富水软弱地层隧道复合加固机理及参数研究

Research on composition mechanism and parameters of reinforcement for long-span tunneling weak watery stratum

水平旋喷技术因具备加固地层和止水的双重功能,成为富水软弱地层隧道预支护的较好选择,然而,受地质条件、材料特性及施工工艺限制,预支护体本身存在着不可避免的缺陷,若与掌子面加固复合应用可较好克服缺陷,针对两者复合机理进行分析,同时依托具体工程进行参数讨论。研究结果表明:水平旋喷桩径及刚度增至一定量时,对地表沉降控制效果不再明显;掌子面加固对掌子面挤出变形控制也有一个较优范围,超过该范围控制效果不明显。说明水平旋喷预支护与掌子面加固不能一味强调加固范围及刚度,应根据具体工程选择最佳值。

Horizontal rotary jet grouting technology usually turns into the better solution for the pre -reinforce-ment of tunnel in weak watery stratum in general,owing to its dual function of stratum reinforcement and water sealing.However,the pre -reinforcement system has unavoidable defects due to the constraints of geological conditions,material characteristics and construction technology.This defect can be overcame by applying the pre-reinforcement with the reinforcements of the tunnel face.In this paper,the composite mechanisms about hori-zontal rotary jet grouting technology and the tunnel face reinforcement were analyzed,and the parameters were discussed based on specific engineering.The results show that the control effect on the ground surface settlement is no longer obvious when the pile diameter and stiffness of horizontal rotary jet grouting increase to a certain a-mount.Moreover,there is also a relatively better range for reinforcement of tunnel face to control extrusion de-formation.If the range was exceeded,the control effect would not be obvious.The above proves that horizontal jet grouting reinforcement and face reinforcement cannot be blindly emphasized reinforcement range and stiffness. We should select the optimum value based on the specific project.