Construction Monitoring – Beijing Metro Lines

Construction-phase safety monitoring for stations on Beijing Metro Lines 12, 8, 17, 19, 28 and the Changping South Extension. A Line 12 station is a two-level underground island-platform station built by the PBA (pile-beam-arch) method, with an effective platform width of 16 m, an overall length of 326.6 m, a standard-section width of 25.5 m and a height of 18.68 m; the arches carry about 12.132 m of overburden and the base slab lies at roughly 30.512 m depth, with shield tunnels passing through after the main structure is completed. The site is highly sensitive, located beneath the Third Ring Road and surrounded by residential communities and bridges, with the works crossing storm, sewage and water mains as well as gas and heating duct lines. Given the complex strata (silty clay, clayey silt and fine sand), an additional K pilot tunnel was installed beneath the central pilot tunnels to satisfy the bearing-capacity requirement, and groundwater is controlled by surface dewatering combined with local dewatering pilot tunnels, monitoring the steel columns' stress and internal forces throughout each construction stage.