Theoretical prediction of ground settlements due to shield tunneling in multi-layered soils considering process parameters

This paper conducts a theoretical analysis of ground settlements due to shield tunneling in multi-layered soils which are usually encountered in urban areas.The proposed theoretical solution which is based on the general form of the Mindlin’s solution and Loganathan-Poulos formula can comprehensively consider the in-process tunneling parameters including:unbalanced face pressure,shield-soil friction,unbalanced tail grouting pressure,unbalanced secondary grouting pressure,overloading during tunneling and the ground volume loss.The method is verified by comparing with the field data from the Qinghuayuan Tunnel Project in terms of the ground surface settlements along the longitudinal and transverse direction.Due to the local settlement or heave caused by the certain tunneling parameters,the ground surface settlements calculated using current solution along the longitudinal direction presents an irregular S-shaped curve instead of the traditional S-shaped curve.Results also find that the effect of the unbalanced secondary grouting pressure and the overloading during tunneling cannot be ignored.

地热利用型盾构法隧道施工探索——以清华园隧道能源管片设计、制作及安装为例

土建工程中的隧道结构兼作浅层地热换热构件时被称作能源隧道。盾构隧道中可先将热交换管安装在预制管片中形成能源管片,现场施工时将各管片连接形成回路,这种隧道称为能源盾构隧道。文章基于国外已有的2个能源盾构隧道管片施工和安装研究实例,结合京张铁路清华园隧道3环27个能源管片的设计、制作及安装工作,从管材的选用、管片的预制、管片的现场安装等方面对地热利用型盾构法隧道的施工方法进行总结梳理,根据施工中遇到的具体问题,从管片制作和现场施工的角度对能源管片规模化施工面临的问题提出可能的解决方法。