Tunnel Discharge Calculation Considering Grouting Circle Effect in Fault Zone
The water-rich mountain tunnels,passing through the fault zone,often encounter the water inrush and discharge during construction,resulting in construction stagnation and groundwater loss.To investigate the influence of grouting on water discharge in fault zones,the simplified tunnel discharge model in fault zone was established based on the composite lining mountain tunnels.The equivalent fault method was used in space,and the fault was used as the supply boundary with the image method.The formula for deep-buried tunnel discharge considering the grouting circle effect was derived.The relations between tunnel discharge and parameters(e.g.,grouting circle thickness,and relative permeability of grouting circle)were obtained.The proposed method applicability and correctness and the semi-analytical solution were verified through the degenerate solutions and numerical models.The parameter analysis was performed on the groundwater level,lining thickness,and grouting circle of tunnel discharge.The result indicates that the main controlling factors for water-rich mountain tunnel discharge in the fault zone are the grouting circle thickness,the relative permeability coefficient of grouting circle,and the lining thickness.Under the condition of constant groundwater level,the tunnel discharge is significantly affected by the distance between fault and tunnel.The thicker the lining,the stronger the water blocking effect,and the smaller the tunnel discharge in the fault zone.The relative permeability coefficient of grouting circle is sensitive to the tunnel discharge effect.When the ratio of surrounding rock permeability coefficient to grouting circle permeability coefficient is less than 50,there is a linear relation between discharge and grouting circle thickness.However,when the grouting circle permeability coefficient is less,the grouting circle thickness has a significant effect on tunnel discharge.For the mountain tunnel waterproof and drainage design,in the case of ensuring grouting circle thickness,the priority should be given to optimizing the grouting material permeability to achieve more efficient groundwater control.In the case of ensuring grouting ring thickness,the priority should be given to optimizing the permeability of grouting material.The study result aims to provide the reference and guidance for the design and construction practice to facilitate the water blocking and grouting study for tunnels crossing fault.
tunnel engineeringseepage fieldimage methodtunnel dischargegrouting circle
NETL
NSTL
万方数据
