Problem Statement
Past Liquefaction Events
The 1964 earthquakes in Niigata, Japan and Alaska brought liquefaction damage to the wider attention of engineers and scientists. More than 250 bridges were damaged by this phenomenon during the 1964 Alaskan earthquake (Gallagher, Pamuk and Abdoun, 2007). Since then liquefaction has caused extensive structural damage and economic losses in urban areas and ports during (Díaz-Rodríguez, et al., 2008):
More recently there has been significant damage caused by liquefaction in the 2011 Tohoku Earthquake in Japan (Bhattacharya et al., 2011) and the 2011 Christchurch Earthquake in New Zealand. An example of the damage to roads in the 2011 New Zealand Earthquake is shown in figure 1.
Past Liquefaction Events
The 1964 earthquakes in Niigata, Japan and Alaska brought liquefaction damage to the wider attention of engineers and scientists. More than 250 bridges were damaged by this phenomenon during the 1964 Alaskan earthquake (Gallagher, Pamuk and Abdoun, 2007). Since then liquefaction has caused extensive structural damage and economic losses in urban areas and ports during (Díaz-Rodríguez, et al., 2008):
- The 1964 earthquake in Niigata, Japan
- The 1964 Alaskan earthquake
- The 1985 Michoaca´n earthquake in Mexico
- The 1989 Loma Prieta earthquake
- The 1994 Northridge earthquake in California
- The 1995 Hyogoken-Nambu earthquake in Kobe, Japan
More recently there has been significant damage caused by liquefaction in the 2011 Tohoku Earthquake in Japan (Bhattacharya et al., 2011) and the 2011 Christchurch Earthquake in New Zealand. An example of the damage to roads in the 2011 New Zealand Earthquake is shown in figure 1.
Figure 1: Liquefaction damage to New Zealand highways during the 2011 Christchurch Earthquake.
Economic and Social Cost
Structural damage due to liquefaction-induced ground failure is a very costly phenomenon. Liquefaction damage in past earthquakes has lead to significant economic losses:
Along with property damage there is significant damage to infrastructure such as roads and bridges leading to longer term disruption to the country’s economy. An example of this damage is shown in figure 2. This damage has led to much research into liquefaction mitigation measures.
Economic and Social Cost
Structural damage due to liquefaction-induced ground failure is a very costly phenomenon. Liquefaction damage in past earthquakes has lead to significant economic losses:
- Much of the damage during the 1964 Niigata Earthquake in Japan was linked to liquefaction of the soil (Gallagher, Pamuk and Abdoun, 2007)
- Also billions of dollars in damage, due to liquefaction, was caused to port facilities in the 1995 Kobe Earthquake (Gallagher, Pamuk and Abdoun, 2007)
Along with property damage there is significant damage to infrastructure such as roads and bridges leading to longer term disruption to the country’s economy. An example of this damage is shown in figure 2. This damage has led to much research into liquefaction mitigation measures.
Figure 2: Collapse of the Showa Bridge due to liquefaction below the bridge piers; 1964 Niigata Earthquake.
Purpose of Research
There are many types of liquefaction mitigation measures available such as gravel drains, solidifying the soil using cement grout and excavating liquefaction-prone soils and replacing them with a compacted fill (click here for more information on current methods). However, these methods are either very expensive or require extensive ground disturbance to implement.
Techniques that can minimize the liquefaction susceptibility of a site, with no ground disturbance can greatly impact practice in geotechnical earthquake engineering. Previous laboratory and field work demonstrate that addition of very small amount of nanoparticles, such as bentonite, laponite and silica particles, to pore fluid can significantly increase the soil's resistance to cyclic loading, hence reduce liquefaction susceptibility.
The intention of the project is to quantify this increase in soil resistance to cyclic loading after permeation with the nanoparticle laponite. If the increase in cyclic resistance is significant this research could help laponite permeation become a common technique in liquefaction mitigation.
Purpose of Research
There are many types of liquefaction mitigation measures available such as gravel drains, solidifying the soil using cement grout and excavating liquefaction-prone soils and replacing them with a compacted fill (click here for more information on current methods). However, these methods are either very expensive or require extensive ground disturbance to implement.
Techniques that can minimize the liquefaction susceptibility of a site, with no ground disturbance can greatly impact practice in geotechnical earthquake engineering. Previous laboratory and field work demonstrate that addition of very small amount of nanoparticles, such as bentonite, laponite and silica particles, to pore fluid can significantly increase the soil's resistance to cyclic loading, hence reduce liquefaction susceptibility.
The intention of the project is to quantify this increase in soil resistance to cyclic loading after permeation with the nanoparticle laponite. If the increase in cyclic resistance is significant this research could help laponite permeation become a common technique in liquefaction mitigation.
References
Bolton, M. and Bhattacharya, S., 2004. Errors in Design Leading to Pile Failures During Seismic Liquefaction. New York, Fifth International Conference on Case Histories in Geotechnical Engineering.
Díaz-Rodrígues, J. A., Antonio-Izarraras, W. M., Bandini, P. and López-Molina, J. A., 2008. Cyclic strength of natural liquefiable sand stabilized with colloidal silica grout. Canadian Geotechnical Journal, Issue 45, pp. 1345-1355.
Gallagher, P. M., Pamuk, A. & Abdoun, T., 2007. Stabilization of Liquefiable Soils Using Colloidal Silica Grout. Journal of Materials in Civil Engineering, 19(1), pp. 33-40.
Figures courtesy of:
Figure 1: www.nzraw.co.nz
Figure 2: Bolton and Bhattacharya, 2004