Timber Pile Ground Improvement for Liquefaction Mitigation

Excess porewater pressure induced by rapid shearing often leads to liquefaction of granular deposits, resulting in excessive deformation (settlement, lateral spreading) and loss of stability of supported structures. Since several devastating earthquakes in the 1960s, practitioners and researchers have developed and evaluated numerous approaches for the mitigation of liquefaction and its deleterious effects on civil infrastructure. Innovations range from vibro-compaction and vibro-replacement of granular deposits, compaction and permeation grouting, deep soil mixing and jet grouting, and installation of large-diameter high density polypropylene (HDPE) earthquake drains (EQDs). These mitigation techniques attempt to improve the ground such that the soil is densified, reinforced, or drained, lowering the potential for excessive ground deformation. Although the foregoing mitigation techniques enjoy strong theoretical and empirical evidence of their effectiveness, each of the methods exhibits the limitation that they use one mode of treatment (densification, reinforcement, or drainage). To overcome these limitations, the effectiveness of conventional and novel drained timber pile ground improvement for the mitigation of liquefaction was evaluated.

Publications arising from this work include:

Gianella, T.N. and Stuedlein, A.W. (2017) "Performance of Driven Displacement Pile-Improved Ground in Controlled Blasting Field Tests," Journal of Geotechnical and Geoenvironmental Engineering, Vol. 143, No. 9, 04017047

Stuedlein, A.W. and Gianella, T.N. (2016) "Observations on the Effect of Driving Sequence and Spacing on Displacement Pile Capacity," Journal of Geotechnical and Geoenvironmental Engineering, Vol. 143, No. 3, 06016026.

Stuedlein, A.W., Gianella, T.N., and Canivan, G.J. (2016) "Densification of Granular Soils using Conventional and Drained Timber Displacement Piles," Journal of Geotechnical and Geoenvironmental Engineering, Vol. 142, No. 12, 04016075.

Gianella, T.N., Stuedlein, A.W., and Canivan,G.J. (2015) "Densification of Liquefiable Soils using Driven Timber Piles", 6th International Conference on Earthquake Geotechnical Engineering, Christchurch, New Zealand, 1 to 4 Nov. 2015.

Funding for this study was provided by the National Academy of Science through the National Cooperative Highway Research Program: Ideas Deserving Exploratory Analysis (NCHRP IDEA) Program under Project Number 180. This support is gratefully acknowledged. The investigators would like to extend thanks to the members of the South Carolina Chapter of the Pile Driving Contractors Association (PDCA). We wish to thank Van Hogan, formerly of the PDCA, for his hard work and dedication in marshalling the various resources required to bring this project to completion. We thank the member firms that have contributed materials, labor, and equipment, and without whom this project could not have been completed: Pile Drivers, Inc., S&ME, Inc., Soil Consultants Inc., Chuck Dawley Surveying, Cox Wood Industries, and Hayward Baker, Inc.

Below, you can view the segment on our research featured in early October 2015 on the show Daily Planet, hosted by the Discovery Channel