SEM Cavern Construction in Downtown LA

摘要

The Regional Connector Transit Corridor is a 1.9-mile-long light-rail (LRT) line that will link existing LRT and subway lines to improve mobility within Downtown Los Angeles and throughout the greater City area. A challenging and risky adverse element of this $1-billion design-build project consists of a 287 ft long, 58 ft wide and 36 ft high track crossover structure which is being constructed at relatively shallow depth in soft rock beneath existing building foundations and major utilities using Sequential Excavation Methods (SEM). Through a combination of monitoring data, test results and field observations this paper correlates construction performance with design assumptions and analysis and demonstrates how collaboration between designer, contractor and owner is key to successfully adapt to changes during construction.