Induced ground movements by the excavation of an underground line in alluvial soils. EPB method

摘要

Two 5.75 m. inner diameter tunnels were constructed in the alluvium of River Turia at Valencia (Spain) as part of the Underground net extension. Tunnels were excavated with an EPB shield 6.52-m outer diameter. Tunnel section should cross a silty clay layer and a sandy gravel layer under ground water level. The paper deals with the analysis of surface settlements measured on the instrumented section that showed higher settlements. At this section, both tunnels change its relative position from a horizontal one, to a vertical position. The Sagaseta's, Peck-Attewell and Verruijt-Booker methods are compared. Sagaseta's elemental solution has been integrated considering both constant and variable depth of tunnel axis.