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应用压汞试验研究了不同应力路径试验前后原状和重塑黄土孔隙分布的变化,探讨了宏观力学特性与孔隙分布的联系。压汞测试结果表明:试验前两种土具有相近孔隙分布的双孔隙结构;两者w=15%试样等含水率试验后孔隙分布接近,两者饱和试样固结不排水试验后孔隙分布差异较大;应力作用主要对粒间孔隙分布产生影响;常规和减围压三轴等含水率试验后粒间孔隙体积分别减小和增大,相同固结压力下固结不排水减围压三轴试验后粒间孔隙体积比常规三轴试验后的大。原状黄土(w=15%)在低围压常规三轴试验后未出现剪切带,试样内不同部位孔隙分布未呈较大差异性。根据原状和重塑黄土相同应力路径试验后的孔隙分布差异,探讨了试样宏观力学特性的微观机理,研究结果表明胶结作用、基质吸力和粒间孔隙比对试样的强度和变形起主要作用。
The changes of pore distribution of undisturbed and remolded loess before and after different stress path tests were studied by mercury intrusion test. The relationship between macroscopic mechanical properties and pore distribution was also discussed. The results of mercury intrusion test showed that the two kinds of soil had two pore structures with similar pore distribution before the experiment. The pore distribution of the two samples with similar moisture content was close to that of the sample with w = 15%, and the pore distribution The difference is larger; the stress effect mainly affects the distribution of intergranular pore; the interparticle pore volume decreases and increases after the triaxial and other triaxial moisture tests, respectively, under the same consolidation pressure, The tripartite pore volume after triaxial test is larger than that after conventional triaxial test. The intact loess (w = 15%) showed no shear band after conventional triaxial test under low confining pressure, and the pore distribution in different parts of the sample showed no significant difference. According to the difference of pore distribution after the same stress path test of undisturbed and remolded loess, the microscopic mechanism of macroscopic mechanical properties of the sample is discussed. The results show that the cementation, the matrix suction and the intergranular void ratio play a major role in the strength and deformation of the sample .