## Budhu, Muni

# Soil Mechanics Fundamentals

This accessible, clear and concise textbook strikes a balance between theory and practical applications for an introductory course in soil mechanics for undergraduates in civil engineering, construction, mining and geological engineering.

*Soil Mechanics Fundamentals* lays a solid foundation on key principles of soil mechanics for application in later engineering courses as well as in engineering practice. With this textbook, students will learn how to conduct a site investigation, acquire an understanding of the physical and mechanical properties of soils and methods of determining them, and apply the knowledge gained to analyse and design earthworks, simple foundations, retaining walls and slopes.

The author discusses and demonstrates contemporary ideas and methods of interpreting the physical and mechanical properties of soils for both fundamental knowledge and for practical applications.

The chapter presentation and content is informed by modern theories of how students learn:

*Learning objectives*inform students what knowledge and skills they are expected to gain from the chapter.*Definitions of Key Terms*are given which students may not have encountered previously, or may have been understood in a different context.*Key Point*summaries throughout emphasize the most important points in the material just read.*Practical Examples*give students an opportunity to see how the prior and current principles are integrated to solve ‘real world’ problems.

**Chapter 1 - Composition and particle sizes**

**Chapter 1** engages students on the composition and particle sizes of soils. , Students learn about soil formation, soil types and composition, particle size distribution, grading curves and their interpretation, and the differences between fine-grained soils - clays and slits - and coarse-grained soils &ndash, sands and gravels. The composition and particle sizes of soils influence the load bearing and settlement characteristics of soils. The learning outcomes from this chapter are an understanding of soils as complex, natural materials, their formation and description for practical purposes, their particle sizes and distribution and interpreting particle size parameters for use in practice.

*Key words: soil formation**, soil description, soil types, coarse-grained soils, fine-grained soils, uniformity coefficient, average grain size, clay, sand, gravel*

**Chapter 2-Physical soil parameters and soil classification**

Chapter 2 informs students on how to simplify soils into three material phases &ndash, solids, liquids and gases, the inter-relationships among these phases and their importance in practical applications. Students learn about and the calculation of important soil parameters such as water content, void ratio, unit weight and relative density for practical applications. , They use these parameters to classify soils and make decisions about the suitability of particular types of soils for typical geoengineering systems. The learning outcomes are an understanding on the proportions of the main constituents in a soil, the calculation of physical soil parameters such as water content and void ratio, an understanding on how water changes the states of soils, particularly fine-grained soils, the determination of index parameters such as liquid limit, and plastic limits, plasticity index, and an understanding on why and how soils are classified for engineering use.

*Key words: water content**, saturation, void ratio, porosity, unit weight, density, liquid limit, plastic limit, plasticity index, classification.*

**Chapter 3 - Soils investigation**

Chapter 3 engages students on the purpose, planning, execution and limitations of a soils investigation. It includes the types of common in situ and laboratory tests to determine physical and mechanical soil parameters, and geophysical methods. A soils investigation is an essential part of the design and construction of structural systems such as buildings, dams, roads and highways. Students learn to plan and execute a soils investigation, how to identify soil types, what testing to perform and the advantages and disadvantages of in situ and laboratory tests. , This chapter informs them on the importance of groundwater and how to locate it. , The learning outcomes are the planning and execution of a soils investigation and an appreciation of its limitations

*Key words: **, soils investigation, phases of a soils investigation, soils report, geophysical methods, shear vane tester, standard penetration test, cone penetration test, soil sampling, groundwater.*

**Chapter 4 - Flow of water through soils**

Chapter 4 introduces students to both one-dimensional and two-dimensional flow of water through soils. It describes how water flows through soil using Darcy&rsquo, s law and Laplace&rsquo, s equation. It describes and outlines procedures for drawing flownets and interpreting flowrate, porewater pressures and seepage condition. The learning outcomes are an appreciation of the importance of the flow of water through soils, the potential for instability and failure of geotechnical structures such as roads, bridges, dams, and excavations, the determination of hydraulic conductivity using constant head and falling head tests, flow rate, sketching and interpreting flow nets, the calculation and importance of porewater pressures, seepage stresses, uplift forces and critical hydraulic gradient.

*Key words: groundwater**, head, hydraulic conductivity, constant head test, falling head test, hydraulic gradient, porewater pressure, flow rate, equipotential, flow net, liquefaction*.

