季冻黄土地区框锚边坡预应力锚杆内力计算方法OA北大核心CSTPCD

Due to insufficient research on interaction mechanism between freeze-thaw soil and anchor,the influence of freeze-thaw of soil on the internal force of anchor cannot be fully considered in engineering practice.Therefore,development of an empirical relationship of collapsible loess cohesion considering the influence of freeze-thaw cycles based on the triaxial shear test on collapsible loess in Xining City is essential.Based on the deformation coordination relationship between the anchor body and the surrounding soil layer,the analytical formula of the axial force and shear stress of the anchorage section of the frame prestressed anchor under freeze-thaw conditions is deduced,and the results of the theoretical calculation are compared with field tests,and the influence is analyzed.Results show that the cohesion of the soil decreases exponentially with increase of freeze-thaw cycles,and the axial force and shear stress of the anchorage section increase sharply in the first 3 cycles,and then become stable after 7 cycles.The axial force at the anchorage front section is more influenced by freeze-thaw cycles than the back end.However,the variation pattem of shear stress along the anchorage with freeze-thaw cycles is same.Results of the field tests proved the rationality of the calculation method,which can provide a reference for design and calculation of frame supporting structure in such areas.