基于随机-关联空间插值法的工程岩体力学参数确定

Determining Mechanical Parameters of Engineering Rock Mass Based on Stochastic-Associative Spatial Interpolation Method

岩体力学参数在空间上存在的结构关联性和随机不确定性是影响工程岩体力学参数设计取值的客观因素之一。基于地质统计学理论,提出随机-关联空间插值法,在工程岩体力学参数概率分布未知的情况下,利用样本矩替换母体矩,描述工程岩体力学参数的随机性,利用变差函数描述样本点之间、样本点和插值点之间的工程岩体力学参数关联性,建立岩体力学参数的空间分布模型,并通过克里格法对场地中的工程岩体力学参数进行空间插值。结合工程实例,在力学参数概率分布未知的情况下建立其概率分布模型;选择不同数量的有效样本对比分析该方法本身对样本数量的依赖性问题;探讨该方法的应用范围以及针对其他情况提出的相应措施,为后续研究打下基础。与试验结果对比,工程实际中3种不同样本的岩体力学参数指标相对误差分别为4.2,4.4,5.3,估值结果可作为工程设计取值的参考依据。

The stochastic and associative feature of mechanical parameters of rock mass is an objective factor that affect the determination of mechanical parameters of engineering rock mass.In line with geological statistic theory,a stochastic-associative spatial interpolation method is proposed for the mechanical parameters of engineering rock mass.The stochasticity of mechanical parameters is described by replacing the parent moment with the sample moment in the condition that the probability distribution is unknown;and the associativity between sample points,sample points and interpolation point is quantified by the variation function.Kriging’s method is used to interpolate the mechanical parameters of engineering rock mass on site.The spatial distribution model of mechanical parameters of engineering rock mass with unknown probability distribution is established and verified through an engineering case.Moreover,the dependency of this method on sample number is expounded through comparative study with different effective sample numbers.With the increase of effective sample number,the relative error between model estimation and test result reduces.In the engineering case study,the relative errors between model estimations and test results of mechanical parameters of three samples are 4.2,4.4,and 5.3,respectively.In addition,the application scope of the present method and corresponding measures for other situations are also discussed for further research.