Post-Liquefaction Pore Pressure Dissipation and Densification in Silty Soils

Pore pressure generation, and post-liquefaction dissipation and densification characteristics are data essential for detailed analysis of performance of sites containing liquefiable sands during and after earthquakes. These characteristics are also necessary for the design, analysis and choice of appropriate ground modification systems to mitigate liquefaction-induced hazards. Past research has addressed such material characteristics for clean sands. However, there are many sites that comprise non-plastic silts or silty sands have experienced liquefaction-induced damage. This paper presents results from an experimental study on silts and silty sands. Pore pressure generation characteristics are evaluated and compared with that of sands. Pre- and post-liquefaction compressibility and coefficient of consolidation, and densification characteristics are determined from undrained cyclic tests data followed by dissipation. Implications of these findings on the earthquake performance of sites containing non-plastic silts and silty sands are discussed. Their impacts on the choice of ground improvement techniques are also discussed

Engineering of Ground for Liquefaction Mitigation

Liquefaction is considered as a major crucial hazard among different seismic risks. Ground improvement methods commonly employed, to improve the natural site conditions under such situations, lead to better performance of various engineering structures built up on. The paper presents various aspects of liquefaction hazard mitigation of loose saturated sands with a spectrum of ground engineering methods. A short discussion on liquefaction hazard associated with loose sand deposits and its evaluation followed by outlines of the ground engineering applications with the main focus on stone columns/granular piles, sand compaction piles, deep soil mixing, and dynamic compaction as liquefaction hazard mitigation measures are presented