Engineering geology
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Engineering geologyis the application ofgeologytoengineeringstudy for the purpose of assuring that the geological factors regarding the location, design, construction, operation and maintenance of engineering works are recognized and accounted for.[1]Engineering geologistsprovide geological andgeotechnicalrecommendations, analysis, and design associated with human development and various types of structures.[2]The realm of the engineering geologist is essentially in the area of earth-structure interactions, or investigation of how the earth or earth processes impact human made structures and human activities.
Engineering geology studies may be performed during the planning, environmental impact analysis, civil or structural engineering design, value engineering and construction phases of public and private works projects, and during post-construction and forensic phases of projects. Works completed by engineering geologists include;geologic hazardsassessment,geotechnical,material properties,landslideand slope stability,erosion,flooding,dewatering,andseismicinvestigations, etc.[3]Engineering geology studies are performed by ageologistor engineering geologist that is educated, trained and has obtained experience related to the recognition and interpretation of natural processes, the understanding of how these processes impact human made structures (and vice versa), and knowledge of methods by which to mitigate hazards resulting from adverse natural or human made conditions. The principal objective of the engineering geologist is the protection of life and property against damage caused by various geological conditions.[4]
The practice of engineering geology is also very closely related to the practice ofgeological engineeringandgeotechnical engineering.If there is a difference in the content of the disciplines, it mainly lies in the training or experience of the practitioner.
History
[edit]Although the study ofgeologyhas been around for centuries, at least in its modern form, the science and practice of engineering geology only commenced as a recognized discipline until the late 19th and early 20th centuries. The first book titled Engineering Geology was published in 1880 by William Penning. In the early 20th centuryCharles Peter Berkey,an American trained geologist who was considered the first Americanengineering geologist,worked on several water-supply projects for New York City, then later worked on the Hoover Dam and a multitude of other engineering projects. The first American engineering geology textbook was written in 1914 by Ries and Watson. In 1921Reginald W. Brock,the first Dean of Applied Science at theUniversity of British Columbia,started the first undergraduate and graduate degree programs in Geological Engineering, noting that students with an engineering foundation made first-class practising geologists. In 1925,Karl Terzaghi,an Austrian trained engineer and geologist, published the first text in Soil Mechanics (in German). Terzaghi is known as the parent of soil mechanics, but also had a great interest in geology; Terzaghi considered soil mechanics to be a sub-discipline of engineering geology. In 1929, Terzaghi, along with Redlich and Kampe, published their own Engineering Geology text (also in German).Engineering geology are the different types of rocks.
The need for geologist on engineering works gained worldwide attention in 1928 with the failure of theSt. Francis Damin California and the death of 426 people. More engineering failures that occurred the following years also prompted the requirement for engineering geologists to work on large engineering projects.
In 1951, one of the earliest definitions of the "Engineering geologist" or "Professional Engineering Geologist" was provided by the Executive Committee of the Division on Engineering Geology of theGeological Society of America.
The practice
[edit]One of the most important roles of an engineering geologist is the interpretation of landforms and earth processes to identify potential geologic and related human-made hazards that may have a great impact on civil structures and human development. The background in geology provides the engineering geologist with an understanding of how the earth works, which is crucial minimizing earth related hazards. Most engineering geologists also have graduate degrees where they have gained specialized education and training insoil mechanics,rock mechanics,geotechnics,groundwater,hydrology,and civil design. These two aspects of the engineering geologists' education provide them with a unique ability to understand and mitigate for hazards associated with earth-structure interactions.
Scope of studies
[edit]Engineering geology investigation and studies may be performed:
- for residential, commercial and industrial developments;
- for governmental andmilitaryinstallations;
- for public works such as a stormwater drainage system,power plant,wind turbine,transmission line,sewage treatmentplant,water treatmentplant,pipeline(aqueduct,sewer,outfall),tunnel,trenchlessconstruction,canal,dam,reservoir,building foundation,railroad,transit,highway,bridge,seismic retrofit,airportand park;
- formineandquarrydevelopments, mine tailing dam,mine reclamationand minetunneling;
- forwetlandandhabitat restorationprograms;
- for government, commercial, or industrial hazardous waste remediation sites;
- forcoastal engineering,sand replenishment,bluff orsea cliffstability,harbor,pierand waterfront development;
- for offshoreoutfall,drilling platformandsub-sea pipeline,sub-sea cable; and
- for other types of facilities.
Geohazards and adverse geological conditions
[edit]Typicalgeologic hazardsor other adverse conditions evaluated and mitigated by anengineering geologistinclude:
- fault ruptureon seismically activefaults;
- seismicandearthquakehazards (ground shaking,liquefaction,lurching,lateral spreading,tsunamiandseicheevents);
- landslide,mudflow,rockfall,debris flow,andavalanchehazards;
- unstable slopesandslope stability;
- erosion;
- slakingandheaveof geologic formations, such asfrost heaving;
- groundsubsidence(such as due toground waterwithdrawal,sinkholecollapse,cavecollapse, decomposition of organic soils, andtectonicmovement);
- volcanichazards (volcanic eruptions,hot springs,pyroclastic flows,debris flow,debris avalanche,Volcanic gasemissions, volcanicearthquakes);
- non-rippableormarginally rippablerock requiring heavy ripping orblasting;
- weak and collapsible soils, foundation bearing failures;
- shallow ground water/seepage; and
- other types of geologic constraints.
An engineering geologist orgeophysicistmay be called upon to evaluate theexcavatability(i.e.rippability) of earth (rock) materials to assess the need for pre-blastingduring earthwork construction, as well as associated impacts due tovibrationduring blasting on projects.
Soil and rock mechanics
[edit]Soil mechanicsis a discipline that applies principles of engineering mechanics, e.g. kinematics, dynamics,fluid mechanics,and mechanics of material, to predict the mechanical behaviour of soils.Rock mechanicsis the theoretical and applied science of the mechanical behaviour of rock and rock masses; it is that branch of mechanics concerned with the response of rock and rock masses to the force-fields of their physical environment. The fundamental processes are all related to the behaviour of porous media. Together, soil and rock mechanics are the basis for solving many engineering geology problems.
Methods and reporting
[edit]The methods used byengineering geologistsin their studies include
- geologic field mappingof geologic structures, geologic formations, soil units and hazards;
- the review of geologic literature, geologic maps, geotechnical reports, engineering plans,environmental reports,stereoscopicaerial photographs,remote sensingdata,Global Positioning System(GPS) data, topographic maps andsatelliteimagery;
- the excavation, sampling and logging of earth/rock materials in drilled borings, backhoe test pits and trenches, fault trenching, and bulldozer pits;
- geophysicalsurveys (such asseismic refractiontraverses,resistivitysurveys,ground penetrating radar(GPR) surveys,magnetometersurveys,electromagneticsurveys, high-resolution sub-bottom profiling, and other geophysical methods);
- deformation monitoringas the systematic measurement and tracking of the alteration in the shape or dimensions of an object as a result of the application of stress to it manually or with anautomatic deformation monitoring system;and
- other methods.
The fieldwork is typically culminated in analysis of the data and the preparation of an engineering geologic report, geotechnical report or design brief, fault hazard or seismic hazard report, geophysical report,ground waterresource report orhydrogeologicreport. The engineering geology report can also be prepared in conjunction with a geotechnical report, but commonly provides the same geotechnical analysis and design recommendations that would be presented in a geotechnical report. An engineering geology report describes the objectives, methodology, references cited, tests performed, findings and recommendations for development and detailed design of engineering works. Engineering geologists also provide geologic data on topographic maps, aerial photographs, geologic maps,Geographic Information System(GIS) maps, or other map bases.
See also
[edit]References
[edit]Further reading
[edit]Engineering geology
[edit]- Brock, 1923, The Education of a Geologist: Economic Geology, v. 18, pp. 595–597.
- Bates and Jackson, 1980, Glossary of Geology: American Geological Institute.
- González de Vallejo, L. and Ferrer, M., 2011. "Geological Engineering". CRC Press, 678 pp.
- Kiersh, 1991, The Heritage of Engineering Geology: The First Hundred Years: Geological Society of America; Centennial Special Volume 3
- Legget, Robert F., editor, 1982, Geology under cities: Geological Society of America; Reviews in Engineering Geology, volume V, 131 pages; contains nine articles by separate authors for these cities: Washington, DC; Boston; Chicago; Edmonton; Kansas City; New Orleans; New York City; Toronto; and Twin Cities, Minnesota.
- Legget, Robert F., and Karrow, Paul F., 1983, Handbook of geology in civil engineering: McGraw-Hill Book Company, 1,340 pages, 50 chapters, five appendices, 771 illustrations.ISBN0-07-037061-3
- Price, David George,Engineering Geology: Principles and Practice,Springer, 2008ISBN3-540-29249-7
- Prof. D. Venkat Reddy, NIT-Karnataka,Engineering Geology,Vikas Publishers, 2010ISBN978-81259-19032
- Bulletin of Engineering Geology and the Environment
Geological modelling
[edit]- Wang H. F., Theory of Linear Poroelasticity with Applications to Geomechanics and Hydrogeology, Princeton Press, (2000).
- Waltham T., Foundations of Engineering Geology, 2nd Edition, Taylor & Francis, (2001).