【摘要】 为研究花岗岩内部结构对其物理力学性质的影响,利用氮吸附原理的比表面积及孔径分析仪测得两种花岗岩的比表面积和孔径分布情况,对比分析了两种花岗岩的密度、孔隙率等物理性质及单轴压缩强度,发现由比表面积和孔径表征的岩石孔隙结构更能合理的解释其宏观力学行为。试验结果表明:比表面积较大的岩样强度较低。比表面积较大的岩样加剧了岩样在加载过程中微裂隙的发育,使试样的力学性能降低;孔体积较大的岩样的强度较低。岩样内部孔隙的存在加剧了内部微裂隙的发育。随着轴向压力的不断加载,这些孔隙被压缩,有的成为了微裂隙发育的通道、有的成为新裂隙产生的起源。这些微裂隙不断延伸、扩张、贯通最终使得试样在压力的作用下破坏;利用排水法测得的孔隙率不能完整的反映岩样内部孔隙的发育状态,而通过氮吸附静态容量法测得的孔体积能够较为完整的反映岩样中孔隙的发育状态。比表面积及孔径分析测试更为准确地得到岩石内部的孔隙结构,测试结果对花岗岩的宏观力学行为做出了合理解释。更多还原

【Abstract】 The physical and mechanical properties of rocks are affected by their internal structure. In order to study the influence of internal structure of granite on its physical and mechanical properties,the specific surface area and pore size distribution of two granites were measured by the specific surface area and pore size analyzer of nitrogen adsorption principle. By comparing and analyzing the density,porosity and uniaxial compressive strength of the two granites,it is found that the pore structure of rock characterized by specific surface area and pore diameter can explain its macroscopic mechanical behavior more reasonably. The results show that rock samples with a larger specific surface area have lower strength. The rock sample with larger specific surface area exacerbates the development of micro-cracks during the loading process,which reduces the mechanical properties of the sample. The rock samples with larger pore volumes have lower strength. The presence of internal pores in the rock sample exacerbates the development of internal microfractures. As the axial pressure is continuously loaded,these pores are compressed,some become channels for the development of micro-cracks,and some become the origin of new fissures.These micro-cracks continue to extend,expand,and penetrate,eventually causing the sample to break under pressure. The porosity measured by the drainage method cannot completely reflect the development state of the pores inside the rock sample,and the pore volume measured by the nitrogen adsorption static volume method can completely reflect the development state of the pores in the rock sample. It can be seen that the specific surface area and pore size analysis test more accurately obtain the pore structure inside the rock,and the test results can also explain the macroscopic mechanical behavior of the granite.更多还原