Experimental Study on Influence of Longitudinal Single Fracture Distribution Position on Instability Characteristics of Surrounding Rock of Cavern
In order to study the influence of the distribution position of longitudinal cracks on the instability character-istics of surrounding rock of caverns,the macroscopic mechanical parameters and failure modes of cavern models were compared and analyzed by biaxial loading tests of cavern models without prefabricated cracks and cavern models with pre-fabricated cracks at different positions as well as combining with digital image technology(DIC).The test results show that with the increase of lateral pressure coefficient(λ),the peak strength and peak strain of the cavern model increase first and then decrease,and reach the maximum when λ=1,while the elastic modulus decreases first and then increases.From the point of view of failure mode,for λ<1,the failure mode of the cavern is gradually changed from tensile failure to tensile-shear composite failure.The fracture is located at the vault and the bottom plate is obviously damaged,while the fracture is located at the straight wall and the bottom foot,and the vault and the bottom foot are seriously damaged.With the increase of λ and λ≥1,the failure of the model is mainly tensile crack.Compared with the other two positions,the fracture is located in the straight wall,and the stability of the cavern is the worst.Under the same λ,the high strain concentration area will shift with the change of crack position,but the high strain area is mainly concentrated at the pre-fabricated crack end and the two bottom feet of the cavern.
万方数据
维普
