西安建筑科技大学学报(自然科学版)

随着应力水平的提高,颗粒破碎现象越来越明显,为了研究颗粒破碎机理以及破碎对粒状材料力学特性的影响.采用人工制备的水泥土球形颗粒模拟易破碎材料,进行固结排水和固结不排水三轴剪切试验,探讨了不同围压作用下颗粒材料的力学特性.固结排水试验采用的围压分别为100 kPa、200 kPa、300 kPa和400 kPa,固结不排水试验采用的围压分别为100 kPa、200 kPa和300 kPa.并基于颗粒流数值模拟方法,对固结排水(CD)试验结果进行了数值模拟.研究结果表明:采用人工制备的水泥球颗粒集合体试样可以进行探讨颗粒材料的颗粒破碎过程及机理; 固结围压越大,试验结束时颗粒破碎越明显,且强度包线呈非线性; 颗粒流数值模拟方法可模拟人工制备易破碎粒状材料在固结排水(CD)试验时的应力-应变和体积变形特性.

With the increase of stress level, the phenomenon of particle crushing becomes more and more obvious, in order to study the mechanism of particle crushing and the impact of crushing on the mechanical properties of granular materials. The artificials cemented sphere particles were employed to simulate the crushing grains, on which CD and CU triaxial tests were conducted to explore the breakage properties of crushing materials. For the samples tested on consolidation drain conditions(CD), the confining pressures applied were 100 kPa, 200 kPa, 300 kPa and 400 kPa and, for the samples tested on consolidation undrain conditions(CU), the confining pressures applied were 100kPa, 200kPa and 300kPa. Furthermore, the tested results were simulated based on the discrete element method of particle flow method. Results demonstrate that the samples composed of the artificial cemented sphere particles could be used to investigate the crushing process and mechanisms of granular materials; with the increase of confining pressures, there are more breakage of particles at the end of test and the strength envelope is nonlinear; the particle flow method could be used to simulate the stress-strain and volumetric deformation properties of artificially prepared crushing materials tested under consolidation drain conditions.

引言
1 易破碎粒状材料的人工制备方法
2 易破碎颗粒材料试验结果及分析
3 数值模拟
4 结论

图1 级配曲线
Fig.1 The grading curve

图2 制备试样<br/>Fig.2 Preparation of the apecimen

图2 制备试样
Fig.2 Preparation of the apecimen

图3 劈裂试验结果<br/>Fig.3 Results of splitting test

图3 劈裂试验结果
Fig.3 Results of splitting test

图4 破裂型式
Fig.4 Splitting pattern

图5 装样图
Fig.5 Assembling the sample

图6 CD试验的应力-应变、体变-轴应变曲<br/>Fig.6 The relationship curves of stress-strain and volumetric strain-axial strain of CD tests

图6 CD试验的应力-应变、体变-轴应变曲
Fig.6 The relationship curves of stress-strain and volumetric strain-axial strain of CD tests

图7 CU试验的应力-应变、孔压-应变曲线<br/>Fig.7 The relationship curves of stress-strain and pore pressure-axial strain of CD tests

图7 CU试验的应力-应变、孔压-应变曲线
Fig.7 The relationship curves of stress-strain and pore pressure-axial strain of CD tests

图8 破碎形态
Fig.8 Breakage pattern

图9 颗粒破碎形式<br/>Fig.9 Breakage pattern of single particle

图9 颗粒破碎形式
Fig.9 Breakage pattern of single particle

图10 级配曲线
Fig.10 Grade size curve

表1 各粒组含量(CD)<br/>Tab.1 Contents of particle size(CD)

表1 各粒组含量(CD)
Tab.1 Contents of particle size(CD)

表2 各粒组含量(CU)<br/>Tab.2 Contents of particle sets(CU)

表2 各粒组含量(CU)
Tab.2 Contents of particle sets(CU)

表3 破碎率
Tab.3 Breakage ratio

图11 应力路径
Fig.11 Stress path

图12 试样模型
Fig.12 Specimen model

图13 单个颗粒计算与试验结<br/>Fig.13 Numerical and tested results of a single particle

图13 单个颗粒计算与试验结
Fig.13 Numerical and tested results of a single particle

表4 模拟参数
Tab.4 Simulation parameters

图14 模拟和试验的应力-应变关系<br/>Fig.14 Stress-strain relationship ofsimulational and tested

图14 模拟和试验的应力-应变关系
Fig.14 Stress-strain relationship ofsimulational and tested

图15 模拟和试验的应力-应变关系<br/>Fig.15 Simulational and test stress-strain relationship

图15 模拟和试验的应力-应变关系
Fig.15 Simulational and test stress-strain relationship

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备注

引言

1 易破碎粒状材料的人工制备方法

2 易破碎颗粒材料试验结果及分析

3 数值模拟

4 结论

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