Numerical Simulation Analysis of Dynamic Response of Concrete Initial Shotcrete Layer under Construction Blasting
Taking the concrete initial shotcrete layer during the excavation of a tunnel as the test object,the soil structure of surrounding rock is described by the Mohr-Coulomb model,and the spring boundary and time history analysis viscous boundary are taken as the boundary conditions of the two models.The dynamic response of the concrete initial shotcrete layer under the action of construction blasting is numerically simulated and analyzed.The test results show that the tensile stress of shotcrete is lower than the limit tensile stress when the distance between blasting centers exceeds 13 m,and the vibration velocity of shot-crete is lower than the safe vibration velocity when the distance between blasting centers exceeds 12 m.Prolonging the age can reduce the vibration speed of the initial shotcrete layer and shorten the safe blasting center distance.The best age is 3 weeks.When the excavation footage is 2 m,the stress value and vibration velocity of the shotcrete layer are the smallest,the damage degree of the shotcrete layer is the lightest,and the required safe blasting center distance is the shortest.The thicker the thick-ness is,the shorter the safe blasting center distance required to control the spraying layer stress and vibration speed within the safe range,and it is more economical to select the spraying layer with a thickness of 30 cm.
construction blastingconcreteintial shotcrete layerdynamic responsenumerical simulation
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维普
