Calculation of the effect of uplift on deformation of existing tunnels under actions of anti-floating anchors
By considering the effect of uplift of the pit bottom on tunnels,a displacement calculation model of shield tunnels with anti-floating anchors caused by the uplift of the pit bottom is established.Based on the image source method,the longitudinal deformation formula of shield tunnels with anti-floating anchors under the horizontal belt caused by the uplift of the pit floor is derived.Combined with engineering examples,the accuracy of the calculation method is verified by comparing the measured values,theoretically calculated values and three-dimensional finite element simulation values and the influence of number of anti-floating anchor rods on the deformation of tunnels is studied.The results show that the tunnel bulge occurs mainly in the areas of strong influence while the inter-ring angle and misalignment occur in the areas of weak influence.The tunnel uplift is mainly affected by the size of the foundation pit.For an excavation length L of the foundation pit,anti-floating anchor rods can reduce the uplift,inter-ring angle and misalignment of tunnels.The inter-ring angle and the misalignment are mainly affected by the size of the foundation pit excavation and always reach the extreme value at±3L/5 .In a certain range,increasing the number of anti-floating rods can effectively reduce the deformation of tunnels,but the control effect is not significant beyond a certain range.
foundation pit engineeringshield tunnelvirtual image techniqueanti-floating anchor roddeformation of tunnel
万方数据
维普
