Joint Propagation in Relatively Undeformed Bedded Sedimentary Rock through Compression Failure Mechanisms

A020 JOINT PROPAGATION IN RELATIVELY UNDEFORMED BEDDED SEDIMENTARY ROCK THROUGH COMPRESSION FAILURE MECHANISMS 1 Abstract The representation of joint (opening –mode fractures) and fracture swarm development is classically presented by a first order phenomenon involving effective traction orthogonal to fracture plane (regional extension). Although commonly used this hypothesis seems to us less realistic in many circumstances and may conflict with geological observations. Therefore we describe fracture growth as a second order phenomena resulting from crack parallel compression. Figure 1 : systematic jointing Figure 2 : fracture swarm (after Auzias[1]) One example of systematic joint characterisation D. PICARD 1 2 C.