Research On Deformation Law Of Loess Tunnel With Different Characteristics

Loess is a special soil in engineering geological rock and soil and has been studied. Because of its unique structure and characteristics of vertical joints and due to age formation, forming region and different water content, practical engineering and ordinary rock tunnel have large differences, showed different characteristics. The characteristics of loess rock engineering, from moisture and liquid index in the process of starting to explore the morphological changes of surrounding rock displacement and mechanical characters of loess tunnel excavation. The deformation characteristics of surrounding rock excavation process of the different characteristics of shallow buried loess tunnel are systematically studied by different groups of indoor model test and numerical simulation method.In the laboratory, Similar material which were made by ratio of orthogonal test are reshaped into model materials with different characters, indoor geomechanical model experiment was carried out with similar formation, simulation of excavation process of displacement of surrounding rock stress field changes. The further analysis of excavation deformation law of surrounding rock by numerical simulation of FLAC 3D, which has made important achievements.This paper research hard plastic、soft plastic and plastic flow of different traits of the loess tunnel excavation process of cavern stability, space deformation patterns. Researching the tunnel side wall in different radial depth of horizontal convergence displacement and the arch of vertical displacement deformation and decay through experiments and numerical simulation and investigating the three characteristics of loess tunnel radial displacement decay. Studing on different parts of tunnel surrounding rock radial pressure and the surrounding rock mass with the water rate and liquid limit changed by a hard plastic transition soft plastic then transition to flow plastic shaped tunnel which face extrusion deformation development rate, vault settlement and ground settlement rate as well as the comparison of horizontal convergence rate. Researching on three characters of loess tunnel excavation process of tunnel displacement of the first week. Putting forward a "slump angle" to determine plastic flow loess tunnel face instability limit state.