Abstract This paper presents a semi-analytical elastoplastic solution for cylindrical cavity expansion in overconsolidated (OC) unsaturated soils under constant water content condition, in which both the OC features and the coupled hydro-mechanical behaviour of soils are properly addressed. The unified hardening model for OC unsaturated soil is further coupled with a void ratio-dependent soil-water characteristic curve to model the coupled hydro-mechanical soil responses during expansion. With the aid of an auxiliary variable, the coupled hydro-mechanical constitutive matrix for the investigated problem is finally formulated as a set of first-order ordinary differential equations in terms of Lagrangian description, with the three net stress components, the suction, and the void ratio as the basic unknowns. The governing differential equations are solved as an initial value problem with the code developed based on the Runge-Kutta algorithm. Parametric studies show that both the overconsolidation ratio and the suction have remarkable impacts on the expansion responses, including the distribution of stress components, the change of degree of saturation as well as the expansion pressures. The proposed solution could provide a reasonable tool for interpretation of the pressuremeter tests and prediction of pile installation effects in overconsolidated unsaturated soils.

中文翻译：

---

超固结非饱和土中圆柱形空腔的膨胀响应：一种半解析弹塑性溶液

摘要 本文提出了一种半解析弹塑性解决方案，用于在恒定含水量条件下超固结 (OC) 非饱和土中的圆柱形空腔膨胀，其中适当地解决了土的 OC 特征和耦合的水力学行为。OC 非饱和土壤的统一硬化模型进一步与孔隙比相关的土壤-水特征曲线相结合，以模拟膨胀过程中耦合的水力-机械土壤响应。在辅助变量的帮助下，研究问题的耦合流体力学本构矩阵最终被表述为一组一阶常微分方程，根据拉格朗日描述，具有三个净应力分量、吸力和空隙率作为基本未知数。控制微分方程作为初值问题使用基于 Runge-Kutta 算法开发的代码求解。参数研究表明，超固结比和吸力对膨胀响应都有显着影响，包括应力分量的分布、饱和度的变化以及膨胀压力。所提出的解决方案可以为超固结非饱和土中压力计测试的解释和桩安装效果的预测提供合理的工具。饱和度和膨胀压力的变化。所提出的解决方案可以为解释压力计测试和预测超固结非饱和土中的桩安装效果提供合理的工具。饱和度和膨胀压力的变化。所提出的解决方案可以为超固结非饱和土中压力计测试的解释和桩安装效果的预测提供合理的工具。