Abstract：The mechanical properties and deformation behavior of soil-rock mixture and underground structure in soil-rock mixture stratum are influenced by the particle size distribution. The mesoscopic structural characteristics of soil-rock mixture were analyzed based on the fractal geometry theory and the relationship between the quality-particle size grading curve and the fractal dimension was determined. The fractal analysis on grain-size of 34 groups of sand-gravel soil in coordinate system was conducted and the results indicated that the sand-gravel in Beijing has the characteristics of self-similarity. The range of the fractal dimension of sand-gravel in Beijing is 2.4–2.6. The variation of the quality-particle size grading curve with the fractal dimension and maximum grain size were analyzed，yielding some new findings regarding the mechanical behavior of soil-rock mixture. It is clear that the whole grading curve can be obtained by combining the fractal geometry theory and the laboratory test on grain size distribution. A program generating the model of sand-gravel stratum is compiled based on the Monte Carlo method using the sphere to represent the shape of stone. Then，3D numerical analysis on tunnel excavation were carried out.
杜修力，张 佩，金 浏，张仁波. 基于分形理论的北京地区砂砾石地层细观建模[J]. 岩石力学与工程学报, 2017, 36(2): 437-445.
DU Xiuli，ZHANG Pei，JIN Liu，ZHANG Renbo. A mesoscopic model of sand-gravel stratum in Beijing based on fractal theory. , 2017, 36(2): 437-445.
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2017, Vol. 36 
