Abstract:In light of that the periodical temperature changing leads to mechanical properties deterioration of rock bolts during the snowmelt period in spring,the relationship between bearing capacity of rock bolts and freeze-thaw cycles was studied. The freeze-thaw cycling experiments were conducted first for rock bolt specimens under different freeze-thaw cycles;and then the pull-out experiments were carried out. The displacement,stress and failure load of bolt,stress of rock,shear strength at the bolt-grout interface were investigated;the failure mode and main destruction factor under freeze-thaw conditions were studied with load transfer mechanism. It is shown that the elastic modulus and strength of mortar decreases along with the increase of freeze-thaw cycles;the mortar near the loading end splits ahead of time and accelerates load transferring to the inside of bolt;the internal stresses of bolt and bond increase. The ultimate bearing capacity of bolt decreases while the deformation of bolt increases under freeze-thaw conditions;the inflection point in load-displacement curve and horizontal segment in slipping curve of bolt will appear in advance along with the increase of freeze-thaw cycles.
许宏发,王 武,江 淼,等. 灌浆岩石锚杆拉拔变形和刚度的理论解析[J]. 岩土工程学报,2011,33(10):1 511-1 516.(XU Hongfa,WANG Wu,JIANG Miao,et al. Theoretical analysis of pullout deformation and stiffness of grouted rock bolts[J]. Chinese Journal of Geotechnical Engineering,2011,33(10):1 511-1 516.(in Chinese))
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