Modeling of Pvd-Improved Embankment Underneath Soft Sensitive Clays Considering Soil Disturbance

Abstract

Plastic Vertical Drains (PVDs) are commonly used in soft soil foundation treatment as a means to facilitate drainage and accelerate the consolidation process, significantly improving foundation strength and stability. However, existing studies mainly focus on the drainage effect and consolidation efficiency of PVD, with limited attention given to the impact of PVD installation on the structure and time-dependent properties of soft soil. This paper investigates the influence of soil disturbance induced by the installation of PVD in soft sensitive clays. Three typical matching techniques for modeling the PVD-improvement under the plane strain condition are adopted for comparison. An advanced elasto-viscoplastic model accounting for anisotropy and destructuration of natural soft clay is employed. A well-documented PVD-improved test embankment is adopted for simulations by the elasto-viscoplastic model combined with three mapping techniques respectively. To quantify the degree of soil disturbance, a new variable, δ, is introduced as an additional input parameter to the model, enabling the consideration of soil disturbance-induced strength degradation and permeability modification. The predictions of settlement, vertical displacement, horizontal displacement and excess water pore pressure, using different values of δ, are compared against field measurements. An appropriate value of δ is determined for each mapping technique based on the quality of the fit to the measurements. The results demonstrate that soil disturbance has a significant impact on settlement. Finally, the performance of the three mapping techniques is evaluated in terms of predictive accuracy and practical applicability.

Keywords: PVD, soft clay, disturbance, viscoplasticity, embankment