Natural gas transmission networks require rapid operational decisions that integrate geographic information systems data, network topology, and time indexed measurements from operational systems. While large language models can reduce the interaction barrier for engineers, text only generation is unreliable for safety critical computations and rarely provides auditable evidence. This paper presents Pipeline-Agent, a decision support system for natural gas pipelines built on verifiable computational reasoning. Pipeline-Agent aligns heterogeneous sources into a unified spatiotemporal schema, creates an explicit plan, executes only deterministic tools within a sandboxed workspace, and returns a verifiable result package that includes intermediate artifacts and execution logs. We further introduce Pipeline-Bench, a benchmark with eighty task templates spanning eight categories. Across evaluation runs, Pipeline-Agent achieves a 2.24 × higher mean score than the best baseline and a 2.56 × higher mean score than OpenAI GPT-5.2 direct generation. The results indicate that tool grounded agents with explicit planning and verification can provide practical and transparent decision support for pipeline operations.

Surface deformation from fault displacement threatens buried pipelines crossing fault zones. Previous studies often idealized fault displacement as a quasi-static load, neglecting dynamic rupture effects. This study investigates the dynamic fault displacement effects on buried High-Density Polyethylene (HDPE) pipelines, specifically for the case where the pipeline is perpendicular to the fault trace. A finite element model incorporating a visco-elastic artificial boundary was established and validated against shaking table tests. Dynamic fault dislocation was simulated via an equivalent load input method. Results show a strong correlation between the displacement pulse period and fault displacement magnitude. As displacement increases, the pipeline enters a plastic state, causing significant cross-sectional deformation and amplifying dynamic effects. Under combined short pulse periods and large dislocations, localized deformation is exacerbated by high-strain-rate material embrittlement and concentrated energy dissipation, impairing safety. Transient peak displacements during dynamic dislocation significantly increase plastic strain. Increasing pipeline wall thickness enhances resistance to dynamic pulses. Compared to soft clay, hard clay sites provide stronger constraints, amplifying the pulse period's influence. Sandy soil sites demonstrate superior resistance to the dynamic effects of fault displacement. The dip angle of the reverse fault has a significant influence on the pipeline's response under dynamic fault displacement loading.