环缝榫槽破坏对相邻环变形及内力的影响

Effect of circumferential seam tenon damage on deformation and internal force of adjacent rings

针对地表超载导致盾构隧道接头破坏的问题,以含环缝榫槽的错缝拼装管片为研究对象,建立了精细化盾构隧道有限元模型.通过施加1∶10盾构隧道-土相互作用模型试验验证的水土荷载,研究了超载下环缝榫槽破坏的规律及对相邻环隧道变形、内力、环缝错台的影响,得出:1)环缝榫槽发生初始破坏的位置处于拱腰处靠近纵缝接头边角的部位,发生破坏的原因是凸榫底部和凹榫顶部相互挤压造成的;2)在超载阶段,环缝榫槽出现破坏的区域与环缝错台量密切相关,当地表超载超过70kPa时,隧道拱腰及顶底的榫槽均开始发生破坏,榫槽破坏位置对应的环缝错台量均大于1.0mm;3)在榫槽破坏发展过程中,环缝错台量先呈线性后呈非线性变化,当环缝榫槽的裂缝贯通至管片表面时,隧道收敛变形开始迅速增大,相邻环的最大弯矩差比初始破坏阶段大3倍,相邻环的最大轴力差比初始破坏阶段大1.9倍.

Aimed at the problem of shield tunnel joint damage due to surface overload,a finite element model of shield tunnel is established that based on the segment with circumferential seam tenon.Though applied the soil load that is verified by 1∶10 scale model test of tunnel and soil interaction,the circumferential seam tenon damage law,and its influence on deformation,internal force and dislocation of shield tunnel under overload are studied.The results show:1)The initial damage position of ring tenon is located at the arch waist near the longitudinal joint corner,the damage reason is caused by the mutual extrusion force of the tenon;2)The tenon damage area is closely related to the circumferential seam dislocation during overload,when the surface overload exceeds 70 kPa,the tenon at the arch waist,top and bottom of the tunnel begin to occur damage,and the dislocations at the damage position are all more than 1.0 mm;3)In the process of the tenon damage,the dislocation shows linear firstly and then non-linear change,when the cracks penetrate to the surface of the segment,the tunnel convergence deformation begin to increase rapidly,in the stage the maximum moment difference of adjacent ring is 3 times larger than that of initial damage stage,and the maximum axial force difference of adjacent ring is 1.9 times larger than that of initial damage stage.