Accession Number : ADA319834

Title :   Computational Modeling of Underground Tunnels in Intact and Jointed Rock.

Descriptive Note : Technical rept. 15 Sep 91-15 Mar 96,

Corporate Author : APTEK INC COLORADO SPRINGS CO

Personal Author(s) : Murray, Yvonne D.

PDF Url : ADA319834

Report Date : JAN 1997

Pagination or Media Count : 59

Abstract : Computational models were developed to predict the dynamic response and damage to reinforced tunnels in rock subjected to ground shock from nuclear weapons. This effort is part of the Underground Technology Program. The finite element calculations were performed with the DYNA3D code using a comprehensive smooth-cap model for intact rock and a nonlinear slideline model for rock joints. Calculated tunnel closures, and free-field stress and velocity histories, compare well with spherical wave tests (SWAT) on aluminum lined tunnels in intact limestone. The intact rock model includes a scalar anisotropic damage formulation for modeling strain-softening and modulus reduction, viscoplastic formulations and rate-shifted damage surfaces for modeling rate effects, and a three-invariant plasticity formulation. Preliminary "stack of bricks" calculations were also performed to verify our joint model, in preparation for future predictions of tunnel response in jointed limestone.

Descriptors :   *TUNNELS, *EXPLOSION EFFECTS, *GEOLOGIC MODELS, CLOSURES, FINITE ELEMENT ANALYSIS, DYNAMIC RESPONSE, GROUND SHOCK, ROCK MECHANICS, SCALAR FUNCTIONS, REINFORCING MATERIALS, NUCLEAR EXPLOSION DAMAGE, CAVITY LINERS, SPHERICAL WAVES.

Subject Categories : Mining Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE