Use of three computer codes in the analysis of tunnel intersection stability under quasi-static loading

This paper presents static stresses in the rock matrix near the intersection of two horizontal, circular cross-section tunnels calculated in response to an in situ pressure and an uniaxial confined compression. Three specific problems are shown, first, the elastic response to an in situ pressure, second, the elastic response to an in situ pressure and an uniaxial confined pressure, and, finally, the elastic-plastic response to the second load combination. Code validation and verification results are summarized by comparing the rock matrix response to the in situ pressure using three different codes. Also, the two finite element codes used are compared with known analytic solutions. 13 refs., 10 figs.