盾构隧道千斤顶推力对管片力学响应影响分析

Analysis of Influence of Jack Thrust on Segment Mechanical Response in Shield Tunnel

以上海隧道股份有限公司承建的昆明市轨道交通2号线二期工程六甲站—龚家村站盾构区间隧道为工程背景,通过MIDAS/GTS软件建立三维有限元非连续接触有限元模型,对盾构隧道推进过程中不同千斤顶推力情况下的管片力学响应进行模拟,并针对千斤顶推力相对于管片表现出的应力应变而产生的实际影响,进行科学系统的综合分析。结果显示:横向水平变形和竖直变形呈减小的趋势,轴向水平变形随着推力的增大而增大,管片的错台量减小;与此同时,由于管片环的持续推移,轴向水平方向由于负载千斤顶推力而引发的变形程度逐步降低;每环管片的最大拉应力和最大压应力均位于连接螺栓手孔处,因此可以推断螺栓孔位置和错台部位易发生开裂破损现象;值得一提的是,当千斤顶推力逐步递增的过程中,管片所能达到的最大拉应力以及相应的压应力,将会首先缓慢降低,又逐渐增大,说明适宜的千斤顶推力有利于管片受力,但是推力过大会导致管片破损。经由本篇论文所获得的研究结果,将能有助于针对地铁盾构进行科学有效的施工控制。

Based on the shield tunnel of Liujia Station-Gongjiacun Station of the second phase of Kunming Rail Transit Line 2,constructed by Shanghai Tunnel Co.,Ltd.,a three-dimensional finite element discontinuous contact finite element model is established by MIDAS/GTS software to analyze the segment forces under different Jack thrust during the shield tunnel propulsion.The mathematical response is simulated,and the actual effect of Jack thrust on the stress and strain of the segment is analyzed scientifically and systematically.The results show that the transverse horizontal and vertical deformations tend to decrease,and the axial horizontal deformations increase with the increase of thrust,and the staggered number of segments decreases.At the same time,the deformation degree of the axial horizontal direction caused by the thrust of the load jack decreases gradually due to the continuous movement of the segment rings.The large tensile stress and the maximum compressive stress are both located at the hand hole of the connecting bolt,so it can be inferred that the location of the bolt hole and the staggered platform are liable to crack and damage.It is worth mentioning that the maximum tensile stress and the corresponding compressive stress of the segment will first slowly decrease when the jack thrust increases gradually.It is shown that proper jack thrust is beneficial to segment stress,but excessive thrust will lead to segment damage.The research results obtained in this paper will be helpful for the scientific and effective construction control of metro shield.