Because of the complexity of groundwater systems and human activities, fuzzy and random uncertainties are two kinds of uncertain factors that exist widely in groundwater systems. The fuzziness of the variables is usually described by membership functions. When the variables obey different membership functions, the fuzzy risk of adverse events may be different. To explore the influence of the membership function type on the reliability of the estimation results of allowable groundwater drawdown, taking groundwater exploitation in desert oasis areas that have great dependence on groundwater as an example, a fuzzy stochastic coupling model of the allowable groundwater drawdown is established. Using the theory of the cut level λ, fuzzy variables are transformed into random variables to obtain the fuzzy risk. The results show that unlike the random risk, the fuzzy random risk is an interval. The membership functions with a normal distribution and quasi-normal distribution have little effect on the fuzzy risk in the case study. When λ < 0.67, the fuzzy risk interval of the triangle membership function is the largest, and its risk interval maximum value of 98.36% can be obtained at λ = 0.1; however, when λ > 0.8, it has the smallest risk interval of all the membership functions. If the skewness of the design parameters is taken into consideration, the lognormal membership function is a better choice, with a fuzzy random risk of 57.68% at λ = 0.5. The results of this paper can also provide references for groundwater exploitation risk assessment.

由于地下水系统和人类活动的复杂性，模糊和随机不确定性是地下水系统中广泛存在的两种不确定因素。变量的模糊性通常由隶属函数描述。当变量服从不同的隶属函数时，不良事件的模糊风险可能会不同。为了探讨隶属函数类型对地下水可允许开采量估算结果可靠性的影响，以沙漠绿洲对地下水的依赖程度较高为例，建立了地下水可允许开采量的模糊随机耦合模型。 。使用切割水平λ的理论，将模糊变量转换为随机变量以获得模糊风险。结果表明，与随机风险不同，模糊随机风险是一个区间。在案例研究中，具有正态分布和准正态分布的隶属函数对模糊风险影响很小。当λ  <0.67时，三角隶属度函数的模糊风险区间最大，在λ  = 0.1时，其风险区间最大值为98.36％。然而，当λ  > 0.8时，它具有所有隶属函数中最小的风险区间。如果考虑设计参数的偏度，则对数正态隶属度函数是一个更好的选择，λ处的模糊随机风险为57.68％ = 0.5。本文的研究结果也可为地下水开发风险评估提供参考。