Research on the Application of Hydraulic Fracturing Method in Crustal Stress Test of Long and Large Tunnel
A newly-built plateau tunnel is taken as the research object,and the magnitude and direction of in-situ crustal stress in the stratum are tested by hydraulic fracturing method to determine the crustal stress state of tunnel surrounding rocks.The results show that the rock stratum of the tunnel is not typical hard and brittle rock.It is preliminarily predicted that there will be no typical rock burst in the tunnel,which is mainly manifested by large deformation,wall rock deviation and peeling.When the buried depth is 146-285 m and 286-465 m,the surrounding rock excavation may experience grade I,slight large deformation and grade II,medium large deformation respectively.When the buried depth is more than 335 m,the surrounding rock is in a high initial stress state after excavation;when the buried depth is more than 660 m,even extremely high initial stress state may occur.It is suggested that the tunnel should be closed early and measured frequently during construction.
hydraulic fracturing methodlong and large tunnelcrustal stresssurrounding rock deformationrock burst
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