论文部分内容阅读
盾构近距离穿越大型立交桥超长桩基础会对桩基础及上部桥梁结构产生不利影响。通过对盾构近距离侧穿超长桩基础过程进行数值模拟,研究了不同深度处盾构掘进对超长桩承载性状、变形和内力的影响。研究表明:盾构近距侧穿超长桩会导致桩身出现较大变形及内力,且隧道轴线与超长桩处于不同相对位置时会对桩的特性产生不同影响。其他条件不变时,盾构从桩身上部的近距离穿越,将引起桩身最大的横向水平位移;盾构从桩身中部近距离穿越则将引起桩身产生沿盾构掘进方向的最大的水平位移;盾构从桩端附近穿越时将引起桩身产生最大的竖向位移;盾构从桩身中下部穿越时将引起桩身产生最大的附加轴力。桩身侧阻在隧道轴线附近呈“S”型,同时桩身轴力最大值也出现在隧道轴线附近。盾构导致桩身产生纵向和横向变形延伸至桥面高度的变形量相当可观。当盾构穿越高架桥梁基础时应该严格控制桩顶水平位移。
Short-distance shield crossing large-scale overpass pile foundation will have an adverse effect on the pile foundation and the structure of the upper bridge. The effects of shield tunneling on the bearing behavior, deformation and internal forces of super-long piles at different depths are studied by numerical simulation of the process of shield piercing with super long piles. The results show that the pile with long-distance piles with long-distance shields leads to large deformation and internal forces of the pile body, and different axial positions of the pile and the super-long pile will affect the pile characteristics differently. When other conditions are not changed, the shield traverses at a short distance from the upper part of the pile body, which will cause the maximum transverse horizontal displacement of the pile body. The short distance between the shield and the middle part of the pile body will cause the pile body to produce the largest Horizontal displacement of the pile. When the shield traverses near the pile end, it will cause the maximum vertical displacement of the pile body. When the shield traverses from the middle to the lower part of the pile body, it will cause the maximum additional axial force of the pile body. The lateral resistance of pile body is in the form of “S” near the tunnel axis, and the maximum axial force of pile body also appears near the tunnel axis. The deformation of the pile caused by the longitudinal and transverse deformation of the pile body extending to the height of the deck is considerable. When the shield through the viaduct bridge foundation should be strictly controlled horizontal displacement.