Abstract: Taking the Longmen Comprehensive Transportation Hub Project in Luoyang as an engineering background,we employed the Midas-GTS/NX finite element software in association with on-site monitoring data to investigate the impact of foundation pit construction on pipeline deformation. We considered various factors of pipeline such as buried depth,buried distance,pipe diameter,pipe material,and the position of internal support. By normalizing variables, we evaluated the influence of these factors on pipeline behavior during foundation pit construction and assessed the safety performance of thermal pipelines. The outcomes reveal that,under the pit angle effect,the deformations at both pit corners are essentially consistent,with vertical displacement,horizontal displacement and bending moment in the middle of the pipeline reaching 1.36 times,1.14 times,and 1.19 times that of the pit corners respectively. Furthermore,the maximum displacement of the pipeline occurs in its middle part under diverse influencing factors. Through variable normalization,we identified that vertical displacement and horizontal displacement of pipeline exhibits the highest sensitivity to buried distance,with relative sensitivities of 0.78 and 0.60,respectively,and conversely,the lowest sensitivity to pipe diameter,with sensitivity values of only 0.12 and 0.08. Evaluation of the safety performance of thermal pipeline reveal that the maximum relative rotation angle remains below 0.1° and the stress safety coefficient reaches 10.52, indicating a satisfactory level of safety.

Key words: deep and large foundation pit, comprehensive transportation hub, adjacent pipelines, mechanical analysis, safety evaluation, sensitivity analysis