Experimental Research On The Physical And Mechanical Properties Of Tunnel Surrounding Rock In The Extent From The Convention And Exhibition Center To San Yao Village Of Xi’an Metro Line No.2

With the deep implementation of the Great Western Development Strategy, westerninfrastructure construction in the rapid rise, the city which situates in the western loess areasalso will build the subway. Focusing on the construction city of the Great WesternDevelopment, the political, economic and cultural status of Xi’an become increasingly evident,and urban functions more and more complex, but public transport issues have become moreand more prominent, therefor development and utilization of underground space, and theconstruction of the subway project to become important tasks to be resolved in a New Age ofXi’an.Through a combination research methods of laboratory experiments and theoreticalanalysis, relying on extent tunnel engineering from convention and exhibition center to sanyao village of Xi’an metro Line No.2, fetches undisturbed soil samples from the constructionsite, and carries on a systematic loess single axle, three axle compressing experiment in thelaboratory. According to experimental results, we analyze physical and mechanical propertiesof loess under different water content, different stress state conditions, and made acomparative analysis of their similarities and differences between experimental results ofsingle axle and three axle compressing experiment. Based on this analysis, the paper furtherstudies the size and the variation rule of the special loess unconfined compressive strength,elastic modulus and Poisson ratio in the different water content conditions in single axlecompressive strength.Triaxial compression experiments, the paper researches the relationshipbetween the triaxial strength properties and the encircle pressure, water content, wet and dry cycle times, and also analyzes the relationship between water content, wet and dry cycle timesand the loess cohesion and internal friction angle.According to experimental data, the paper establishes the damage evolution equation bythe damage evolution control variables as to the wet and dry cycles and loaded strain, obtainsa unified damage extended constitutive relation. Besides, according to the Mohr-Coulombcriterion and experimental data, we also respectively establish a loess strength failure criterionwith water content effect and wet and dry cycle effect.