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    贾蓬, 钱一锦, 毛松泽, 徐雪桐, 卢佳亮. 晶粒尺寸对花岗岩动态劈裂力学特性及断面粗糙度影响的试验研究[J]. 应用基础与工程科学学报, 2024, 32(5): 1449-1462. DOI: 10.16058/j.issn.1005-0930.2024.05.018
    引用本文: 贾蓬, 钱一锦, 毛松泽, 徐雪桐, 卢佳亮. 晶粒尺寸对花岗岩动态劈裂力学特性及断面粗糙度影响的试验研究[J]. 应用基础与工程科学学报, 2024, 32(5): 1449-1462. DOI: 10.16058/j.issn.1005-0930.2024.05.018
    JIA Peng, QIAN Yijin, MAO Songze, XU Xuetong, LU Jialiang. Experimental Study on the Effect of Grain Size on Dynamic Splitting Mechanical Properties and Fracture Surface Roughness of Granite[J]. Journal of Basic Science and Engineering, 2024, 32(5): 1449-1462. DOI: 10.16058/j.issn.1005-0930.2024.05.018
    Citation: JIA Peng, QIAN Yijin, MAO Songze, XU Xuetong, LU Jialiang. Experimental Study on the Effect of Grain Size on Dynamic Splitting Mechanical Properties and Fracture Surface Roughness of Granite[J]. Journal of Basic Science and Engineering, 2024, 32(5): 1449-1462. DOI: 10.16058/j.issn.1005-0930.2024.05.018

    晶粒尺寸对花岗岩动态劈裂力学特性及断面粗糙度影响的试验研究

    Experimental Study on the Effect of Grain Size on Dynamic Splitting Mechanical Properties and Fracture Surface Roughness of Granite

    • 摘要: 岩石的晶粒尺寸对岩石的动力学特性具有重要影响,为探明晶粒尺寸对花岗岩动态劈裂力学特性及断裂面粗糙度特征的影响,分别对两种晶粒尺寸的花岗岩进行不同应变率条件下的冲击劈裂试验.结果表明:两种晶粒尺寸的花岗岩动态劈裂强度与最大吸收能均随应变率的提升而增加,具有明显的应变率效应;晶粒尺寸对相近应变率条件的花岗岩动态劈裂强度与最大吸收能影响不明显;但粗细粒花岗岩能量利用率随应变率增加降低,降低趋势差异明显,粗粒花岗岩存在阈值应变率,平均应变率小于35.24s-1时,能量利用率降低明显,大于35.24s-1时降低缓慢;粗粒花岗岩的最终破坏模式表现为Ⅱ型劈裂破坏,随应变率增加端部楔形破坏区向中心延伸,而细粒花岗岩的最终破坏模式表现为随应变率增加,由Ⅰ型劈裂破坏变为Ⅱ型劈裂破坏.利用三维断面扫描所得的断面数据进行两类花岗岩断面粗糙程度的量化分析,结果表明,粗粒花岗岩的断面粗糙度指标Z2Rs在相同应变率条件下总体上均大于细粒花岗岩,用断面粗糙度指标Z2预测花岗岩的动态劈裂力学指标的效果优于Rs.

       

      Abstract: It is known that grain sizes has a significant impact on the dynamic mechanical characteristics of the rock.In order to investigate the effect of grain size on the dynamic splitting mechanical properties and the fracture surface roughness of granite,dynamic splitting tests of different strain rates were carried out on coarse- and fine-grained granite samples.The results show that the dynamic splitting strength and maximum absorbed energy of the two types of granite samples increase with the increase of strain rate,showing a significant strain rate effect.The grain size has no significant effect on the dynamic splitting strength and the maximum absorbed energy under similar strain rate conditions.The energy efficiency of coarse- and fine-grained granite samples decreases with the increase of the strain rate with different decreasing trends.There exists a threshold strain rate for coarse-grained granites,and the energy efficiency decreases significantly under average strain rates less than 35.24s-1,while decreases slowly for strain rates greater than 35.24s-1.The final fracture mode of the coarse-grained granite is the type-Ⅱ splitting,and the end wedge damage zone develops towards the center with the increase of strain rate; while the final fracture mode of the fine-grained granite changes from type-Ⅰ splitting to type-Ⅱ splitting with the increase of the strain rate.Quantitative analysis of the roughness of the coarse- and fine-granite fracture surface based on the 3D section scanning data shows that the section roughness indices Z2 and Rs of coarse-grained granite are generally greater than those of the fine-grained granite under the same strain rate,and the dynamic splitting parameters predicted based on the section roughness index Z2 is superior to Rs.

       

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