单一沙坝型海滩平衡剖面形态预测公式

Empirical Equilibrium Beach Profile Formula of Sandy Beach with a Single Sandbar

基于戴河口至洋河口海滩养护后的海滩平衡剖面实测资料,以存在离岸单一沙坝的低能砂质海滩为研究对象,分析其海滩剖面形态演变,提出以背景剖面和沙坝剖面叠加的单一沙坝型海滩平衡剖面预测公式。背景剖面基于最大信息熵原理充分考虑沙坝向岸侧和离岸侧差异,沙坝剖面则采用3~4个参数以抛物线函数形式分段描述非对称性沙坝形态。该平衡剖面公式对戴河口至洋河口岸段养护后的海滩剖面拟合效果较好,且成功应用于北戴河老虎石海滩和美国佛罗里达Fort Myers海滩,能较准确反映存在离岸单一沙坝低能海滩的平衡剖面特性。

Based on the beach profile survey data after the beach nourishment project on the coast between the Daihe Estuary and the Yanghe Estuary,the sandy beach under the low-energy condition with a single offshore sandbar was selected to investigate its morphological evolution process.A new equilibrium profile function with a single bar,which is comprised of background profile and barred profile,is derived.The background profile is based on the principle of maximum entropy to consider the difference between onshore and offshore side of the beach profiles,while the barred profile is described by 3 to 4 parameters to show the asymmetric sandbar shape in the form of parabolic function.The new shape function fits well with the measured post-nourishment beach profile from the Daihe Estuary to the Yanghe Estuary,which also has been successfully applied to the Tiger-Rock Beach in Qinhuangdao and the Fort Myers Beach in Florida.It indicates that the new shape function can accurately reflect the characteristic of the low-energy beach with a single sandbar.