刚性桩复合地基极限承载力计算新方法

发布时间：2018-02-12 07:48

本文关键词： 刚性桩复合地基极限承载力基础宽度置换率承载力发挥系数　出处：《广州大学》2017年硕士论文　论文类型：学位论文

【摘要】：刚性桩复合地基虽然在工程中得到广泛应用已久,但目前对设计理论和计算方法还是存在些不足。刚性桩复合地基承载力按规范采用特征值法计算,但特征值法难以反映地基最终的实际状态。建筑桩基技术规范对桩基计算的是极限承载力,与复合地基承载力特征值不匹配。复合地基桩间土承载力发挥系数β没具体取值方法,难以做到在不同地质条件和不同基础情况下给出对应的β值。本文对刚性桩复合地基承载力进行研究,并针对上述问题,提出一种刚性桩复合地基极限承载力计算新方法。该方法从稳定的角度分析求解刚性桩复合地基的极限承载力,采用修正密度法对桩土相互作用进行转换,分别求桩间土发挥的极限承载力、桩的极限承载力。考虑基础的破坏模式分别计算整体滑动破坏、中线滑动破坏、自由滑动破坏三种破坏模式下的极限承载力。通过计算分析均质地基、成层地基条件下,基础宽度、置换率对刚性桩复合地基影响。指出:桩间土的极限承载力、复合地基的极限承载力与置换率的关系;随基础宽度的变化,复合地基达到极限承载力时其破坏模式也会发生变化;复合地基极限承载力、桩间土的极限承载力与基础宽度的关系;基础宽度和置换率对桩间土承载力发挥系数的影响;基础埋深对复合地基承载力的影响。通过该承载力计算方法可以方便的计算加固区在加固前和加固后的桩间土部分极限承载力,以此可以针对具体地基给出具体桩间土承载力影响系数。采用该计算方法对现场足尺寸试验和现场工程案例进行计算,将计算结果与试验结果、工程案例实际情况进行对比,指出该计算方法与试验结果有较好的吻合度,能正确反映工程实际状况。
[Abstract]:Although the rigid pile composite foundation has been widely used in engineering for a long time, there are still some shortcomings in the design theory and calculation method. The bearing capacity of rigid pile composite foundation is calculated by eigenvalue method according to the specification. However, the eigenvalue method can not reflect the ultimate actual state of the foundation. The ultimate bearing capacity of the pile foundation is calculated by the technical code of the building pile foundation. The bearing capacity of composite foundation is not matched with the characteristic value of bearing capacity. It is difficult to give the corresponding 尾 value under different geological conditions and different foundations. In this paper, the bearing capacity of rigid pile composite foundation is studied, and aiming at the above problems, A new method for calculating the ultimate bearing capacity of rigid pile composite foundation is presented, in which the ultimate bearing capacity of rigid pile composite foundation is calculated from the stability point of view, and the modified density method is used to transform the pile-soil interaction. The ultimate bearing capacity of the soil between the piles and the ultimate bearing capacity of the pile are calculated respectively. Considering the failure mode of the foundation, the whole sliding failure and the central line sliding failure are calculated respectively. The ultimate bearing capacity under three failure modes of free sliding failure is calculated and analyzed. The influence of foundation width and replacement rate on the composite foundation with rigid piles is analyzed by calculating and analyzing the ultimate bearing capacity of soil between piles. The relationship between ultimate bearing capacity and replacement rate of composite foundation, the failure mode of composite foundation when it reaches ultimate bearing capacity will change with the change of foundation width, the ultimate bearing capacity of composite foundation, the ultimate bearing capacity of composite foundation, The relationship between the ultimate bearing capacity of soil and the width of foundation, the influence of the width of foundation and replacement ratio on the coefficient of bearing capacity between piles; The influence of the depth of foundation on the bearing capacity of composite foundation can be used to calculate the ultimate bearing capacity of soil between piles before and after reinforcement. In this way, the influence coefficient of soil bearing capacity between concrete piles can be given according to the concrete foundation. The calculation method is used to calculate the field enough size test and the field engineering case, and the calculation results are compared with the test results and the actual situation of the engineering case. It is pointed out that the calculation method is in good agreement with the test results and can accurately reflect the actual situation of the project.
【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1

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