Owner
Los Angeles Department of Water and Power - LADWP
Client
AECOM
Cost
$14.5 million USD
Timeframe
July 2016
— November 2016
Services performed
Site supervision for SEM/NATM works
Description
The constructed tunnel is part of the City Trunk Line project in L.A. (replacement of an existing water trunk line). The tunnel is located at the junction of Riverside Drive and Whitsett Avenue. It is between eight and ten feet in diametre and has a total length of 252 feet. To fit between the existing structures in the ground (foundation piles of a bridge), the tunnel follows an S-shape and is divided into sections with different geometries. The tunnel was built using NATM/SEM construction methods. The primary support measures included fibre reinforced shotcrete, lattice girders and spiles (rebar spiles and grouted pipe spiles).
Geology
Wash deposits consisting of moderately dense sand, silty sands and sandy silts.
Location
Los Angeles, USA
Highlights
- Tunnelling through a reduced section between existing foundation piles of a bridge
- Tunnelling below an artificial water channel
South shaft
Completed tunnel section