黄土骨架颗粒的架空结构体系控制着其主要力学行为,应用非连续变形分析方法可从微观揭示其力学行为的本质。采取陕西省泾阳南塬的L5(Q2)黄土原状样,进行各种土力学试验,测定其物理力学性质参数;采用光学显微镜和图像处理软件得到土样的微观结构图像,描绘颗粒形态,建立该土样的非连续变形分析微观结构模型,并模拟了土样在1.0,12.5,25.0,50.0,100.0,200.0,400.0 kPa荷载作用下的压缩变形。结果得到:土样在压缩过程中,微观结构变化图像及压缩曲线和室内固结试验结果较为接近,说明采用非连续变形分析方法模拟黄土的微观变形特性是可行的。研究结果为分析黄土的微观物理力学性质提供了一种思路。
Abstract
Mechanical behavior of loess is controlled by overhead structure of skeleton particle, and microstructure of loess could reveal its mechanical behavior by Discontinuous Deformation Analysis(DDA). In order to simulate the characteristics of consolidation of microscopic loess, we carried out test on undisturbed L5(Q2) loess specimens from southern Jingyang plateau of Shaanxi province, and measured the physical and mechanical parameters of loess. Then we obtained microstructure image and particle morphology of the specimens by using optical microscope and image processing software. On this basis, we established soil microstructure model and simulated the compression deformation under load of 1.0, 12.5, 25.0, 50.0, 100.0, 200.0, 100.0 kPa, respectively. Finally, we obtained microstructure image and compression curve of the model in the compression process, which are close to the results of indoor test. Results show that DDA is feasible for simulating the characteristics of the microscopic deformation of loess and this paper provides an idea for analyzing the microscopic physical and mechanical properties of loess.
关键词
黄土 /
骨架颗粒的架空结构 /
固结试验 /
微观结构 /
非连续变形分析
Key words
loess /
overhead structure of skeleton particle /
consolidation tests /
microscopic structure /
discontinuous deformation analysis
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参考文献
[1] 周 健,池毓蔚,池 永,等.砂土双轴试验的颗粒流模拟[J].岩土工程学报,2000,22(6):701-704.
[2] 周 健, 池 永. 颗粒流方法及 PFC2D 程序[J]. 岩土力学, 2000, 21(3): 271-274.
[3] 廖雄华, 周 健, 徐建平, 等. 粘性土室内平面应变试验的颗粒流模拟[J]. 水利学报, 2002, (12): 11-17.
[4] 蒋明镜,胡海军,彭建兵. 结构性黄土一维湿陷特性的离散元数值模拟[J].岩土力学,2013,34(4):1121-1130.
[5] 蒋明镜,李 涛,胡海军. 结构性黄土双轴压缩试验的离散元数值仿真分析[J].岩土工程学报,2013,35(增2):242-246.
[6] SHI G H, GOODMAN R E. Two Dimensional Discontinuous Deformation analysis[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 1985, 9(6): 541-556.
[7] 邬爱清, 丁秀丽, 卢 波, 等. DDA 方法块体稳定性验证及其在岩质边坡稳定性分析中的应用[J]. 岩石力学与工程学报, 2008, 27(4): 664-672.
[8] 邬爱清,丁秀丽,李会中,等. 非连续变形分析方法模拟千将坪滑坡启动与滑坡全过程[J]. 岩石力学与工程学报,2006,25(7):1297-1303.
[9] 王书法,李树忱,李术才,等. 节理岩质边坡变形的DDA模拟[J]. 岩土力学,2002,23(3):352-354.
[10]张国新,李广信,郭瑞平. 不连续变形分析与土的应力应变关系[J]. 清华大学学报(自然科学版),2000,40(8):102-105.
[11]郭培玺,林绍忠. 粗黏料力学特性的DDA数值模拟[J]. 长江科学院院报,2008,25(1):58-60,69.
基金
陕西省自然科学基础研究计划项目(2016JM4018);中央高校基本科研业务专项基金(310826161022)