Imperial College London
Portrait Picture

Professor of Rock Mechanics

Faculty of Engineering, Department of Earth Science & Engineering

Chair in Rock Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 7412r.w.zimmerman

 
 
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Location

 

2.38DRoyal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

254 results found

ZIMMERMAN RW, CHEN G, HADGU T, BODVARSSON GSet al., 1993, A NUMERICAL DUAL-POROSITY MODEL WITH SEMIANALYTICAL TREATMENT OF FRACTURE MATRIX FLOW, WATER RESOURCES RESEARCH, Vol: 29, Pages: 2127-2137, ISSN: 0043-1397

Journal article

Zimmerman RW, Bodvarsson GS, Flint AL, Flint LEet al., 1993, Inverse procedure for estimating the unsaturated hydraulic conductivities of volcanic tuffs, Pages: 1052-1058

A procedure is developed for estimating the hydraulic conductivity function of unsaturated volcanic tuff, using measurements of the sorptivity and capillary pressure functions. The method assumes that the sorptivity is a linear function of the initial saturation, as is suggested by experimental data. The procedure is tested on a vitrified tuff from the Calico Hills unit at Yucca Mountain, and the predicted conductivities are in reasonable agreement with measured values. Further tests of this method are needed to establish whether or not it can be routinely used for conductivity predictions.

Conference paper

HADGU T, ZIMMERMAN RW, BODVARSSON GS, 1993, COUPLING OF A RESERVOIR SIMULATOR AND A WELLBORE SIMULATOR FOR GEOTHERMAL APPLICATIONS, Geothermal Resources Council 1993 Annual Meeting, Publisher: GEOTHERMAL RESOURCES COUNCIL, Pages: 499-505, ISSN: 0193-5933

Conference paper

ZIMMERMAN RW, CHEN DW, COOK NGW, 1992, THE EFFECT OF CONTACT AREA ON THE PERMEABILITY OF FRACTURES, JOURNAL OF HYDROLOGY, Vol: 139, Pages: 79-96, ISSN: 0022-1694

Journal article

ZIMMERMAN RW, 1992, HASHIN-SHTRIKMAN BOUNDS ON THE POISSON RATIO OF A COMPOSITE-MATERIAL, MECHANICS RESEARCH COMMUNICATIONS, Vol: 19, Pages: 563-569, ISSN: 0093-6413

Journal article

Zimmerman RW, Kumar S, 1991, Fluid-mechanical model for blood flow in lung alveoli, Pages: 51-56, ISSN: 0272-5673

The flow of blood through the inter-alveolar septum of animal lung has often been modeled as an incompressible Newtonian fluid flowing between two parallel plates or membranes that are held apart and supported by cylindrical posts of septal tissue. The object of this modeling is to determine the manner in which the geometrical morphology of the septa affects the relationship between the drop in pressure and the volumetric flow rate of the blood. This flow is analyzed using a Brinkman-type equation, which is a hybrid of the Navier-Stokes equations and Darcy's law for flow through porous media, and a simple closed-form expression for the flow resistance is obtained. The results compare very well with experimental data from the literature that were obtained from a mechanical model with the same parallel-plate and cylindrical-post geometry.

Conference paper

Zimmerman RW, 1991, Approximate expressions for stress concentrations in elastic solids containing multiple holes or inclusions, Pages: 71-75, ISSN: 0160-8835

Kienzler and Duan (1987) and Greenwood (1989) have recently derived expressions for the hoop stresses around a circular hole in an infinite elastic sheet, in terms of the stresses that would exist in the sheet in the absence of the hole. These results are used here to find approximate expressions for the hoop stress concentrations in elastic sheets that contain two circular holes. This is done by considering the initial stress state to be the (readily calculable) state that would exist around a single hole. Application of this procedure leads to closed-form expressions that are fairly accurate whenever the smallest distance between the holes is not less than about one hole radius.

Conference paper

ZIMMERMAN RW, 1991, ELASTIC-MODULI OF A SOLID CONTAINING SPHERICAL INCLUSIONS, MECHANICS OF MATERIALS, Vol: 12, Pages: 17-24, ISSN: 0167-6636

Journal article

ZIMMERMAN RW, BODVARSSON GS, 1991, AN APPROXIMATE SOLUTION FOR ONE-DIMENSIONAL ABSORPTION IN UNSATURATED POROUS-MEDIA - REPLY, WATER RESOURCES RESEARCH, Vol: 27, Pages: 2161-2162, ISSN: 0043-1397

Journal article

ZIMMERMAN RW, KUMAR S, BODVARSSON GS, 1991, LUBRICATION THEORY ANALYSIS OF THE PERMEABILITY OF ROUGH-WALLED FRACTURES, INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES & GEOMECHANICS ABSTRACTS, Vol: 28, Pages: 325-331, ISSN: 0148-9062

