软岩地基中大直径布袋桩抗拔试验研究

发布时间：2018-02-05 01:09

本文关键词： 布袋抗拔桩极限承载力预测模型静载试验　出处：《岩土力学》2015年S2期 　论文类型：期刊论文

【摘要】：西北地区深大基础工程日益增多,兼顾基础抗浮和耐久性问题的研究空白,借助西宁火车站综合改造工程,引入大直径布袋桩技术,有效解决了基础抗浮和耐久性问题;选择6根试桩进行了现场单桩抗拔载荷试验,最大加载量为9 060 k N;运用MATLAB软件分别拟合出3种抗拔极限承载力预测函数模型的曲线,同时运用PLAXIS软件对不同等级荷载桩-土位移进行模拟,并与实测的荷载-位移曲线对比分析。研究发现:双曲线和幂函数模型较适合此类抗拔桩极限承载力预测;本地区类似地基预测大直径缓变形抗拔桩极限荷载所需的极限位移标准应由0.030D减小为0.025D;仅根据土层的物理力学特征确定抗拔桩桩周土的极限摩阻力不够完善,至少还要考虑埋深不同对具有相似物理力学特征土层性质的影响。
[Abstract]:With the increasing number of deep and large foundation projects in Northwest China, the study of anti-floating and durability of foundation has been neglected. With the aid of Xining railway station comprehensive transformation project, the technology of large diameter cloth bag pile has been introduced. Effectively solve the foundation anti-floating and durability problems; Six test piles were selected to test the uplift load of single pile in the field, and the maximum loading amount was 9 060 KN; The curves of three kinds of ultimate bearing capacity prediction function models were fitted by MATLAB software, and the pile-soil displacement of different classes of loads were simulated by PLAXIS software. The results show that the hyperbolic and power function models are more suitable for the prediction of ultimate bearing capacity of this kind of pile. In this area, the limit displacement standard for predicting the limit load of large diameter slowly deformed uplift pile should be reduced from 0.030D to 0.025D. According to the physical and mechanical characteristics of soil layer, it is not perfect to determine the ultimate frictional resistance of the soil around the pile, and at least consider the influence of different buried depth on the properties of soil layer with similar physical and mechanical characteristics.
【作者单位】：兰州理工大学土木工程学院;后勤工程学院建筑工程系;
【基金】：国家自然科学基金项目(No.11272353)
【分类号】：TU473.1
【正文快照】： 1引言西北地区的深基础工程日益增多,相应的基础抗浮问题变得日益突出。相对于软土地基而言,本地区的地基条件相对较好,但是以往未被重视的强风化岩层,泥岩层与石膏岩层相互夹杂,节理裂隙发育,遇水极易软化,长时间暴露在空气中易崩解,强度大量丧失,导致地基土强度骤降[1];同时

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