Experiment on Performance of Buried Pipelines Across San Andreas Fault

摘要

A field experiment designed to investigate the performance of buried pipelines at a fault crossing has been constructed near Parkfield, CA. The site was chosen to capitalize on the predicted recurrence of the 1966 Parkfield-Cholame earthquake sequence. Monuments for measuring lateral offset and strong motion seismometers have been placed at the site and are being monitored. Thirty-six strain gages have been attached to two segments of welded steel pipe to measure length changes and flexure. Twelve displacement transducers have been installed in jointed ductile iron pipe to measure rotation and extension at the joints. The accomplishments of 1988 include measuring the stress-strain properties of the pipeline steel and shear strength of the interface between sand and steel. Three strong motion seismometers were put in place. Survey monuments were also emplaced and are monitored regularly by the US Geological Survey. The concrete anchors which are intended to prevent relative displacement between the pipe and the adjacent soil at the ends of the welded steel pipes were enlarged. Future work includes upgrading the data acquisition rate such that the strain measurements and ground strains derived from the seismometers are both resolved up to 8-10 Hz and further reducing noise in a few strain gage channels.