摩擦系数对水电站垫层蜗壳结构特性的影响

结合某水电站垫层蜗壳结构，针对蜗壳与垫层、蜗壳与混凝土之间的摩擦系数对蜗壳结构特性的影响进行了三维有限元分析。结果表明，蜗壳与垫层之间的摩擦系数对蜗壳外围混凝土的应力、结构位移的影响很小；蜗壳与混凝土之间的摩擦系数对结构位移影响甚微，但是对蜗壳下半周混凝土的应力和配筋影响较大，尤其在底部位置，当摩擦系数由0.25增大到0.60时，环向应力平均增幅约为14%，配筋面积平均增幅达到30%左右。此前已完成的许多研究中将此摩擦系数取为0.25，根据相关实验研究该值偏小，对蜗壳外围钢筋混凝土结构是偏不安全的。因此，在垫层蜗壳结构的接触非线性计算中，应选择合理的蜗壳与混凝土之间的摩擦系数。

Effect of Friction Coefficient on Structural Characteristics of Spiral Case with Cushion Layer in Hydropower Station

In accordance with the spiral case with cushion layer in one hydropower station, the effect of the friction coefficient between the spiral case and the cushion layer on the structural mechanical characteristics of the spiral case, together with the effect of friction coefficient between the spiral case and the concrete, was analyzed by finite element method. The results show that the coefficient of friction between the spiral case and the cushion layer has small effect on the stress and displacement of the surrounding concrete. Similarly, the friction coefficient between the spiral case and the concrete has no obvious effect on the displacement of the surrounding concrete. However, it makes a great difference to the stress and reinforcement of the concrete. When the friction coefficient increases from 0.25 to 0.60, particularly at the bottom, the circumferential stress of each section increases by around 14% and the areas of reinforcement by about 30% on average. However, it seems that this friction coefficient value 0.25 used in many previous researches, is a bit smaller according to relevant tests, thus it is relatively unsafe for the reinforced concrete structure. Therefore, the coefficient of friction between the spiral case and concrete should be selected carefully in the contact nonlinear analysis.