Numerical study on mechanical properties of pipeline installed via horizontal directional drilling under static and dynamic traffic loads
Hongfang Lü, Xinmeng Jiang, Zhao-Dong Xu, Niannian Wang, David Thomas Iseley
Abstract
The present study investigates the mechanical behavior of pipes installed via horizontal directional drilling method, a typical trenchless method for highway-crossing pipeline installation, under traffic loads. The effects of both stationary and moving vehicles are considered in the analysis. Results from the static analysis indicate that the pipe experiences maximum stress at its top, with minimum stress at its bottom. Furthermore, the stress change in soil is more significant than that in the pipeline as the vehicle weight increases. When a moving vehicle passes over the pipeline, the stress of the pipeline remains relatively constant. No significant change in pipe stress is observed with changes in vehicle weight and speed. However, when the vehicle speed approaches 100 km/h, the maximum soil stress decreases significantly. Conversely, the pipe stress is higher when the vehicle is stationary compared to when it is moving. A comparison is made between the mechanical behavior of pipes installed via horizontal directional drilling and open-cut methods under traffic loads, with the results revealing that the stress of pipelines installed via horizontal directional drilling method is higher than those installed via open-cut method in both static and dynamic analyses. Nonetheless, the stress variation amplitude of pipelines installed via horizontal directional drilling method is smaller during vehicular passage, thus indicating a lower possibility of fatigue failure caused by traffic loads.