大型水电站半垫层蜗壳非线性联合承载力分析

Analysis on nonlinear joint bearing capacity of semi-cushionspiral case of large hydropower station

为研究钢衬-混凝土摩擦及其之间的粘性滑移等因素对水电站半垫层蜗壳结构承载能力的影响,以某水电站蜗壳结构为工程背景,在理论分析的基础上,建立了考虑钢衬与外围混凝土摩擦接触、钢筋与混凝土粘结滑移的非线性数值模型,探讨了半垫层蜗壳非线性联合承载力特性。研究结果表明,在静水压力等荷载作用下,外围混凝土虽在薄弱区域出现局部损伤带,但损伤区域的损伤值较小,混凝土裂缝开展宽度也小于规范规定。此外,钢衬及钢筋应力水平远低于其屈服强度,可以保证蜗壳结构有足够的安全储备,不会因为强度不足而引起结构的破坏。整体而言,研究对象的应力及超载能力均满足要求,设计安全储备较高。

In order to study the influences from the factors of the friction between steel lining and concrete as well as the viscous slip between them,etc.on the bearing capacity of the semi-cushion spiral case of hydropower station,a nonlinear numerical model is established under the consideration of the frictional contact between steel lining and its surrounding concrete and the bond-slip between the reinforcing bar and its surrounding concrete on the basis of the relevant theoretical analysis by taking the spiral case structure of a hydropower station as the engineering background,and then the characteristics of the nonlinear joint bearing capacity of the semi-cushion spiral case are discussed.The study result shows that under the effects of the loads of hydrostatic pressure,etc.,the damaging value of the damage area is less though the local damaged zone of the surrounding concrete occurs within the weak area therein,while the opening width of the concrete crack is also less than the relevant specification.Additionally,the stress levels of both the steel lining and the reinforcing bar are far less than their yielding strengths,thus can ensure the sufficient safety reserves of the spiral case structure,and then the failure of the structure cannot be caused by insufficient strength.Generally speaking,both the stress and overload capacity of the study object can meet the relevant requirement with higher safety reserves.