严寒地区碾压混凝土坝越冬层面温控防裂研究

发布时间：2018-12-27 10:10

【摘要】：进行严寒地区碾压混凝土坝越冬层面温控防裂研究,为越冬层面温控防裂设计提供理论依据。针对严寒地区某碾压混凝土重力坝,考虑碾压混凝土热力学参数随龄期的变化、碾压混凝土浇筑进度对温度应力的影响,对碾压混凝土重力坝施工期和运行期全过程进行三维有限元仿真计算分析,着重分析越冬层面应力分布特征。结果表明:约束区和非约束区的越冬层面温度应力分布特征相似,但约束区越冬层面温度应力较大;未采取温控措施时,越冬层面上、下游侧铅直方向温度应力较大,致使越冬层面上、下游侧易出现水平裂缝;越冬层面中部顺水流方向温度应力也较大,因此中部易出现沿坝轴线方向裂缝。提出了采取表面保温、升温水管、微膨胀混凝土、设置水平人工短缝四种措施改善越冬层面的温度应力。采用表面保温和微膨胀混凝土可有效减小越冬层面上、下游侧和中部各个方向的温度应力;采用升温水管和设置水平人工短缝可有效减小越冬层面上、下游侧铅直方向应力。
[Abstract]:In order to provide theoretical basis for the design of overwintering temperature control and crack prevention of RCC dam in severe cold area, the temperature control and crack prevention at wintering level is studied. In view of a roller compacted concrete gravity dam in severe cold area, considering the variation of thermodynamic parameters of roller compacted concrete with age, the effect of rolling compacted concrete pouring schedule on temperature stress is considered. Three-dimensional finite element simulation analysis was carried out for the whole process of construction and operation of RCC gravity dam, and the stress distribution characteristics of overwintering plane were emphatically analyzed. The results show that the distribution of temperature stress in the overwintering layer is similar to that in the unconfined zone, but the temperature stress in the confined zone is larger than that in the unconfined zone. When the temperature control measures are not taken, the temperature stress in the vertical direction of the downstream side is larger than that in the overwintering level, which leads to the horizontal cracks in the downstream side. The temperature stress along the direction of water flow is larger in the middle of the overwintering layer, so cracks along the axis of the dam are easy to appear in the middle part. Four kinds of measures, such as surface insulation, heating pipe, slightly expansive concrete and horizontal artificial short joint, are put forward to improve the temperature stress of wintering layer. The surface heat preservation and micro-expansion concrete can effectively reduce the temperature stress on the overwintering layer, downstream side and central direction, and the horizontal artificial short joint and the heating pipe can effectively reduce the vertical stress on the overwintering layer and the downstream side.
【作者单位】：西安理工大学水利水电学院;
【基金】：国家自然科学基金(51409207) 中国博士后科学基金(2015M582765XB) 西安理工大学科技创新计划(2016CX24)
【分类号】：TV698.23

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