基于 PFC2D 的土石混合体直剪试验模拟

Simulation of Direct Shear Test of Soil-Rock Mixture Based on PFC2D

摘要

为了建立不同含石量土石混合体细观参数的高效标定方法,提升直剪试验离散元模拟的准确性,基于 PFC2D 程序,结合 Python 编程实现蒙特卡洛随机块石生成,构建了土石混合体数值试样。 采用 cluster 颗粒集合体模拟不规则块石,系统开展了块石与土体细观参数的标定研究,提出了基于单轴拉伸、单轴压缩、双轴压缩与直剪试验的细观参数分级标定流程,探究了含石量对土石混合体抗剪强度特性的影响。 结果表明,随着含石量的增大,土石混合体的黏聚力先增大后减小,在含石量为 60%时达到峰值;内摩擦角则持续上升。 研究明确了接触模型中关键细观参数对宏观力学行为的影响规律,模拟得到的内摩擦角、黏聚力与现场原位试验结果十分接近。

Abstract

In order to establish an efficient calibration method for the microscopic parameters of soil-rock mixtures with different rock contents and improve the accuracy of the discrete element simulation of direct shear tests, numerical model samples of soil-rock mixtures were constructed based on the particle flow code in 2 dimensions (PFC2D) and Python programming to realize Monte Carlo random generation of rock blocks. A cluster particle aggregate was used to simulate irregular rock blocks, and a systematic study was conducted on the calibration of microscopic parameters between rock blocks and soil particles. A microscopic parameter grading calibration process based on uniaxial tension, uniaxial compression, biaxial compression, and direct shear tests was proposed. The influence of rock content on the shear strength characteristics of soil-rock mixtures was investigated. The results show that with increasing rock content, the cohesion of the soil-rock mixture initially rises and subsequently declines, peaking at 60% rock content, while the internal friction angle increases monotonically. The study has clarified the influence of key microscopic parameters in the contact model on macroscopic mechanical behavior, and the simulated internal friction angles and cohesion values are very close to the results of in-situ tests.

关键词

土石混合体 / 直剪试验 / 颗粒流模型 / 细观参数 / 含石量

Key words

soil-rock mixture / direct shear test / particle flow model / microscopic parameters / rock content

参考文献

[1] 石崇, 王盛年, 刘琳, 等 . 基于数字图像分析的冰水堆积体结构建模与力学参数研究[J]. 岩土力学, 2012, 33(11): 3393-3399.

[2] Shi Chong, Wang Shengnian, Liu Lin, et al. Structure modeling and mechanical parameters research of outwash deposits based on digital image analysis[J]. Rock and Soil Mechanics, 2012, 33(11): 3393-3399.

[3] 涂国祥, 黄润秋, 邓辉, 等 . 某巨型冰水堆积体强度特性大型常规三轴试验[J]. 山地学报, 2010, 28(2): 147-153.

[4] Tu Guoxiang, Huang Runqiu, Deng Hui, et al. Study on the strength and deformation behavior of a huge outwash deposits based on large-scale triaxial tests[J]. Journal of Mountain Science, 2010, 28(2): 147-153.

[5] 赵明华, 刘建军, 罗宏, 等 . 土石混填体抗剪强度特性及影响因素的试验研究[J]. 岩土力学, 2017, 38(4): 965-972.

[6] Zhao Minghua, Liu Jianjun, Luo Hong, et al. Experimental studies of shear strength characteristics and influencing factors of soil-rock aggregate mixture[J]. Rock and Soil Mechanics, 2017, 38(4): 965-972.

[7] 杨忠平, 雷晓丹, 王雷, 等 . 含石量对土石混合体剪切特性影响的颗粒离散元数值研究[J]. 工程地质学报, 2017, 25(4): 1035-1045.

[8] Yang Zhongping, Lei Xiaodan, Wang Lei, et al. Impact of stone content to shear properties of soil-rock mixture using particle flow code simulation[J]. Journal of Engineering Geology, 2017, 25(4): 1035-1045.

[9] 罗亚琼, 张超, 马婷婷 . 考虑含石量与颗粒级配特征影响的土石混合体抗剪强度特性研究[J]. 公路, 2022, 67(12): 47-53.

[10] Luo Yaqiong, Zhang Chao, Ma Tingting . Research on shear strength characteristics of soil-rock mixture considering the influence of rock content and particle gradation[J]. Highway, 2022, 67(12): 47-53.

[11] 王涛, 朱俊高, 刘斯宏 . 不同细料含量土石混合料塑性行为离散元模拟[J]. 力学学报, 2022, 54(4): 1075-1084.

[12] Wang Tao, Zhu Jungao, Liu Sihong . Dem simulation on plasticity behavior of soil-rock mixtures with different fine contents[J]. Chinese Journal of Theoretical and Applied Mechanics, 2022, 54(4): 1075-1084.

[13] Zhang Zhenping, Sheng Qian, Fu Xiaodong, et al. An approach to predicting the shear strength of soil-rock mixture based on rock block proportion[J]. Bulletin of Engineering Geology and the Environment, 2020, 79(5): 2423-2437.

[14] Gao Wei, Iqbal J, Hu Ruilin . Investigation of geomechanical characterization and size effect of soil-rock mixture:a case study[J]. Bulletin of Engineering Geology and the Environment, 2021, 80(8): 6263-6274.

