基于非均质地层参数表征的颗粒流模型构建

Construction of a particle flow model based on the characterization of heterogeneous formation parameters

摘要:

非均质地层参数的获取与表征方法是浅层地质体改造的重要依据。基于非均质地层的地质建模，表征具有随机不确定性和模糊不确定性的土体表观参数和物理力学参数。利用 Weibull 分布统计描述局部地层信息，并应用Diamond-Square分形插值方法，结合差分盒子维计算非均质地层分形维数，进一步合理演算整体地层参数。采用PFC3D数值模拟软件，结合马尔科夫链蒙特卡洛方法采样数据，对非均质地层块石颗粒及土颗粒进行建模。通过非均质地层模拟结果，发现其破坏过程与应力应变曲线要比均质土体复杂得多，由于块石大颗粒的含量、分布特性对土样力学性质影响显著。本文建模方法有助于非均质地层参数表征研究。

Abstract:

The method of obtaining and characterizing heterogeneous formation parameters is an important basis for the reconstruction of shallow geological bodies. Geological modeling based on heterogeneous formation is intended to characterize the apparent parameters and physical and mechanical parameters of the soil with stochastic uncertainties and fuzzy uncertainties. The Weibull distribution is used to describe the local stratum information， and the Diamond-Square fractal interpolation algorithm， combined with calculation of the fractal dimension of the heterogeneous formation by the differential box-counting， is applied to calculate the overall stratum parameters. The PFC3D numerical simulation software， combined with data sampling by the Markov chain Monte Carlo method， is used to model the rock particles and soil particles in the heterogeneous formation. The simulation results of the heterogeneous formation indicate that its failure process and stress-strain curve are much more complicated than those of the homogeneous formation since the content and distribution characteristics of large rock particles have a significant impact on the mechanical properties of the soil. The modeling method in this paper is helpful to the study on heterogeneous formation parameter characterization.