GPRS Locates Underground Tunnel System in Dallas, Texas

A General Contractor in Dallas, Texas reached out to GPRS (Ground Penetrating Radar Systems, INC.) for an interesting “pipeline” video camera inspection. We say line because what the GC thought may have just been a storm line, ended up being an abandoned tunnel system from the early 1900’s! The site the GC was working on used to be an old State Hospital that had constructed underground tunnels to move equipment and sometimes people through. The tunnel ended up being approximately 6’x6’ of hand laid brick!

This project was different due to the nature of the work. Typically, GPRS is inspecting a storm or sanitary system but with this project the client did not know this tunnel system existed. When the RovverX Crawler entered the tunnel, it was probably the first time in close to 100 years that anyone had been down there! This was a fun project as both GPRS personnel and the client were excited and interested to see what was down there. At the end of the day, GPRS located the tunnel, and our client was able to continue pouring the foundation for their new building.

Inspections typically take place from one access point to the other and are usually preferred to move downstream. All features inside the sewer line from one manhole to the other are marked on the official NASSCO grading scale. This allows for fully comprehensive and consistent inspections across all projects in every one of our markets. This particular project was simply a locate so GPRS utilized the onboard sonde built into the RovverX Crawler and used our EM Locating equipment to mark out the tunnel system above ground. Having this locate done will now save our client time and money as they know where they can drill and where they cannot. Looking at the image below you wouldn’t believe that that small opening at the bottom of the pit would open into a 6’x6’ brick tunnel!

GPRS runs the sophisticated Envirosight RovverX Inspection Crawler. With six-wheel drive, 12 quick change wheel options, and full pan and tilt 360-degree inspection camera, the RovverX is the workhorse of inspection robots. In addition to the robotic crawler, GPRS runs a 200’ self-leveling push camera in order to inspect any sewer pipes less than six inches in diameter. GPRS can fully inspect mainlines, laterals, and manholes and each member of the GPRS VPI team is NASSCO certified in Pipeline Assessment Certification Program (PACP), Manhole Assessment Certification Program (MACP), and Lateral Assessment Certification Program (LACP).

GPRS is a nationwide utility locating service with experts in underground utility locating, concrete scanning and video pipe inspections (CCTV). For more information on GPRS VPI services in the Dallas region, please contact Michael Wheeler at 470.553.4874 or michael.wheeler@gprsinc.com to talk over your project and schedule a free site walk for your upcoming project.