Finite Element Modeling of the Bearing Capacity for Transmission Tower Foundations on Expansive Soil
To satisfy the increasing power demands, lots of transmission lines are constructed in the middle-west of China. Expansive soil widely distributes in these areas, and the safety of foundation for transmission line tower needs to be evaluated. Based on con
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Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China [email protected] 2 Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China State Grid Henan Economic Research Institute, Zhengzhou 450052, China
Abstract. To satisfy the increasing power demands, lots of transmission lines are constructed in the middle-west of China. Expansive soil widely distributes in these areas, and the safety of foundation for transmission line tower needs to be evaluated. Based on consolidated drained triaxial tests, the cohesion and internal friction angle of unsaturated expansive soil were obtained. The compressive and uplift bearing capacities of the plate foundation for transmission line tower foundation were analyzed by 3D finite element modeling. The failure mode of the plate foundation under compressive load shows a local shear mode. For the uplift bearing capacity, the failure mode shows an annular apophysis mode around the plate foundation at the surface. The influence of the saturation of soil on the bearing capacity is more obvious than the uplift bearing capacity of a plate foundation. Keywords: Expansive soil Shear strength Bearing capacity Numerical simulation
Transmission line tower
1 Introduction With the rapid development of economy, more and more transmission lines are being constructed in the middle-west of China, i.e. Henan province, where natural resources and electric power are lacking. It is urgent to construct transmission lines in these areas to satisfy the power demands of people’s living and industrial production. The expansive soil distributed area usually affects the safety of the foundation for transmission lines. It is important to study the mechanical behavior of expansive soil and its influence on the bearing capacity of foundation. Mechanical behaviors of unsaturated soil are usually described by the two independent stress state variables [1–5], especially the theory based on the two stress state variables (r − ua) and (ua − uw) [6, 7]. The shear strength of expansive soil has been widely studied in the past decades. Based on wetting-drying cycle tests of Nanyang unsaturated expansive soil, Miao et al. [8] investigated the soil-water characteristic curve and shear strength. A hyperbolic equation of suction stress and suction strength © Springer Nature Singapore Pte Ltd. 2018 L. Hu et al. (Eds.): GSIC 2018, Proceedings of GeoShanghai 2018 International Conference: Multi-physics Processes in Soil Mechanics and Advances in Geotechnical Testing, pp. 102–110, 2018. https://doi.org/10.1007/978-981-13-0095-0_12
Finite Element Modeling of the Bearing Capacity
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was presented to describe the influence of suction. Sheng et al. [9] compared three kinds of shear strength equations to experimental data, and the empirical and phenomenological equations were shown be applicable to all kinds of unsaturated soil. Based on the in-suit plate loading tests on unsaturated expansive soil, Xu [10] analyzed the
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