Which of the following methods is NOT a way to mitigate liquefaction?

The correct answer highlights that excavation is not an effective method to mitigate liquefaction. Liquefaction occurs in saturated soils, typically during seismic events, where the soil loses strength and behaves like a liquid due to pore water pressure exceeding the soil's ability to support loads.

Compaction is a well-established method for addressing liquefaction because it increases the density of the soil, reduces void spaces, and enhances its strength characteristics. By densifying the soil, the potential for liquefaction is significantly decreased during seismic activities.

Drainage helps mitigate liquefaction by reducing pore water pressure. It allows water to escape from the soil during seismic loading, which helps the soil maintain stability and prevent the loss of strength.

Grouting involves injecting a material into the soil to fill voids and enhance stability. This process can significantly improve the soil’s properties, making it more resistant to liquefaction by increasing cohesion and reducing the soil's compressibility.

Excavation alone does not address the underlying issue of soil saturation and does not improve the soil’s resistance to liquefaction. If anything, removing soil can create additional instability, especially if adequate measures are not taken to manage the groundwater conditions. Thus, while excavation may be part of a larger remediation strategy,