装配式配筋UHPC内衬管环力学性能试验研究OA

To address the conflict between lining thickness and rehabilitation effect in trenchless repair of structural defects in large-diameter pipelines,this study proposes a prefabricated inner liner ring made of reinforced ultra-high-performance concrete(UHPC).Innovatively,iron-based shape memory alloy(Fe-SMA)rebars were incorpo-rated to introduce self-prestressing in the thin-walled curved segments,thereby enhancing their structural perfor-mance without increasing wall thickness.Three-edge bearing tests were conducted to comparatively evaluate the effects of concrete type,reinforcement scheme,reinforcement ratio,and prestress activation state on the structural performance.The bending moment distribution and crack propagation characteristics were systematically analyzed.The results indicate that the maximum bending moments occur at the crown and invert of the ring,followed by the springlines,while the shoulder and haunch exhibit relatively lower bending moments.The failure mode is governed by plastic hinge formation,and no premature damage initiates at the assembly joints.Compared with specimens with-out prestress activation,the cracking load and the load corresponding to a crack width of 0.2 mm increase by 44.4％and 35.6％,respectively,after activating the Fe-SMA rebar.The self-prestressing effect significantly enhances crack resistance of the thin-walled UHPC liner ring.The findings provide a reference for the design optimization and engineering application of thin-walled UHPC lining structures.