Example Problem: Factor of Safety against Liquefaction

Example Problem 1: A soil layer at a depth of 5 meters has a calculated Cyclic Resistance Ratio (CRR) of 0.25 based on SPT data. A design earthquake generates a Cyclic Stress Ratio (CSR) of 0.20 at this depth. Calculate the Factor of Safety against liquefaction. Is the soil layer safe from liquefaction?

Example Problem 2: A site in a highly seismic region features a thick deposit of uniform, clean sand. At a depth of $6 \, m$, the total vertical stress is $112 \, kPa$ and the effective vertical stress is $82.57 \, kPa$. The design earthquake produces a peak ground acceleration of $0.35g$. Calculate the Cyclic Stress Ratio (CSR) assuming a stress reduction factor of $0.95$.

Example Problem 3: Continuing from Problem 2, standard penetration testing at the $6 \, m$ depth yielded a Cyclic Resistance Ratio (CRR) of approximately $0.16$. Calculate the Factor of Safety against liquefaction.