Evaluation of uniform delivery of colloidal nano-Silica stabilizer to liquefiable silty sands

Liquefaction is one of the most important and complex topics in geotechnical earthquake engineering. In recent years, passive site stabilization method has been proposed for non-disruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction using colloidal nano-silica stabilizer. In this research, ۴ box models were used to investigate the ability to uniformly deliver colloidal nano-silica stabilizer to liquefiable loose mixes of sand with variations in silt content from ۰ to ۳۰% using ۵ low-head injection and ۲ extraction wells. After delivery was completed the models were cured for ۳۰ days. Then the treated soil was excavated and a few samples were extracted for dynamic loading testing. According to the results, colloidal silica can be delivered uniformly in silty sand formations. With the same conditions, the amount of fine grained soil (silt content) strongly affected delivery time. The passive stabilization method can be appropriate for deposits with up to ۲۰% fine graded silt, a concentration of ۵ wt% colloidal silica is expected to be able to effectively mitigate the liquefaction risk of these deposits. The strains during seismic cyclic loading will probably be less than ۳% and little permanent strain should result.

Keywords:

Colloidal nano-silica , Earthquake , Liquefaction , physical model , Silty sand , Stabilization