Liquefaction Mitigation by Chemical Grouting-Video

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The presentation described a 2008 liquefaction-mitigation project at a sailing school in Newport Beach, California. The building addition was close to a seawall, existing foundations, utilities, and tieback anchors, ruling out vibration-based and higher-pressure ground-improvement methods. The team selected low-pressure, pH-neutral colloidal silica permeation grouting to bind the shallow liquefiable sand while minimizing environmental and structural risks.<br /><br />A grid of treatment zones covered the upper 15 feet of soil, with a 53% replacement ratio. The grout was activated with salty water and injected through 154 holes, totaling 466 cubic meters. Ground and seawall movement were closely monitored; neither experienced significant deformation, and construction continued without disrupting classes or harming marine life. Laboratory testing of recovered samples showed the treated soil gained cohesion, with an unconfined compressive strength of about 25 psi.<br /><br />In discussion, the presenters noted that seawater helped set the grout, while low-salinity groundwater could cause it to redisperse.

Keywords

liquefaction mitigation

colloidal silica grouting

Newport Beach

seawall stabilization

permeation grouting