Trenchless Technology, March 2016
Guanfeng (Andy) An, chief engineer of Guangzhou Municipal Group, was searching for an effective solution to apply to the rehabilitation of a 200-ft stretch of an arch tunnel on a stormwater collection line in the old town section of Guangzhou. The City was formerly known as Canton, and is the capital of Guangdong Province of the People’s Republic of China.
Root intrusion and corrosion had caused severe damage to the brick-and-masonry structure, which is more than a century old. The City’s Pearl River is just a block away, creating a high groundwater table. Its hydraulic pressure had collapsed the weakened line, causing severe leaking. Heavy silt covered more than 30 percent of the pipeline’s bottom.
The City was seeking a structural rehabilitation and infiltration control solution, with a 50-year service life. Guanfeng compared four possible rehabilitation methods and chose SprayWall, a spray-applied liner from Sprayroq Inc. SprayWall was chosen for its durability, waterproofing and especially its structural characteristics, to hold up against further hydraulic pressure.
Guanfeng had first been introduced to Sprayroq protective and structural coatings at an ASCE Pipeline conference industry conference in Xiamen, China, in 2011. At the conference, Xiamen Anyue Trenchless Technology Engineering Ltd., Southeast China’s Sprayroq Certified Partner (SCP), performed an onsite Sprayroq process demo to the conference attendees. Guanfeng was impressed by the demonstration, and began spending considerable time learning about both the protective and structural properties of Spraywall’s material, the application process and the expected service life.
He believed this trenchless rehabilitation project would be an ideal opportunity to demonstrate the efficacy of Sprayroq products to the city’s utility departments. As the project’s general contractor, Guangzhou Municipal Group contracted Xiamen Anyue. They would be responsible for inspection, cleaning and rehabilitation of the tunnel. Sprayroq and Xiamen Anyue personnel provided onsite consultation on specific technology, installation and design issues.
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