Ground settlement prediction of embankment treated with prefabricated vertical drains in soft soil

Siswoko Adi Saputro,Hung Jiun Liao,Agus Setyo Muntohar,P Hajek,W.T Chan,R Sriravindrarajah,B.A Hidayat,M.B Ismail,S Kristiawan,A.L Han,B.S Gan

doi:10.1051/matecconf/201819503014

Abstract

Excessive settlement due to consolidation can cause damage to the structure’s rest on soft soil. The settlement takes place in relatively longer. The preloading and prefabricated vertical drain (PVD) is often applied to accelerate the primary settlement. The issue in this research is the estimation of the settlement. The Asaoka method and the finite element method using PLAXIS-2D are used to estimate the final settlement of a PVD treated embankment. For the former, a complete record of the settlement was required; for the latter, some ground parameters are needed for the PLAXIS-2D analysis, such as the permeability of the soil. Because the installation process of PVD tends to influence the permeability of the in-situ soil around the PVD, the soil permeability after the installation of PVD needs to be adjusted. The numerical results were compared with actual settlement data to find out the best-fit input parameters (i.e. soil permeability) of the actual data. It was found that the best-fit soil permeability (k) used in the numerical study was about one-half of the k value determined from the laboratory test. The Root Mean Square Deviation shows that the settlement predicted by the numerical analysis has approximately 30% of the actual settlement.

Highlights

The ground settlement due to consolidation is often experienced in the construction work on soft soil
1.2 Ground improvement The preloading combined with prefabricated vertical drain (PVD) method was used in this construction site to speed up the consolidation rate of the soft clayey soil
Analytical using Asaoka Method and finite element analysis of the ground settlement of the PVD-improved soft clay has been comparable to the field measurement

Summary

Introduction

The ground settlement due to consolidation is often experienced in the construction work on soft soil. In the Asaoka Method, the magnitude of actual ground settlement can be predicted without the parameters used in the consolidation analysis, such as pore water pressure data, drainage length, maximum soil strain and consolidation coefficient. The case report of Achmad Yani Airport project was used to evaluate the effectiveness of the Asaoka Method for predicting the final ground settlement of the PVD-improved the soft soil. The ground settlement was numerically modelled using PLAXIS 2D finite element method (FEM). The numerical model was performed to investigate the effect of coefficient of permeability on the settlement behavior of the improved soft soil with PVD. 1.2 Ground improvement The preloading combined with prefabricated vertical drain (PVD) method was used in this construction site to speed up the consolidation rate of the soft clayey soil.

Numerical modelling

PVD properties

Findings

Result and discussion

Conclusion