1 Semester

60 Hours

Hawthorn, Sarawak

HES2155 Geomechanics

Nil

Credit Points: 12.5 Credit Points

Related Course/s:

Aims & Objectives:

During this unit we aim to introduce engineering students to the fundamentals and basic techniques used in geotechnical engineering. This unit is intended to specifically introduce students to design and construction principles of civil / geotechnical engineering structures such as earth retaining structures, shallow foundations, residential slabs and footings, deep foundations, and the stability of sloping ground.

After successfully completing the unit, students should be able to:

• Demonstrate an understanding of lateral earth pressures to determine active, passive and at rest lateral earth pressures (and associated forces) on retaining structures based on Mohr circles and the Mohr-Coulomb failure criteria of soils
• Determine the bearing capacity for various shallow foundations and be able to design suitable shallow footing systems for strength and settlement
• Understand how combined shallow footings work and be able to design appropriate combined footings for various sites and soil conditions
• Understand the soil – structure interaction between residential slab footings and active type soils. Thus, be able to select appropriate shallow footing systems for residential structures and design them in accordance with Australian Standard AS2870 for various site/soil conditions
• Determine the strength capacity of deep foundations and be able to design suitable deep foundations for strength and settlement
• Analyse sloping ground against slope failure and assess the factor of safety using various methods of analysis
• Demonstrate an understanding of general construction issues for the design and construction of retaining walls, shallow foundations, deep foundations and residential slabs and footings
• Undertake basic technical investigations by performing a literature review, compile and analyse the information gathered, and produce a brief and concise (journal style) report with an appropriate conclusion
• Perform a brief and concise oral presentation of technical material, which simulates a conference style presentation

Teaching Methods:

Assessment:

Generic Skills Outcomes:

• Ability to apply knowledge of basic science and engineering fundamentals
• Ability to communicate effectively, not only with engineers but also with the community at large
• Ability to undertake problem identification, formulation and solution
• Ability to utilize a systems approach to design and operational performance
• Ability to function effectively as an individual and in a multi-disciplinary and multi-cultural teams, with the capacity to be a leader or manager as well as an effective team member
• Understanding of the principles of sustainable design and development.
• Expectation of the need to undertake lifelong learning, and capacity to do so

Content:

Lateral Earth Pressures and Design of Retaining Walls (20%)

• Introduction to types / classes of earth retaining structures
• Lateral earth pressure calculations for (restrained) at-rest conditions
• Theory of stress–strain behaviour of soils behind retaining walls unrestrained conditions
• Rankine's active and passive lateral earth pressure calculations detailing the effect of water pressure on retaining walls
• Coulomb's active and passive earth pressure theory and Coulomb's graphical solution (including wall friction and non vertical walls)
• Stability and design concepts of retaining structures as well as construction issues

Bearing Capacity and Design of Shallow Foundations (25%)

• Simple bearing capacity theory including local and general shear failure, factor of safety, eccentric loads, inclined loads, influence of water table, moments and overturning of shallow foundations
• Extended bearing capacity theory to include various theories from Meyerhof, Hansen and Vesic to evaluate the accuracy of each method
• Hansen's Modified method of bearing capacity analysis for sloping ground
• Bearing capacity analysis of layered soils
• Site investigation requirements for shallow foundations
• Analysis and design of combined footings (Rectangular, Trapezoidal and Strap type combined footings)
• Construction issues of shallow foundations and combined footings
• Remedial underpinning methods of shallow foundations

Residential Slabs and Footings Design to AS2870 (15%)

• Site Classification to AS2870 by characteristic surface movement
• Design of stiffened raft slabs, waffle raft slabs, standard strip footings and pier/beam/slab systems
• Modification of Standard Slabs (AS2870) using Engineering Principles
• Construction issues for residential slabs and footings

Piling and Design of Deep Foundations (25%)

• Types of piles (bored vs. displacement) and the materials used in deep foundations
• Design of single piles for friction and end bearing strength in cohesive and non-cohesive soils
• Settlement of single piles
• Design of piles groups for strength and settlement
• Pile construction and factors to consider
• Lateral forces on piles (short and long mechanism)
• Site investigation techniques for deep foundations

Slope Stability Analysis (15%)

• Types, causes and examples of sloping ground failure
• Theory for the stability of infinite non-cohesive slopes and all finite slopes
• Analysis of finite slopes by the Mass Procedure, Ordinary Method of Slices, and Bishop's Modified Method of Slices – all detailing the significance of pore pressures, triaxial tests, and the influence of tension cracks
• Site investigation for slope stability analysis
• Slope stabilisation methods and use of stability charts

References: