梁山隧道深埋富水陡倾软弱带突水涌泥机制分析及旋喷技术

梁山隧道是厦深铁路福建段的控制工程之一,施工中遇到深埋富水陡倾软弱带,多次导致突水涌泥及洞顶塌陷情况。通过研究突水涌泥及洞顶塌陷的灾害特征,分析得到突水涌泥机制,即:在这种多因素复杂地质条件下,隧道开挖导致形成极高的渗透压力差,并产生新的地下临空通道,在地下水渗透压力作用和自身重力作用下,全风化物质涌入隧道,形成突水涌泥;而软弱构造带塌陷的主要原因为地下水位的急剧下降。通过调研、理论分析及试验等方法,确定采用长距离水平旋喷桩通过软弱带,并提出其布置形式、施工工艺及检验标准。工程实践证明,采用长距离水平旋喷桩作为预加固手段是可行且有效的。

Analysis on Mechanism of Water Gushing and Mud Inflow When Tunneling through Deep-covered Steep Water-rich Fracture Zone and Application of Horizontal Jet Grouting Piles:Case Study on Liangshan Tunnel

Liangshan tunnel is one of the key works on Xiamen Shenzhen railway. During the construction of the tunnel, water gushing and mud inflow often occur, due to the deep covered water rich steep soft fracture zone met. In the paper, the characteristics of the water gushing, mud inflow and ground surface collapse are studied, and the water gushing and mud inflow mechanism is analyzed. It is concluded that fully weathered materials and ground water under the effect of high seepage pressure difference induced by tunnel excavation are the main causes for the water gushing and mud inflow, and that the ground surface collapse is induced by the sudden drop of the ground water level. After investigation, theoretical analysis and tests, it is determined that long distance horizontal jet grouting piles be used to reinforce the fracture zone. The layout, construction process and inspection standard of the jet grouting piles are also presented in the paper. The practice shows that the long distance horizontal jet grouting piles mentioned are feasible and effective in the consolidation of the fracture zone.