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利用有限元分析法,对西安穿越地裂缝带的地铁隧道与土体在地铁荷载下的动力相互作用进行了三维模拟,分析了整体式隧道和分段式隧道两种情况下衬砌与土接触压力的分布规律和衬砌下部土中动应力的传递规律及影响范围,并将地铁列车荷载引起的动应力与初始静应力进行了比较,得出了地铁动荷载与重力荷载之间的强度差异。分析表明,列车从上盘往下盘运行过程中,在地裂缝附近,下盘拱底与土附加接触压力较正常值大,上盘则较正常值小,下盘拱顶与土附加接触拉应力较正常值大,上盘拱顶与土之间则产生附加接触压应力;土中竖向动应力从衬砌底传递至下部11 m过程迅速减小,动应力对此范围以外的土体影响较小;地裂缝附近分段式隧道条件下土中竖向动应力较大;就本次模拟工况而言,地铁动荷载产生的动应力比初始静应力要小很多,初始应力与动应力的最小倍数在60倍以上。
The finite element analysis is used to simulate the dynamic interaction between subway tunnel and soil mass under the subway load in Xi’an through the ground fissure zone. The contact pressure between the lining and soil under the condition of monolithic tunnel and segmented tunnel is analyzed The law of distribution of dynamic stress and the influence range of dynamic stress in the soil beneath lining are compared. The dynamic stress caused by subway train load is compared with the initial static stress, and the intensity difference between dynamic load and gravity load of subway is obtained. The analysis shows that when the train runs from the upper plate to the lower plate, the additional contact pressure between the bottom of the lower plate and the soil is larger than the normal value and the upper plate is smaller than the normal value, and the additional contact between the lower plate and the dome The stress is larger than the normal value and the additional contact compressive stress is generated between the top plate and the soil of the upper plate. The vertical dynamic stress in the soil decreases rapidly from the bottom of the lining to the bottom by 11 m, and the dynamic stress affects the soil outside this range And the vertical dynamic stress in the soil under the segmented tunnel near the ground fissure is relatively large. For this simulated working condition, the dynamic stress generated by the subway dynamic load is much smaller than the initial static stress. The initial stress and dynamic stress The minimum multiple of 60 times.