复合振冲碎石桩加固机理及施工过程数值模拟

采用振动荷载作用下超孔隙水压力产生的能量模型，考虑耗散能量和孔径扩张的影响及相互作用，并进行合理的简化，对复合振冲碎石桩施工过程做了数值模拟。采用有限差分离散求解复合振冲碎石桩边值问题，编制相应的数值程序，基于模拟结果详细讨论了排水井的存在对复合振冲碎石桩孔隙水压力发展变化的影响。最后对普通碎石桩和复合碎石桩的地基加固效果进行对比分析。数值模拟结果表明，复合振冲碎石桩由于排水井的存在，使地基加固范围明显增大，并且可以应用于渗透系数较小的粉土和砂质粉土地基中。

Reinforcement mechanism of vibro-stone columns with additional wicks and numerical analysis

An energy model of excess pore pressure generation under vibration loading was adopted to simulate the installation process of composite vibro-stone columns. The interaction between the energy dissipation and hole expansion was taken into account and a reasonable simplification was made in the simulation. The finite difference method was used to discretize the reinforced area and to solve the boundary value problem. A numerical program was developed to simulate the installation process of composite vibro-stone columns. The influence of wicks on the variation of pore pressure for composite vibro-stone columns was discussed in details. Finally, the reinforcement results were compared between traditional stone columns and composite vibro-stone columns. Numerical simulation indicates that the reinforced areas of composite vibro-stone columns are obviously lager than those of the traditional stone column duo to the existence of additional wicks. This reinforcement method is not only suitable for the sand ground but also valid for the silt or silt-sand ground.