ISSN: 0149-6115
Published Online: 1 May 2007
Page Count: 9

Study of a Displacement Measurement Method Inside a Small-Sized Model Ground in Laboratory Test

Baek, Wonjin
Department of Civil and Environmental Engineering,Yamaguchi,

Moriwaki, Takeo
Department of Civil and Environmental Engineering, Kure College of Technology,Hiroshima,

Sasaki, Yasushi
Japan Institute of Construction Engineering, Nissey Toranomon Building,Tokyo,

(Received 6 August 2006; accepted 28 January 2007)

Abstract

In order to understand the complex mechanism of the three-dimensional consolidation behavior of clayey ground improved by the vertical drain system, it is desired to observe the three-dimensional displacements inside the model ground in a series of laboratory tests. However, there is no available example to measure the internal displacement in a small-sized model ground in the laboratory tests because it is impossible to disregard the influence of burying the measuring equipment into the small-sized ground. Baek (2002, 2004) proposed a method for measuring the radial displacement in a specimen with vertical drain by measuring the intensity of the magnetic field induced by a very small magnet buried in the specimen by magnetometers set outside the specimen. This measuring method using calibration curves, which show relationships between the position of the magnet and the measured intensity of the magnetic field in the calibration test, was modified by using the theoretical solution of the magnetic field induced by a magnet (Baek 2006). In this paper, combining these previous studies, the whole system for measuring the displacement inside a small-sized model ground improved by vertical drain is described. Then, the reliability of the internal displacements obtained by these methods is discussed in comparison with the numerical solutions obtained by the finite difference method based on the three-dimensional elasto-viscous consolidation theory.

Keywords:
radial displacement, measuring method, magnetic field, three-dimensional consolidation test, vertical drain

Paper ID: GTJ100751
DOI: 10.1520/GTJ100751
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