Capacity of Cone‐Shaped Hollow Flexible Reinforced Concrete Foundation (CHFRF) in Sand under Horizontal Loading

Abstract

The cone-shaped hollow flexible reinforced concrete foundation (CHFRF) is an innovative type of mountain wind turbine foundation, which outperforms the regular mountain wind turbine foundation in reducing the steel and concrete and protecting the surrounding vegetation for the cavity absorbs soil obtained from excavating the foundation pit. Moreover, the rubber layer installed between the wall of CHFRF and the surrounding ground increases foundation flexibility and releases the larger overturning moment induced by wind. The rubber layer is made of alternately laminated rubber and steel. The objectives of this research are to study the lateral bearing behaviors of the CHFRF under monotonic and cyclic lateral loading in sand by model tests and FEM simulations. The results reveal that the CHFRF rotates during loading; and, in the ultimate state, the rotation center is located at a depth of approximately 0.6–0.65 times the foundation height and is 0.15–0.18 times the diameter of the foundation away from its centerline as well. The lateral bearing capacity of the CHFRF improves with the increase of embedded depth and vertical load applied to the foundation. Moreover, compared to the CHFRF without the rubber layer, the rubber layer can reduce the earth pressure along the wall of CHFRF by 22% and decrease the deformed range of the soil surrounding the foundation, revealing that it can reduce the loads transferred to the surrounding soil for extending the service life of the foundation. However, the thickness and stiffness of the rubber layer are important factors influencing the lateral bearing capacity and the energy dissipation of the foundation. Moreover, it should be noted that the energy dissipation mainly comes from the steel of the rubber layer rather than rubber.

Field Monitoring and Numerical Analysis of the Reinforced Concrete Foundation of a Large‐Scale Wind Turbine

“…e steel reinforcement cage is linked to the concrete using the embedded technique [30]. Coulomb's friction law with a friction coefficient of 0.35 is applied to simulate the tangential behavior between the foundation and the subsoil [4,9]. e contact in the normal direction at the interface between the foundation and the subsoil is considered to be a hard contact.…”

“…As a clean, safe, and sustainable natural source, wind energy becomes increasingly important in power supply [1][2][3]. Plenty of new wind farms have been installed in mountainous and hilly regions in many countries as a strategy for narrowing the regional energy disparity [4,5]. For instance, from 2016 to 2020, China has built 42,000 MW wind turbines in its central eastern and southern regions [6,7], where there are mainly hilly, plateau, and mountainous terrains.…”

“…Nevertheless, only a few related works have been reported in the field of wind turbines [3,4]. e work of Harte et al [20] and Taddei et al [21] stated that the soil-structure interaction plays an important role in the performance of wind turbine shallow foundations.…”