Induced Partial Saturation (IPS) Through Transport and Reactivity for Liquefaction Mitigation

Investigator(s): Sabanayagam Thevanayagam

Start date: 2011   |  End date: 2014

Funding Source: National Science Foundation

Project Team Members: The research program is under the directorship of Profs. Yegian and Alshawabkeh at Northeastern University, in collaboration with Prof. Thevanayagam of University at Buffalo, Prof. Stokoe of University of Texas at Austin, Prof. Farid of Boise State University, Dr. Steidl of University of California at Santa Barbara, and Prof. Youd, formerly at Brigham Young University.

Abstract: Devastating effects of earthquakes on the built environment are often due to ground failure associated with liquefaction. Liquefaction is loss of bearing capacity of water-saturated sandy soils leading to failure of engineered structures. While a number of measures to prevent liquefaction have been developed, such mitigation techniques are often very costly and inapplicable to sites with existing structures.

Initial preliminary research conducted at Northeastern University has demonstrated that generating gas bubbles in saturated sands, thus inducing partial saturation (IPS), prevents the occurrence of liquefaction during earthquakes. Also, minute gas bubbles, once introduced within the void spaces of sands, remain entrapped even under ground shaking. This team’s research will advance the IPS technique to field applications, which will involve injection of a very low concentration of an eco-friendly chemical, and through ground water flow and chemical reactivity slowly generate gas bubbles within a sand deposit. The development and implementation of a cost-effective and practical field technique for prevention of ground failure due to liquefaction will have world-wide impact on human safety and protection of property from earthquake hazard.

The research will take advantage of unique experimental and field facilities of NSF's George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). Research at University at Buffalo, under the direction of Prof. Thevanayagam, involves large scale liquefaction experiments on sand, treated with the IPS technique, using the 6m deep NEES geotechnical laminar soil box simulating field conditions subjected to real-world earthquakes.