مطالعه شبیه سازی عددی نفوذ میدان تنش زمین در ثبات جاده

We adopt the concept of generalized plane strain to model a roadway in a stress field. This can avoid limitations caused by simplifying the stress analysis as plane strain. FLAC3D was used to investigate the maximum tensile stress and displacement of a roadway in a known stress field for angles, between the roadway axial direction and the maximum principal stress of 0°, 30°, 45°, 60° and 90°. This theory was applied to the analysis of an engineering case. The results indicate that stress and displacement of the surrounding rock increase as the angle, increases. This provides some significant guidance for a reasonable layout of roadways in a known stress field.

Mining activities are mainly carried out in the upper strata of the Earth’s crust and are subject to ground stress, stope roof-control and surface subsidence and movement. So the layout of roadways and supports is different from the general case[1-4]. Previous design and construction of roadways rarely took into account ground stress fields, which are an important factor in the stability of rock surrounding the roadway. Gail considered the horizontal stresses around underground mine tunnels to be greater than vertical stresses because of the directionality of the stress field[5-8]. We report here numerical simulations using FLAC3D to establish a model for investigation of the maximum tensile stress and displacement of a roadway in a known stress field. The model is conditioned on the assumption that the angle between the roadway axial direction and the maximum principal stress is different. This provides a basis for reasonable layout of roadways within a known stress field.

A generalized plane strain approach was used to analyze the impact of the ground stress field on roadwaystability. The numerical simulation software FLAC3D was used to model the problem. Traditional analysis generally uses a two-dimensional model with a different lateral pressure ratio. We have used a three-dimensional model and FLAC3D to analyze the impact of stress while considering the distribution of tensile stress, the displacement of the roof and sides of the roadway and the vertical stress. The main conclusions are: 1) The tensile stress in the surrounding rock increases as the angle, α , increases. For α <30° the tensile stress is relatively small and the effect of stress on the surrounding rock is also small. When α is more than 45° the tensile stresses gradually increase with increasing α . This indicates that the influence of ground stress on the stability of the surrounding rock increases as the angle changes. 2) The displacement of the roof and sides increases as the angle, α , increases. In some places the sides of the roadway are displaced in a negative direction due to compression. This indicates that points oft zero displacement must exist on the surface somewhere. 3) The vertical stress in the roof and sides increases and tends to a certain value as the angle, α , increases. The convergence of the roof is greater than that of the sides