The Biot-Cosserat continuum theory is combined with isogeometric analysis (Biot-CIGA) to simulate dynamic strain localization in saturated soils. The results demonstrate that Biot-CIGA can solve the ill-posed problem of saturated soils caused by strain-softening properties and non-associated flow rules, thereby obtaining a convergent, mesh-independent numerical solution. Compared with the finite element analysis of Biot-Cosserat continuum (Biot-CFEA), the high-order continuity of Biot-CIGA provides a smooth pore pressure gradient field and thus ensures the local mass balance of pore fluids. Additionally, the Biot-CIGA describes the inflow and outflow of pore fluids in the element, which means it is able to accurately simulate the volumetric strain of the element. Simulation results also show that the Biot-CIGA method can also effectively alleviate the mesh distortion in shear bands when materials experience large deformation. Last but not least, because Biot-CIGA adopts NURBS as its shape functions, it can conduct simulations directly on CAD models, which not only maintains the precise geometry, but also avoids an expensive intermediate meshing step.

Biot-Cosserat连续谱理论与等几何分析（Biot-CIGA）相结合，模拟了饱和土壤中的动态应变局部化。结果表明，Biot-CIGA可以解决由于应变软化特性和非关联流规则引起的饱和土不适定问题，从而获得了收敛的，网格无关的数值解。与Biot-Cosserat连续体（Biot-CFEA）的有限元分析相比，Biot-CIGA的高阶连续性提供了平滑的孔隙压力梯度场，从而确保了孔隙流体的局部质量平衡。此外，Biot-CIGA描述了元件中孔隙流体的流入和流出，这意味着它能够准确地模拟元件的体积应变。仿真结果还表明，当材料发生较大变形时，Biot-CIGA方法还可以有效减轻剪切带中的网格变形。最后但并非最不重要的一点是，由于Biot-CIGA采用NURBS作为其形状函数，因此可以直接在CAD模型上进行仿真，这不仅保持了精确的几何形状，而且避免了昂贵的中间啮合步骤。