In this paper, an elastoplastic solution is developed for cylindrical cavity expansion in anisotropic unsaturated soils under constant water content conditions. The most prominent features of the solution can be attributed to 1) the stress–strain behaviour of unsaturated soil is subtly coupled with the saturation-suction behaviour; 2) both the mechanical and hydraulic behaviours are modelled as elastoplastic processes; and 3) an anisotropic critical state soil model for saturated soil is extended to an unsaturated situation to consider the effects of the initial stress anisotropy and stress-induced anisotropy of the natural unsaturated soils. The problem is formulated as a system of first-order differential equations and solved as an initial value problem. A numerical code that can judge the hydraulic yield condition of soil particles during the cavity expansion process is developed based on the Runge-Kutta algorithm to solve the governing equations. Parametric analyses, which cover a wide range of suctions, overconsolidation ratios, degrees of initial stress anisotropy, are conducted to investigate the effects of these important factors on the expansion responses in unsaturated soils. The proposed solution could potentially be applied to interpret pressuremeter tests and model pile installation effects in anisotropic unsaturated soils.

在本文中，为在恒定含水量条件下各向异性非饱和土壤中的圆柱形空腔膨胀开发了一种弹塑性解决方案。该解决方案最突出的特点可归因于：1）非饱和土的应力-应变行为与饱和-吸力行为微妙地耦合；2) 机械和水力行为都被建模为弹塑性过程；3) 将饱和土的各向异性临界状态土模型扩展到非饱和情况，考虑天然非饱和土的初始应力各向异性和应力诱导各向异性的影响。该问题被表述为一阶微分方程组，并作为初值问题求解。基于Runge-Kutta算法，开发了一种能够判断空腔膨胀过程中土颗粒水力屈服条件的数值代码，求解控制方程。参数分析涵盖了广泛的吸力、过固结比、初始应力各向异性程度，以研究这些重要因素对非饱和土膨胀响应的影响。所提出的解决方案有可能用于解释各向异性非饱和土壤中的压力计测试和模型桩安装效果。进行了研究这些重要因素对非饱和土壤膨胀响应的影响。所提出的解决方案有可能用于解释各向异性非饱和土壤中的压力计测试和模型桩安装效果。进行了研究这些重要因素对非饱和土壤膨胀响应的影响。所提出的解决方案有可能用于解释各向异性非饱和土壤中的压力计测试和模型桩安装效果。