FOUNDATION ENGINEERING
UPLIFT PRESSURE UNDER HYDRAULIC STRUCTURES SEEPAGE THROUGH AN EARTH DAM ON AN IMPERVIOUS BASE L CASAGRANDE’S SOLUTION FOR SEEPAGE THROUGH AN EARTH DAM 8 10 PAVLOVSKY’S SOLUTION FOR SEEPAGE THROUGH AN EARTH DAM 8 11 FILTER DESIGN 8 12 SUMMARY PROBLEMS REFERENCES IN SITU STRESSES INTRODUCTION STRESSES IN SATURATED SOIL WITHOUT SEEPAGE STRESSES IN SATURATED SOIL WITH UPWARD SEEPAGE STRESSES IN SATURATED SOIL WITH DOWNWARD SEEPAGE SEEPAGE FORCE HEAVING IN SOIL DUE TO FLOW AROUND SHEET PILES USE OF FILTERS TO INCREASE THE FACTOR OF SAFETY AGAINST HEAVE EFFECTIVE STRESS IN PARTIALLY SATURATED SOIL CAPILLARY RISE IN SOILS 9 10 EFFECTIVE STRESS IN THE ZONE OF CAPILLARY RISE 9 11 SUMMARY STRESSES IN A SOIL MASS NORMAL AND SHEAR STRESSES ON A PLANE THE POLE METHOD OF FINDING STRESSES ALONG A PLANE STRESSES CAUSED BY A POINT LOAD VERTICAL STRESS CAUSED BY A VERTICAL LINE LOAD VERTICAL STRESS CAUSED BY A HORIZONTAL LINE LOAD VERTICAL STRESS CAUSED BY A VERTICAL STRIP LOAD (FINITE WIDTH AND INFINITE LENGTH) VERTICAL STRESS CAUSED BY A HORIZONTAL STRIP LOAD LINEARLY INCREASING VERTICAL LOADING ON AN INFINITE STRIP 10 10 VERTICAL STRESS DUE TO EMBANKMENT LOADING 10 11 VERTICAL STRESS BELOW THE CENTER OF A UNIFORMLY LOADED CIRCULAR AREA 10 12 VERTICAL STRESS AT ANY POINT BELOW A UNIFORMLY LOADED CIRCULAR AREA 10 13 VERTICAL STRESS CAUSED BY A RECTANGULARLY LOADED AREA 10 14 INFLUENCE CHART FOR VERTICAL PRESSURE 10 15 WESTERGAARD’S SOLUTION FOR VERTICAL STRESS DUE TO A POINT LOAD 10 16 STRESS DISTRIBUTION FOR WESTERGAARD MATERIAL 10 17 SUMMARY COMPRESSIBILITY OF SOIL CONTACT PRESSURE AND SETTLEMENT PROFILE RELATIONS FOR ELASTIC SETTLEMENT CALCULATION IMPROVED RELATIONSHIP FOR ELASTIC SETTLEMENT FUNDAMENTALS OF CONSOLIDATION ONE-DIMENSIONAL LABORATORY CONSOLIDATION TEST VOID RATIO–PRESSURE PLOTS NORMALLY CONSOLIDATED AND OVERCONSOLIDATED CLAYS EFFECT OF DISTURBANCE ON VOID RATIO–PRESSURE RELATIONSHIP 11 10 CALCULATION OF SETTLEMENT FROM ONE-DIMENSIONAL PRIMARY CONSOLIDATION 11 11 CORRELATIONS FOR COMPRESSION INDEX (CC) 11 12 CORRELATIONS FOR SWELL INDEX (CS) 11 13 SECONDARY CONSOLIDATION SETTLEMENT 11 14 TIME RATE OF CONSOLIDATION 11 15 CONSTRUCTION TIME CORRECTION OF CONSOLIDATION SETTLEMENT 11 16 DETERMINATION OF COEFFICIENT OF CONSOLIDATION 11 17 CALCULATION OF CONSOLIDATION SETTLEMENT UNDER A FOUNDATION 11 18 METHODS FOR ACCELERATING CONSOLIDATION SETTLEMENT 11 19 SUMMARY