مقاله انگلیسی رایگان در مورد روش طراحی مناسب پایه های شمعی جهت تقویت توربین بادی – الزویر 2018

Wind energy, an alternative to conventional energy produced by burning fossil fuels, is a renewable and clean energy which produces no greenhouse gas emissions during operation, consumes no water, and uses only a little land. With the rapidly growing world population, it is essential to increase the production of energy using sustainable sources such as wind to meet the demand. One of the cost-effective ways to increase the production of wind energy is to build taller towers. Since a higher and steadier wind speed can be accessed at higher elevations, building taller towers can increase the wind energy production of a single turbine. The study of Lewin (2010) revealed that an increase in turbine elevation from 80 m to 100 m would result in a 4.6% higher wind speed which translates to a significant 14% increase in power output. A further increase in tower height from 80 m to 120 m would result in an 8.5% higher wind speed and a 28% increase in power output. It should also be noted that the higher initial construction cost and the lower operational cost of wind turbines make it economical to build a few taller towers rather than several normally sized towers to maximize the wind energy production. Increase in tower height, however, leads to significant geotechnical engineering challenges because the foundation design loads (vertical load, horizontal load, and bending moment) increase with the increasing tower height. Larger loads not only result in the larger foundations demanding significant resources to be allocated for the design and construction of the foundations, but they also present challenges in choosing the appropriate type of foundation as well as the optimal design parameters. Among the many types of foundations used for supporting wind turbines, a piled-raft foundation is considered to be effective for supporting tall wind turbines, especially for improving serviceability requirements (Shrestha, 2015). The centrifuge model tests performed by Sawada and Takemura (2014) on three types of model foundations (piled-raft, pile group, and raft alone) subjected to vertical, lateral, and bending moment loads also show that the vertical bearing capacity of the piled-raft foundation is the largest among the three foundations considered. This may be due to the higher bearing capacity of the raft and the increase in pile capacity due to the increase in soil stiffness caused by the raft contact stress. The same study also concludes that the settlement due to various loads can be reduced by using a piled-raft foundation.