14 Matching Results

Search Results

Advanced search parameters have been applied.

Re-alignment: It is the tunnel floor which moves, isn`t it?

Description: It is shown that on the months to years time scale, accelerator tunnels built in compacted geological strata exhibit a movement of the floor systematic (unidirectional) in each point. Attempts to characterize the movement through one global number (a <rms> deviation) based on a random model are conceptionally wrong and can only lead to erroneous design decisions for future accelerators. In the extrapolation limit, differences are especially pronounced for differential movements in the case of short (days) time spans, and for accumulated movements in the case of long (years) time spans.
Date: October 1, 1995
Creator: Pitthan, R.
Partner: UNT Libraries Government Documents Department

Mine stability evaluation of panel 1 during waste emplacement operations at WIPP

Description: The specific objectives of the work were defined by the Environmental Evaluation Group (EEG) as follows: (1) assess the stability of panel 1 during the proposed operation of waste emplacement; (2) estimate the amount of time before room closure would be expected to transfer rock loads to the waste packages. The work consisted of (1) an analysis of geotechnical data and a review of the Department of Energy`s (DOE) plans for waste emplacement in panel 1, (2) an evaluation of ground conditions based on data analysis and observations of changes in ground conditions since the first evaluation in 1993 (USBM 1993), and (3) preparation of a report and presentation of the results to EEG staff. Excluded from this study are radiological safety issues and policies. The study is based on data provided by DOE and Westinghouse Electric Corporation (operator of the site) and conversations with DOE and Westinghouse personnel. MTI cannot independently verify the accuracy of the data within the scope of this study and recommends independent evaluations of data gathering, quality assurance procedures, and structural designs. The operator has the ultimate responsibility for structural designs and has expressed a strong commitment to ensuring worker safety.
Date: July 1, 1998
Creator: Maleki, H.
Partner: UNT Libraries Government Documents Department

Global positioning system reobservations over the Eastern United States Strain Monitoring Network

Description: In the period March--May, 1990, a 45 station geodetic network, originally established in November--December, 1987, was reobserved using global positioning system (GPS) technology. This network, known as the Eastern US Strain network, was established for the purpose of determining strain and deformation in the central and eastern US. This 1990 reobservation was the first of a series of reobservations scheduled to take place over a decade in order to place meaningful constraints on the small differential movements involved.
Date: June 1, 1996
Creator: Strange, W.E.
Partner: UNT Libraries Government Documents Department

Drift scale thermomechanical analysis for thermal loading and retrievability studies

Description: Currently, the repository portion of the Mined Geologic Disposal System for the disposal of spent nuclear fuel and high level radioactive waste is in the advanced conceptual design (ACD) stage. As a part of the Thermal Loading Systems Study and the Retrievability Period Systems Study, a numerical method was used to estimate the stability of emplacement drifts. Drift stability is an important performance issue, particularly for the concept of a waste package (WP) in an open drift. Drift stability is both a preclosure and postclosure issue. Specifically, preclosure worker safety and WP retrievability can be affected by drift stability. Important postclosure drift stability issues are the potential for rockfall which might damage a WP or the potential formation of cracks and upheaval of rock masses which may alter the hydrologic performance of the repository. In the current study, thermomechanical analyses, using the Discontinuous Deformation Analysis (DDA) numerical code, were performed to support the thermal loading study and the retrievability study. The coupled effects between thermal and mechanical behavior induced by the excavation, thermal loading and rapid cooling were analyzed using rock-mass models. Input data for the jointed-rock pattern, in situ stress condition, and the material properties of intact rock and rock joints were adopted from the Yucca Mountain Site Characterization Project.
Date: December 31, 1995
Creator: Tsai, F.C.
Partner: UNT Libraries Government Documents Department

