# Safety Analysis of Buried Corrosion-Defect Gas Pipeline in Ceramic Soil Layer Under Blasting Action
## 4 Numerical Simulation of Corroded Defective Gas Pipelines
### Numerical Simulation and Field Test and Theoretical Comparison
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Monitoring Points** & **Field Test (MPa)** & **Numerical Simulation (MPa)** & **Error (\%)** & **Theoretical Model (MPa)** & **Error (\%)** \\ \hline D1 & 158 & 170 & 7.59 & 154 & 2.53 \\ D2 & 185 & 195 & 5.40 & 199 & 7.56 \\ D3 & 220 & 245 & 11.36 & 200 & 9.09 \\ D4 & 174 & 192 & 10.34 & 157 & 9.77 \\ D5 & 160 & 172 & 7.51 & 150 & 6.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of field test and numerical simulation data with theoretical model data. Figure 8: Strain curve of channel 1 data under experimental conditions (\(S_{1}\) measuring axial point). Figure 7: Comparison of field test, numerical simulation, and theoretical model data. the effective stress of the pipeline gradually decreases and stabilizes. When the blasting seismic wave propagates in the pipeline, the effective stress on the central section of the pipeline is the largest, and the effective stress takes the central section of the pipeline as the symmetric plane along the pipeline axis, making the central section of the pipeline the dangerous section. It can be seen that the effective stress corresponds to the distribution law of the vibration velocity of the pipeline. Analysis of the Effect of blasting on the Stress of Corroded Gas Pipelines with Different Elastic Moduli  
With the acceleration of urban infrastructure construction, blasting operations are becoming more and more frequent in urban construction. However, the vibration effect of blasting may pose a potential safety threat to nearby buried pipelines, especially corroded gas pipelines. As an important index to measure the ability of material to resist elastic deformation, elastic modulus has a significant effect on the stress change of pipeline under blasting vibration. Therefore, this paper aims to discuss the stress variation law of corroded gas pipeline under different elastic moduli. This paper provides a theoretical basis for the safety evaluation and maintenance of pipelines. In this paper, the stress changes of corroded gas pipelines due to different elastic moduli (100 GPa, 120 GPa, 150 GPa, 180 GPa, 200 GPa) under the same blasting parameters are studied. The experiment adopts the control variable method, by adjusting the elastic modulus of the pipeline. The maximum stress change of the pipeline under blasting vibration was observed and recorded in order to reveal the intrinsic relationship between the elastic modulus and the stress of the pipeline. The stress variation law of corroded gas pipeline under different elastic moduli of blasting is shown in Figure 10 below. Under the same blasting parameters, the stress response experiments of corroded gas pipelines with different elastic moduli (100 GPa, 120 GPa, 150 GPa, 180 GPa, 200 GPa) were carried out. The experimental results show that with the increase of elastic modulus, the maximum stress of the pipeline under blasting vibration increases first and then tends to be stable. Specifically, when the elastic modulus increases from 100 GPa to 150 GPa, the maximum stress of the pipeline increases significantly. For example, a pipe with a 100 GPa elastic modulus has a maximum stress of 250 MPa, while a pipe with a 150 GPa elastic modulus may have a maximum stress of 350 MPa, showing an increase of about 40%. The increase in this stage is mainly due to the increased rigidity of the material, which causes the pipe to produce a greater stress response when subjected to the same blasting vibration. Figure 9: Distribution diagram of effective stress in pipeline. However, when the elastic modulus continues to increase from 150 GPa to 200 GPa, the maximum stress increase of the pipeline significantly slows down and even becomes stable. For example, the maximum stresses of pipes with 180 GPa and 200 GPa elastic moduli may be 370 MPa and 380 MPa, respectively, demonstrating an increase of only about 2.7%.