Fracture Mechanics Characterization of an AnisotropicGeomaterial

Argillites are considered worldwide as potential host rock for high level radioactive waste given the low permeability and strong adsorption potential. However, the excavation of the galleries of a repository would produce a disturbed zone around the boundaries rich of new fractures which may enhance the conductivity of the rock along the gallery axis. Several mine-by experiments have been performed in underground rock labs to investi- gate the features of the disturbed zone. In Mont Terri URL (Kanton Jura, Switzerland) the EZ-B experiment was specifically conceived for the measurement of excavation induced fractures around a small chamber. The host rock of the URL is a particularly compact and resistant argillite, known as the Opalinus Clay (OPA) excavated and OPA samples were subjected to fracture mechanics tests at the rock mechanics lab of IGAG-CNR in Torino, Italy. The tests aimed at the understanding aspects of the fracturing process occurring in OPA of Mont Terri, which may be considered a transversely isotropic geomaterial, whose planes of isotropy coincide with the beddin

Mathematical Problems in Rock Mechanics and Rock Engineering

With increasing requirements for energy, resources and space, rock engineering projects are being constructed more often and are operated in large-scale environments with complex geology. Meanwhile, rock failures and rock instabilities occur more frequently, and severely threaten the safety and stability of rock engineering projects. It is well-recognized that rock has multi-scale structures and involves multi-scale fracture processes. Meanwhile, rocks are commonly subjected simultaneously to complex static stress and strong dynamic disturbance, providing a hotbed for the occurrence of rock failures. In addition, there are many multi-physics coupling processes in a rock mass. It is still difficult to understand these rock mechanics and characterize rock behavior during complex stress conditions, multi-physics processes, and multi-scale changes. Therefore, our understanding of rock mechanics and the prevention and control of failure and instability in rock engineering needs to be furthered. The primary aim of this Special Issue “Mathematical Problems in Rock Mechanics and Rock Engineering” is to bring together original research discussing innovative efforts regarding in situ observations, laboratory experiments and theoretical, numerical, and big-data-based methods to overcome the mathematical problems related to rock mechanics and rock engineering. It includes 12 manuscripts that illustrate the valuable efforts for addressing mathematical problems in rock mechanics and rock engineering

Evaluation of many load tests of passive rock bolts in the Czech Republic

Within the research project "FR-TI4/329 Research and development - creating an application system for the design and analysis of soil and rock anchors including the development of monitoring elements", an extensive stage of field load tests of rock bolts was carried out. The tests were conducted at 14 locations with varied rock composition. Before the initial tests, a loading stand was designed and constructed. A total of 201 pieces of tensile tests of bolts having lengths from 0.5 up to 2.5 m, a diameter of 22-32 mm, were performed. These were fully threaded rods, self-drilling rods, and fiberglass rods. The bolts were clamped into the cement and resin. The loading tests were always performed until material failure of bolts or shear stress failure at the interface cement-rock. At each location, basic geotechnical survey was carried out in the form of core drilling in a length of 3.0 metres with the assessment of the rock mass in situ, and laboratory testing of rock mechanics. Upon the completion of testing protocols, rock mass properties analysis was performed focusing on the evaluation of shear friction at the grouting-rock interface

Dynamic Analysis of Deep Mining Disaster Control in China and its Application in the Ivory Coast’s Mining Activities

With the increasing depth of mining, rock burst is on the rise. China’s deep mining industry faces such a threat. A major problem of deep mining is high ground stress, which is the major factor of rock burst. Due to the complexity of the rock burst mechanisms, complexity of induced factors as well as suddenness and randomness of rock burst occurrences, studies of rock burst prediction and control for safe mine exploitation is far from satisfying. The purpose of this paper is to examine of rock burst phenomenon in order to understand both stability in rock mechanics and the prediction of instability disasters in rock mechanics for application in the Ivory Coast mining sector with reference to the current Chinese mining industry

Second law of thermodynamics and the failure of rock materials

The relation of nonequilibrium thermodynamics to some failure and fracture theories of rock mechanics is investigated. The basic concepts are given to connect failure to the properties of material equations describing the elastic properties. The resulted in thermodynamic conditions are proved to be compatible with classical localization and failure theories of solid materials. Compatibility with experiments and some empirical, adhoc failure criteria of rocks is also demonstrated

