论文部分内容阅读
在成都地区某基坑支护工程开展了深基坑条件下桩锚支护结构受力与变形特性现场试验,研究了冠梁上土压力与内力变化规律、锚索轴力及支护桩侧向位移分布特征。结果表明:(1)在基坑中部,冠梁对桩顶侧向位移有一定的协调作用,角点处冠梁协调作用较弱,应适当提高冠梁刚度,并将其与其他部位断开;(2)锚索轴力沿基坑深度呈类抛物线型分布,且(0~2/3)倍基坑最终开挖深度he范围内的中上层锚索对支护桩顶侧向位移影响比较明显,施工时应尽量控制该深度范围的开挖速度及重点关注中上层锚索预应力损失;(3)受边界效应影响,基坑变形具有空间效应特征,具体表现为基坑中部大于角点处、长边大于较短边,边界效应对其影响范围大致为1h_e。
In a foundation pit supporting project in Chengdu, a field test of the bearing and deformation characteristics of pile-anchor retaining structure under deep foundation pit was carried out. The variation rules of earth pressure and internal force on crown beam, Distribute the features to the displacement. The results show that: (1) In the middle part of the foundation pit, the crown beam has a certain coordination effect on the lateral displacement of pile top, and the coordination of the crown beam at the corner point is weak. The crown beam stiffness should be increased properly and disconnected from other parts ; (2) The axial force of anchor cable is parabolic distributed along the depth of foundation pit, and the influence of the middle and upper anchorage cables on the lateral displacement of top of supporting piles within (0 ~ 2/3) times the final excavation depth he It is obvious that the excavation speed of this depth range should be controlled and the loss of prestressing force of the middle and upper cables should be controlled as far as possible during the construction. (3) Due to the boundary effect, the deformation of the foundation pit has the space effect characteristic, Point, the long side is larger than the shorter side, the border effect of its impact range of roughly 1h_e.