弧底梯形混凝土衬砌渠道冻胀破坏力学模型研究

Mechanics Model of Frost-Heaving Damage of Concrete Lining Trapezoidal Channel with Arc-Bottom

针对宁夏引黄灌区混凝土衬砌结构冻胀破坏严重现状,以渠基土为典型湿陷性黄土的弧底梯形砼衬砌渠道为研究对象,建立考虑法向冻结力分布的弧底梯形混凝土衬砌渠道冻胀破坏力学模型,计算最大法向冻结力、最大法向冻胀力和衬砌板内力的表达式,并对衬砌板厚度进行验算。结果表明,渠坡板法向冻结力从渠顶至坡脚位置呈线性增大分布,坡板以受剪应力为主,在自重和法向冻结力共同作用下容易产生冻胀裂缝。渠底板受两端坡板约束,以受轴向压力为主,法向冻结力呈均匀分布。

In view of the serious condition of frost heave damage of concrete lining structures in the yellow irrigation area of Ningxia,the authors established the mechanical model of frost heave damage of the arc bottom trapezoidal concrete lining channels considering the distribution of normal freezing force.the expression of maxuimun normol freezing force,maximun normal frost heaving force and inner force of lining plate is calculated,and the thickness of linning board is cheked.The results show that channel slope's the normal freezing distributing from canal top to slope bottom linearly increase.The slope plate is dominated by shear stress.Frost heaving cracks are prone to occur under the combined action on dead weightt and normal freezing force.Channel floor is constrained by the slope plates at both ends,which is mainly subjected to axial pressure and the normal freezing force is uniformly distributed.