徐闻增容风电项目大直径单桩基础冲刷防护研究及应用

Research and application on erosion protection for large diameter single pile foundation in Xuwen Zengrong Wind Power Project

我国海上风电发展迅速,由近海发展到深远海,单机容量由5 MW发展到12 MW,海上风电向大型化发展,单桩直径增大后冲深变大,选择合适的防冲刷方案对风电场长期安全运行起关键作用。文章研究徐闻增容风电项目大直径单桩冲刷,通过多频次扫测单桩周边水深,掌握单桩冲刷规律。单桩冲刷在早期进展迅速,冲刷45 d冲刷坑达最大,之后冲刷坑处于动态平衡状态,徐闻海域地质冲刷坑适用于Richardson公式算出的冲深,取0.75倍计算值与实际冲深较为接近,冲坑的最大深度为桩径的0.75~0.85倍,冲刷半径为冲刷深度的5~6倍。土工布网兜石防冲刷效果明显,日均冲刷量为无防护的1.6%、为普通网兜石的38.9%。土工布网兜石在较好节约成本的前提下取得好的防冲刷效果,此方法值得推广,能为后续类似项目提供借鉴。

China's offshore wind power has developed rapidly,from offshore to deep sea,with single unit capacity increasing from 5 MW to 12 MW.Offshore wind power is developing to large-scale,and the scouring depth becomes larger after the increase of single pile diameter.Selecting a suitable anti-erosion scheme plays a key role in the long-term safe operation of wind farms.In this paper,the erosion of large diameter single piles in Xuwen Zengrong Wind Power Project was studied,the water depth around single pile was measured by multi-frequency scanning,and the rule of single pile erosion was mastered.Single pile scouring progressed rapidly in the early stage,and the scouring pit reached its maximum within 45 days of scouring,after which the scouring pit was in a dynamic equilibrium state.The geological scouring pit in Xuwen Sea area was suitable for the scouring depth calculated by the Richardson formula.The calculated value of 0.75 times was relatively close to the actual scouring depth,and the maximum depth of the scouring pit was 0.75-0.85 times of the pile diameter.The scouring radius is 5-6 times the scouring depth.The anti-erosion effect of geotextile netted stone is obvious,and the daily erosion volume is 1.6%of the non-protective condition and 38.9%of the ordinary netted stone.Geotextile netted stone can achieve good anti-erosion effect under the premise of better cost saving.This method is worth popularizing and can provide reference for similar projects in the future.