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FAST MULTIPOLE BEM SIMULATION OF
OVERCORING IN AN IMPROVED CONICAL-END BOREHOLE STRAIN MEASUREMENT METHOD



Toru Takahashi, Shoichi Kobayashi and Naoshi Nishimura
(Department of Global Environment Engineering,
Kyoto University, Kyoto 606-8501, Japan)


ABSTRACT    The present paper describes an application of the fast multipole BEM (FMBEM) to simulate the overcoring process in the improved conical-end borehole strain measurement method which is used in order to estimate initial stress states in rock mass. In implementation, use is made of piecewise constant elements with collocation technique to discretize the boundary. The GMRES algorithm is also utilized in solving the system of equations. The FMBEM together with the GMRES is most advantageously applied to such problems as ones with rather complicated boundaries even including moving boundaries and also as ones require a large-scale and high-speed computation with sufficient accuracy.
Key words    Fast Multipole BEM, GMRES, Strain Measurement, Conical-end Borehole, Funnel-end Borehole, Initial Stresses



 

Toru Takahashi 平成11年10月13日