Instrumentation of an Unsaturated Expansive Soil Slope
Zhan, TL
Associate Professor, Department of Civil Engineering, Zhejiang University, Hangzhou, China

Ng, CW
Professor, Department of Civil Engineering, Hong Kong University of Science & Technology, Hong Kong

Fredlund, DG
Professor, Department of Civil Engineering, University of Saskatchewan, Saskatoon, Canada

(Received 18 August 2004; accepted 9 August 2006)

Abstract

To understand the complex soil-water interaction in an unsaturated expansive soil slope subjected to rainfall infiltration, a comprehensive instrumentation and monitoring program was carried out on an 11-m high cut slope in Hubei of China. The instrumentation included jet-filled tensiometers, thermal conductivity suction sensors, moisture probes, earth pressure cells, inclinometers, vertical movement points, artificial rainfall simulator, a tipping bucket rain gage, a vee-notch flow meter, and an evaporimeter. The technique and experience associated with each of the instrumentations are presented in this paper with an emphasis on the difference from the instrumentation in nonexpansive soils. In particular, a deliberate sealing scheme was adopted to prevent the potential bypass water flow through the shallow cracks into the installation holes for the suction sensors and the moisture probes. All the instruments worked well throughout the two month monitoring period, during which two artificial rainfall events were created. The recorded responses in pore-water pressure, water content, horizontal stress, and soil deformation were reasonably consistent with one another.

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Author Zhan TL, Ng CW, Fredlund DG Title Instrumentation of an Unsaturated Expansive Soil Slope Symposium , Committee on