水位下降诱发含水层–弱透水层1维黏弹性固结分析

弱透水层黏性土与含水层砂土的蠕变性是造成地面沉降长期发展的重要原因之一。基于广义开尔文黏弹性模型，结合一维固结理论和连续性条件，得到了水位变化下弱透水层-含水层长期变形控制方程和定解条件。利用Laplace变换，基于矩阵传递法和边界转换法，分别推导了双层土体各位置的水头时间关系式，给出了水位变化引起的土体孔压、沉降和固结度发展的计算公式。采用了Stehfest方法实现数值逆变换，编写计算程序，验证了两种求解方法的正确性，并进一步分析了矩阵传递法和边界转换法在计算精度和效率方面的差别。最后，通过数值算例，探讨了土体的黏滞性、渗透性、土层性质的差异以及水头下降速率对水位变化引起土层变形的影响。

One-dimensional Viscoelastic Consolidation Analysis of Aquifer–Aquitard Due to Drawdown of Water Level

It is one of the main reasons for the long-term development of land subsidence that the creep of clay in aquitard and sand in aquifer. Based on the generalized Kelvin viscoelastic model, combined with one-dimensional consolidation theory and continuity condition, the equation governing consolidation and definite solution condition of long-term deformation of the aquitard -aquifer foundation owing to groundwater level variation are obtained. Using Laplace transform, based on matrix transfer method and boundary transform method, the relationship between water head and time at each position of the soil layer has been derived respectively, and the calculation formulas of pore water pressure, settlement and consolidation degree of soil caused by water level change are given. The Stehfest method is used to compute the number inverse transformation; in the meanwhile, the correctness of the two solutions is verified by writing a computation program. Furthermore, the difference between matrix transfer method and boundary transformation method in calculation accuracy and efficiency is analyzed. Finally, more numerical examples have been conducted to investigate the influences of viscosity of skeleton, soil layer permeability, difference of soil properties and water head falling rate on soil deformation caused by groundwater level variation.