超浅埋复合地层插刀式矩形顶管施工及扰动控制技术研究OA

[Objective]Rectangular pipe jacking is widely used in urban underground infrastructure construction in China and is developing toward ultra-shallow burial,large cross sections,complex strata,and long distances.[Methods]Based on the ultra-shallow-buried rectangular pipe-jacking project in composite strata on the east side of Putian Station,which underpasses an operating railway,the construction method for a new type of rectangular pipe-jacking machine(the inserting-knife rectangular pipe-jacking machine)and the safety control technology for adjacent construction were introduced in detail.The reinforcement effect of disturbance control technology for adjacent construction of ultra-shallow-buried rectangular pipe jacking was analyzed based on the field monitoring results,and the construction disturbance characteristics and disaster-causing mechanisms in the complex geological and structural environment were further analyzed.[Results]During the underpass,the maximum surface settlement caused by the inserting-knife rectangular pipe-jacking machine was 163.67 mm,far exceeding the allowable value.However,the deformation of the D-type temporary beams remained within the safe range,and the beams played a key role in reinforcing the tracks,thereby ensuring the normal operation of high-speed railway trains.[Conclusion]Under comprehensive protection based mainly on D-type temporary beams and track speed restriction,excavation methods adapted to different geological conditions are adopted,enabling safe tunneling by a large-section rectangular pipe-jacking machine in a complex and sensitive environment containing hard rock for the first time and providing a reference for rectangular pipe-jacking construction under shallow-buried,complex geological conditions.Based on field monitoring and actual construction conditions,three types of disaster-causing mechanisms and corresponding control measures for inserting-knife rectangular pipe-jacking construction are summarized.