Annual stability evaluation of Waste Isolation Pilot Plant

Description: A stability evaluation of the underground workings of the Waste Isolation Pilot Plant (WIPP) was completed by the US Bureau of Mines` WIPP evaluation committee. This work included a critical evaluation of the processes employed at WIPP to ensure stability, an extensive review of available deformation measurements, a 3-day site visit, and interviews with the Department of Energy (DOE) and Westinghouse staff. General ground control processes are in place at WIPP to minimize the likelihood that major stability problems will go undetected. To increase confidence in both short- and long-term stability throughout the site (underground openings and shafts), ground stability monitoring systems, mine layout design, support systems and data analyses must be continuously improved. Such processes appear to be in place at WIPP and are discussed in this paper.
Date: June 1, 1993
Partner: UNT Libraries Government Documents Department

Two-dimensional nonlinear finite element analysis of well damage due to reservoir compaction, well-to-well interactions, and localization on weak layers

Description: In this paper the authors present the results of a coupled nonlinear finite element geomechanics model for reservoir compaction and well-to-well interactions for the high-porosity, low strength diatomite reservoirs of the Belridge field near Bakersfield, California. They show that well damage and failures can occur under the action of two distinct mechanisms: shear deformations induced by pore compaction, and subsidence, and shear deformations due to well-to-well interactions during production or water injection. They show such casting damage or failure can be localized to weak layers that slide or slip under shear due to subsidence. The magnitude of shear displacements and surface subsidence agree with field observations.
Date: May 1996
Creator: Hilbert, L.B. Jr.; Fredrich, J.T.; Bruno, M.S.; Deitrick, G.L. & Rouffignac, E.P. de
Partner: UNT Libraries Government Documents Department

Air intake shaft performance tests (Shaft 5): In situ data report (May 1988--July 1995). Waste Isolation Pilot Plant (WIPP) Thermal/Structural Interactions Program

Description: Data are presented from the Air Intake Shaft Test, an in situ test fielded at the Waste Isolation Pilot Plant (WIPP). The construction of this shaft, well after the initial three access shafts, presented an unusual opportunity to obtain valuable detailed data on the mechanical response of a shaft for application to seal design. These data include selected fielding information, test configuration, instrumentation activities, and comprehensive results from a large number of gages. Construction of the test began in December 1987; gage data in this report cover the period from May 1988 through July 1995, with the bulk of the data obtained after obtaining access in November, 1989 and from the heavily instrumented period after remote gage installation between May, 1990, and October, 1991.
Date: July 1, 1995
Creator: Munson, D.E.; Hoag, D.L.; Ball, J.R.; Baird, G.T. & Jones, R.L.
Partner: UNT Libraries Government Documents Department

Evaluation of potential surface rupture and review of current seismic hazards program at the Los Alamos National Laboratory. Final report

Description: This report summarizes the authors review and evaluation of the existing seismic hazards program at Los Alamos National Laboratory (LANL). The report recommends that the original program be augmented with a probabilistic analysis of seismic hazards involving assignment of weighted probabilities of occurrence to all potential sources. This approach yields a more realistic evaluation of the likelihood of large earthquake occurrence particularly in regions where seismic sources may have recurrent intervals of several thousand years or more. The report reviews the locations and geomorphic expressions of identified fault lines along with the known displacements of these faults and last know occurrence of seismic activity. Faults are mapped and categorized into by their potential for actual movement. Based on geologic site characterization, recommendations are made for increased seismic monitoring; age-dating studies of faults and geomorphic features; increased use of remote sensing and aerial photography for surface mapping of faults; the development of a landslide susceptibility map; and to develop seismic design standards for all existing and proposed facilities at LANL.
Date: December 9, 1991
Partner: UNT Libraries Government Documents Department

