New to the Ninth Edition
 This edition includes many new example problems as well as revisions to
existing problems. This book now offers more than 185 example problems
to ensure understanding. The authors have also added to and updated the
book’s end-of-chapter problems throughout.
 In Chapter 1 on “Geotechnical Engineering: A Historical Perspective,” the
list of ISSMGE (International Society for Soil Mechanics and Geotechnical
Engineering) technical committees (as of 2013) has been updated. A list of
some important geotechnical engineering journals now in publication has
been added.
 Chapter 2 on “Origin of Soil and Grain Size” has a more detailed discussion
on U.S. sieve sizes. British and Australian standard sieve sizes have also been
added.
 Chapter 3 on “Weight-Volume Relationships” now offers an expanded discussion
on angularity and the maximum and minimum void ratios of granular
soils.
 Students now learn more about the fall cone test used to determine the liquid
limit in Chapter 4, which covers “Plasticity and Structure of Soil.”
 In Chapter 6 on “Soil Compaction,” a newly-developed empirical correlation
for maximum dry density and optimum moisture content has been added.
 In Chapter 7 on “Permeability,” sections on permeability tests in auger holes,
hydraulic conductivity of compacted clay soils, and moisture content-unit
weight criteria for clay liner construction have been added.
 Pavlovsky’s solution for seepage through an earth dam has been added to
Chapter 8 on “Seepage.”
 Chapter 10 on “Stresses in a Soil Mass,” has new sections on:
• Vertical stress caused by a horizontal strip load,
• Westergaard’s solution for vertical stress due to a point load, and
• Stress distribution for Westergaard material.

 An improved relationship for elastic settlement estimation has been incorporated
into Chapter 11 on “Compressibility of Soil.” This chapter also has a
new section on construction time correction (for ramp loading) of consolidation
settlement.
 Chapter 12 on “Shear Strength of Soil” now includes some recently-published
correlations between drained angle of friction and plasticity index of clayey
soil. Additional content has been included on the relationship between undrained
shear strength of remolded clay with liquidity index.
 The generalized case for Rankine active and passive pressure (granular
backfill) now appears in Chapter 13 on “Lateral Earth Pressure: At-Rest,
Rankine, and Coulomb” (Section 13.10). Additional tables for active earth
pressure coefficient based on Mononobe-Okabe’s equation have been added.
 In Chapter 14 on “Lateral Earth Pressure: Curved Failure Surface,” the passive
earth pressure coefficient obtained based on the solution by the lower
bound theorem of plasticity and the solution by method of characteristics
have been summarized. Also, the section on passive force walls with earthquake
forces (Section 14.7) has been expanded.
 In Chapter 15 on “Slope Stability,” the parameters required for location of
the critical failure circle based on Spencer’s analysis have been added.
 Chapter 16 on “Soil Bearing Capacity for Shallow Foundations,” includes a
new section on continuous foundations under eccentrically-inclined load.
 Chapter 18 is a new chapter titled “An Introduction to Geosynthetics,” which
examines current developments and challenges within this robust and rapidly
expanding area of civil engineering.