... of resolution may result in misestimation of effective roughness because resolution determines how precise details are captured by the measurement. To improve our understanding on the proper resolution for roughness measurement, effect of micro-scale asperities on the shear behavior of rock joints...

... representation of the fracture asperity. It was found that satisfactory agreement between the numerical and laboratory experimental results could not be obtained with the present 3D fracture model where the simple isotropic linear elasticity and linear interface stiffness with the classic Coulomb friction...

.... In this study, a mesoscale flow-reactive model was developed, which could simulate dynamic coupling of acid flow, reactive transport and dissolution, and the mechanical deformation of asperities on the rough acid-etched fracture surface under normal closure stress. The results show that the evolution of natural...

... behavior asperity Relaxation Behavior direct shear relaxation test relaxation test joint roughness post-failure region 1. INTRODUCTION The long-term stability of underground rock structures is highly dependent on the time-dependent behavior of the rock mass. It is the overall response...

... of cohesive interlocking asperities during shearing, which suggest that rougher fractures are difficult to reactivate. (2) Rough fracture surfaces show velocity strengthening behavior in the initial shearing stage and their strengthening behaviors evolve to velocity neutral and velocity weakening with greater...

... morphology contact area fracture surface fracture asperity surface roughness deformation 1. INTRODUCTION Most of the shale gas reservoirs in southern China are located at depths of 3500~4500 m. It is likely to form a combination of stem fracture and branch fractures in the hydraulic fracturing...

... separation and treating friction normal load specimen Upstream Oil & Gas joint surface dilation sample sled friction angle sample plate apparatus direct shear testing apparatus load cell cylinder rotation asperity hydraulic cylinder 1. INTRODUCTION Direct shear testing is commonly...

... discontinuity. The gypsum blocks had perfectly matched contact surfaces with a half-cycle sine wave profile that spanned the central third of the discontinuity, surrounded by planar surfaces. The amplitude of the half-cycle sine wave was varied and ranged between 2 to 10 times the height of the asperities...

... ABSTRACT: Shear behavior of rough rock joints is considerably complex, as the failure process is governed by non-uniform degradation of asperities. To investigate the nonlinear shear behavior of rough joints, a series of experimental and numerical tests were conducted on saw-toothed mortar...

... ABSTRACT: In geologic formation, the natural fracture as flow conduit is a dominant factor for the subsurface fluid flow. Most of these natural fractures remain open in deep earth mainly through the self-propping by some discrete asperities, the integrity of asperity plays an important role...

... specimens containing through-going saw cuts of various geometries. Specimens containing larger asperities were observed to respond less effectively to injection treatment: shear stress releases of up to 5.9 MPa were triggered on planar fault surfaces compared to 0.7 MPa on surfaces with various sizes...

... results demonstrated that the initial phase of slipping was significantly influenced by asperity interlocking and breakdown, and the asperity breakdowns created secondary fractures. We present direct observations of the real contact area with progressive wearing of the shear surface. The real contact area...

... ABSTRACT: In rocks, dilation is caused by the irregularities and asperities on the joint surface climbing over each other. This results in an increase in the joint opening, which increases the permeability of the rock mass. Understanding the dilation response is of great importance...

... ABSTRACT: Laboratory studies of acoustic emission events with seismic signatures have used the point source assumption. Given the millimeter-scale size and clustering of the asperities and the centimeter-scale distances to the sensors, the records can convey information about the source...

... solution in detail. Pressure solution that occurs at both grain contacts and contacting asperities within fractures was incorporated in the model. By using the developed THMC numerical model, long-term prediction of rock permeability was conducted by replicating the subsurface environment near...

... at stressed asperities that explains the observed dependency of wear-rates on the mechanical impulse. Introduction The resistance of faults to slip serves as a proxy for the strength of the crust. In addition, the static and dynamic frictional strength of rocks are fundamental for understanding faults...

... Abstract: Fluid transport during hydraulic fracturing can be either proppant or asperity dominated. In the absence of proppants, dilatancy of the natural fractures during shear reactivation is required to provide sufficient aperture and hydraulic conductivity. If a hydraulic fracture...

... Abstract: A better understanding of the strength distributions and the seismic response of asperities failing within a cohesive (or breakdown) region of the growing shear rupture is important in many engineering disciplines, such as, hydraulic fracture and induced seismicity...

... the evolution of asperity damage and discontinuity void space morphology as a result of shearing. In this paper, a methodology that combines the use of two recent technologies (micro-X-ray computed tomography and combined finite-discrete element modeling) is described to study these aspects of discontinuity...

... Abstract Measurement of the shear to normal compliance ratio is one of the few remote sensing techniques available for estimating the in situ properties of fractures. We present an accurate yet efficient method for predicting the normal and shear compliance of fractures using an asperity...