Soft clay consolidation accelerated by prefabricated vertical drains

• Main Author: Neo, Ying Min
• Other Authors: Low Bak Kong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Civil engineering::Geotechnical
• Online Access: https://hdl.handle.net/10356/138427
• Institution: Nanyang Technological University

Vertical drains were first used in the United States of America in 1923, and widely used in Asian countries in the 1950s. The technique has been in place for a long time and is primarily employed to accelerate consolidation of relatively soft clay. This project analyses the rate and magnitude of consolidation of clays, with the installation of prefabricated vertical drains, with loadings imposed either by embankments or reclamation fills. It assesses the effect of the vertical drains on the consolidation settlement rate and compares theoretical results with measured results. Methodologies presented in this report are: Asaoka Method, Hyperbolic Method, Terzaghi 1-Dimensional Equation and Visual Basic Programming. This project will look at two case studies: Singapore Changi East Reclamation Project and Hong Kong Chek Lap Kok Airport. The investigation of these two projects are limited to the instrumental test site and test results observed on the field. Each test consists of four test zones, with three test zones of different drain spacing and one control zone without the installation of vertical drains. The field results have shown the accelerated consolidation is present with the installation of the vertical drains, as well as with closer drain spacing. Discrepancies in results obtained will be discussed in this report.