Classed as a heavy civil project, the Perth City Link Project was a $360 million rail job which involved a number of infrastructure changes to the Perth CBD to allow for a new tunnel and the sinking of the Fremantle Line between William and Lake/King Street. Geomotion was contracted to monitor the integrity of the track by installing a string of 95 Longitudinal EL Beams and 47 Transverse Beams, as well as 3,000 data points to be displayed on the ARGUS near-real-time software. These data points included robotic total stations, piezometers, in-place inclinometers, crackmeters, load cells, strain gauges, EL beam sensors, vibration monitors and tiltsensors.
A number of steps were conducted to build the tunnel including laying the foundations, constructing a diaphragm wall, lowering the water table, and excavating the tunnel. The removal of the quantity of soil along with the other construction work could well have had an impact on the structures surrounding the works, some of which were heritage listed. To monitor these structures Geomotion installed crackmeters and tiltmeters in conjunction with robotic total stations to provide alerts if any movement above the pre-established parameters was exceeded.
Over the life of the project a gigalitre (one billion litres) of water was pumped out of the construction area, treated and pumped back into the ground. To monitor this massive undertaking the consultants, GHD, opted for an innovative and successful installation of Geomotion’s Rippas. These units recorded the data and regularly uploaded that data to a dedicated web page, providing engineers with up-to-date knowledge of how the water table was behaving.