Using large hydraulic shakers to induce liquefaction in the field

摘要

Current field liquefaction evaluation techniques rely on empirical correlations between liquefaction resistance and in-situ test parameters, such as the standard penetration test blow count and the cone penetration test tip resistance, to predict the field performance of liquefiable soils during earthquakes. A more direct approach would involve dynamically loading a soil deposit in-situ in a manner similar to an earthquake and measuring the response of the soil to that loading. A new field testing technique has been developed based on this premise. This technique employs a truck-mounted hydraulic shaker, typically called a vibroseis in geophysical exploration, to shake the ground surface and generate stress waves that dynamically load the soil deposit. The soil response is monitored using embedded instrumentation to evaluate the pore pressure generation characteristics in terms of induced shear strains, excess pore pressures, and number of loading cycles.