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境界要素法論文集 Vol.15(1998年12月) JASCOME

改良型円錐孔底応力解放法への多重極積分方程式法の適用

AN APPLICATION OF MULTIPOLE INTEGRAL EQUATION METHOD
TO AN IMPROVED OVER-CORING METHOD OF CONICAL-END BORE-HOLE

高橋 徹, 小林  昭一, 西村 直志

Toru TAKAHASHI, Shoichi KOBAYASHI and Naoshi NISHIMURA

 1)京都大学大学院,   ¯(〒606-01 京都市左京区吉田本町,Email:ttaka@gspsun1.gee.kyoto-u.ac.jp)

2)京都大学工学研究科,¯(〒606-01 京都市左京区吉田本町,Email:skoba@gee.kyoto-u.ac.jp)

3)京都大学工学研究科,¯(〒606-01 京都市左京区吉田本町,Email:nchml@gee.kyoto-u.ac.jp)

The present paper describes an application of a three dimensional multipole boundary integral equation method to an improved over-coring stress relief method of a conical-end bore-hole, which is used to estimate stress states in rock mass from the measured strains on the face of a funnel-end bore-hole ( a conical-end bore-hole attached at its appex with a small-diameter inspection bore-hole) induced by over-coring with the same diameter as that of the bore-hole. Since the geometry of the over-coring is complicated and moreover precise conversion matrix is required in obtaining stresses from the measured strains, the fast multipole method is most advantageously applied. In implementation, piecewise constant shape functions with collocation technique are used to discretise the boundary integral equation and the resulting equation is solved using preconditioned GMRES. The strains induced by over-coring are simulated and shown for simple states of initial stresses.

Key Words:

Multipole Integral Equation Method, FMM, GMRES, Conical-end Bore-hole, Funnel-end Bore-hole, Improved Over-coring Method, Initial Stresses





N. Nishimura
Wed Dec 16 21:06:14 JST 1998