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This webinar was co-sponsored by ASCE's Geo-Institute(GI) and ASCE Continuing Education

Instructor:  Delwyn G. Fredlund, O.C., P.Eng., FEIC

Course Length: 1.5 Hours

Purpose and Background

Unsaturated soil mechanics has rapidly become an integral part of geotechnical engineering practice. It also has been difficult for practicing geotechnical engineers to receive sufficient technical training on the theory of unsaturated soil behavior and on acceptable engineering protocols to use in practice. This webinar focuses on the problems that need to be addressed in unsaturated soil mechanics prior to its implementation in routine geotechnical engineering practice. Each of the basic problems related to unsaturated soil mechanics have been addressed through extensive research studies and the geotechnical engineering profession has now witnessed a rapid growth in the application of unsaturated soil mechanics in engineering practice.

The primary problems that needed to be resolved prior to the implementation of unsaturated soil mechanics can be stated as follows: 1) the need to understand the fundamental, theoretical behavior of an unsaturated soil, particularly from a stress state standpoint, 2) the formulation of suitable constitutive equations that were tested for uniqueness in describing unsaturated soil behavior, 3) the ability to formulate and solve one or more highly nonlinear partial differential equations using numerical methods, 4) the determination of indirect techniques for the estimation of unsaturated soil property functions, and 5) in situ and laboratory devices for the measurement of a wide range of soil suctions. Several of the problems faced in unsaturated soil mechanics required a paradigm shift in thinking prior to implementation. These paradigm shifts are also discussed in this webinar.

This webinar explains the nature of each of the above problems and describes the solutions that have emerged out of worldwide research studies. Computer technology has played a major role in achieving practical geotechnical engineering solutions. Computer technology has played an important role with regard to: i.) the estimation of unsaturated soil property functions, and, ii.) the solution of highly nonlinear partial differential equations. Breakthroughs in the in situ and laboratory measurement of soil suction are allowing unsaturated soil theories and formulations to be verified through use of monitoring and the “observational method”.

Learning Outcomes and Seminar Benefits

The first and most fundamental objective of this webinar is to teach geotechnical engineers to “think in a manner consistent with the way the unsaturated soil behaves”. This can be accomplished through learning how to describe all unsaturated soil behavior in terms of changes in the stress state of an unsaturated soil. The secondary objectives are to illustrate the procedures and engineering protocols that can be used to solve practical engineering problems involving unsaturated soils. Part of the secondary objectives will involve emphasizing the estimation techniques that have proven successful for the determination of unsaturated soil property functions.

Upon completion of this course, you will be able to:

• Hear about the latest research findings related to unsaturated soil mechanics
• Explore new solution procedures
• Determine recommended engineering protocols that should help mitigate costly errors that can occur in engineering practice
• Examine new approaches to solve unsaturated soils problems
• Become familiar with monitoring methodologies that can be used for unsaturated soils
• Become aware of numerous new application areas where superior engineering can be done through the application of unsaturated soil mechanics
• University professors will acquire material that can be incorporated into their undergraduate and graduate engineering programs

Assessment of Learning Outcomes

Students' achievement of the learning outcomes will be assessed via a short post-assessment (true-false, multiple choice and fill in the blank questions).

Intended Audience

Practicing geotechnical and geoenvironmental engineers will benefit from this webinar. Some of the most active areas of application in recent years have involved mining and natural resources, as well as waste management. The webinar will also be helpful to university professors as there is great value in having the material on unsaturated soils incorporated into university curriculi on soil mechanics. In addition, soils technicians will find the webinar to be of value, since the laboratory testing of unsaturated soils is an integral part of the practice of unsaturated soil mechanics.

Seminar Outline

• Introduction to unsaturated soil mechanics
• Problems that needed to be resolved prior to the implementation of unsaturated soil mechanics in engineering practice
• Nature of an unsaturated soil and the description of its stress state
• The measurement of soil suction
• Constitutive equations for water flow through an unsaturated soil
• Constitutive equations for air flow, heat flow, shear strength, and volume-mass through an unsaturated soil
• Role and measurement of the soil-water characteristic curve, SWCC
• Equations for the description of the SWCC
• Incorporation of the SWCC in each of the constitutive relations
• Formulation of partial differential equations for each constitutive behavior
• Solving problems related to convergence to correct solutions
• "Challenges" for the future application of unsaturated soil mechanics

How to Earn your CEUs/PDHs and Receive Your Certificate of Completion

To receive your certificate of completion, you will need to complete a short on-line post-test and receive a passing score of 70% or higher within 1 year of purchasing the course.

How do I convert CEUs to PDHs?

1.0 CEU = 10 PDHs [Example: 0.1 CEU = 1 PDH]