Engineering geology is the application of
the geology to engineering study 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.
Engineering geologists provide geological
and geotechnical recommendations, analysis,
and design associated with human development
and various types of structures.
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; geological hazard assessments, geotechnical,
material properties, landslide and slope stability,
erosion, flooding, dewatering, and seismic
investigations, etc.
Engineering geology studies are performed
by a geologist or 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 against 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.
The practice of engineering geology is also
very closely related to the practice of geological
engineering and geotechnical engineering.
If there is a difference in the content of
the disciplines, it mainly lies in the training
or experience of the practitioner.
== History ==
Although the study of geology has 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 century Charles Berkey,
an American trained geologist who was considered
the first American engineering 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 1921 Reginald W. Brock, the first Dean
of Applied Science at the University 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).
The need for geologist on engineering works
gained worldwide attention in 1928 with the
failure of the St. Francis Dam in California
and the death of 426 people.
More engineering failures which 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 the Geological Society of America.
== The practice ==
One of the most important roles as an engineering
geologist is the interpretation of landforms
and earth processes to identify potential
geologic and related man-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 in soil 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 ==
Engineering geology investigation and studies
may be performed:
for residential, commercial and industrial
developments;
for governmental and military installations;
for public works such as a stormwater drainage
system, power plant, wind turbine, transmission
line, sewage treatment plant, water treatment
plant, pipeline (aqueduct, sewer, outfall),
tunnel, trenchless construction, canal, dam,
reservoir, building foundation, railroad,
transit, highway, bridge, seismic retrofit,
power generation facility, airport and park;
for mine and quarry developments, mine tailing
dam, mine reclamation and mine tunneling;
for wetland and habitat restoration programs;
for government, commercial, or industrial
hazardous waste remediation sites;
for coastal engineering, sand replenishment,
bluff or sea cliff stability, harbor, pier
and waterfront development;
for offshore outfall, drilling platform and
sub-sea pipeline, sub-sea cable; and
for other types of facilities.
== Geohazards and adverse geological conditions
==
Typical geologic hazards or other adverse
conditions evaluated and mitigated by an engineering
geologist include:
fault rupture on seismically active faults
;
seismic and earthquake hazards (ground shaking,
liquefaction, lurching, lateral spreading,
tsunami and seiche events);
landslide, mudflow, rockfall, debris flow,
and avalanche hazards ;
unstable slopes and slope stability;
erosion;
slaking and heave of geologic formations,
such as frost heaving;
ground subsidence (such as due to ground water
withdrawal, sinkhole collapse, cave collapse,
decomposition of organic soils, and tectonic
movement);
volcanic hazards (volcanic eruptions, hot
springs, pyroclastic flows, debris flow, debris
avalanche, gas emissions, volcanic earthquakes);
non-rippable or marginally rippable rock requiring
heavy ripping or blasting;
weak and collapsible soils, foundation bearing
failures;
shallow ground water/seepage; and
other types of geologic constraints.An engineering
geologist or geophysicist may be called upon
to evaluate the excavatability (i.e. rippability)
of earth (rock) materials to assess the need
for pre-blasting during earthwork construction,
as well as associated impacts due to vibration
during blasting on projects.
== Soil and rock mechanics ==
Soil mechanics is 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 mechanics is 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 ==
The methods used by engineering geologists
in their studies include
geologic field mapping of geologic structures,
geologic formations, soil units and hazards;
the review of geologic literature, geologic
maps, geotechnical reports, engineering plans,
environmental reports, stereoscopic aerial
photographs, remote sensing data, Global Positioning
System (GPS) data, topographic maps and satellite
imagery;
the excavation, sampling and logging of earth/rock
materials in drilled borings, backhoe test
pits and trenches, fault trenching, and bulldozer
pits;
geophysical surveys (such as seismic refraction
traverses, resistivity surveys, ground penetrating
radar (GPR) surveys, magnetometer surveys,
electromagnetic surveys, high-resolution sub-bottom
profiling, and other geophysical methods);
deformation monitoring as 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 an automatic 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
water resource report or hydrogeologic report.
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
