Rate Effect on the Direct Shear Behavior of Granite Rock Bridges at Low to Subseismic Shear Rates

Abstract

Lithological, mechanical, and frictional heterogeneity within the fault zone occurs over many different scales and exerts an important control over fault strength, slip stability and earthquake nucleation (Barnes et al., 2020;Faulkner et al., 2010;Tesei et al., 2014). To define the effect of fault heterogeneity, a detailed understanding of the rupture propagation along heterogeneous faults is required. Laboratory experiments approach the problem by using gouge materials with varying friction strength to simulate heterogeneous faults (Bedford et al., 2022;Buijze et al., 2021). Recent laboratory experiments and field observations note that, as well as frictional strength evolution, faults also recover cohesion through processes such as pressure solution during interseismic periods

A comparative study of progressive failure of granite and marble rock bridges under direct shearing

“…The curved coalescence patterns and the failure surfaces of granite rock bridges at all normal stresses (Figs. 4 and 5 ) indicate the same mode of macroscopic tensile failure, consistent with previous experimental works on granite rock bridges with similar conditions of persistence, normal stress and shear rate 14 , 32 . According to Lajtai’s tensile failure criteria on rock bridge, the inclination of macroscopic tensile fracture would get smaller when the normal stress increases 9 .…”

Spatial Variations of Deformation along a Strike-Slip Fault: A Case Study of Xianshuihe Fault Zone, Southwest China

“…The damage caused by the compressive stress state in the strike-slip fault is generally stronger than that in the normal fault in the tensile stress state. [68,69], because the size and angle of the mentioned fractures in the rock samples greatly affect the stress distribution pattern around the specimen during testing [70][71][72]. Similar variations in stress distribution can also occur around active fault zones due to differences in the geometric spreading of faults.…”

Response Mechanism of the Residual Strength to the Mesostructure of the Shear Surface in the Gravelly Slip Zone of Ancient Landslides

“…Instead, it exhibits an irregular microscale geometry with a “rough” or “uneven” structure (Figure 2). This irregular microscale geometry has the potential to control the frictional resistance and mechanical properties of slip zones (Candela et al., 2012; Davidesko et al., 2014; Luo et al., 2022; Shibasaki et al., 2017), thereby influencing the reactivation and evolution of ancient landslides. To better understand the macromechanical behavior of gravelly slip zones and their response to the mesostructure of shear surfaces, the mesostructure of shear surfaces needs to be quantitatively characterized, and the underlying mechanisms need to be investigated.…”