Effect of corrosion on buried pipe responses under external load: Experimental and numerical study

Punch-through corrosion on decommissioned buried steel pipes not only leads to soil migration and ground settlement, but also reduces the load bearing capacity of buried pipes. To investigate the impact of corrosion on buried pipe responses, a 600-mm diameter plain steel pipe was buried and tested under static load. At the pipe crown and springline, a 150-mm diameter hole to simulate corrosion was drilled prior to burying the pipe. Then, a series of three-dimensional finite element simulations were performed to study the effects of cover depth, corrosion size, and pipe wall-thickness on the responses of corroded pipes. The pipe strains are the highest right underneath the loading pads, and increase with increasing applied load and decreasing cover depth. The simulated corrosion holes magnify the pipe stress based on both the experimental and numerical results. However, this stress concentration effect is the most significant within a lateral distance of twice the radius of the simulated corrosion hole. The above conclusions apply to the holes created at both the springline and crown. However, under the same applied load, a higher maximum pipe stress is measured when a hole is located at the crown.

Automated summary

Punch-through corrosion on decommissioned buried steel pipes has detrimental effects on soil migration, ground settlement, and load bearing capacity. Experimental and numerical investigations were conducted to study the effects of cover depth, corrosion size, and pipe wall-thickness on the responses of corroded pipes. The results showed that pipe strains were highest underneath the loading pads, and increased with applied load and decreased cover depth. The simulated corrosion holes magnified the pipe stress, with the most significant effect observed within a lateral distance of twice the radius of the corrosion hole. Interestingly, higher maximum pipe stress was measured when the corrosion hole was located at the crown.