松散地层条件下小净距隧道进洞方案技术研究

Study on the scheme of small net tunnel entry under loose formation conditions

根据以往工程经验,当隧道在松散地层条件下进洞时,通常采取全部卸载松散堆积体或采取地表深孔注浆改良地层的方案,但这两种方案也存在大开挖、造价高等方面的不利影响。随着隧道设计与施工技术的不断进步,工程项目中需要寻求一种更经济、安全、合理、有效的进洞解决方案。论文以已建成项目——厦门北站连接线工程为依托,通过现场分析及结合类似工程经验,提出卸载部分松散体+仰坡浅层注浆+洞内双层大管棚预支护为主体的进洞方案,并针对小净距隧道穿越松散地层提出了针对性的措施。

According to the previous engineering experience,when the tunnel enters the tunnel under the condition of loose stratum,it usually takes all the unconsolidated bulk or deep hole grouting to improve the formation,but these two schemes also have adverse effects on large excavation and high cost. With the continuous improvement of tunnel design and construction technology,a more economical,safe,reasonable and effective solution for entering the tunnel is needed. Based on the completed project,the connecting line project of Xia Men North Railway Station,through the field analysis and the experience of similar projects,this paper puts forward the project of unloading part of loose bulk ＋ shallow grouting with shallow slope and double layer large pipe shed in the tunnel as the main body,and puts forward some pertinent measures for the small distance tunnel through the loose formation of the loose stratum.