Research On Stress And Deformation Law Shallow-buried Bilateral Bias Neighborhood Tunnel

With the recent rapid development of high-grade highways and high-speedrailways construction, Neighborhood Tunnel Project which through the soil stratabecome more and more, due to the problem of shallow depth and bilateral bias are oneof the most difficult issues in tunnel construction, the resulting flow of constructionmechanical effect is more complex, it is necessary for this such tunnel constructionmechanical effects to analyze. In this paper, based on an actual tunnel project, whichrelying on many point of views, such as theoretical analysis, field monitoring andnumerical simulation, the tunnel surrounding rock pressure distribution, deformation ofdisplacement, in-depth researched and discussed the stress distribution, deformation ofdisplacement, and other supporting structure stress. The main work and results are asfollows:(1) A tunnel in Fujian Province as the analysis object, had carried on the finiteelement simulation of construction process, from the perspective of two-dimensionalnumerical analysis of such tunnel surrounding rock pressure distribution, deformation ofdisplacement, force supporting structure features and studied the distribution of plasticzone, and compared the results of numerical simulation with the on-site monitoring data.In the construction process, the sidewall and bottom arches appeared more obviousstress concentration in the folder rock, disturbance greater than that in other regions;after excavation hole construction had a greater impact on the first excavation holestress distribution, mainly showing in stress increases, but stress areas were decreased;Due to the effect of double bias, the vertical displacement of the inverted arch is greaterthan the vault, resulting in a more obvious the inverted arch bottom drum phenomenon; horizontal displacement changed toward to the buried depth of the slope, and two holesin the lateral displacement of the area and change value is greater than two holes inside.(2) The finite element software is adopted to establish the numerical model, byconsidering different construction processes, compared of the two procedures rockpressure distribution and displacement deformation law, and then obtained theexcavation construction process at the same time around of the hole the mutualinfluence is bigger, the principal effects were shear stress in the rock folder, excavatedholes at the same time in the folder had a greater shear stress, produced shear failureprone to disturbances.(3) Using the orthogonal experiment table and the extreme difference analysismethod, to explore the rock pressure in the tunnel depth, spacing and bias angle of thethree factors affecting the distribution of deformation and displacement law, drawn upfor the tunnel depth rock pressure and support structure forces the greatest impact, butthe impact on the tunnel bias angle maximum displacement, especially a greater impacton the horizontal displacement.