Research on Risk Assessment on Large Deformation of Loess Tunnels underneath Residential Areas

Abstract

With the continuous development of loess tunnel construction in western China, there are more and more complex situations, which have received extensive attention and research. However, there is a lack of research on the interaction between tunnel excavation and land subsidence when mountain tunnel passes through the settlement area of village residents. During the excavation of Anxing tunnel through residential area, the average deformation value is as high as 202 mm, while the average deformation value of non-residential section is lower than the actual control value, and the average deformation value is 78 mm. In order to expand the survey samples, through literature statistics, it is found that among the 67 cases of large deformation of loess tunnel, 16 cases occurred considerable deformation in the residential area, accounting for 23.9%. The influence of the strength and frequency of human activities on the regional geology of residents can not be ignored and should be regarded as an independent factor. On this basis, combined with other main factors affecting the large deformation of the tunnel, a risk assessment model is established, and the influence degree of human activities and other factors on the tunnel deformation is quantitatively analyzed and verified by fuzzy analytic hierarchy process (AHP). The results show that the risk assessment grade of Anxing tunnel is graded III, and the risk assessment model of large deformation in residential area under the tunnel is in good agreement with the engineering practice. It can provide reference for the risk assessment of similar projects.