真空动力固结软土地基流固耦合动力特性分析

Analysis of fluid-solid coupling dynamic characteristics of vacuum dynamic consolidation soft soil foundation

针对真空动力固结饱和软土地基过程产生的大变形和流固耦合特征,基于大变形非线性有限元法构建了轴对称流固耦合模型,并引入人工边界条件模拟夯击波的传播,同时采用精细时程积分和两点递进格式相结合的交替迭代算法对模型进行解耦计算。结果表明:真空动力固结有效影响半径可取2.5 r,平均有效加固深度宜取9.0 m,真空负压和动力固结冲击荷载相互影响对于饱和软土地基位移增幅效果明显,且可以显著降低软土地基液化的可能性。同试验值的对比结果也验证了数值分析的有效性。

According to the characteristics of large deformation and fluid-solid couplingin the process of vacuum dy⁃namic consolidation(VDC)to saturated soft soil,An axisymmetric fluid-solid coupling model is constructed based on the nonlinear finite element method of large deformation,and the propagation of tamping wave is simulated by using artificial boundary conditions.At the same time,the model is decoupled by using the iterative algorithm of fine time integral and center difference.The results show that the effective influence radius of vacuum dynamic consolidation(VDC)should be 2.5r,the average effective depth of reinforcement can be up to 9.0 m,and the possibility of liquefaction of soft soil foun⁃dation can be significantly reduced due to the the interaction of load.The results compared with the experimental results also verify the validity of the numerical analysis.