全断面富水砂层土压平衡盾构喷涌控制技术研究

Research on gushing control technology of high-pressure full-face sandy earth pressure balance shield

以西安地铁十四号线盾构下穿灞河工程为依托,通过对盾构下穿高水压全断面砂层过程中喷涌问题进行原因分析,并针对性地提出多种喷涌控制手段,有效地抑制了喷涌的再次发生。研究表明:对于全断面富水砂层盾构喷涌的控制,采用泡沫剂+钠基膨润土等常规材料进行渣土改良是可行的;盾构掘进参数优化、降低开挖面水头、盾尾水流通路封堵及停机保压是防喷涌的辅助措施;盾构掘进参数优化应以防超挖、快速通过、避免长时间停机及设备检修为原则,寻找最佳土压平衡参数,最大限度减少下穿过程中对地层的扰动。

Based on the Xi’an Metro Line 14 shield undercrossing the Bahe River project,this paper analyzes the causes of shield gushing in the process of shield undercrossing the whole section sand layer with high water pressure,and adopts a variety of gushing control measures to effectively suppress the recurrence of gushing and successfully complete the shield reception.The main achievements are as follows:for the control of high water pressure full-face sand shield gushing,it is feasible to use conventional materials such as foam agent+sodium bentonite for slag soil improvement;optimization of shield tunneling parameters,lowering the head of excavation face,blocking the flow path of shield tail,and shutting down and keeping pressure as auxiliary measures to prevent gushing;the optimization of shield tunneling parameters should be based on the principle of preventing overbreak,fast passing,avoiding long-term shutdown and equipment maintenance,so as to find the best earth pressure balance point parameters and minimize further disturbance to the stratum during the tunneling process.