NEWS 2007

Posted November 27, 2007

Event December 06, 2007

CGS Cross Canada Lecture Tour:

As part of the Cross-Canada Lecture Tour series, the U of A and the GSE will be hosting two presentations by Dr. Paul Mayne, PhD, P.E. Georgia Institute of Technology, on Thursday December 6. These presentations will be:

Critical State Soil Mechanics For Dummies

A simplified approach to CSSM for practice is presented to show the simple link between one-dimensional consolidation tests and direct shear (and direct simple shear) response of soils. Amazingly, the vast majority of geotechnical engineers in practice has still not adopted the framework of critical-state soil mechanics (CSSM), yet the supporting research and clear evidence have been available for over a half-century (e.g., Hvorslev, 1960).

With respect to strength characteristics, CSSM is a valuable framework to interrelate concepts of frictional strength and consolidation, normally-consolidated and overconsolidated behavior, contractive vs. dilative response, undrained vs. drained strengths, porewater pressure generation, and other matters.

Location: Woodvale Community Facility, Tournament Room. Located on the Millwoods Golf Course, 4540 - 50 Street
Time: Registration at 5:30pm, Dinner at 6:00pm
Date: Thursday December 6, 2007
Cost: $20 Students, $40 Members, $45 Non-Members Please confirm attendance by noon, Tuesday December 04, 2007 by emailing sean.birch@amec.com

Integrated Ground Behavior: In-Situ and Laboratory Testing

In complement to drilling and sampling operations for site exploration, results from in-situ tests are increasingly used to derive soil properties and parameters for geotechnical analysis and design. The interpretations of initial state and stress-strain-strength-flow characteristics are calibrated with laboratory test data obtained from high-quality samples, if possible. Yet, inconsistencies often result because no unified framework is available for evaluating all of the in-situ devices, including cone, dilatometer, pressuremeter, and vane. Current interpretation procedures use a hybrid of empirical, analytical, experimental, and/or numerical methods, whereas a comprehensive-integrated numerical simulation of all field tests is needed. In the interim, a semi-analytical-empirical methodology suffices. As the seismic piezocone test with dissipation phases (SCPTu) offers an optimal collection of five separate readings (qt, fs, ub, t50, and Vs) of soil behavior within a single sounding. The relevance of the small-strain shear modulus (G0 = Gmax = ρTVs2) in the initial stiffness response of soils and various associated methods of modulus reduction formulations to obtain values of G at appropriate shear strain levels are discussed. These include procedures to evaluate the in-situ stress state, shear strength, small-strain shear modulus, approximate means to derive nonlinear stress-strain-strength response, and permeability characteristics for application to geotechnical problems. Several selected case studies are presented to illustrate the versatility of this in-situ method for routine geotechnical use.

Location: Room 2-001 NREF (Civil Engineering Building, University of Alberta)
Time: 12:00pm - 1:20pm
Date: Thursday December 6, 2007
Cost: Free