SHEAR STRENGTH OF SOIL MOHR–COULOMB FAILURE CRITERION INCLINATION OF THE PLANE OF FAILURE CAUSED BY SHEAR LABORATORY TEST FOR DETERMINATION OF SHEAR STRENGTH PARAMETERS DIRECT SHEAR TEST DRAINED DIRECT SHEAR TEST ON SATURATED SAND AND CLAY GENERAL COMMENTS ON DIRECT SHEAR TEST TRIAXIAL SHEAR TEST-GENERAL CONSOLIDATED-DRAINED TRIAXIAL TEST 12 10 CONSOLIDATED-UNDRAINED TRIAXIAL TEST 12 11 UNCONSOLIDATED-UNDRAINED TRIAXIAL TEST 12 12 UNCONFINED COMPRESSION TEST ON SATURATED CLAY 12 13 EMPIRICAL RELATIONSHIPS BETWEEN UNDRAINED COHESION (CU) AND EFFECTIVE OVERBURDEN PRESSURE (O9) 12 14 SENSITIVITY AND THIXOTROPY OF CLAY 12 15 STRENGTH ANISOTROPY IN CLAY 12 16 VANE SHEAR TEST 12 17 OTHER METHODS FOR DETERMINING UNDRAINED SHEAR STRENGTH 12 18 SHEAR STRENGTH OF UNSATURATED COHESIVE SOILS 12 19 SUMMARY GEOTECHNICAL ENGINEERING PRIOR TO THE 18TH CENTURY THE RECORD OF A PERSON’S ?RST USE OF SOIL AS A CONSTRUCTION MATERIAL IS LOST IN ANTIQUITY IN TRUE ENGINEERING TERMS, THE UNDERSTANDING OF GEOTECHNICAL ENGINEERING AS IT IS KNOWN TODAY BEGAN EARLY IN THE 18TH CENTURY (SKEMPTON, 1985) FOR YEARS, THE ART OF GEOTECHNICAL ENGINEERING WAS BASED ON ONLY PAST EXPERIENCES THROUGH A SUCCESSION C H A P T E R TABLE 1 1 MAJOR PYRAMIDS IN EGYPT PYRAMID/PHARAOH LOCATION REIGN OF PHARAOH DJOSER SAQQARA 2630–2612 B C SNEFERU DASHUR (NORTH) 2612–2589 B C SNEFERU DASHUR (SOUTH) 2612–2589 B C SNEFERU MEIDUM 2612–2589 B C KHUFU GIZA 2589–2566 B C DJEDEFRE ABU RAWASH 2566–2558 B C KHAFRE GIZA 2558–2532 B C MENKAURE GIZA 2532–2504 B C FIGURE 1 1 A VIEW OF THE PYRAMIDS AT GIZA (COURTESY OF JANICE DAS, HENDERSON, NEVADA) FOUNDATION ENGINEERING FIGURE 1 2 LEANING TOWER OF PISA, ITALY (COURTESY OF BRAJA M DAS, HENDERSON, NEVADA) SHOWS A VIEW OF THE THREE PYRAMIDS AT GIZA THE CONSTRUCTION OF THE PYRAMIDS POSED FORMIDABLE CHALLENGES REGARDING FOUNDATIONS, STABILITY OF SLOPES, AND CONSTRUCTION OF UNDERGROUND CHAMBERS WITH THE ARRIVAL OF BUDDHISM IN CHINA DURING THE EASTERN HAN DYNASTY IN 68 A D , THOUSANDS OF PAGODAS WERE BUILT MANY OF THESE STRUCTURES WERE CONSTRUCTED ON SILT AND SOFT CLAY LAYERS IN SOME CASES THE FOUNDATION PRESSURE EXCEEDED THE LOAD-BEARING CAPACITY OF THE SOIL AND THEREBY CAUSED EXTENSIVE STRUC- TURAL DAMAGE ONE OF THE MOST FAMOUS EXAMPLES OF PROBLEMS RELATED TO SOIL-BEARING CAPACITY IN THE CONSTRUCTION OF STRUCTURES PRIOR TO THE 18TH CENTURY IS THE LEANING TOWER OF PISA IN ITALY (SEE FIGURE 1 2) CONSTRUCTION