SSC, Sundt, PCL, Kiewit All Play Vital Role in Phoenix

“Our deepest dig was 33 feet underground,” said Veidmark. “That was inside the water treatment plant. Our work teams had to keep the equipment running yet remain vigilant while tunneling under roads and important structures. We stayed away from a reservoir and a traffic intersection. Often, they found some previously undiscovered underground structure. They had to decide whether to have it removed or tunnel deeper or go around it.”

The final segment of SSC’s installations was for PCL Construction. The digging team installed three 96-in. tunnels at the origination point of the pipeline, the 24th Street Water Treatment Plant. Using the same skid steer method as in earlier digs, the workers encountered solid rock conditions, averaging 18 in. per shift of tunnel advancement.

These three tunnels — 35 ft., 115 ft. and 101 ft. in length — connect four pits for installation of a 72-in. waterline. Three of the four pits were constructed as semi-permanent structures to allow for the angles and elevations necessary to complete the connections.

Not only did work teams have to deal with hard rock, but also surprising weather emerged.

“Several times our teams came to work and discovered that the pit had been flooded in the night,” Veidmark said. “We simply pumped out the water and went to work.”

Veidmark is proud of the work that he and his team accomplished for the general contractors in charge of the overall projects.

“Tunnelling allows life on the surface to go on in a normal manner,” he said. “It means fewer traffic backups with cars idling for long periods of time. Also, when working underneath a neighborhood we can keep the worksite clean and try to be as invisible as possible.”

With other tunneling projects coming for the future, companies like SSC Underground must consider their options.

“Workers are becoming harder to find, so we sometimes look to larger and more efficient equipment to do the job,” Viedmark said. “Large tunnel boring machines should be considered as well as improved geotechnical information. We are hoping improved technology will provide answers in our business.”  CEG photos courtesy of SSC Underground.)