introduction of engineering geology
Post on 14-Jun-2015
6.879 Views
Preview:
TRANSCRIPT
KEY OF MODERN DEVELOPMENT
Dr . VINAY KUMAR PANDEY, Ph.D., M.Sc. (Geology), M. Sc. (Disaster Mitigation)
Dept Of Geology, Lucknow University, Lucknow, India.
E-mail: vinay78pandey@gmail.com
TOWER OF PISA, ITALY
ROAD DAMAGE DUE TO SHINKAGE OF SUBSOIL
ROAD DAMAGER DUE TO SMALL RAIN
SMALL BRIDGE WASH OUT DUE TO LACK OF PROTECTION WORK
LOOSE SOIL
ROAD CONSTRUCTED ON SLOPE WASH MATERIAL WITH UNPROPER PROTECTION
EFFECT OF FLOOD
LOSS DUE TO LACK OF SAFETY AWERNACE
SLIDE DUE TO FLOOD
DANGER ZONE
WHY THIS HAPPENED SOLUTION
POOR SUBSURFACE
CONDITION
LACK OF SAFTY MEASURES
LACK OF AWERNASE
STRUCTURE
CONSTRUCTED WITHOUT
PROPER STUDY OF
DEFORMABILTY.
STUDY OF AREA IN VIEW OF
SOIL-SUBSOIL NATURE FOR
CONSTRUCTION, SAFETY
AND REMEADY MEASURES
INCLUDING ECONOMICAL
VALUE BEFORE FINALIZE
THE PROJECT.
FOR STUDY THE NATURE OF
SOIL-SUBSOIL AND ITS
CONSTRUCTION
PROPERTIES COMES UNDER
ENGINEERING GEOLOGY
SOIL BEARING CAPACITY FAILED
ENGINEERING GEOLOGYEngineering geology is the application of geology in design,
construction and performance of civil engineering works.
Engineering geological 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.
Soil/Rock deformability pattern, stability are main concern
of Engineering Geology.
HISTORY OF ENGINEERING GEOLOGYThe first book entitled Engineering Geology was published
in 1880 by William Penning.
The first American engineering geology text book was
written in 1914 by Ries and Watson.
The need for geologist on engineering works gained world
wide attention in 1928 with the failure of the St. Francis
dam in California and the loss of 426 lives.
More engineering failures which occurred the following
years also prompted the requirement for engineering
geologists to work on large engineering projects.
IMPORTANCE OF ENGINEERING GEOLOGY IN DEVELOPMENT
• To recognise potential difficult ground conditions prior to
detailed design and construction
• It helps to identify areas susceptible to failure due to
geological hazards
• To establish design specifications
• To have best selection of site for engineering purposes
• To have best selection of engineering materials for
construction
AREA COVERED BY ENGINEERING GEOLOGY Geological Hazard
Geotechnical
Material Properties
Landslide & Slope stability
Erosion
Flooding
Dewatering
Seismic Studies Etc.
Most important roles of the engineering geologist is the
interpretation of landforms and earth processes to identify
potential geologic and related man-made hazards that may
impact civil structures and human development.
1lb (Pound) = 0.454 kg
CHINA
BASIC METHODS USED BY ENGINEERING GEOLOGIST
Geological field mapping of geological structures, formations, soil
units and hazards.
Review of Geological literatures, maps, Geotechnical reports,
engineering plans, environmental reports, Arial photographic studies,
remote sensing data, topographical map etc.
The surface and subsurface investigations as the excavation, sampling
and logging of earth/rock materials in drilled borings, backhoe test
pits and trenches, fault trenching, and bulldozer pits, Geomechanical
test, hydrological tests etc.
Geophysical survey.
Deformation monitoring of soil (Plate load Test), Rock on surface &
subsurface.
Recommendation for safety measures.
MAIN FACTORS AFFECTING THE ROCK QUALITY
Topography of area
Types Soil/rock on Surface as well as Subsurface.
Degree of weathering
Number of Joint sets
Spacing between joints
Cavity
Filling material
Dewatering/ ground water inflow
Direction and amount of Dip and strike
EFFECT OF DISCONTINUTY STRIKE & DIP ORIENTATION IN EXPLORATION/TUNNELING
STRIKE PERPENDICULAR TO TUNNEL AXIS
STRIKE PARALLEL TO TUNNEL AXIS
Drive with dip: Dip 45-90°
Drive with dip: Dip 20-45°
Dip 45-90° Dip 20-45°
Very favorable Favorable Very favorable Fair
Drive against dip: Dip 45-90°
Drive against dip: Dip 20-45°
Dip 0-20° , Irrespective of strike angle
Fair Unfavorable Fair
METHODS OF STUDY THE ROCK QUALITY A number of Geotechnical parameters govern condition of
Rock mass and the nature of its discontinuities. Main two are:-
(1) RMR (2) Q SYSTEM
(1) RMR (Rock Mass rating):
Bieniawski (1973), proposed RMR system, also know as
‘Geomechanics Classification” for jointed rock masses. Many
modifications has undergone time to time.
Five basic parameters considered for RMR: STRENGTH OF
ROCK, RQD (Rock Quality Designation), SPACING OF JOINTS,
CONDITION OF JOINTS & GROUND WATER CONDITION.
Final RMR value related to five classes of rock mass i.e. ‘very
good’, ‘good’’, ‘fair’, ‘poor’, ‘very poor’ rock.
METHODS OF STUDY THE ROCK QUALITY Q- SYSTEM (ROCK MASS QUALITY)
Proposed by Basedon in 1974, based on the study of 200 tunnel case histories.
The rock quality Q is determined by estimating six parameters. These are
RQD, JOINT SET NUMBER (Jn), JOINT ROUGHNESS NUMBER (Jr), JOINT
ALTERATION NUMBER (Ja) AND STRESS REDUCTION FACTOR (SRF).
Q= (RQD/Jn) x (Jr/Ja) X (Jw/SRF) (Barton et. al. 1974)
The numerical value Q ranges from 0.001 (for exceptionally poor quality
squeezing ground) to 1000 (for exceptionally good quality rock which is
practically unjointed).
Q-value is divided into 9 categories of rock quality which are related to
support requirement depending upon excavation span and intended use of
excavation.
SURFACE/SUBSURFACE INVESTIGATION
INVESTIGATIONS
FIELD INVESTIGATIONS LABOURATURY INVESTIGATIONS
(A) Geotechnical (a) Physical properties of Soil & Rock
(B) Hydrological (b) Geomechanical Properties(C) Geophysical (c ) Petrological studies of rock
& soil(D) Construction material
Main Field tests are Drilling, Pit excavation, Deformability test
(Goodman Jack Test & Hydro Fracture test), Load bearing capacity test
(Plate Load Test), Water Percolation test (permeability test), Earth
resistivity test, Seismic reflection test (know the subsurface fault/ shear
zone), aggregate test , topographical studies etc.
Studies of Satellite imageries is very useful to understand the
topography, geomorphology of area.
On the basis of RMR and Q Value, geologist
suggest supporting system in excavated
rock/soil.
On the basis of geotechnical & geologist
report project designer has fixed the
structure design and remedies measures.
RESULTS
CAREER IN ENGINEERING GEOLOGY
Infrastructure Projects as Hydro Power Plant, Tunnels for railway/transport, Canal, Dam, reservoir, highways, bridges, buildings, water treatment plant, land use, environmental studies etc.
For Mine and Quarry excavations, mine reclamation.
For coastal engineering, sand replenishment, sea cliff stability, water front development.
For offshore drilling platform, sub sea pipeline and cables etc.
top related