Development of a Microcracking Technique for Measuring in Situ Stress and Strain
Author: Richard L. Stowe
Publisher:
Published: 1967
Total Pages: 78
ISBN-13:
DOWNLOAD EBOOKRead and Download eBook Full
Author: Richard L. Stowe
Publisher:
Published: 1967
Total Pages: 78
ISBN-13:
DOWNLOAD EBOOKAuthor: Richard L. Stowe
Publisher:
Published: 1967
Total Pages: 62
ISBN-13:
DOWNLOAD EBOOKAuthor: Richard L. Stowe
Publisher:
Published: 1967
Total Pages: 56
ISBN-13:
DOWNLOAD EBOOKAuthor: R. L. Stowe
Publisher:
Published: 1967
Total Pages: 50
ISBN-13:
DOWNLOAD EBOOKA laboratory study of the relation between the magnitude of static and dynamic stresses to which hardened portland cement grout specimens were subjected and the degree of resulting internal microcracking in the specimens had indicated that this relation might permit use of grout cylinders as mechanical-type strain gages for measuring free-field strain in in situ material adjacent to high-yield explosions. This possibility was tested in conjunction with a high-explosive cratering shot detonated by the Air Force Weapons Laboratory. Before the test, 11 grout mixtures covering a range of strengths from 50 percent below to 50 percent above the stresses predicted to result from the 16,000-pound field explosion were proportioned in the laboratory, and 330 2- by 4-inch specimens were prepared. Static compressive tests were performed on specimens of each mixture at 7 and 28 days age, and unconfined, uniaxial, dynamic compression tests were performed at various increments of the estimated ultimate stress. The specimens were then sawed; slices were prepared and photographed. The photographs were enlarged and examined to determine internal microcracking. In the field, three 5-1/2-inch-diameter by 42-foot-deep boreholes were drilled 20, 30, and 40 feet from the point of detonation. Specimens of the 11 grout mixtures were placed in the holes in a medium-matching grout, subjected to the blast, recovered (except for about a third of the instruments which were lost in the crater), returned to the laboratory, and examined for extent of induced microcracking. The laboratory data were used for standard curves from which a correlation of the field data was made.
Author:
Publisher:
Published: 1967-05
Total Pages: 1470
ISBN-13:
DOWNLOAD EBOOKAuthor: Antonio A. Munjiza
Publisher: John Wiley & Sons
Published: 2004-04-21
Total Pages: 348
ISBN-13: 0470020172
DOWNLOAD EBOOKThe combined finite discrete element method is a relatively new computational tool aimed at problems involving static and / or dynamic behaviour of systems involving a large number of solid deformable bodies. Such problems include fragmentation using explosives (e.g rock blasting), impacts, demolition (collapsing buildings), blast loads, digging and loading processes, and powder technology. The combined finite-discrete element method - a natural extension of both discrete and finite element methods - allows researchers to model problems involving the deformability of either one solid body, a large number of bodies, or a solid body which fragments (e.g. in rock blasting applications a more or less intact rock mass is transformed into a pile of solid rock fragments of different sizes, which interact with each other). The topic is gaining in importance, and is at the forefront of some of the current efforts in computational modeling of the failure of solids. * Accompanying source codes plus input and output files available on the Internet * Important applications such as mining engineering, rock blasting and petroleum engineering * Includes practical examples of applications areas Essential reading for postgraduates, researchers and software engineers working in mechanical engineering.
Author: R. L. Stowe
Publisher:
Published: 1967
Total Pages: 72
ISBN-13:
DOWNLOAD EBOOKAuthor:
Publisher:
Published: 1969
Total Pages: 62
ISBN-13:
DOWNLOAD EBOOKContents: Reports from U.S. Army Engineer Waterways Experiment Station and St. Paul District Hydraulic Laboratory; Reports published and distributed by Waterways Experiment Station for other Corps of Engineers agencies; Engineer manuals.
Author: B. Amadei
Publisher: Springer Science & Business Media
Published: 2012-12-06
Total Pages: 524
ISBN-13: 9401153469
DOWNLOAD EBOOKRock masses are initially stressed in their current in situ state of stress and to a lesser natural state. Whether one is interested in the extent on the monitoring of stress change. formation of geological structures (folds, faults, The subject of paleostresses is only briefly intrusions, etc. ), the stability of artificial struc discussed. tures (tunnels, caverns, mines, surface excava The last 30 years have seen a major advance our knowledge and understanding of rock tions, etc. ), or the stability of boreholes, a in the in situ or virgin stress field, stress. A large body of data is now available on knowledge of along with other rock mass properties, is the state of stress in the near surface of the needed in order to predict the response of rock Earth's crust (upper 3-4km of the crust). masses to the disturbance associated with those Various theories have been proposed regarding structures. Stress in rock is usually described the origin of in situ stresses and how gravity, within the context of continuum mechanics. It is tectonics, erosion, lateral straining, rock fabric, defined at a point and is represented by a glaciation and deglaciation, topography, curva second-order Cartesian tensor with six compo ture of the Earth and other active geological nents. Because of its definition, rock stress is an features and processes contribute to the current enigmatic and fictitious quantity creating chal in situ stress field.