引洮工程封闭渡槽输水期间热力耦合分析

Coupled thermo-mechanical analysis of a closed aqueduct of the Gansu Tao Diversion Project during operation

引洮工程位于甘肃省季节性冻土地区,基于甘肃引洮供水工程沿线封闭渡槽在全年正常输水运行时的环境温度条件,根据传热学及有限元基本理论,建立了寒区封闭渡槽热力耦合分析的有限元数值模型,对其全年正常运行过程中的温度及热应力分布规律进行了数值研究.结果表明:在全年正常输水运行条件下,引洮工程封闭渡槽在长期运行过程中由于水温和气温所造成的温差均能在渡槽截面的横向、竖向及纵向产生很大的拉应力,其值均超过了混凝土的抗拉强度(1.43 MPa),且全年大部分时间内渡槽壁面内外的温差都很大,在渡槽腹板和底板都将产生较大拉应力,因而存在一定的开裂风险,会在渡槽的长期运行中留下安全隐患,应引起设计、施工及运营部门的重视.

The Gansu Tao Diversion Project（GTDP） is located in seasonally frozen soil regions in Gansu Province,China.Based on the environmental temperature conditions for the closed aqueduct along the GTDP under normal water running,and according to the basic theory of heat transfer and finite element,a thermo-mechanical coupling numerical model for the closed aqueduct in cold regions is established to study numerically temperature and thermal stress distributions of the aqueduct for a whole year.The results show that the horizontal,vertical and longitudinal tensile stresses on the cross-section of the closed aqueduct resulted from water and air temperature difference exceed concrete tensile strength in the long-run process.Furthermore,the temperature difference between inside and outside walls of the closed aqueduct is relatively large so that a larger tensile stress will appear in more than half a year.Therefore,a certain cracking and security risk will exist in the long run.The design,construction and operation departments should be greatly focusing on such issues.It is hoped that the analysis results in this study can provide a scientific basis for effective design and safety maintenance of water supply aqueducts in other cold regions.