Event
Invited Seminar. Ning Lu, Ph.D.
Wednesday, April 9, 2025
12:30 p.m.-1:30 p.m.
KEB 1107/1111
Robert Herschbach
301 405 2057
rherschb@umd.edu
http://go.umd.edu/nlu
he Department of Civil and Environmental Engineering invites you to a seminar featuring Ning Lu, Ph.D., Colorado School of Mines.
A Paradigm for Predicting Rainfall-Induced Landslides
Wednesday, April 9
12:30-1:30 p.m. | Kim Engineering Building, Room 11107/1111
University of Maryland
Register: go.umd.edu/nlu
Virtual option available
ABOUT OUR SPEAKER
Ning Lu has achieved breakthroughs in the concept of effective stress in soils. He has unified soil effective stress under both saturated and unsaturated conditions, moving beyond the classical Terzaghi and Bishop effective stress representations. For his seminal work on soil effective stress, he received the American Society of Civil Engineers' (ASCE) Norman Medal twice: first in 2007 for conceptualization of suction stress, and again in 2022 for formulation of a practical closed form effective stress equation. He recently received ASCE’s Karl Terzaghi Award for seminal contributions to the understanding of the fundamental mechanisms governing the behavior of unsaturated soils and their implications for slope stability and other geotechnical problems. In the past two decades, he has formulated a new paradigm for slope stability under variably saturated conditions. For that work, he received ASCE's 2017 R. B. Peck Award, and M. A. Biot Medal. He is a distinguished member of ASCE and a fellow of the Geological Society of America. He has published two widely used textbooks: Unsaturated Soil Mechanics (John Wiley and Sons, 2004), and Hillslope Hydrology and Stability (Cambridge University Press, 2013).
ABSTRACT
This seminar will highlight two major advancements in predicting rainfall-induced landslides that stemmed from several multi-year field hydro-mechanical monitoring. The first significant breakthrough is the capability of handling the transient field of effective stress in variably saturated slopes under rainfall conditions. Using effective stress analysis preserves the rigor, simplicity, and practicality of the classical slope stability methodologies (e.g., limit equilibrium). The second is to quantify the field of the local factor of safety (FS), which radically departs from the classical one-FS-for-one-slope paradigm and allows identification of failure initiation and progression zones in slopes. The new hydro-mechanical framework for slope stability design and analysis only requires three parameters in addition to the classical shear strength and seepage parameters. These parameters are used to uniquely define slope materials’ constitutive relations of the soil water characteristic curve, hydraulic conductivity function, and suction stress characteristic curve. Several field cases are used to illustrate the validity, accuracy, and simplicity of the new hydro-mechanical framework for slope stability analysis.
