渔港避风锚地面积计算的随机模拟

Stochastic simulation for calculating haven area for fishery port design

计算避风锚地的面积是渔港规划设计的重要内容之一。《渔港总体设计规范》(SC/T 9010-2000)推荐采用确定性方法计算避风锚地面积。由于没有规定输入参数代表值的确定方法,实际应用时参数取值带有很大的随意性和经验性,从而导致计算结果的不确定性。引入Monte Carle方法建立了渔港避风锚地面积计算的随机模拟模型,采用不同的概率分布刻划各相关参数,从而获得避风锚地面积的概率分布。实例计算表明,无论采用何种概率分布假定,得到的避风锚地面积均近似地服从正态分布,且不同概率分布假定对95%保证率的避风锚地面积值影响不大;当船长、船宽均取各分组船型的最大值,水深取相应区域水深的平均值,每组渔船之间安全距离及每组渔船数量取规范给定的平均值时,规范方法计算的避风锚地面积保证率在95%左右,从而为规范方法输入参数的确定提供了依据。

Calculation of the haven area is one of the important contents in fishery port design.Master Design Code of Fishery Port（SC/T 9010-2000）recommends a deterministic method to find out the required mooring area of a fishery port.Since the code does not provide detailed scheme of how to define representative values of the input parameters,the selection of the values is always arbitrary and empirical,which results in the uncertainty of the calculated result.This paper presents a stochastic simulation model for calculating the haven area by introducing into the Monte Carle method.In the model,different probability distributions for input parameters are assumed to get the probability distribution of the haven area.The simulated results of a practical example show that the resulted haven area accords approximately with the normal distribution,no matter which probability distribution is selected for input parameter.And the values of the haven area with 95% guaranteed certainty differ slightly for different assumption of probability distribution.Additionally,when the maximum of the fishing boat length and width,the mean depth of relevant area and mean values of the safe distance between boat groups and boat number defined by the code are taken,the guaranteed certainty of the haven area calculated with the standard method is around 95%.This provides scientific foundation for getting the representative values in calculating haven area when using the code.