Persistent Link:
http://hdl.handle.net/10150/185768
Title:
Heat flow into underground openings: Significant factors.
Author:
Ashworth, Eileen.
Issue Date:
1992
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
This project investigates the heat flow from the rock into ventilating airways by studying various parameters. Two approaches have been used: laboratory measurement of thermal properties to study their variation, and analytic and numerical models to study the effect of these variations on the heat flow. Access to a heat-flux system and special treatment of contact resistance has provided the opportunity to study thermal conductivity as a function of moisture contained in rock specimens. For porous sandstone, tuff, and concretes, thermal conductivity can double when the specimens are soaked; the functional dependence of conductivity on moisture for the first two cases is definitely non-linear. Five previous models for conductivity as a function of porosity are shown not to explain this new phenomenon. A preliminary finite element model is proposed which explains the key features. Other variations of conductivity with applied pressure, location, constituents, weathering or other damage, and anisotropy have been measured. In the second phase of the research, analytical and numerical methods have been employed to consider the effects of the variation in the thermal properties plus the use of insulation on the heat flow from the rock into the ventilated and cooled airways. Temperature measurements taken in drill holes at a local mine provide confirmation for some of the models. Results have been provided in a sensitivity analysis mode so that engineers working on other projects can see which parameters would require more detailed consideration. The thermal conductivity of the rock close to the airways is a key factor in affecting heat loads. Dewatering and the use of insulation, such as lightweight foamed shotcretes, are recommended.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Finite element method.; Finite differences.; Heat equation.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Geological Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
McPherson, M.J.; Harpalani, S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHeat flow into underground openings: Significant factors.en_US
dc.creatorAshworth, Eileen.en_US
dc.contributor.authorAshworth, Eileen.en_US
dc.date.issued1992en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThis project investigates the heat flow from the rock into ventilating airways by studying various parameters. Two approaches have been used: laboratory measurement of thermal properties to study their variation, and analytic and numerical models to study the effect of these variations on the heat flow. Access to a heat-flux system and special treatment of contact resistance has provided the opportunity to study thermal conductivity as a function of moisture contained in rock specimens. For porous sandstone, tuff, and concretes, thermal conductivity can double when the specimens are soaked; the functional dependence of conductivity on moisture for the first two cases is definitely non-linear. Five previous models for conductivity as a function of porosity are shown not to explain this new phenomenon. A preliminary finite element model is proposed which explains the key features. Other variations of conductivity with applied pressure, location, constituents, weathering or other damage, and anisotropy have been measured. In the second phase of the research, analytical and numerical methods have been employed to consider the effects of the variation in the thermal properties plus the use of insulation on the heat flow from the rock into the ventilated and cooled airways. Temperature measurements taken in drill holes at a local mine provide confirmation for some of the models. Results have been provided in a sensitivity analysis mode so that engineers working on other projects can see which parameters would require more detailed consideration. The thermal conductivity of the rock close to the airways is a key factor in affecting heat loads. Dewatering and the use of insulation, such as lightweight foamed shotcretes, are recommended.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectFinite element method.en_US
dc.subjectFinite differences.en_US
dc.subjectHeat equation.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeological Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorMcPherson, M.J.en_US
dc.contributor.advisorHarpalani, S.-
dc.contributor.committeememberKemeny, J.M.en_US
dc.contributor.committeememberNeuman, S.en_US
dc.contributor.committeememberKulatilake, P.H.S.W.en_US
dc.identifier.proquest9220695en_US
dc.identifier.oclc700943260en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.