Field instrumentation for performance assessment of Geobarrier System

Harianto Rahardjo,Chien Looi Wang,Johnny Liang Heng Wong,Alfrendo Satyanaga,Eng Choon Leong,Zhai Qian,P Delage,J.-M Pereira,Y.-J Cui,A.-M Tang,S Ghabezloo

doi:10.1051/e3sconf/20160915006

Abstract

The saturated hydraulic conductivity of a coarse-grained material is normally higher than that of a fine-grained material. However, the unsaturated hydraulic conductivity of the coarse-grained material decreases much faster than that of the fine-grained material with increasing matric suction and consequently the coarse-grained material can be less permeable than the fine-grained material in unsaturated condition. A capillary barrier system with a fine-grained layer over a coarse-grained layer will act as a hydraulic barrier to minimize rainwater infiltration into the original soil. Geobarrier system (GBS) which can function as both a cover system (i.e. prevention of rainwater infiltration) and a retaining structure was designed and will be constructed at Orchard Boulevard in Singapore. Numerical simulations were carried out to determine the optimallocations of instruments that can be used to assess the performance of GBS during dry and wet periods. The monitoring results from tensiometers, earth pressure cells and weather station would be used to validate the results from the numerical analyses

Highlights

Many factors can potentially determine slope failures, including climatic conditions, seismic activities, geological features, topography, vegetation and a combination of these factors [1]
The pore-water pressure at point TA2 at the bottom of fine recycled concrete aggregate (RCA) within the slope retained with Geobarrier system (GBS) remained constant around -65 kPa during rainfall
This indicated that GBS performed well in reducing rainwater infiltration into the underlying soil layer below GBS

Summary

Introduction

Many factors can potentially determine slope failures, including climatic conditions, seismic activities, geological features, topography, vegetation and a combination of these factors [1]. The pore-water pressure variations from seepage analyses and the stress distributions from stressstrain analyses were used to determine the location of instruments that would be used to assess the performance of GBS in minimizing rainwater infiltration and retaining the lateral earth pressures of the soil from the steep slope.

Results

Conclusion