准饱和黄土中暗穴水动力扩展响应的研究

为分析强降水过程中暗穴扩展机理,在野外调查资料的基础上,建立了准饱和黄土暗穴的扩展计算模型,概化为弹性准饱和土层中无限长圆柱形孔洞表面受水压力的动力响应问题。通过引入势函数,得到了Lap lace变换域中的应力、位移及孔隙水压力的解析表达式,并利用数值逆变换方法求得时域解,分析了降雨历时及饱和度等因子对暗穴动力响应的影响。结果表明,水动力是引起黄土暗穴扩展的主要因素,水压力作用历时对位移及应力有较大的影响,同时饱和度的细微变化对径向位移有显著影响。

HYDRODYNAMIC RESPONSE OF THE UNDERGROUND CYLINDRICAL CAVITY IN NEARLY SATURATED LOESS

To analyze the expansion of the cylindrical cavity in loess,a reasonable numerical model was presented based on field investigation.The potential function theory and Laplace transform technique wwere used to solve the problem.The analytical solution of stresses,pore pressure and displacement induced by inner water pressure were derived in Laplace transform domain.Numerical results were obtained by inverse Laplace transformation.The effects of rainfall duration and saturation on dynamic response of the cavity were discussed.It shows that the hydrodynamic force is the key factor of the cavity expansion in loess.The rainfall duration has great effects on the stress and displacement. The influence of saturation on displacements is remarkable.