饱和土中球形沼气池的动力响应

采用解析方法研究饱和土中球形沼气池的频域响应.将土体视为流固两相介质,饱和土体的动力学行为采用Biot理论模拟,建立具有球形沼气池饱和土体的动力方程.通过引入势函数,得到饱和土体的位移、应力和孔隙水压力等的解析表达式.将模具结构视为均匀弹性介质,根据弹性理论,推导模具结构的位移和应力解.根据土体和模具结构接触面以及模具结构内边界的连续性条件,确定待定系数的具体表达式.与单相土中球形沼气池动力响应的结果、有无模具结构的结果、有限元方法、边界单元法进行对比分析.考察饱和土和模具结构各参数对位移和孔压幅值的影响,结果表明：流体压缩性系数对响应幅值的影响与接触面的孔隙水渗透性有关；边界透水情形下流固耦合系数对系统动力响应的影响远大于不透水情形下的系统动力响应.

Dynamic response of a spherical biogas digester in saturated soil

Using the analytical method, frequency response of the spherical biogas digester in saturated soil were investigated. The soil was regarding as fluid-solid biphasic media. The dynamic equations of saturated soil with a spherical biogas digester were established by the Biot’s theory. By the potential function, the analytical expressions for displacement, stress and pore water pressure of saturated soil were obtained. The die structure was treated as the uniform elastic medium. The solutions for displacement and stress of die structure were derived by the elastic theory. By utilizing the inner boundary condition of the die structure and the continuity conditions between the soil and the die, the unknown coefficients were determined. The results of dynamic response of the spherical biogas digester in saturated soil and in single phase soil, the results of with and without die structure, and the results of finite element method and boundary element method were respectively compared and analyzed. The dynamic response of the die structure was analyzed for different parameters of the soil and the die. It shows that the influence of fluid compressibility coefficient on the response amplitude depends on the permeability of the pore water at the boundary. The influence of the interaction coefficient between the soil skeleton and the pore water on the response for the permeable system is more larger than those of the impermeable system.