【摘要】 大石峡引水压力隧洞上平段为钢筋混凝土衬砌，内水压力标准值为0.99 MPa,需要设置一定数量钢筋控制衬砌裂缝分布及其宽度。通过采用基于修正摩尔-库伦准则的弹塑性损伤混凝土有限元法和预设裂缝法，建立非线性数值模拟模型，其中用植入式杆单元模拟钢筋力学效应，用具有抗拉和滑移力学特性的节理单元来模拟衬砌上的预设裂缝。结果表明：仅衬砌内层和内外层均布置钢筋对混凝土衬砌塑性损伤区即开裂出现时机和位置基本没有影响，只对塑性区分布的范围稍有影响；布置钢筋方式对钢筋应力影响较小，钢筋混凝土塑性模型计算的两种情况的钢筋应力相差1.6%,预设裂缝模型计算的相差22.1%。两种数值模型计算出的钢筋混凝土衬砌裂缝宽度均小于规范允许值，满足结构限裂要求。更多还原

【Abstract】 The upper flat section of Dashixia headrace pressure tunnel is lined with reinforced concrete, and the standard value of internal water pressure is 0.99 MPa and a certain amount of reinforcement shall be provided to control the distribution and width of lining cracks. In this paper, using the elastic-plastic damage concrete finite element method based on the modified Mohr Coulomb criterion and the preset crack method, a nonlinear numerical simulation model is established in which the embedded bar element is used to simulate the mechanical effect of reinforcement, and the joint element with tensile and sliding mechanical properties is used to simulate the preset cracks on the lining. The results are as follows: as for placement of reinforcement only in the inner lining and placement of reinforcement on both the inner and outer lining, there is no difference on the occurrence time and location of the plastic damage area of the concrete lining, i.e. the crack, but only slight difference on the distribution range of the plastic area; the type of placing reinforcement has little influence on the reinforcement stress and the difference of reinforcement stress between the two cases calculated by the reinforced concrete plastic model is 1.6%, and the difference calculated by the preset crack model is 22.1%. The crack width of reinforced concrete lining calculated by the two numerical models is less than the allowable value of the specification, which meets the requirements of structural crack limit.更多还原