ISSN: 0149-6115
Published Online: 12 July 2006
Page Count: 8

Instrumentation of an Unsaturated Expansive Soil Slope

Zhan, TLT
Associate Professor,Zhejiang University,

Ng, CWW
Professor,Hong Kong University of Science & Technology,

Fredlund, DG
Professor,University of Saskatchewan,

(Received 15 December 2005; accepted 30 May 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.

Keywords:
instrumentation, expansive soil, crack, suction, water content, horizontal stress, soil deformation

Paper ID: GTJ12704
DOI: 10.1520/GTJ12704
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