| Summary: | 碩士 === 國立中興大學 === 土木工程學系所 === 104 === In Taiwan area, the petrochemical industry was flourish in the seventies, derived products including asphalt pavement, man-made fiber, etc. As the climate of Taiwan is hot and humidity, the underground pipelines of petrochemical factories commonly used to transport gas and liquid chemicals are susceptible to oxidative corrosion. Furthermore, industrial and household underground pipelines are often staggered because of the time factor, therefore, the management and maintenance is not easy. For example, due to long-term contact with water, surface corrosion or damage may occur in pressured pipelines, especially near leaking water pipes or poor drainage area. There are studies on pipelines damaged or corrosion, though the study on those of underground pipelines is still limited. This research investigates the behavior of pressured underground pipes with damaged or corrosion by numerical simulation and physical modeling. And the verified numerical model was used to analyze actual cases.
There are three parts of this paper, the first part is physical model experiment, we install strain gages near the damage part of a pipe, measuring the strain with adding internal pressure and surface loading in sandbox. The second part is numerical analysis, we built the same numerical model as the physical model, and compared with the results with those from physical modeling. The last part is using verified numerical model to simulate different conditions, and discussing the effect of damaged pipelines with surface loading, diameter of pipe, depth of soil, and different location and size of corrosion. Finally, CIPP, a No-dig rehabilitation technology, was simulated and its performance was illustrated.
The major findings of this study are summarized as below. Comparing the results from physical modeling experiments and numerical analysis, it show the trend of strain were the same and the error is minimal. The strain of corrosion pipe on top or side were different when surface loading greater than internal pressure. Pipe damaged location will affect stress and strain of other undamaged location. No matter how large the surface loading is, the stress and displacement of large corrosion were greater than small one.
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