Study of VCM Improved Soft Soil Properties Using Non-Destructive and Destructive Techniques

Diandri Fakhri Alditra,Suttisak Soralump,Susit Chaiprakaikeow

doi:10.3390/geosciences10080300

Diandri Fakhri Alditra, Suttisak Soralump + Show 1 more

Open Access

https://doi.org/10.3390/geosciences10080300

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Journal: Geosciences	Publication Date: Aug 6, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: Kasetsart University

Abstract

In Bangkok, the demand for housing is extensively high due to the city growing rapidly, so some swampy areas are filled with soil. A Prefabricated Vertical Drain (PVD) with the Vacuum Consolidation Method (VCM) is required to make the soil applicable for construction. However, it is difficult to monitor the soil strength during the process because the airtight sheet will be broken. This research aims to study the possibility of using the Spectral Analysis of Surface Waves (SASW) test to monitor the effectiveness of the VCM method and to study the development of shear-wave velocity over the consolidation period. Multiple instruments were installed on site, namely, vacuum gauges, settlement plates, and a piezometer, as well as a borehole to monitor the pump pressure, settlement, porewater pressure, and soil properties. Ten SASW tests were taken to measure the change in shear-wave velocity (Vs) over 7 months. The results showed an increment in the Vs along with increments in the settlement and undrained shear strength (Su), as well as a decrement in pore pressure during the consolidation period. The correlation between Vs and soil settlement was developed to predict the amount of settlement using Vs. These all indicated the potential of using the SASW method for soil improvement monitoring purposes.

Highlights

In Bangkok, the demand for housing is extremely high due to the city growing rapidly
Test to monitor the effectiveness of the Vacuum Consolidation Method (VCM) method and to study the development of shear-wave velocity over the consolidation period
The results showed an increment in the Vs along with increments in the settlement and undrained shear strength (Su), as well as a decrement in pore pressure during the consolidation period

Summary

Introduction

In Bangkok, the demand for housing is extremely high due to the city growing rapidly. This raises the question as to where the new housing should be, since most of the area has already been occupied. Some swampy areas were filled with soil to meet this demand. The function of soil improvement is to increase the soil strength and performance in order to be able to withstand the load applied to the soil due to the construction. One of the examples of the soil improvement method is using a Prefabricated Vertical Drain (PVD) for a faster consolidation rate [1]. A PVD can be applied together with the Vacuum Consolidation Method (VCM)

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Conclusion