Yaskovets Z. Soil-structure interaction effect on the stress state of pipelines in the areas of mine productions

Object of research - the effect of soil displacements on the stress state of pipelines in the mine productions influence areas. The aim of the study - development of the numerical and analytical methods for calculating the stress state of underground pipelines located in hazardous landslide zones caused by mine workings, taking into account the history of the soil surface longitudinal displacements. Research methods - analytical and numerical methods for solving differential equations, instrumental determination of actual pipe deformations during mining productions, computer simulation. A mathematical model and numerical solution procedure were developed to determine the stress state of underground pipelines under the actions of soil longitudinal displacements, taking into account the elastic-plastic soil-structure interaction. To estimate the stress state of underground pipelines during mining workings an algorithm is proposed which accounts for the history of the soil surface longitudinal displacements development. The basic principles were formed and hardware diagnostic tools were created for monitoring the stress state of pipeline sections in the areas of mine workings. The results of the monitoring of the stress state showed the correctness of the computational methods of analysis. In addition, monitoring results were used to investigate the processes of stress relaxation in time after the exit of the mine excavation from the zone of gas pipeline influence. It was found that the relaxation process proceeds faster in the zones of tensile stresses of the pipeline than in the zones of compressive ones. On the basis of the established calculation procedure, general approaches have been implemented to formulate measures for the safe operation of underground pipelines. According to the results of experimental and numerical studies, it was confirmed that bellows compensator DN 100 can be used to countervail axial movements in gas pipeline sections located in the areas of mine workings. The research results were used by the mine departments of CJSC «DTEK Pavlogradugol» in analyzing the stress state of the pipeline and determining ways to ensure their safe operation in areas of mine productions.