡体进行自重条件下稳定性的初步模拟, 结果显示, 以海底之下约100 m的浅层水合物富集层为界, 其上的沉积层中最大剪应力呈现楔形分布的高值条带, 与该处滑坡后的阶梯状地貌吻合, 验证了地质模型的准确性和建模方法的有效性。

关键词: 三维地质建模, ANSYS Workbench, 天然气水合物, 海底滑坡