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Papers by Paul Michaels

The Boise Hydrogeophysical Research Site (BHRS) is a wellfield designed to support hydrologic and... more The Boise Hydrogeophysical Research Site (BHRS) is a wellfield designed to support hydrologic and geophysical research with the near-term goal of developing methods for mapping three-dimensional (3D) heterogeneous distributions of permeability in coarse-grained sedimentary aquifers by combining geophysical data (indirect but abundant, inexpensive, and minimally or non-invasive) with hydrologic data (direct but sparse, expensive, and invasive). The approach for meeting this goal is to thoroughly characterize a field-scale control volume/test cell in a natural heterogeneous fluvial aquifer where the 3D distributions of hydrologic, geologic, and geophysical parameters - and relationships between them - are being determined, and then to develop methods to jointly invert geophysical and hydrologic data for the permeability distribution. The BHRS is located on a gravel bar adjacent to the Boise River; the aquifer at the BHRS is shallow and unconfined. In 1997-1998, 18 wells were cored thr...

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1996

Designing geophysical investigations for transportation related projects requires special attenti... more Designing geophysical investigations for transportation related projects requires special attention to the constraints imposed by right-of-way, irregular topography, noise from traffic, and the need to avoid the interruption of traffic flow. A geophysical engineer needs to be prepared to consider these design issues that are not addressed in a standard procedure such as ASTM D-5777. The author presents design strategies that address these issues, and illustrates the concepts with case histories taken from bridge and highway projects. Beam steering, broadside shooting, and non-traditional designs that preserve alternative analysis options are presented. Transportation engineers who augment traditional subsurface geotechnical surveys with engineering geophysics are better prepared to avoid costly delays and redesign of projects due to differing site conditions. INTRODUCTION Application of geophysical methods to transportation projects falls into three general areas. First, there is th...

These case histories will be of interest to both civil engineers and geophysicists. They document... more These case histories will be of interest to both civil engineers and geophysicists. They document the use of a variety of geophysical methods in support of civil engineering projects. Geophysical methods presented include electrical, seismic, and magnetic (specifically Time Domain EM (TDEM), DC Resistivity, Ground-Penetrating Radar (GPR), Electromagnetic, Seismic Tomography, Refraction, Reflection, Doppler Shift Sonar, Side Scan Sonar, and Magnetics). Whether mapping an aquifer for a public water supply, planning a waste disposal project, or investigating the causes of a landslide, geophysical techniques support engineers in their work to serve the public welfare. Transportation engineers will find that seismic tomography is an attractive alternative to the falling weight deflectometer (FWD) method of evaluating pavements. Lastly, both contractors and owners will be interested in how geophysics can reduce the risk in differing site condition (DSC) clauses by identifying site conditi...

Geo-Risk 2017, Jun 1, 2017

Symposium on the Application of Geophysics to Engineering and Environmental Problems 1994

Symposium on the Application of Geophysics to Engineering and Environmental Problems 1997, 1997

The Idaho Transportation Department (ITD) commissioned a geophysical study to aid in the design o... more The Idaho Transportation Department (ITD) commissioned a geophysical study to aid in the design of a replacement for an existing concrete span bridge. Because the river current was too swift to place geophones in the river, the solution was to shoot p-wave profiles in a reciprocal geometry (phones on land, shots in the river). In addition to the refraction work, a down-hole seismic profile was acquired to calibrate the surface data. Geotechnical boreholes drilled on the north and south river banks detected a laterally varying soil profile. The south-bank hole encountered 9.1 m of granular overburden, followed by 8.5 m of silt with bands of siltstone and arkosic sandstone. The north-bank hole encountered 13.5 m of granular overburden, followed by 4.5 m of arkosic sandstone. The seismic down-hole survey (south bank) determined that the compacted silt was 2.5 times stiffer than the granular overburden. The damping value of the silt was 80% of the granular soil’s damping. The author int...