[15] Zhou Zhong, Xing Kai, Yang Hao, et al. Damage mechanism of soil-rock mixture after freeze-thaw cycles[J]. Journal of Central South University, 2019, 26(1): 13-24.

[16] Yao Yongsheng, Li Jue, Ni Junjun, et al. Effects of gravel content and shape on shear behaviour of soil-rock mixture:experiment and DEM modelling[J]. Computers and Geotechnics, 2022, 141: 104476.

[17] Dang Wengang, Konietzky H, Frühwirt T . Rotation and stress changes on a plane joint during direct shear tests[J]. International Journal of Rock Mechanics and Mining Sciences, 2016, 89: 129-135.

[18] Tu Yiliang, Ren Siyu, Li Lushan, et al. Comparative analysis on shear mechanical properties of soil-rock mixture under direct shear and simple shear tests[J]. Construction and Building Materials, 2024, 444: 137830.

[19] Zhang Yusen, Zheng Hong, Lin Shan . Preserved structure modeling of soil-rock mixtures and physical cover generation based on finite element meshes[J]. Engineering Geology, 2023, 323: 107225.

[20] Zhao Lianheng, Huang Dongliang, Zhang Shuaihao, et al. A new method for constructing finite difference model of soil-rock mixture slope and its stability analysis[J]. International Journal of Rock Mechanics and Mining Sciences, 2021, 138: 104605.

[21] Li Changsheng, Zhang Dan, Du Shasha, et al. Computed tomography based numerical simulation for triaxial test of soil-rock mixture[J]. Computers and Geotechnics, 2016, 73: 179-188.

[22] Xu Wenjie, Wang Shi, Zhang Haiyang, et al. Discrete element modelling of a soil-rock mixture used in an embankment dam[J]. International Journal of Rock Mechanics and Mining Sciences, 2016, 86: 141-156.

[23] Gao Wenwei, Yang Hairong, Hu Ruilin . Soil-rock mixture slope stability analysis by microtremor survey and discrete element method[J]. Bulletin of Engineering Geology and the Environment, 2022, 81(3): 121.

[24] 任明辉, 赵光思, 浦海, 等 . 无黏性松散土石混合体剪切特性的结构效应及强度模型构建[J]. 岩石力学与工程学报, 2024, 43(7): 1707-1721.

[25] Ren Minghui, Zhao Guangsi, Pu Hai, et al. Structural effects of shearing properties of loose cohesionless soil-rock mixture and development of strength model[J]. Chinese Journal of Rock Mechanics and Engineering, 2024, 43(7): 1707-1721.

[26] 郝保钦, 张昌锁, 王晨龙, 等 . 岩石 PFC2D 模型细观参数确定方法研究[J]. 煤炭科学技术, 2022, 50(4): 132-141.

[27] Hao Baoqin, Zhang Changsuo, Wang Chenlong, et al. Study on determination micro-parameters of rock PFC2D model[J]. Coal Science and Technology, 2022, 50(4): 132-141.

[28] 陈鹏宇, 孔莹, 余宏明 . 岩石单轴压缩 PFC^2D 模型细观参数标定研究 [J]. 地下空间与工程学报, 2018, 14(5): 1240-1249.

[29] Chen Pengyu, Kong Ying, Yu Hongming . Research on the calibration method of microparameters of a uniaxial compression PFC^2D model for rock [J]. Chinese Journal of Underground Space and Engineering, 2018, 14(5): 1240-1249.

[30] 曹雪山, 赖喜阳, 额力素, 等 . PFC2D 中平行粘结参数对直剪强度参数的影响研究[J]. 河北工程大学学报(自然科学版), 2019, 36(3): 16-20.

[31] Cao Xueshan, Lai Xiyang, E Lisu, et al. Study on the influence of parallel bond parameters in PFC2D on the direct shear strength parameters[J]. Journal of Hebei University of Engineering(Natural Science Edition), 2019, 36(3): 16-20.

[32] 张新松, 李长圣, 钟军, 等 . 基于神经网络的土石混合体 CT 图像分割及三维重建[J]. 工程地质学报, 2025, 33(3): 1230-1239.

[33] Zhang Xinsong, Li Changsheng, Zhong Jun, et al. CT image segmentation and 3D reconstruction of soilrock mixture based on neural network[J]. Journal of Engineering Geology, 2025, 33(3): 1230-1239.

[34] 傅华, 韩华强, 凌华 . 堆石料级配缩尺方法对其室内试验结果的影响[J]. 岩土力学, 2012, 33(9): 2645-2649.

[35] Fu Hua, Han Huaqiang, Ling Hua . Effect of grading scale method on results of laboratory tests on rockfill materials[J]. Rock and Soil Mechanics, 2012, 33(9): 2645-2649.

[36] 王有林, 赵志祥, 许晓霞, 等 . 西藏某水电站坝前大型冰水堆积体稳定性研究[J]. 西北水电, 2021(6): 38-43.

[37] Wang Youlin, Zhao Zhixiang, Xu Xiaoxia, et al. Study on the stability of a large outwash deposits in front of a power station dam in Tibet[J]. Northwest Hydropower, 2021(6): 38-43.

基金资助

国家自然科学基金青年基金资助项目(52109122)

中央高校基本科研业务费专项资金资助(B240201050)