水电站蜗壳结构设计参数H与D值影响敏感性分析

Sensitivity Analysis of Design Parameters H and D for Steel Spiral Case of Hydropower Station

在HD值相同的条件下,改变H值和D值,应用三维有限元程序对蜗壳结构进行线性和非线性分析,以研究H值和D值对蜗壳结构受力特性影响的敏感性。得出参数敏感性的影响规律是,随D值减小(H值增大),钢衬和混凝土的应力呈增大趋势,钢衬承载比逐渐增大,裂缝宽度和范围减小;当D值较大时,腰线处混凝土应力和钢筋应力分布规律与传统相反,即外侧应力大于内侧。故当HD值相同、H值较小、D值较大时,应增加钢筋量,且在腰线处外侧配筋大于内侧。

In order to study the influence of H and D on the stress of steel spiral case structure,suppose HD is invariable,the three-dimensional finite element method is used for the linear and nonlinear analyses of the spiral case structures with different H and D.The simulating results indicate that,with the reduction of D and the increase of H,the circumferential stresses of steel spiral case and surrounding concrete show increasing trend,the bearing ration of steel spiral case also increases,while the width and extent of cracks both reduce.When D is large enough,the law of stress distribution of rebar and concrete is opposite to the traditional,that is the stresses in outer side are larger than those in the inner side.So,when HD is invariable,H is smaller enough and D is bigger enough,ratio of reinforcement will be increased and in belt case,ratio of reinforcement in outer side is bigger than those in inner side.