By rosebell
In the previous week an investigation into the partial collapse of the under-construction Clearwater Tunnel has been commissioned by Los Angeles County Sanitation Districts (LACSD) and contractor FlatironDragados.
Following the collapse, which occurred around 8-10km from the sole access portal, thirty-one people were rescued.
The investigation will look at the safety, engineering and structural integrity of the tunnel. Clearwater Tunnel operations have been halted while the investigation takes place and LACSD said there was no timeframe for the process.
According to the organisation: “Safety remains the highest priority of the Los Angeles County Sanitation Districts. We will continue to co-ordinate with all relevant agencies and provide updates as they become available.”
In accordance with preliminary information, the incident occurred under Western Avenue, almost 113m beneath ground, as LACSD said. Survey crews at the site verified there was no surface damage or discernible movement at the location, and the area was safe.
Over the TBM operation during construction, survey crews have been monitoring the road above the tunnel alignment and the area had been monitored since September 2024 and as recently as April this year, with no discernible movement, LACSD said.
Follpwing the day of the partial collapse, survey crews are due to monitor the area daily, 90m either side of the site. Readings will be taken across the road in 15m increments.
In order to addressing concerns over the existing infrastructure, the Clearwater Tunnel is designed, whereas currently wastewater is conveyed in two tunnels – one built in 1937 and the other in 1958. They are not built to modern seismic standards and rainstorms in recent years have nearly exceeded their capacity.
