材料期刊网

在关键块体稳定性的研究过程中,传统方法需要通过力学试验获得岩体力学参数,然而由于岩体结构复杂,力学试验样本数量有限,很难确定某一个力学参数的概率密度分布,严重影响传统随机概率可靠性分析方法的准确性.当采用区间非概率可靠性分析方法计算可靠度时,通常采用区间数来表示参数的取值,能够较好地反映样本数据较少时参数取值的不确定性,确定某一参数的取值范围比确定参数的概率分布容易.根据区间数学理论,采用区间数表示参数取值,在分析参数取值特性基础上,采用岩体区间强度值,以此反映围岩可靠性分析的不确定性特征.通过探讨区间非概率可靠性指标求解方法,建立爆破荷载下区间可靠性综合分析模型.将提出的方法应用到具体工程中.结果表明:区间非概率可靠性分析与安全系数区间范围和随机可靠度相比,具有无需求解概率密度函数,通过较少样本的区间表示即可实现可靠性分析,能够表征关键块体整体稳定可靠特征的优点.

The mechanical parameters of rock obtained from laboratory tests are vital important to the stability investigations on key blocks. However, due to the restraints from the complicated rock structure and the limitation of available test data, it is difficult to determine the accurate probabilistic distribution of any mechanical parameter. Therefore, problems might be encountered in the traditional reliability analysis characterized by random probability. In the reliability indication process characterized by non-probabilistic reliability with interval theory, parameters are represented by the intervals which reflect the uncertainty caused by the limited sample data. In addition, it is easier to determine the value range rather than the probabilistic distribution of specific parameters. Based on the interval mathematical theory and the related analysis of parameter properties, the uncertainty of the reliability analysis of surrounding rock was indicated by the interval values of rock strength. The comprehensive analytical model was established by probing the computing method for the index of interval non-probability. Moreover, the interval value of safety index and the random reliability are obtained by applying proposed method in a specific engineering scenario. The following results were concluded, safety analysis index can only be used in the single stability evaluation of a specific parameter. While systematic evaluation of key blocks can not be conducted by applying safety index analysis. The engineering application of the random probabilistic method is restrained by the obtained result varying in a large range. The difficulties encountered in the indication process of probabilistic density function and the great data volume are needed, the determination of the probabilistic density function is not required when applying non-linear reliability analysis based on interval theory and, thus, the reliability analysis can be conducted based on interval presentation of limited sample data. The entire reliability characteristics of key blocks stability can be represented accordingly.