Numerical modeling of a highly explosive source in an elastic‐brittle rock mass

Abstract

A highly explosive source is input in an elastic‐brittle rock mass and the resulting near‐source complexities are considered. This study is undertaken with a three‐dimensional numerical model similar to the discrete element method. This model can simulate the creation of the damage zone with the associated block motions as well as the elastic wave propagation. Free‐field ground motion data are recorded to determine the reduced displacement potential (RDP). In a fully elastic numerical model, as expected, the RDP computation corresponds to the analytical one‐dimensional problem of a spherically symmetric explosive source acting in a homogeneous elastic medium. When fracturing occurs, during the creation of the damage zone, block motions are observed, and the RDP computations are affected. For an ideal system which conserves energy, the potential elastic energy is converted to kinetic energy during the fracturing process resulting in an apparent RDP which is larger than in the homogeneous elastic case. This three‐dimensional approach is undeniably advantageous where a global description of the heterogenous effects of block motions and the continuous aspects of wave propagation are considered simultaneously.

Mechanical stratigraphy and the transition from trishear to kink-band fault-propagation fold forms above blind basement thrust faults: A discrete-element study

“…Cundall and Strack, 1979;Bardet and Proubet, 1992;Kuhn, 1999), and a number of geological and geophysical problems in two and three dimensions (Saltzer and Pollard, 1992;Antonellini and Pollard, 1995;Scott, 1996;Donze´et al, 1996;Strayer and Huddleston, 1997;Camborde et al, 2000;Iwashita and Oda, 2000;Toomey and Bean, 2000;Strayer and Suppe, 2002;Place et al, 2002;Finch et al, 2003;Strayer et al, 2004;Hardy and Finch, 2005).…”

Deformation and fault activity in space and time in high-resolution numerical models of doubly vergent thrust wedges

“…The discrete-element technique was first applied to simulate the failure of a system of semi-brittle jointed rock blocks by Cundall (1971) and is derived from the particle dynamics method, widely applied in chemistry and physics to imitate liquid and gas behaviours (Allen and Tildesley, 1987;Gould and Tobochnik, 1988). Since then, further developments of the discrete-element method have addressed problems in soil mechanics and granular media (e.g., Cundall and Strack, 1979;Bardet and Proubet, 1992;Kuhn, 1999), and a number of geological and geophysical problems in two and three dimensions (Saltzer and Pollard, 1992;Antonellini and Pollard, 1995;Scott, 1996;Donze´et al, 1996;Strayer and Huddleston, 1997;Camborde et al, 2000;Iwashita and Oda, 2000;Toomey and Bean, 2000;Strayer and Suppe, 2002;Place et al, 2002;Finch et al, 2003Finch et al, , 2004Strayer et al, 2004;Hardy and Finch, 2005, 2006, 2007.…”

Discrete‐element modelling of extensional fault‐propagation folding above rigid basement fault blocks

“…An increase in the number of pre‐existing fractures resulted in a transition from brittle to macroscopically ductile behaviour. Later, Donzé et al (1996) employed a similar approach to minimise the effect of preferential directions of fracture in a face‐centred cubic geometry, where randomly selected links were forced to remain intact throughout the deformation process (equivalent to a large breaking separation) and other links experience a finite rupture threshold (breaking separation). This consequently introduces local isolated heterogeneities into the media simulating the natural heterogeneity of rock.…”

“…Discrete-element models are becoming quite commonly used in the description of the non-linear interaction of a large number of particles (e.g. Donze¤ et al, 1996;Kuhn, 1999;Camborde et al, 2000;Finch et al, 2003). Unlike continuum techniques, these methods use simple particle interactions and therefore permit the dynamic evolution of a system to be observed.…”

“…Further developments of the discrete-element method addressed problems in soil mechanics and granular media (e.g. Cundall & Strack, 1979;Bardet & Proubet, 1992, Kuhn, 1999, and a number of geological and geophysical problems in two and three dimensions (Saltzer & Pollard, 1992;Antonellini & Pollard, 1995;Donze¤ et al 1996;Scott, 1996;Strayer & Huddleston, 1997;Camborde et al, 2000;Iwashita & Oda, 2000;Strayer & Suppe, 2002;Finch et al, 2003).…”