NEHRP Clearinghouse
- Title
- Cyclic Undrained Behavior of Nonplastic and Low Plasticity Silts.
- File
- PB90183518.pdf
- Author(s)
- Walker, A. J.; Stewart, H. E.
- Source
- National Science Foundation, Washington, DC., July 26, 1989, 207 p.
- Identifying Number(s)
- NCEER-89-0035
- Abstract
- The report describes dynamic testing carried out on plastic and non-plastic silts. The plastic silt was prepared by mixing non-plastic silt with controlled amounts of Kaolin clay. Testing was carried out using a quasi-static resonant column/torsional shear device, which has the capability of measuring dynamic properties over a wide range of strain amplitudes. The main parameters investigated in the study were the effects of cyclic shear strain amplitude on the potential for pore pressure generation, and the variation of shear modulus and damping ratio, for different specimen plasticities. The dynamic tests consisted of a resonant column testing phase which was concluded at the initiation of excess pore pressure generation, followed by strain control torsional shear testing. Results showed that the general dynamic response of the silts was similar, in some respects, to that of sands. In particular, pore pressure generation response with varying strain level was found to resemble closely that of a sand of similar relative density. Increasing plasticity was found to reduce the silt's level of pore pressure response. The reduction, however, was not significant for plasticity indices of 5 or less.
- Keywords
- Silts; Dynamic tests; Plastic properties; Earthquake engineering; Dynamic response; Shear strain; Liquefaction; Pore pressure; Soil dynamics; Shear tests; Soil mechanics; Earthquakes