既有高层建筑地下增层开挖桩端阻力损失

发布时间：2018-12-12 00:00

【摘要】：针对既有高层建筑地下增层开挖引起原基础底板下桩基承载力损失的问题,在嵌岩桩极限端阻计算公式的基础上,分别应用简化公式以及Mindlin应力解考虑开挖引起的附加应力,计算开挖后极限端阻损失.利用有限元法计算桩端阻力并与理论计算结果进行对比,研究增层开挖条件下桩端极限阻力损失比随不同增层开挖宽度和深度的变化规律,分析桩端参数对桩端阻力损失比的影响.结果表明:损失比随增层开挖宽度的增大而增大,开始增大较快然后变缓并趋于稳定;损失比随增层开挖深度的增大而增大,大致呈线性趋势;岩体的质量越好,损失比越小,当组成岩体的岩块强度较高时更明显;随着桩体嵌入基岩深度的增加,损失比先减小后趋于稳定,当岩体质量较好时更明显.
[Abstract]:In view of the loss of bearing capacity of pile foundation under the original foundation floor caused by the excavation of underground adding layer of existing high-rise building, based on the calculation formula of ultimate end resistance of rock-socketed pile, the simplified formula and Mindlin stress solution are applied to consider the additional stress caused by excavation, respectively. The ultimate end resistance loss after excavation is calculated. The finite element method is used to calculate the pile tip resistance and the results are compared with the theoretical results. The variation of the ultimate resistance loss ratio of the pile end with the width and depth of the pile end excavation under the condition of increasing layer excavation is studied. The influence of pile end parameters on pile tip resistance loss ratio is analyzed. The results show that the loss ratio increases with the increase of the width of the increasing layer, increases rapidly and then slows down and tends to be stable, and the loss ratio increases with the increase of the depth of the increasing layer, which shows a linear trend. The better the quality of rock mass is, the smaller the loss ratio is, and the more obvious the strength of the rock mass is, with the increase of the depth of the pile-embedded bedrock, the loss ratio decreases first and then becomes stable, and it becomes more obvious when the quality of rock mass is better.
【作者单位】：浙江大学滨海和城市岩土工程研究中心;浙江大学软弱土与环境土工教育部重点实验室;浙江理工大学建筑工程学院;
【基金】：国家自然科学基金资助项目(51078377)
【分类号】：TU473.1

【参考文献】