User:Chaozhanghnu/sandbox

Ning Lu is a Chinese-American civil engineer. He was born and grown up in Fuzhou, the capital of subtropical coastal province Fujian, China. He left his hometown shortly after his high school to attend Wuhan University of Technology for his B.S. and first M.S. He then began his oversea journey to the United States where he received his M.S. and Ph.D. from the Johns Hopkins University, Baltimore, Maryland.

He is renowned for conceptualization of suction stress for unifying effective stress in soil, and for conceptualization of soil sorptive potential for unifying matric potential for soil water potential. Effective stress is the cornerstone of a century-old branch of mechanics called soil mechanics and was first defined by Karl von Terzaghi for quantifying strength and deformation of soil and rock under water saturated conditions in engineered and natural earthen environment. For years, effective stress is widely used as the basis for design and analysis of engineered earthen structures. Expansions of Terzaghi's effective stress to partially saturated conditions, which is more prevalent in the earth shallow environment, have been largely based on pore water pressure, by either scaling capillary pressure to a stress variable, or directly using capillary pressure as a stress variable. Lu is the first person to demonstrate that capillary pressure is not a stress quantity, and mechanical energy can be stored in soil water by a physical mechanism other than capillary pressure, namely sorptive pressure. He and his co-workers used both capillary pressure and sorptive pressure to define suction stress , which captures all the known physical mechanisms contributing to effective stress under both saturated and partially saturated conditions. For his seminal contribution to conceptualization of suction stress, he received Norman Medal in 2007 and J. J. Croes Medal in 2010 from American Society of Civil Engineers. In 2017, he was awarded M. A. Biot Medal by American Society of Civil Engineers for his "outstanding contributions to the fundamental understanding of the mechanics of unsaturated porous materials." .

He and his co-workers also discovered that sorptive pressure, though is a mechanical stress in pore water, originates from and co-exists with electromagnetic field called soil sorptive potential. Soil sorptive potential is a combined electromagnetic potential due to several soil sorptive mechanisms, namely, van der Waals, electrical double layer , surface hydration , and cation hydration. Soil sorptive potential provides a thermodynamic basis to define soil water potential. Sorptive pressure, together with capillary pressure, provides a rigorous pressure variable for thermodynamic quantifications of commonly occurred physical phenomena in the earth’s shallow environment such as water flow, heat transfer, electric flow, chemical transport, super-freezing of soil water, phase transition, high pore water density, and effective stress.

His conceptualizations of suction stress and soil sorptive potential root in his passionate curiosity on the dynamic evolution of the earth’s landscapes; why natural and manmade hillslopes often catastrophically fail under certain extreme rainfall conditions. Lu established a coupled hydromechanical framework to predict the initiation of landslides by following the natural sequences of landslide occurrence: rainwater infiltrates into soil and changes soil moisture and water potential (soil sorptive potential), soil water potential changes soil inter-particle stress (suction stress or effective stress), leading to failure of soil or landsliding. He was bestowed R. B. Peck Award by American Society of Civil Engineers in 2017 for his "multiyear case study monitoring the subsurface hydrological and mechanical conditions leading to landslide occurrence on the coastal bluffs between Seattle and Everett, WA, and for using the data collected to develop a new hydromechanical framework for slope-stability analysis." . He teaches at Colorado School of Mines, Golden, Colorado and is a resident of Boulder, Colorado. He is an elected fellow of American Society of Civil Engineers, Geological Society of America, and Engineering Mechanics Institute, and a lifetime member of American Geophysical Union.