NDM tunnelling for storm water under Corniche Road

NDM tunneling for the stormwater pipeline under Corniche Road included micro-tunneling for a DN 1800 mm ID, 56 m long stormwater drainage tunnel. The tunnel was to be made 4 m below ground level under the busy Corniche Road. Thus, instrumentation monitoring was critical for the safety of infrastructure and lives. 

Consultants decided on continuous monitoring during tunneling, as it was being done in silty soil just 4 m below a busy road. The monitoring plan included instrumentation around the micro-tunneling jacking machine's driving and receiving pits. Instruments were also installed in the monitoring arrays across the tunnel alignment.

Encardio-rite’s sister concern, Encardio-rite Geosystems LLC in UAE, was awarded an I&M sub-contract for the complete monitoring solutions that included

• Supply, installation, and monitoring of geotechnical instruments that included inclinometer, piezometer, borehole extensometer, earth pressure cell, and settlement points
• Drilling works 
• Optical Surveying
• Daily & weekly reporting with evaluation & Interpretation

Monitoring and surveying were scheduled every 2 hours, 24 x 7, during excavation and tunneling works. As the monitoring and surveying were being done on and around the busy road, it was scheduled precisely to meet the tunneling works, adhering to the permitted time frames from the Authorities. The teams worked in shifts 24 x 7 to meet the challenging demands of the Project.