考虑隧道周围软土压缩性和渗透性的非线性变化,建立二维非线性渗流固结控制方程,利用一种交替隐式差分法进行求解,得到隧道完全透水、完全不透水和半透水三种情况下平均固结度随时间的发展规律;通过将退化解与现有解析解进行对比,验证了差分解的正确性.同时,分析了压缩指数Cc 和渗透指数Ck 对隧道周围软土固结度变化的影响规律.结果表明:隧道透水性是影响固结度发展变化的重要因素;Cc 对固结度发展的影响小于Ck;渗流固结会导致隧道周围土体的有效应力场发生变化,平均固结度随着Ck 的增大而减小.若不考虑土体非线性,将会对固结度计算产生较大误差.
Considering the nonlinear changes of compressibility and permeability of soft soil around the tunnel,a two-dimensional nonlinear seepage consolidation control equation is established,which is solved by an alternating implicit difference method,and the development law of the average degree of consolidation with time under the three conditions of complete permeability,complete impermeability,and semi permeability of the tunnel is obtained.By comparing the degenerate solution with the existing analytical solution,the correctness of the difference solution is verified.In addition,the effects of compression index Cc and permeability index Ck on the consolidation degree of soft soil around the tunnel are analyzed.The results show that the permeability of tunnel is an important factor affecting the development and change of consolidation degree.The influence of compression index Cc on the development of degree of consolidation is less than that of permeability index Ck.Seepage consolidation will change the effective stress field of the soil around the tunnel,and the average degree of consolidation decreases with the increase of permeability index Ck.If the nonlinearity of soil is not considered,there will be a large error in the calculation of degree of consolidation.