Research For Rheology And Blasting Excavation Method In Carbonaceous Schist Tunnel Of Huashigou

This paper research the rheological behavior of carbonaceous schist and theexcavation method of tunnel blasting, and provide reference to solve problems inHuashigou tunnel such as uncontrolled large deformation and tunnel seriously overbreakand underbreak in the process of excavation. Through the analyze of rock massrheological theory, find out the rheological regularity of carbonaceous schist, and useFLAC3D to simulate the different excavation and supporting methods, then theconclusion are listed as follow: using top and bottom benching excavation method isclose to actual situation, the initial supporting can suppress the tunnel initial deformationwell, and secondary lining also has a better effect on control the deformation, then thedeformation tends to convergence. The effect on control deformation of tunnel is best ifconstruct the initial supporting and secondary lining in time and closed loop as early aspossible; On the basis of summarizing previous tunnel blasting method, combined withthe construction site actual situation of Huashigou tunnel, proposed to use weak blastingand mechanical joint excavation method, the main measures are:1) the excavation usingthe half section are steps method;2) Weakened the tunnel blasting design and reduce thesmooth blasting holespacing;3) the reserved water softening layer;4) mechanicaltrimming, then the early support;5) A working face within carbonaceous schist andnon-carbonaceous schist partition blasting design, and so on. This can reduce thedisturbance of surrounding rock greatly, and overbreak have been effectively controlled,It has obtained the good effect of excavation, and the overall construction efficiency isrelatively high, It can offer reference for future similar projects.