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Field monitoring of a saprolite cut slope

by Li, Aiguo

Abstract (Summary)
(Uncorrected OCR) Abstract of thesis entitled Field Monitoring of a Saprolite Cut Slope submitted by Li Aiguo for the degree of Doctor of Philosophy at the University of Hong Kong in February 2003 This thesis investigates the mechanism of rainfall-induced slope failure through a study based on a full-scale field monitoring conducted in a saprolite cut slope in Hong Kong. The slope was a gentle hillside, which was cut to accommodate road construction, and consisted mainly of saprolite. To characterize the soil properties of the slope, a detailed site investigation was carried out prior to and during construction and instrumentation. A number of instruments, including soil moisture probes, tensiometers, open standpipes and piezometers, inclinometers, earth pressure cells, and a rain gauge were installed in the slope, and site investigation included borehole drilling, soil sampling, field and laboratory tests. Field monitoring of the slope was conducted during two rainy seasons. The pre-excavation slope was monitored during the first rainy season of 2001. Following excavation in December 2001, the post-excavation slope was also monitored during another rainy season in 2002. The study included an analysis of the variations of rainfall intensity, soil moisture content, matric suction, ground water level, slope deformation, horizontal earth pressure during the period of monitoring. It further included an analysis of the rainfall infiltration and field soil-water characteristics. Finally, seepage analysis and stability analysis were also carried out. The rainfall infiltration analysis at the crest of the pre-excavation slope showed that the actual rainfall infiltration was around 70% of the total rainfall, which is consistent with previous measurements of vegetated saprolite in Hong Kong. The field soil-water characteristics analysis showed that there was negligible hystersis for the field soil-water characteristic curves. Seepage analysis showed that perched water could develop in the slope during heavy rainfall, and that the perched water might meet the deep ground water level in the slope during a very high return period of rainfall. Slope stability analysis demonstrated that a high return period of rainfall could decrease the stability of the slope dramatically, while evaporation during the dry season could increase the stability of the slope substantially.
Bibliographical Information:

Advisor:

School:The University of Hong Kong

School Location:China - Hong Kong SAR

Source Type:Master's Thesis

Keywords:slopes soil mechanics china hong kong landslides

ISBN:

Date of Publication:01/01/2003

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