NEHRP Clearinghouse
- Title
- Liquefaction Evaluation of Densified Sand at Approach to Pier 1 on Treasure Island, California, Using SASW Method.
- File
- PB98172513.pdf
- Author(s)
- Andrus, R. D.; Stokoe, K. H.; Chung, R. M.; Bay, J. A.
- Source
- October 1998, 84 p.
- Identifying Number(s)
- NISTIR-6230
- Abstract
- Areas of improved and unimproved soil near berthing Pier 1 at Treasure Island, California, were investigated by the Spectral-Analysis-of-Surface-Waves (SASW) test. The upper 12 m of sand fill beneath the approach to the peir had been densified by a vibratig probe technique in 1985. The area of improved soil, which is 23 m wide and 93 m long, performed well during the 1989 Loma Prieta earthquake on a 240-m-long alignment that extended across the area of improved soil using a seismic vibrator as the principal source with receiver spacings from 7.6 m to 76 m. Average shear wave velocities determined for the densified and undensified sand fill below the water table were 192 m/s and 167 m/s, respectively. Two simplified analytical procedures based on shear wave velocity correctly predict no liquefaction for the densified sand, and marginal liquefaction for the undensified sand. Although less conservative, liquefaction assessment procedures based on the SPT and CPT provide similar predictions.
- Keywords
- Liquifaction; Sinkholes; California; Earthquake engineering; Treasure Island; Noncohesive soils