Study of Feasibility of Using Wissa-Type Piezometer Probe to Identify Liquefaction Potential of Saturated Fine Sands.

摘要

A two-phase study was performed to investigate the feasibility of using the pore pressure response from a penetrating Wissa piezometer probe to indicate the potential for liquefaction in saturated fine sand. The Wissa probe is a cone penetrometer, similar to the Dutch cone penetrometer, with a sensing element at the tip for measurement of pore pressures. Phase I was a field study consisting of three piezometer probe tests to a depth of about four and one-half meters in each of two areas; Area 1 containing deposits of loose, easily liquefiable mine tailings sand, and Area 2 containing similar deposits compacted by a vibratory roller to a condition of stable relative density. Tests in Area 1 produced generally positive excess pore pressures, while tests in Area 2 produced generally small negative pore pressure response. Comparison of pore pressure data with relative density, as estimated from approximate correlations with penetrometer resistance, suggest that this type of probe sounding can detect very unstable, saturated, clean, fine sands with relative densities below about 20 percent. However, there may be a broad range of relative density in which the piezometer probe response is insensitive to relative density.