Reevaluation of the factors influencing the consolidation of ground by incorporating prefabricated vertical drains

Abstract

In the consolidation of ground by incorporating prefabricated vertical drains, there are a number of rigorous and approximate solutions that can be utilized. These solutions are affected by many factors. Due to a high level of complexity, design and back analysis are generally inefficient in predicting the consolidation behaviour. In this study, the existing solutions for the combined vertical and radial consolidation and the recommended values of each parameter were reviewed. A parametric study was then performed to examine the appropriateness of the solutions and the effects of each factor on the total degree of consolidation U vh to the combined consolidation. Results show that the effect of vertical drainage on U vh is sufficiently insignificant, and the peak influence occurs at U vh of less than 60%. All the solutions for the radial consolidation, except for Hansbo's solution, gave rise to the almost identical results. Hansbo's solution affected well resistance only. It was noted, however, that the significance of well resistance depends on soil permeability and the discharge capacity of drains which is compared to the effects of spacing and smear.

Analyzing consolidation data to predict smear zone characteristics induced by vertical drain installation for soft soil improvement

“…There are some factors such as equivalent diameter, apparent opening size (AOS), and discharge capacity of prefabricated vertical drain, as well as smear zone that control the efficiency of geosynthetic vertical drains (Lee and Chung 2010). Installation of the prefabricated vertical drains using mandrel induces disturbance of the soil surrounding the drain, resulting in a smear zone of reduced permeability adversely affecting the consolidation process (Choo et al 2013).…”