Journal article

KUMAR S, ZIMMERMAN RW, BODVARSSON GS, 1991, PERMEABILITY OF A FRACTURE WITH CYLINDRICAL ASPERITIES, FLUID DYNAMICS RESEARCH, Vol: 7, Pages: 131-137, ISSN: 0169-5983

Journal article

MARTEL SJ, ZIMMERMAN RW, 1991, APPLICATION OF LINEAR ELASTIC FRACTURE-MECHANICS TO THE QUANTITATIVE-EVALUATION OF FLUID-INCLUSION DECREPITATION - COMMENT, GEOLOGY, Vol: 19, Pages: 663-664, ISSN: 0091-7613

Journal article

ZIMMERMAN RW, BODVARSSON GS, 1991, A SIMPLE APPROXIMATE SOLUTION FOR HORIZONTAL INFILTRATION IN A BROOKS-COREY MEDIUM, TRANSPORT IN POROUS MEDIA, Vol: 6, Pages: 195-205, ISSN: 0169-3913

Journal article

Zimmerman RW, Kumar S, Bodvarsson GS, 1991, Lubrication theory analysis of the permeability of rough-walled fractures, Pages: 535-541

Lubrication theory is used to study the permeability of rough-walled rock fractures. Two idealized models of a fracture, in which the roughness follows a sinusoidal or a sawtooth variation, are studied in detail. The results are similar to those found previously from numerical analysis of fractures with random aperture distributions, in that the ratio of the hydraulic aperture depends mainly on the mean and the standard deviation of the aperture distribution. Higher-order approximations to the Navier-Stokes equations are then studied, and it is concluded that the validity of the lubrication approximation requires the fracture walls to be smooth over lengths on the order of one standard deviation of the aperture.

Conference paper

Schlueter EM, Cook NGW, Zimmerman RW, Witherspoon PAet al., 1991, Predicting permeability and electrical conductivity of sedimentary rocks from microgeometry, Pages: 355-364

Hydraulic permeability and electrical conductivity of sedimentary rocks are predicted from the microscopic geometry of the pore space. The cross-sectional areas and perimeters of the individual pores are estimated from two-dimensional scanning electron micrographs of rock sections. The hydraulic and electrical conductivities of the individual pores are determined from these geometrical parameters, using Darcy's law and Ohm's law. The effective medium theory from solid-state physics is then used to determine an effective average conductance of each pore. Finally, the pores are assumed to be arranged on a cubic lattice, which allows the calculation of overall macroscopic values for the permeability and the electrical conductivity. Preliminary results using Berea, Boise, Massilon and Saint-Gilles sandstones show reasonably close agreement between the predicted and measured transport properties.

Conference paper

Zimmerman RW, 1991, Compressibility of sandstones, Compressibility of sandstones

This book discusses the elastic volumetric response of sandstones to variations in stress. The theory and data presented apply to the deformations that occur, for example, due to withdrawal of fluid from a reservoir, or due to the redistribution of stresses caused by the drilling of a borehole. Part 1 concerns the effect of stress on deformation and discusses porous rock compressibility coefficients. Part 2 deals with the relationship between pore structure and compressibility, and presents methods that permit quantitative prediction of the compressibility coefficients. Part 3 is a brief summary of experimental techniques that are used to measure porous rock compressibilities in the laboratory. A reference list, author index and subject index are provided. -after Publisher

Journal article

Zimmerman RW, 1991, Compressibility of Sandstones, Amsterdam, Publisher: Elsevier, ISBN: 9780444883254

Book

ZIMMERMAN RW, BODVARSSON GS, KWICKLIS EM, 1990, ABSORPTION OF WATER INTO POROUS BLOCKS OF VARIOUS SHAPES AND SIZES, WATER RESOURCES RESEARCH, Vol: 26, Pages: 2797-2806, ISSN: 0043-1397

Journal article

Kumar S, Zimmerman RW, Bodvarsson GS, 1990, Study of fractal aperture distribution and flow in fractures, Pages: 559-564

This study examines the roughness profiles and aperture distributions of fractures and faults by using concepts from fractal geometry. Simple models of flow of fluid in rough fractures are also discussed. A deterministic fractal representation of the roughness profile is presented which is shown to have many distinct advantages over other numerical methods, such as information compression, uniqueness and repeatability of surface simulation, retention of statistical information, and self-similarity over many scales. Also the fractal representation enables an isotropic surface and an aperture distribution to be simulated by examining a measured profile. Saturated fluid flow in fractures is then computed using a combined Navier-Stokes and Darcy equation.

