基于有限云模型的深基坑安全性研究

为降低基坑安全评价指标等级边界信息的随机性和模糊性给评价结果带来的不利影响，构建基于有限区间云理论的基坑安全综合评价模型。依据基坑安全性评价指标分类标准，计算出各评价指标隶属于不同分类等级的云数字特征，然后利用博弈论组合赋权法明确各评价指标的权重，并结合有限正向云发生器，得到评价对象的综合确定度，最后根据最大隶属原则确定基坑安全性等级。将该方法应用于工程实践中，并在评价过程中与传统云模型、可拓法进行对比分析。研究结果表明：运用该方法所获取的基坑安全性评价结果与可拓法评价结果一致，符合工程实际，且克服了传统云模型在处理指标值远离两端云期望值时的弊端，可为基坑安全评价研究提供一种新思路。

Research on the Safety of Deep Foundation Pit Based on Finite Cloud Model

Deep foundation pit engineering is a large and complex system engineering，and its safety evaluation is influenced and controlled by many uncertainty factors，which has the characteristics of limited interval distribution of evaluation indexes and fuzzy grade boundaries. In order to reduce the adverse effects of randomness and ambiguity of boundary information of foundation pit safety evaluation index on the evaluation results，a comprehensive evaluation model of foundation pit safety based on finite interval cloud theory was constructed.According to industry standards and related research results，the evaluation index system and classification criteria of foundation pit safety were determined，and the cloud digital features of each evaluation index belonging to different classification levels were calculated.The cloud model was generated by using MATLAB programming software with the positive cloud generator of limited interval.According to the measured data of the sample，the degree of certainty of each security level was calculated.Analytic hierarchy process (AHP) is easy to calculate and the results are clear，but the process of judgment matrix subjectivity and consistency checking is complicated.Entropy weight method can determine the weight according to the degree of index variation，which can avoid the interference of human factors.However，it strictly follows the mathematical rules and often ignores the intentions of decision makers.Therefore,after considering the advantages and disadvantages of two methods，the game theory was used to optimizes and fuses the weights obtained by AHP and entropy weight method.Considering the subjective and objective factors comprehensively，the combination weights of each evaluation index for foundation pit safety were defined.The comprehensive determination degree of the evaluation object was obtained by combining the single factor determination degree of the index value belonging to each safety grade.Finally，the safety grade of foundation pit was determined according to the principle of maximum membership.This method was applied to engineering practice，and compared with traditional cloud model and extension method in the evaluation process.The results show that the model has good feasibility and validity in the study of foundation pit safety evaluation.The results obtained by this method are consistent with those obtained by extension method，which is in line with engineering practice.It overcomes the drawbacks of traditional cloud model when the index values are far from the expected values of both ends of the cloud.It can also provide a new idea for the study of foundation pit safety evaluation.