**Chapter 5 - Soil compaction**

Chapter 5 engages students on the fundamentals of soil compaction, why it is important and how to specify and monitor soil compaction in the field. , It emphasizes the differences between soil compaction and soil consolidation. The learning outcomes are an understanding of soil compaction, the determination of maximum dry unit weight and optimum water content from standard and modified Proctor tests, the specifications of soil compaction criteria for field applications, the identification of suitable field compaction equipment, and the specification and interpretation of quality control tests.

*Keywords: compaction**, maximum dry density, maximum unit weight, optimum water content, Proctor tests, field compaction, compaction equipment, degree of compaction*

**Chapter 6 - Effective stresses and stress distribution**

Chapter 6 informs students on the distribution of stresses in soils from common surface loads using , Boussinesq&rsquo, s solution. , It discusses the importance of Boussinesq&rsquo, s assumptions of a semi-infinite, homogeneous, linear, isotropic, elastic soil for students to get an appreciation for the limitations of the calculated stresses. This chapter also presents the concept of effective stress with and without the influence of seepage stresses. This is a central concept in geo-engineering. , The learning outcomes are an understanding on the stresses imposed in soils from surface loads, the assumptions made in the solution for these stresses, the calculation of stresses from common surface loads, the understanding of the concept of effective stress, the calculation of total and effective stresses, and porewater pressures for common soil types and profiles.

*Key words: stress**, effective stress, porewater pressure, surface loads, stress distribution, seepage stress*

**Chapter 7 - Soil Settlement**

Chapter 7 deals with soil settlement for both coarse-grained and fine-grained soils. , It informs students on how to estimate soil settlement for coarse-grained based on the assumption of elastic soil behavior. It explains the limitations of using elasticity and the difficulties of making reliable predictions of settlement. , Students learn about the basic concept of soil consolidation for fine-grained soils, the determination of consolidation parameters, and methods to calculate primary consolidation settlement and secondary compression. , The learning outcomes are an understanding of , the types of settlement in soils, the differences in settlement between coarse-grained and fine-grained soils, a basic understanding of consolidation of fine-grained soils under vertical loads, the calculations of the amount and time rate of settlement of soils, the importance of differential settlement, and an appreciation of the limitations in estimating soil settlement.

*Key words: settlement**, consolidation, overconsolidation, normal consolidation, pre-consolidation pressure, excess porewater pressure, compression index, coefficient of consolidation, secondary compression*

**Chapter 8 -Shear Strength of Soils**

Chapter 8 engages students on the shear strength of soils. The shear strength of soils is interpreted using the contemporary idealization of them as dilatant-frictional materials rather than their conventional idealization as cohesive-frictional materials. This chapter presents and discusses typical stress&ndash, strain responses of coarse-grained and fine-grained soils, the implications of drained and undrained conditions, the influence of cohesion, soil suction and cementation on the shear strength of soils, the interpretation and limitations of using Coulomb, Mohr-Coulomb and Tresca failure criteria, and tests such as direct shear and triaxial to determine shear strength. The learning outcomes are an understanding of the concept of shear strength of soils, typical stress-strain behavior of soils, the differences between drained and undrained shear strength, the appropriate use and interpretation of soil test results using three common soil failure criteria to obtain soil strength parameters and an appreciation of the limitations of soil failure criteria.

*Key words: shear strength**, friction angle, cohesion, undrained shear strength, soil suction, cementation, dilation, critical state, peak shear strength, critical state shear strength, Coulomb, Mohr-Coulomb, Tresca, failure criteria*

**Chapter 9 - Some common applications of soil mechanics**

Chapter 9 (available on line) presents some common applications of soil mechanics principles. , These applications include simple shallow and deep foundations, lateral earth pressures on simple retaining walls and the stability of infinite slopes. , Simple soil profiles are used in these applications to satisfy a key assumption (homogeneous soil) used in the interpretation of soil behavior. , The content of this chapter is not intended to be a course on Foundation Engineering but for students to get an appreciation of rudimentary applications of soil mechanics principles. The learning outcomes are an estimation of the safe bearing capacity of soils for a shallow footing supporting vertical loads, the load capacity of single piles supporting vertical loads, the lateral earth pressures on a vertical, smooth retaining wall supporting a horizontal backfill, and the stability of an infinite slope.

*Key words: bearing capacity**, shallow foundations, deep foundations, piles, slopes, retaining walls, earth pressures, factor of safety, skin friction, end bearing capacity*

- Author(s)
- Budhu, Muni
- Publisher
- John Wiley and Sons, Inc.
- Publication year
- 2015
- Language
- en
- Edition
- 1
- Page amount
- 376 pages
- Category
- Technology, Energy, Traffic
- Format
- Ebook
- eISBN (ePUB)
- 9781118897713
- Printed ISBN
- 9780470577950