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随着大跨度桥梁工程的建设和上部结构荷载的增大,在一些地区已出现嵌岩深度超过5倍桩径的深长嵌岩桩基。基于自平衡测试技术,根据青岛海湾大桥两根桩基的静载荷测试报告,对大直径深长嵌岩桩的桩侧阻力进行了研究分析,主要内容包括桩顶等效荷载位移曲线分析,桩周岩层侧阻力大小、桩周岩层侧阻力与位移关系、桩侧与桩端阻力分担比等。研究结果表明,该地区大直径深长嵌岩桩的桩顶的Q-S曲线主要是缓变型为主;从桩侧岩层摩阻力来看,勘探报告所提供的岩层极限侧阻力数值偏小;从桩侧、桩端阻力分布来看,在软岩地区嵌岩深度大小对承载力影响较大,嵌岩比越大,桩端分担的阻力越小。
With the construction of the long-span bridge project and the increase of the superstructure load, deep-embedded rock-socketed piles with socketed depth exceeding 5 times of pile diameter have appeared in some areas. Based on the self-balance test technique, according to the static load test report of two pile foundations of Qingdao Bay Bridge, the lateral resistance of pile with large diameter and long rock depth is studied and analyzed. The main contents include the analysis of equivalent displacement curve of pile top, The lateral resistance of rock strata, the relationship between the lateral resistance and displacement of the strata around the pile, and the ratio of the resistance between the pile side and the pile. The results show that the QS curve of pile top of large-diameter deep rock-socketed piles in this area is mainly of slow-changing type. From the point of view of the frictional resistance of pile-side strata, the limit value of lateral rock resistance provided by the exploration report is small; , The distribution of pile tip resistance, the depth of rock-socketed in soft rock area has a greater impact on the bearing capacity, the greater the sock-in-rock ratio, the smaller the resistance shared by pile ends.