GEOTECHNICAL GEOTECHNICAL ENGINEERING – FROM THE BEGINNING NATURAL SLOPE – SLOPE – is what we now refer to as the ANGLE OF REPOSE 1.1 INTRODUCTION SOIL – SOIL – is defined as the uncemented aggregate of mineral grains and decayed organic matter (solid particles) with liquid and gas in the empty spaces between the solid particles SOIL MECHANICS – MECHANICS – is the branch of science that deals with the study of the physical properties of soil and the behavior of soil masses subjected to various types of forces SOIL ENGINEERING – ENGINEERING – is the application of the principles of soil mechanics to practical problems GEOTECHINICAL GEOTECHINICAL ENGINEERING – ENGINEERING – is the sub discipline of civil engineering that involves natural materials found close to the surface of the earth.
Natural slopes of CLEAN DRY SAND AND ORDINARY EARTH were 31° and 3 3 45°, unit weights 18.1 kN/m and 13.4 kN/m - BERNARD FOREST DE BELIDOR published a book proposing a theory for lateral earth pressure on retaining walls that was a follow- up to Gautier’s study. He also specified a soil classification system - FRANCIS GADROY conducted first laboratory model testing retaining walls, also observed the existence of slip planes in the soil at failure - J. J. MAYNIEL summarized Gadroy’s findings - JEAN RODOLPHE PERRONET studied slope stability and distinguished intact ground and fills 1.4 CLASSICAL SOIL MECHANICS – PHASE 1 (1776 – 1856)
th
1.2 GEOTECHNICAL ENGINEERING PRIOR TO THE 18 CENTURY - First use of soil as a construction material is lost in antiquity - Understanding of geotechnical engineering began in the early th 18 century - Ancient Civilizations - Lived on Rivers - Nile (Egypt) - Tigris and Euphrates (Mesopotamia) - Huang Ho (Yellow River, China) - Indus (Indus) - Early Structures Structures - Dykes dating 2000 B.C. built in Indus to protect the town of Mohenjo Dara - Dikes built for irrigation during the Chan Dynasty in China (1120 B.C. – 249 B.C.) - Isolated pad footings and strip-and-raft foundations in Ancient Greek civilizations - Ancient pyramids used as tombs for Pharaohs and their consorts were built in Egypt (2700 B.C.) - Pagodas were during the Eastern Han dynasty, China (68 A.D.) - Notable Structures Facing Soil-Bearing Capacity Foundation Problems Prior th 18 Century - Leaning Tower of Pisa in Italy - Construction began in 1173 A.D. - Weighs 15,700 metric tons, circular base diameter of 20m - Tilted east, north, west and finally south - Weak clay layer underneath the foundation was the problem - Closed in 1990 due to fear of collapse - 70 metric tons of earth removed, tower now leans 5 degrees - Garisenda Tower and Asinelli Tower in Italy - Garisenda Tower - 48 meters high, 4210 metric tons - Tilted 4 degrees - Asinelli Tower - 97 meters high, 7300 metric tons - Tilted 1.5 degrees - Scientists and Engineers saw the problem and began to address the properties of soil - From 1700 – 1927, geotechnical engineering can be split into 4 major periods - Preclassical (1700 – 1776 A.D.) - Classical Soil Mechanics, Phase 1 (1776 – 1856 A.D.) - Classical Soil Mechanics, Phase 2 (1856 – 1910 A.D.) - Modern Soil Mechanics (1910 – 1927 A.D.) 1.3 PRECLASSICAL PERIOD OF SOIL MECHANICS (1700 – 1776)
- Concentrated on NATURAL SLOPE AND UNIT WEIGHT OF TYPES OF SOILS - French engineer, HENRY GAUTIER studied the natural slopes of soils
- CHARLES AUGUSTIN COULOMB used principles of calculus for maxima and minima to determine the true position of sliding surface in soil behind a retaining wall, used laws of friction and cohesion - GASPARD CLAIRE MARIE RICHE DE BRONY published a textbook, NOUVELLE ARCHITECTURE HYDRAULIQUE that included Coulomb’s theory - JACQUES FREDERIC FRANCAIS & CLAUDE LOUIS MARIE HENRI NAVIER studied special cases of Coulomb’s theory - JEAN VICTOR PONCELET added a graphical method to Coulomb’s theory. He was the first to use the symbol φ for soil friction angle. He provided the first ultimate bearing-capacity for shallow foundations - ALEXANDRE COLLIN provided the details for deep slips in clay slopes, cutting and embankments. He said that failure takes place when mobilized cohesion exceeds the existing cohesion of the soil. He observed that the actual failure surfaces could be approximated as arcs of cycloids. - This era of soil was ended by a book by WILLIAM JOHN MACQUORN RANKINE. He provided a theory on earth pressure and equilibrium of earth masses. It is a simplification of Coulomb’s. 1.5 CLASSICAL SOIL MECHANICS – PHASE 2 (1856 – 1910)
- This period involved many experiments on SAND - HENRI PHILIBERT GASPARD DARCY published the permeability of sand filters. Darcy defined the term, COEFFICIENT OF PERMEABILITY (or HYDRAULIC CONDUCTIVITY) CONDUCTIVITY) of soil - SIR GEORGE HOWARD DARWIN conducted tests determining the overturning moment of a hinged wall retaining sand in loose and dense states of compaction - JOSEPH VALENTIN BOUSSINESQ developed the theory of stress distribution - OSBORNE REYNOLDS demonstrated phenomenon of dilatency of sand - JOHN CLIBBORN & JOHN STUART BERESFORD studied the flow of water through sand bed and uplift pressure - Clibborn’s study was published in the TREATISE ON CIVIL ENGINEERING, VOL. 2: IRRIGATION WORK IN INDIA, and TECHINICAL PAPER NO. 97 - Beresford’s work on the uplift pressure on the Narora Weir on the Ganges River was documented in TECHINCAL PAPER NO. 97 1.6 MODERN SOIL MECHANICS (1910 – 1927)
- This period research of CLAY’s CLAY’s properties and parameters were published - ALBERT MAURITZ ATTERBERG defined CLAY-SIZE FRACTIONS as the percentage by weight of particles smaller than 2 microns in size - Realized the important role of clay in soil and the plasticity - Explained consistency of soils by defining liquid, plastic and shrinkage limits - Defined the plasticity index
- JEAN FONTARD investigated the failure of a dam in Charmes, France. Determined the shear strength parameters of clay. - ARTHUR LANGLEY BELL developed relationships for lateral pressure and resistance in clay as well as bearing capacity of shallow foundations in clay - WOLMAR FELLINUS developed the stability analysis of saturated clay slopes. He established correct numerical solutions for the STABILITY NUMBERS of circular slip surfaces passing through the toe of the slope - KARL TERZAGHI developed the theory of consolidation for clays. It was published in the book ERDBAUMECHANIK 1.7 GEOTECHNICAL ENGINEERING AFTER 1927
- ERDBAUMECHANIK AUF BODENPHYSIKALISHER GRUNDLAGE by Karl Terzaghi started this era in the development of soil mechanics - Terzahgi was recognized as the leader of soil mechanics; he was the guiding spirit for soil mechanics and geotechnical engineer for the next quartercentury - He attended the first INTERNATIONAL SOCIETY OF SOIL MECHANICS AND FOUNDATION ENGINEERING (ISSMFE) - In 1997 ISSMFE was changed to ISSMGE (INTERNATIONAL SOCIETY OF SOIL MECHANICS AND GEOTECHNICAL ENGINEERING) 1.8 END OF AN ERA - RALPH B. PECK was the last of the early giants of modern soil mechanics - Died on February 18, 2008 - His last project was the Rion-Antirion Bridge in Greece - Authored more than 250 technical publications
