GROUND-BORNE VIBRATION MEASUREMENTS OF DRILL?AND-BLAST EXCAVATION, SHEET PILE INSTALLATION, AND TBM EXCAVATION IN SANDSTONE AND SHALE MéLANGE

摘要

Ground-borne vibration generated by construction activities is often a significantrnpublic concern during the planning and construction phases of a project. Publishedrnvibration data for various excavation methods are limited and include projects constructedrnin different geologic materials that range from soft ground to hard rock, and itrnhas been shown that ground-borne vibration levels are sensitive to the type of geology.rnGround-borne vibration measurements conducted during drill-and-blast excavation,rnsheet pile installation, and tunnel boring machine (TBM) excavation at the New CrystalrnSprings Bypass Tunnel Project in San Mateo, California, are reviewed. This projectrnwas excavated in Franciscan Complex rock, which is a highly heterogeneous mixturernof harder sandstone and a weaker, sheared shale mélange matrix, also referred tornas “block in matrix” rock. The proximity of the tunnel and access shafts to residentialrnhomes, as well as existing water supply lifelines, prompted strict limitations on noisernand vibration for construction activities.