Liquefaction: Soils in Motion. How Structures Respond to an Earthquake

Overview

Objectives/Goals My objective was to understand liquefaction, the process that causes the soil to collapse and liquefy during an earthquake, and see which soils were more susceptible to this occurrence. My experiment was designed to see what would happen to the soils and structures during an earthquake. My goals were to find out which soils were strong on their own or could be combined with another soil to make it more stable during an earthquake and liquefaction event. The results could help define the type of soil to best build on to reduce earthquake and liquefaction damage. Methods/Materials In order to create an earthquake simulation, I built a shake table. Constructing the shake table consisted of these main components: wood, marbles, a glue gun, rubber bands, and closet handle casters. I also researched the four most common soils to build on, and acquired samples of each: pea-sized gravel, clay soil, sand, and loam. These soils were then divided into containers. A block of wood was used to represent a building and inserted into the soil. The tests were first performed without water. The container was shaken for three individual time periods; 30 seconds, 1 minute, and 3 minutes. The soils were then retested including water to simulate liquefaction. Using a protractor I measured the degree the building sank in the soil after each simulation. Observations were made on whether the block shifted, collapsed, sank, or did not move and also on how the soil responded to the shaking and liquefaction simulation; did the soil crack, liquefy, shift or stay intact. Results The results were that clay soil on its own or in combination with one of the three other soils responded the best in strength and stability and would possibly limit damage during a liquefaction occurrence. Conclusions/Discussion Liquefaction is devastating and more study needs to be done on how we can stabilize the soil, by either adding additives to the soil to react better during an earthquake or improving and increasing the speed of water absorption to limit liquefaction damage. There are real-life examples that show how structures reacted and failed during a liquefaction event. We need to learn from this when we rebuild, and either not rebuild there or make adjustments to the soil by adding a more stable soil to the mix.

Competition history

• CSEF 2012 Earth & Planetary Sciences · Entry J0808

Resources

• CSEF project summary ↗

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