Coupled rock motion and gas flow modeling in blasting

Description: The spherical element computer code DMC (Distinct Motion Code) used to model rock motion resulting from blasting has been enhanced to allow routine computer simulations of bench blasting. The enhancements required for bench blast simulation include: (1) modifying the gas flow portion of DMC, (2) adding a new explosive gas equation of state capability, (3) modifying the porosity calculation, and (4) accounting for blastwell spacing parallel to the face. A parametric study performed with DMC shows logical variation of the face velocity as burden, spacing, blastwell diameter and explosive type are varied. These additions represent a significant advance in the capability of DMC which will not only aid in understanding the physics involved in blasting but will also become a blast design tool. 8 refs., 7 figs., 1 tab.
Date: January 1, 1991
Creator: Preece, D.S. (Sandia National Labs., Albuquerque, NM (United States)) & Knudsen, S.D. (RE/SPEC, Inc., Albuquerque, NM (United States))
Partner: UNT Libraries Government Documents Department

Modelling surface motion and spall at the Nevada Test Site. Los Alamos Source Region Project

Description: Spallation of the ground surface accompanies all underground nuclear explosions of significant yield. This report discusses computer modelling used to investigate the physical processes that govern spallation and the amplitude and wavelength of motion at the free surface under a variety of conditions. Four events are selected: MERLIN which was conducted in desert alluvium; HEARTS which was conducted in tuff beneath the water table in Yucca Flat; TOWANDA which was conducted beneath the water table on Pahute Mesa; and HOUSTON which was conducted above the water table in very dense rock and Pahute Mesa. These span the range of test environments for Los Alamos underground nuclear tests.
Date: January 1, 1992
Creator: App, F. N. & Brunish, W. M.
Partner: UNT Libraries Government Documents Department

G-tunnel welded tuff mining experiment preparations

Description: Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a mine-by in welded tuff so that predictive-type information could be obtained regarding the response of the rock to a drill and blast excavation process, where smooth blasting techniques were used. Included in the study were evaluations of and recommendations for various measurement systems that might be used in future mine-by efforts. This report summarizes the preparations leading to the recording of data. 17 refs., 27 figs., 5 tabs.
Date: January 1, 1991
Creator: Zimmerman, R.M.; Bellman, R.A. Jr.; Mann, K.L. & Zerga, D.P.
Partner: UNT Libraries Government Documents Department

Intermediate scale borehole (Room C): In situ data report (January 1989--June 1993)

Description: Data are presented from the intermediate scale borehole test, an in situ test fielded in the pillar separating Rooms C1 and C2 at the Waste Isolation Pilot Plant (WIPP). The test was to provide data on the influence of scale, if any, on the structural behavior of underground openings in salt. These data include selected fielding information, test configuration, instrumentation activities, and comprehensive results from a large number of gages. Construction of the test began in December 1989, with the drilling of the intermediate scale borehole in December 1990. Gage data in this report cover the period from January 1989 through June 1993.
Date: November 1, 1994
Creator: Munson, D. E.; Christian-Frear, T. L.; Baird, G. T.; Labreche, D. A.; Ball, J. R.; Jones, R. L. et al.
Partner: UNT Libraries Government Documents Department

Discontinuous behavior near excavations in a bedded salt formation

Description: Discontinuous behavior is being observed and measured in the vicinity of excavations constructed in a bedded salt formation 650 m below ground surface for the Waste Isolation Pilot Plant (WIPP) Facility. The 2 m thick salt layer in the immediate roof acts as a beam, shearing along a thin overlying anhydrite/clay seam. The floor of the excavations is comprised of a 1 m thick salt layer underlain by a 1 m thick predominately anhydrite layer (referred to as MB139). In the ribs, there is limited fracturing within the first meter of most larger excavations. Vertical fractures develop in pillars at most intersections. The discontinuous behavior is qualitatively consistent with analyses of the formation behaving as a layered medium (elastic beam analysis) and limited tensile and compressive failure of the rock salt. The significance of the discontinuous behavior is that can dominate the effective fluid transport properties of the formation near the excavation, and therefore requires considerations in the design of repository seals. Furthermore, the discontinuous behavior must be monitored and is a very important consideration in the maintenance program designed to assume a safe underground environment. 22 refs., 17 figs.
Date: October 1, 1990
Creator: Stormont, J.C.
Partner: UNT Libraries Government Documents Department