Due to the brittle behaviour of rocks during deformation in surficial conditions, numerous fractures develop, both extension joints and faults. The ratio between the number of extension joints and the number of faults, j/f, which form in a rock mass has been investigated. In order to simulate the stress evolution and the consequent generation of fractures during time, a mechanical model is proposed, while a specific computer program has been prepared. The model takes into account i) the stochastic distribution of the tensile strength of rocks, ii) the temporal and local stress variations caused by continuous fracturing events and iii) the sealing effect occurring along fractures with time. Several geological parameters, such as the tectonic stress rates and their ratio, the depth (i.e. the confining pressure) and the role of the pore-fluid pressure have been also considered. In the companion paper, numerical calculations and comparison with field examples are discussed.
Extensional joints and faults: a 3D model for quantifying their ratio. Part 1: theory
CAPUTO, Riccardo;SANTARATO, Giovanni
1998
Abstract
Due to the brittle behaviour of rocks during deformation in surficial conditions, numerous fractures develop, both extension joints and faults. The ratio between the number of extension joints and the number of faults, j/f, which form in a rock mass has been investigated. In order to simulate the stress evolution and the consequent generation of fractures during time, a mechanical model is proposed, while a specific computer program has been prepared. The model takes into account i) the stochastic distribution of the tensile strength of rocks, ii) the temporal and local stress variations caused by continuous fracturing events and iii) the sealing effect occurring along fractures with time. Several geological parameters, such as the tectonic stress rates and their ratio, the depth (i.e. the confining pressure) and the role of the pore-fluid pressure have been also considered. In the companion paper, numerical calculations and comparison with field examples are discussed.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
