Scroll to top

Liquefaction: Potential and Challenges

On April 21rd, 2016, RDI once again held their invited lecture in this year. The speaker was Mr. Fritz Nababan from Civil Engineering Department at Institute of Technology Bandung. He presented a lecture, entitled Liquefaction: Potential and Challenges.

Liquefaction is a term used in materials sciences to refer to any process which either generates a liquid from a solid or a gas, or generates a non-liquid phase which behaves in accordance with fluid dynamics. Liquefaction can occur when a site with saturated relatively loose, cohesion less soils (usually sands or silts) experience strong earthquake ground motion. When seismic forces excite the saturated granular layers, the loose soil structure tends to contract generating excess pore water pressure, accompanied by a reduction in soils’ strength. This causes the soil to behave as a viscous liquid rather than soil.

The consequences of liquefaction for shallow foundations include the reduction in foundation support through the loss of bearing capacity, excessive settlement, lateral spreading, and flow failures. In deep foundations, liquefaction can cause reduction in lateral capacity, additional downdrag forces, and/or additional demand on the piles from lateral spreading or flow failures.

The presence of liquefiable soil does not mean the building site has to be abandoned, or that expensive deep foundations are required. Soils can be stabilized to mitigate the potential for liquefaction with a number of ground improvement techniques. The most commonly used to date are vibro compaction, vibro replacement, deep soil cement mixing, dynamic compaction, and compaction grouting. Cement grouting, chemical grouting, or jet grouting are also viable options.