Conference paper

Zimmerman RW, Bodvarsson GS, 1990, Combined analytical/numerical approaches to solving fluid flow problems in the unsaturated zone at Yucca Mountain, Pages: 818-824

Various analytical and numerical approaches are presented for the study of unsaturated flow processes in the vicinity of the Yucca Mountain, Nevada, the proposed site of an underground radioactive waste repository. Approximate analytical methods are used to study absorption of water from a saturated fracture into the adjacent rock. These solutions are incorporated into a numerical simulator as fracture/matrix interaction terms to treat problems such as flow along a fracture with transverse leakage into the matrix. An automatic fracture/matrix mesh generator is described; it allows for more efficient mesh generation for fractured/porous media, and consequently leads to large savings in computational time and cost.

Conference paper

Zimmerman RW, Bodvarsson GS, Kwicklis EM, 1990, Absorption of Water Into Porous Blocks of Various Shapes and Sizes, Water Resources Research, Vol: 26, Pages: 2797-2806, ISSN: 0043-1397

Approximate solutions are presented for absorption of water into porous spherical, cylindrical, and slablike blocks whose characteristic curves are of the van Genuchten‐Mualem type. The solutions are compared to numerical simulations of absorption into blocks of the Topopah Spring member (Paintbrush tuff) from the site of the proposed nuclear waste repository at Yucca Mountain, Nevada. Guided by these results, a scaling law, based on the ratio of surface area to volume, is then proposed for predicting the rate of absorption into irregularly shaped blocks. This scaling law is tested against a numerical simulation of absorption into an irregularly shaped, 2‐dimensional polygonal block and is shown to be a good approximation. Copyright 1990 by the American Geophysical Union.

Journal article

Zimmerman RW, Bodvarsson GS, 1989, Semi-analytical solutions for flow problems in unsaturated porous media, Pages: 23-28

Semi-analytical solutions are developed for two unsaturated flow problems that are relevant to characterizing the hydrological behavior of Yucca Mountain, the site of a proposed nuclear waste repository. The 'integral' or 'boundary-layer' approach is used to find a closed-form approximate solution for absorption of water from a saturated fracture into an unsaturated semi-infinite formation. This solution is then programmed into a numerical code as a source/sink term for fracture elements, and used to study the problem of flow along a fracture with transverse leakage to the rock matrix.

Conference paper

Zimmerman RW, 1989, THERMAL CONDUCTIVITY OF FLUID-SATURATED ROCKS, JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, Vol: 3, Pages: 219-227, ISSN: 0920-4105

Journal article

ZIMMERMAN RW, BODVARSSON GS, 1989, INTEGRAL METHOD SOLUTION FOR DIFFUSION INTO A SPHERICAL BLOCK, JOURNAL OF HYDROLOGY, Vol: 111, Pages: 213-224, ISSN: 0022-1694

Journal article

ZIMMERMAN RW, BODVARSSON GS, 1989, AN APPROXIMATE SOLUTION FOR ONE-DIMENSIONAL ABSORPTION IN UNSATURATED POROUS-MEDIA, WATER RESOURCES RESEARCH, Vol: 25, Pages: 1422-1428, ISSN: 0043-1397

Journal article

Chen DW, Zimmerman RW, Cook NGW, 1989, The effect of contact area on the permeability of fractures, Pages: 81-88

The permeability of a rock fracture is controlled primarily by the geometry of its void space. In order to focus on the tortuosity induced by the contact area, we consider an idealized fracture consisting of two parallel plates propped open by isolated asperities. Boundary-element calculations, analogue electrical conductivity measurements, and an effective medium approximation are used to study the permeability of fractures with circular, elliptical, and irregular asperity shapes.

Conference paper

ZIMMERMAN RW, 1988, STRESS-CONCENTRATION AROUND A PAIR OF CIRCULAR HOLES IN A HYDROSTATICALLY STRESSED ELASTIC SHEET, JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME, Vol: 55, Pages: 487-488, ISSN: 0021-8936

Journal article

KING MS, ZIMMERMAN RW, CORWIN RF, 1988, SEISMIC AND ELECTRICAL-PROPERTIES OF UNCONSOLIDATED PERMAFROST, GEOPHYSICAL PROSPECTING, Vol: 36, Pages: 349-364, ISSN: 0016-8025

Journal article

ZIMMERMAN RW, 1988, STRESS SINGULARITY AROUND 2 NEARBY HOLES, MECHANICS RESEARCH COMMUNICATIONS, Vol: 15, Pages: 87-90, ISSN: 0093-6413

Journal article

ZIMMERMAN RW, 1988, 2ND-ORDER APPROXIMATION FOR THE COMPRESSION OF AN ELASTIC PLATE CONTAINING A PAIR OF CIRCULAR HOLES, ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK, Vol: 68, Pages: 575-577, ISSN: 0044-2267

Journal article

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