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Liquefaction SPT-Based

Simplified seismic liquefaction potential per NCEER (Youd et al.) with SPT-based CRR, CSR and FoS evaluation.

Inputs

Method — Youd et al. (NCEER 2001)
  • CSR = 0.65·(amax/g)·(σv/σv')·rd. Stress-reduction rd = 1 − 0.00765·z (z≤9.15 m).
  • Corrected (N1)60 = N · CN; CN = √(100/σv') (capped at 1.7).
  • (N1)60cs = (N1)60 + Δ(N1)60 (fines correction by Idriss-Boulanger).
  • CRR_7.5 from (N1)60cs (NCEER chart). MSF = 174/Mw^2.56. CRR = CRR_7.5 · MSF.
  • FoS = CRR/CSR. FoS < 1 → liquefaction triggered.

Results

σv (total)
σv' (effective)
CSR
(N1)60cs
CRR (Mw=7.5)
CRR (adj.)
FoS
Status