Pore geometry as a control on rock strength

This study was funded via RJW's University of Leicester start-up fund, as part of AAB's PhD project. We thank Don Swanson and Mike Poland at HVO, Hawai'i, for their help and advice during fieldwork planning and sample collection in the Koa'e fault system, and the National Park Service for granting a research permit to collect rock samples. Sergio Vinciguerra is thanked for access to the Rock Mechanics and Physics lab at the British Geological Survey and Audrey Ougier-Simonin is thanked for her help preparing samples and advice during testing. We thank Mike Heap (EOST Strasbourg) and an anonymous reviewer for their detailed and careful comments that greatly improved the manuscript.Peer reviewedPostprin

Junior Order of United American Mechanics, Wade Hampton Council Records - Accession 1682

Contained within the Junior Order of United American Mechanics, Wade Hampton Council Records is primarily financial records, including old checks and bank statements, however there is also a printing plate with the seal of the JOUAM, and two identical ribbons presented to the Wade Hampton Council. This particular council no longer exists, however the overall Order is still running. Anyone interested in older financial records of this council will find this collection useful, as well as anyone interested in the organization’s seal. The records are all early 20th century, so anyone interested in how finance was conducted during that time, regardless of relation to the Order, may also have interest.https://digitalcommons.winthrop.edu/manuscriptcollection_findingaids/2685/thumbnail.jp

Triaxial compression testing of multicomponent geomaterials from quartz-poor (syenitic) systems

This paper focuses on mafic microgranular enclaves enclosed in quartz-poor igneous rocks and their effect on strength properties of the rock massif. The study examines host rock–enclave multicomponent geomaterials from enclave-bearing syenitic rocks from the Třebíč Massif exposed in the Královec quarry near Jaroměřice nad Rokytnou in the Czech Republic. A series of laboratory tests were performed to describe strength properties of individual constituents of the multicomponent geomaterials. We mainly focused on triaxial compression tests, however, rebound hardness, uniaxial compressive strength and indirect tensile strength were determined as well. The obtained results indicate that enclaves and even the contact zones between the enclaves and host rocks do not have any negative influence on the rock strength. In contrast, enclaves represent “stress concentrators” within such multicomponent systems. Strength properties of various multicomponent geomaterials are practically an unexplored topic in the field of rocks mechanics and future studies are needed to establish a robust database describing the behaviour of such geocomposites

Extension Of Numerical Manifold Method For Plasticity And Fracture Modelling Of Rock Mass

Previous studies on numerical modelling of geotechnical engineering problems indicate the importance of modelling in safe and sustainable designing of geotechnical projects. Generally, the stability of built engineering structures in rock is directly influenced by stability of the rock mass that contains the structure. In addition, the economical engineering design usually suggests the usage of existing rock to support the underground structure hence minimizing the additional handling of support systems. Therefore, an accurate and precise assessment of rock stability is required, that can be hugely achieved by modelling the rock mass stability. However, many approximations considered in the traditional modelling techniques of the rock mass were not able to simulate both discontinuity and continuum problems. Hence, new models have been developed and improved for providing accurate modelling techniques for rock mechanics. The Numerical Manifold Method (NMM) developed by Shi (1997) is one of the hybrid continuum–discontinuum models which is suitable for modelling complex problems in rock mechanics. However, the NMM method requires extension for solving the plasticity and cracking problems to model rock mass stability and determines reliable simulation results

Identifikasi Jenis Batuan Candi Dukuh, Candi Ngempon dan Candi Gedong Songo Menggunakan Sonic Viewer-sx 5251

Rock identification with rock mechanics properties of rock samples to determine the type of Dukuh temple , Ngempon temple and Gedong songo temple, with the ultrasonic wave method using Sonic Viewer SX - 5251. Travel time of ultrasonic waves on the sample is used to obtain S and P wave velocity. Data has processing using Excel software. Value of the S and P wave velocity, shear modulus , rock elasticity , and Poisson 's Ratio will be correlated with rock density tables, P and S wave velocity tables and rock mechanics properties table it can be seen kind of rock from each of the rock physics properties. The research result shows that rock composite Ngempon temple, Dukuh temple , and Gedong Songo are Andesite. In addition to the density values which obtained, the level of rocks weathering can be defermind as well. Dukuh B rock sample with a density of 2.66 gm /cm3 can be classified in level I, it show that those rocks are strong and good. On the other samples of the Ngempon temple, gedong Songo or from another Dukuh the density values which obtained are from 2.33 to 2.49 can be classified at level II or it can be said to be strong enough