Mechanical analysis of parabolic cross-section frost heave in frozen soil regions with high goundwater level
XIAO Min1, WANG Zhengzhong2,3,4*, WU Lang1, XIONG Zhihao1, GE Jianrui 5, CUI Hao1, YANG Xiaosong6
1. College of Construction Engineering, Jiangxi S&T Normal University, Nanchang, Jiangxi 330013, China; 2. Arid and Cold Regions Water Engineering Safety Research Center, Northwest A&F University, Yangling, Shaanxi 712100, China; 3. Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, China; 4. State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-environment and Resources, CAS, Lanzhou, Gansu 730050, China; 5. College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 6. College of Water Conservancy and Construction Engineering, Tarim University, Alaer, Xinjiang 843300, China
Abstract：Considering the particularity that the groundwater level and local geometric characteristics of each section of the canal section are different point by point. Combined with Winkler assumption, calculation method of normal frost heaving force and trangential freezing force of parabolic channel lining in high groundwater table and the calculation formula of internal force of section was presented. Consi-dering the influence of curvature of curved beam, the calculated method of section internal force and anti crack checking formula based on curved beam theory was proposed. By taking a parabolic-shaped canal in Hebei Province of China as example, distributions of section axial force, bending moment and normal stress distribution of the lining section were calculated. The results show that axial force gra-dually increase to the maximum from top to bottom, and all of them are pressures. The lining plate is mainly convex to the inside under the negative bending moment, and only turns from negative to positive to convex to the outside when it is near the bottom of the canal. Because of arc effect, compressive stress occupied the main part then tensile stress only arose in both insides of lower middle part of the canal lining and outsides of bottom center. These two parts under tensile stress are most likely to crack. The comparative analysis between straight beam theory and curved beam theory was performed to calculate the section stress of the lining plate and make a comparative analysis. It is found that the relative error between he two is 11.78% near the bottom center, and the calculated value of the straight beam theory is small and unsafe, so it is more reasonable to conduct stress analysis based on the curved beam theory.