OF THE TOWER BEGAN IN 1173 A D WHEN THE REPUBLIC OF PISA WAS ?OURISHING AND CONTINUED IN VARIOUS STAGES FOR OVER 200 YEARS THE STRUCTURE WEIGHS ABOUT 15,700 METRIC TONS AND IS SUPPORTED BY A CIRCULAR BASE HAVING A DIAMETER OF 20 M (< 66 FT) THE TOWER HAS TILTED IN THE PAST TO THE EAST, NORTH, WEST, AND, ?NALLY, TO THE SOUTH RECENT INVESTIGATIONS SHOWED THAT A WEAK CLAY LAYER EXISTED AT A DEPTH OF ABOUT 11 M (< 36 FT) BELOW THE GROUND SURFACE COMPRESSION OF WHICH CAUSED THE TOWER TO TILT IT BECAME MORE THAN 5 M (< 16 5 FT) OUT OF PLUMB FOUNDATION ENGINEERING WITH THE 54 M (< 179 FT) HEIGHT (ABOUT A 5 5 DEGREE TILT) THE TOWER WAS CLOSED IN BECAUSE IT WAS FEARED THAT IT WOULD EITHER FALL OVER OR COLLAPSE IT RECENTLY HAS BEEN STABILIZED BY EXCAVATING SOIL FROM UNDER THE NORTH SIDE OF THE TOWER ABOUT 70 METRIC TONS OF EARTH WERE REMOVED IN 41 SEPARATE EXTRACTIONS THAT SPANNED THE WIDTH OF THE TOWER AS THE GROUND GRADUALLY SETTLED TO ?LL THE RESULTING SPACE, THE TILT OF THE TOWER EASED THE TOWER NOW LEANS 5 DEGREES THE HALF-DEGREE CHANGE IS NOT NOTICEABLE, BUT IT MAKES THE STRUCTURE CONSIDERABLY MORE STABLE FIGURE 1 3 IS AN EXAMPLE OF A SIMILAR PROBLEM THE TOWERS SHOWN IN FIGURE 1 3 ARE LOCATED IN BOLOGNA, ITALY, AND THEY WERE BUILT IN THE 12TH CENTURY THE TOWER ON THE LEFT IS USUALLY REFERRED TO AS THE GARISENDA TOWER IT IS 48 M (< 157 FT) IN HEIGHT AND WEIGHS ABOUT 4210 METRIC TONS IT HAS TILTED ABOUT 4 DEGREES THE TOWER ON THE RIGHT IS THE ASINELLI TOWER, WHICH IS 97 M HIGH AND WEIGHS 7300 METRIC TONS IT HAS TILTED ABOUT 1 3 DEGREES AFTER ENCOUNTERING SEVERAL FOUNDATION-RELATED PROBLEMS DURING CONSTRUCTION OVER CENTURIES PAST, ENGINEERS AND SCIENTISTS BEGAN TO ADDRESS THE PROPERTIES AND FIGURE 1 3 TILTING OF GARISENDA TOWER (LEFT) AND ASINELLI TOWER (RIGHT) IN BOLOGNA, ITALY (COURTESY OF BRAJA M DAS, HENDERSON, NEVADA) FOUNDATION ENGINEERING 106 TO PEAT — — THE ?RST LABORATORY MODEL TEST RESULTS ON A 76-MM-HIGH (< 3 IN ) RETAINING WALL BUILT WITH SAND BACK?LL WERE REPORTED IN 1746 BY A FRENCH ENGINEER, FRANCOIS GADROY (1705–1759), WHO OBSERVED THE EXISTENCE OF SLIP PLANES IN THE SOIL AT FAILURE GADROY’S STUDY WAS LATER SUMMARIZED BY J J MAYNIEL IN 1808 ANOTHER NOTABLE CON- TRIBUTION DURING THIS PERIOD IS THAT BY THE FRENCH ENGINEER JEAN RODOLPHE PERRONET (1708–1794), WHO STUDIED SLOPE STABILITY AROUND 1769 AND DISTINGUISHED BETWEEN IN- TACT GROUND AND ?LLS FOUNDATION ENGINEERING