Influence of pipe jacking burial depth and caving body particle size on mechanical properties of pipe jacking

XIAO Fukun; LAO Zhiwei; XIE Kai; KONG Lingxue; HAO Chuanbo

doi:10.13347/j.cnki.mkaq.20240739

Abstract：The pipe jacking rescue method is to form an emergency life passage safely and efficiently by jacking a prefabricated pipe through the caving and collapse blockage area.In order to study the macro-mesoscopic mechanical properties of the caving body un-der the action of pipe jacking under the conditions of different pipe jacking depths and particle sizes of the caving body,combining the similar simulation test and numerical simulation test of jacking pipe in caving body,the effects of pipe jacking burial depth and particle size of caving body on the resistance of jacking pipe and particle displacement are explored,and the macro-mesoscopic para-meters of caving body are further investigated from the viewpoints of coordination number,force chain and energy of caving body.The results show that:the jacking resistance and particle displacement as a whole increase with the increase of particle size of caving body and pipe jacking burial depth,and the displacement zone is mainly divided into the extrusion and disturbance zone in front of and behind the pipe opening and the shear sliding zone directly above the pipe opening;the amplitude of the fluctuation of the co-ordination number and the difference of the drop increase with the increase of particle size of caving body and pipe jacking burial depth,and the force chain in front of the pipe opening is damaged and continuously expanded,thus forming a shear sliding surface;with the increase of particle size of caving body and pipe jacking burial depth,the elastic potential energy,kinetic energy and dissipa-tion energy are positively correlated in the jacking process,and the jacking is mainly divided into the early small strain disturbance stage and large strain shear sliding stage.