SMALL BRIDGE WASH OUT DUE TO LACK OF PROTECTIONWORK LOOSE SOIL
ROAD CONSTRUCTED ONSLOPE WASH MATERIAL WITHUNPROPER PROTECTION
EFFECT OF FLOOD
LOSS DUE TO LACK OFSAFETY AWERNACE DANGER ZONE SLIDE DUE TO FLOOD
WHY THIS HAPPENED SOLUTION STUDY OF AREA IN VIEW OF POOR SUBSURFACE SOIL-SUBSOIL NATURE FOR CONDITION CONSTRUCTION, SAFETY AND REMEADY MEASURES LACK OF SAFTY MEASURES INCLUDING ECONOMICAL VALUE BEFORE FINALIZE THE LACK OF AWERNASE PROJECT. STRUCTURE CONSTRUCTED FOR STUDY THE NATURE OF SOIL-SUBSOIL AND ITS WITHOUT PROPER STUDY CONSTRUCTION PROPERTIES OF DEFORMABILTY. COMES UNDER ENGINEERING GEOLOGY
SOIL BEARING CAPACITYFAILED
ENGINEERING GEOLOGY Engineering 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 GEOLOGY The 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
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/TUNNELINGSTRIKE PERPENDICULAR STRIKE PARALLEL TO TUNNEL AXISTO TUNNEL AXIS Drive with dip: Dip Drive with dip: Dip 20- Dip 45-90° Dip 20-45° 45-90° 45° Very favorable Favorable Very favorable FairDrive against dip: Dip Drive against dip: Dip Dip 0-20° , Irrespective of strike angle 45-90° 20-45° 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 INVESTIGATIONSFIELD 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.
RESULTSOn 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.
CAREER IN ENGINEERING GEOLOGYInfrastructure 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.