Reducing the Impact of Earthquakes Ground Shaking on Infrastructure

Stacy S. Chao, Troy High School

Abstract

In Southern California, earthquakes have historically caused significant damage to infrastructure, deaths, and financial damage. Although Southern California is heavily impacted by earthquakes, other seismically active regions around the world are also affected by earthquakes. Reinforcement methods such as stone columns, jet grouting, and deep soil mixing are commonly used in areas with weak soil in order to both improve the foundation support and reduce the structural deformations caused by earthquakes. The objective of this study was to analyze the effectiveness of deep soil mixing soil cement panels in order to reduce the seismic ground shaking intensity on soft clay sites. An aluminum laminar box was constructed and filled with soft clay on top of a single axis shake table. The Granular Kaolin Clay was mixed with 40% by weight water and placed into the laminar box. The clay was then consolidated to a vertical pressure of 1.5 psi. Soil-cement panels were made with Kaolin Clay and tap water in a proportion of 1:1.9:2.9. These panels were put into the soft clay to replace 10% and 20% of the total surface area of the soft clay. Five accelerometers were installed into the soft clay, all put at different locations, in order to allow it to read different ground motions during several different earthquakes. This allowed us to record the sinusoidal function and ground motions during several earthquakes applied to the model. The results showed that there was a clear improvement with reinforcing the weak soil areas with the deep soil-mixing panel in the laminar box. When comparing the 20% replacement ratio with the 10% replacement ratio, it was found that the 10% replacement ratio was more efficient. The 10% replacement ratio significantly lowered the amplification factor while using less material compared to the 20% replacement ratio.

 
Nov 12th, 2:30 PM Nov 12th, 2:45 PM

Reducing the Impact of Earthquakes Ground Shaking on Infrastructure

HUB 265

In Southern California, earthquakes have historically caused significant damage to infrastructure, deaths, and financial damage. Although Southern California is heavily impacted by earthquakes, other seismically active regions around the world are also affected by earthquakes. Reinforcement methods such as stone columns, jet grouting, and deep soil mixing are commonly used in areas with weak soil in order to both improve the foundation support and reduce the structural deformations caused by earthquakes. The objective of this study was to analyze the effectiveness of deep soil mixing soil cement panels in order to reduce the seismic ground shaking intensity on soft clay sites. An aluminum laminar box was constructed and filled with soft clay on top of a single axis shake table. The Granular Kaolin Clay was mixed with 40% by weight water and placed into the laminar box. The clay was then consolidated to a vertical pressure of 1.5 psi. Soil-cement panels were made with Kaolin Clay and tap water in a proportion of 1:1.9:2.9. These panels were put into the soft clay to replace 10% and 20% of the total surface area of the soft clay. Five accelerometers were installed into the soft clay, all put at different locations, in order to allow it to read different ground motions during several different earthquakes. This allowed us to record the sinusoidal function and ground motions during several earthquakes applied to the model. The results showed that there was a clear improvement with reinforcing the weak soil areas with the deep soil-mixing panel in the laminar box. When comparing the 20% replacement ratio with the 10% replacement ratio, it was found that the 10% replacement ratio was more efficient. The 10% replacement ratio significantly lowered the amplification factor while using less material compared to the 20% replacement ratio.