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Applications in Civil EngineeringSurficial DepositsSurficial Deposits

Investigation of shallow surficial deposits is one of the most effective applications of geophysical methods, both seismic and electrical.

This work is included as a part of the regular exploration work, in the several state highway departments of the United States, for sand and gravel deposits and in the classification of highway excavation before the material is moved. Applications in Civil EngineeringGroundwater: Geophysical MethodCan geophysical methods be used successfully to determine the existence and position of groundwater?

Geophysical Method

Geophysical methods by themselves will not "discover" groundwater, yet they can be of considerable assistance in determining subsurface conditions that are favorable to the occurrence of groundwater, although a drill hole must always be put down to make actual confirmation.

Applications in Civil EngineeringGroundwater: BoreholesBoreholes

They are often necessary to verify only the groundwater surface.

Applications in Civil EngineeringGroundwater: Resistivity of RocksResistivity of rock It depends mainly on two factors, held in the pores and discontinuities of the rock,:

Porosity of the rock Salinity of the solution

In general, resistivities are high for dense, impervious rocks and low for porous, water-bearing rocks. Applications in Civil EngineeringGroundwater: Resistivity of RocksFor Example:Bruckshaw and Dixey give the following typical values for resistivity.

Fresh crystalline rocks 20, 000- 1,000,000 ohm cm Consolidated sedimentary rocks 1,000- 50,000 ohm cm Recent unconsolidated formations 50- 5,000ohm cm

Applications in Civil EngineeringConstruction OperationsGeophysical Explorations early examples achieved notable results in civil engineering applications:

1. The Bridge TunnelThe Bridge River Tunnel was completed in 1930 for the British Columbia Electric Railway Company, Ltd.

The 3,960-rn (13,200ft) tunnel passes through Mission Mountain at a depth of 720 m (2,400ft) below the summit. It was constructed in connection with hydroelectric development and is located 175 km (100ml) northeast of Vancouver. Applications in Civil EngineeringConstruction OperationsGeophysical Explorations early examples achieved notable results in civil engineering applications:

2. New England Power Associations Hydroelectric Station

The first application of geophysical methods to civil engineering work in North America was made in 1928 at the site of the Fifteen Mile Falls hydroelectric station of the New England Power Association on the Connecticut River near Littleton, New Hampshire.Applications in Civil EngineeringConstruction OperationsGeophysical Explorations early examples achieved notable results in civil engineering applications:

3. Larger Federal Engineering OrganizationsProbably the most extensive use of geophysical methods in the practice of civil engineering has been in the United States:the U.S. Army Corps of Engineersthe Bureau of Reclamationthe Federal Highway AdministrationURBAN Site Exploration

Cross Section of a BuildingURBAN Site Exploration

Cross Section of an Urban SiteURBAN Site ExplorationThroughout the world, a large proportion of civil engineering works is carried out in urban areas, where most large buildings are located.

Civil engineers charged with the design and construction of urban public works are well aware that the geology beneath city streets will be just as complex, as interesting, and as vital to their work as is geology of sites far beyond city limits. URBAN ExplorationSite area searches for published records of urban geology should begin with the respective national or state (or provincial) geological survey.

Some surveys have published this useful information in the form of maps, others as smaller-scale maps supplemented by descriptive memoirs.URBAN ExplorationBoston, MassachusettsBoston, Massachusetts

Boston must be given pride of place in any listing, since in the first published copy of the Journal of the Boston Society of Civil Engineers (1914) there appeared a paper by J.R. Worcester, entitled "Boston Foundations," in which an assembly of boring records was featured. URBAN ExplorationBoston, MassachusettsBoston, Massachusetts

URBAN ExplorationBoston, MassachusettsCommittee

The purpose of this Committee is to gather data regarding the character of the sub-soils in Boston and adjacent areas, and to present it to the Society in such form as to add to the general knowledge and to make it available for reference by any who may wish to get a clear idea of the geological construction under this City. URBAN ExplorationNew York, New YorkNew York, New York

URBAN ExplorationNew York, New YorkNew York, New York

As early as 1902, the U.S. Geological Survey published the New York City Folio as no. 83 of its Atlas; this was followed in 1905 by the publication of Bulletin no. 270.

The Configuration of the Rock Floor of Greater New York, based on a study of over 1,400 borings. URBAN ExplorationSan Francisco and Oakland, CaliforniaSan Francisco and Oakland, California

URBAN ExplorationSan Francisco and Oakland, CaliforniaSan Francisco and Oakland, California

In 1957, there was published a map showing the engineering geology of the Oakland West Quadrangle, followed in 1958 by a companion map of the geology of the San Francisco North Quadrangle.

URBAN ExplorationMontreal, QuebecMontreal, Quebec

URBAN ExplorationMontreal, QuebecMontreal, Quebec

In 1966, the Montreal City Planning Department (Service d Urbanisrne) published as their Bulletin no. 4, a color brochure of convenient size (by the use of folding plates) illustrating very clearly the general bedrock and soil geology of the island of Montreal and the immediately adjacent areas. URBAN ExplorationMontreal, QuebecA fine geologic map accompanies Geological Report no. 152 of the Geological Exploration Service of the Quebec Ministry of Natural Resources. This work has now been even further extended (1986) as a "Cities of the World" paper in the Bulletin of the Association of Engineering Geologists.URBAN ExplorationPittsburgh, PennsylvaniaPittsburgh, Pennsylvania

URBAN ExplorationPittsburgh, PennsylvaniaPittsburgh, Pennsylvania

On a somewhat different scale is a publication of the Topographic and Geological Survey of Pennsylvania dealing with the geology of the Pittsburgh area as prepared in cooperation with the Pittsburgh Geological Society.

URBAN ExplorationPittsburgh, PennsylvaniaThe dour pages of references to publications relating to the geology of the Pittsburgh area alone make thus publication worthwhile as a starting point for the more detailed studies required for urban civil engineering work.URBAN ExplorationArchival RecordsArchival Records

Urban Areas Past HistoryURBAN ExplorationArchival RecordsArchival Records

All urban areas have some form of records of their past history.

Some may be very sketchy and so not of much use in site studies, but others may reveal information of great value.

URBAN ExplorationArchival RecordsIn earlier times, the local public library was the usual repository for old city maps, old prints showing the location before modern growth began, and similar historical records.

Today, many cities have their own specialist archival staffs, and in the case of some larger cities, their own archives.

URBAN ExplorationArchival RecordsNow that archival material is being properly collected, search is also warranted in the archives of the respective state (or province), or even the national archives, since their map rooms often contain unsuspected treasures.URBAN ExplorationNew York, New YorkNew York, New York

The twin towers of the World Trade Center at the foot of Manhattan in New York City are known around the world.

Their foundations rest on the well-known Manhattan schist, in an excavation 21.3 m (70 ft) deep, and cover an area of six city blocks.