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2018

Symposium on the Application of Geophysics to Engineering and Environmental Problems 1999

Seismological Research Letters

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008, 2008

The Boise Hydrogeophysical Research Site (BHRS) is a wellfield designed to support hydrologic and... more The Boise Hydrogeophysical Research Site (BHRS) is a wellfield designed to support hydrologic and geophysical research with the near-term goal of developing methods for mapping three-dimensional (3D) heterogeneous distributions of permeability in coarse-grained sedimentary aquifers by combining geophysical data (indirect but abundant, inexpensive, and minimally or non-invasive) with hydrologic data (direct but sparse, expensive, and invasive). The approach for meeting this goal is to thoroughly characterize a field-scale control volume/test cell in a natural heterogeneous fluvial aquifer where the 3D distributions of hydrologic, geologic, and geophysical parameters - and relationships between them - are being determined, and then to develop methods to jointly invert geophysical and hydrologic data for the permeability distribution. The BHRS is located on a gravel bar adjacent to the Boise River; the aquifer at the BHRS is shallow and unconfined. In 1997-1998, 18 wells were cored thr...

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1996

Designing geophysical investigations for transportation related projects requires special attenti... more Designing geophysical investigations for transportation related projects requires special attention to the constraints imposed by right-of-way, irregular topography, noise from traffic, and the need to avoid the interruption of traffic flow. A geophysical engineer needs to be prepared to consider these design issues that are not addressed in a standard procedure such as ASTM D-5777. The author presents design strategies that address these issues, and illustrates the concepts with case histories taken from bridge and highway projects. Beam steering, broadside shooting, and non-traditional designs that preserve alternative analysis options are presented. Transportation engineers who augment traditional subsurface geotechnical surveys with engineering geophysics are better prepared to avoid costly delays and redesign of projects due to differing site conditions. INTRODUCTION Application of geophysical methods to transportation projects falls into three general areas. First, there is th...

These case histories will be of interest to both civil engineers and geophysicists. They document... more These case histories will be of interest to both civil engineers and geophysicists. They document the use of a variety of geophysical methods in support of civil engineering projects. Geophysical methods presented include electrical, seismic, and magnetic (specifically Time Domain EM (TDEM), DC Resistivity, Ground-Penetrating Radar (GPR), Electromagnetic, Seismic Tomography, Refraction, Reflection, Doppler Shift Sonar, Side Scan Sonar, and Magnetics). Whether mapping an aquifer for a public water supply, planning a waste disposal project, or investigating the causes of a landslide, geophysical techniques support engineers in their work to serve the public welfare. Transportation engineers will find that seismic tomography is an attractive alternative to the falling weight deflectometer (FWD) method of evaluating pavements. Lastly, both contractors and owners will be interested in how geophysics can reduce the risk in differing site condition (DSC) clauses by identifying site conditi...

Geo-Risk 2017, Jun 1, 2017

Symposium on the Application of Geophysics to Engineering and Environmental Problems 1994

Symposium on the Application of Geophysics to Engineering and Environmental Problems 1997, 1997

The Idaho Transportation Department (ITD) commissioned a geophysical study to aid in the design o... more The Idaho Transportation Department (ITD) commissioned a geophysical study to aid in the design of a replacement for an existing concrete span bridge. Because the river current was too swift to place geophones in the river, the solution was to shoot p-wave profiles in a reciprocal geometry (phones on land, shots in the river). In addition to the refraction work, a down-hole seismic profile was acquired to calibrate the surface data. Geotechnical boreholes drilled on the north and south river banks detected a laterally varying soil profile. The south-bank hole encountered 9.1 m of granular overburden, followed by 8.5 m of silt with bands of siltstone and arkosic sandstone. The north-bank hole encountered 13.5 m of granular overburden, followed by 4.5 m of arkosic sandstone. The seismic down-hole survey (south bank) determined that the compacted silt was 2.5 times stiffer than the granular overburden. The damping value of the silt was 80% of the granular soil’s damping. The author int...

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2018

Symposium on the Application of Geophysics to Engineering and Environmental Problems 1999

Seismological Research Letters

Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008, 2008

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