Preventing Ground Failure Due to Earthquakes

Professors Mishac Yegian and Akram Alshawabkeh were awarded a $1.2M NSF grant from the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) to use Induced Partial Saturation (IPS) to try and prevent ground liquefaction from occurring under structures during earthquakes. The goals of this research are to conduct fundamental research exploring the feasibility of inducing partial saturation under field conditions, and to demonstrate the effectiveness of IPS in preventing the occurrence of liquefaction. The outcome of this research will have significant impact on human safety and protection of property from earthquake hazards.

Source: News @ Northeastern

Two North­eastern engi­neering pro­fes­sors have been awarded a $1.2 mil­lion research grant to advance their work in devel­oping a cost- effective method to pre­vent ground failure during earth­quakes, a major cause of destruc­tion to build­ings con­structed on water- saturated sandy soils.

The solu­tion could be simple: Just add bubbles.

Mishac Yegian, a Dis­tin­guished Pro­fessor of Civil and Envi­ron­mental Engi­neering, and Akram Alshawabkeh, a pro­fessor of civil and envi­ron­mental engi­neering, were awarded the grant from the National Sci­ence Foundation’s George E. Brown, Jr. Net­work for Earth­quake and Engi­neering Simulation.

While a number of mea­sures exist to pre­vent liq­ue­fac­tion — when solid soil turns to liquid and can no longer hold up the struc­tures it sup­ports — those mit­i­ga­tion tech­niques are often pro­hib­i­tively expen­sive and cannot be applied to sites with existing structures.

Yegian’s and Alshawabkeh’s pre­lim­i­nary research has demon­strated that gen­er­ating gas bub­bles in sat­u­rated sands — a process they call “induced par­tial sat­u­ra­tion” — pre­vents liq­ue­fac­tion during earth­quakes. The tiny gas bub­bles, which fill the spaces between grains of sand, remain entrapped in the soil even during strong earth­quakes. The bub­bles absorb the pres­sure that an earth­quake would oth­er­wise apply to water, pre­venting liquefaction.

The grant will allow the induced par­tial sat­u­ra­tion research to move into the field, where Yegian and Alshawabkeh plan to inject a low con­cen­tra­tion of an environmentally- friendly chem­ical into the ground that, with the help of ground water flow and chem­ical reac­tivity, will help gen­erate oxygen gas bub­bles within a sand deposit, a tech­nique that can be used before or after a building is constructed.

The devel­op­ment of a cost- effective and prac­tical method to pre­vent liq­ue­fac­tion will have a broad impact on human safety and the pro­tec­tion of prop­erty from the destruc­tion of earthquakes.

“We think we have found a cre­ative and daring solu­tion that would have ben­e­fits in the United States and world­wide,” Yegian said. “There would be a whole new industry that could emerge from this work. Engi­neers so often work on build­ings one at a time, but earth­quakes don’t — they hit entire com­mu­ni­ties. We believe our work can help keep entire com­mu­ni­ties safe from earthquakes.”

Work funded by the grant, part of the National Earth­quake Haz­ards Reduc­tion Pro­gram, is being com­pleted in col­lab­o­ra­tion with researchers from other insti­tu­tions including the State Uni­ver­sity of New York at Buf­falo, the Uni­ver­sity of Texas at Austin, Boise State Uni­ver­sity and the Uni­ver­sity of Cal­i­fornia at Santa Barbara.

Related Faculty: Akram N. Alshawabkeh, Mishac K. Yegian

Related Departments:Civil & Environmental Engineering