NEHRP Clearinghouse
- Title
- Prediction of Pore Water Pressure Buildup and Liquefaction of Sands during Earthquakes by the Cyclic Strain Method.
- File
- PB83111617.pdf
- Author(s)
- Dobry, R.; Ladd, R. S.; Yokel, F. Y.; Chung, R. M.; Powell, D.
- Source
- July 1982, 176 p.
- Identifying Number(s)
- NBS-BSS-138
- Abstract
- A cyclic strain approach for evaluating the buildup of excess pore water pressures and the potential for liquefaction of level sandy sites during earthquakes is proposed in this report. This strain approach is based on the premise that, for undrained loading of sand, there is a predictable correlation between cyclic shear strain and excess pore water pressure; also, that there is a threshold shear strain below which there is no sliding at the contacts between sand particles and no pore water pressure buildup can occur. As the result, a sand deposit will not develop excess pore pressures if the induced seismic shear strain is less than the threshold strain. Both theoretical evidence and experimental verification suppoting the cyclic strain approach and the existence of the threshold, are presented in the report. Based on all there findings, a specific design method is proposed for predicting if excess pore pressures will develop at a specific site during a design earthquake.
- Keywords
- Stress strain diagrams; Seismic loads; Shear strain; Earthquake engineering; Pore pressure; Liquefaction; Shear modulus; Liquefaction (Soils); Cyclic loads; Sands; Earthquakes