In this subsection, a simulation model of underground pipeline leaks was created. Modeling the flow fields of overhead pipelines and underground pipelines with different soil porosity was conducted. The influence of the underground environment and soil porosity on the pipeline leakage field was analyzed. The influence of changes in the underground environment and soil porosity on the loss of kinetic energy at gas leakage was defined. Thus, the law of change in the characteristics of the sound signal of a leak on the pipe wall was obtained. Based on the results of study, it was determined the area of damage to a gas pipeline which is depended on proportionality of the diameter of the gas jet. As the gas is released from a crack in the gas pipeline and with different porosity of the pipe material, the gas diffusion occurred. As a result, the explosion zone increased which ultimately the release of gases into the environment under the influence of pressure increased.

As a non-destructive technique, ground penetrating radar (GPR) is extensively used for detecting underground pipelines. To find out the distribution of underground pipelines and avoid the damage for them. In this paper, the underground pipelines with different materials were simulated using gprMax, i.e., concrete, copper, iron, and PVC pipelines. Peplinski's semi-empirical soil was taken into account to ensure that the soil environment more closely real conditions. In order to get clearer and highlight echo signals, the average method was used. A discussion about different kinds of pipelines B-scan profile to analyze the electromagnetic properties of the microwave propagation in underground media. At last, a comparative analysis was conducted on the B-scan images of the four-pipeline model under uniform soil and simulated soil conditions to evaluate the impact of different soil conditions on the echo signals. Through analyzing the electromagnetic characteristics of underground pipelines to verify the advantages of ground penetrating radar in the measurement of underground pipelines.