【作者】 李立杨；

【导师】 王成华；

【作者基本信息】 天津大学 ， 结构工程， 2008， 硕士

【摘要】 本文主要采用ABAQUS有限元分析软件了高低双排桩支护结构。通过建立考虑桩土相互作用的平面有限元模型,土体采用修正剑桥模型,计算高低双排桩桩身的侧向变形、弯矩以及作用在桩身的土压力,分析了基坑开挖深度、宽度、双排桩排距、桩身刚度、土体性质等因素对双排桩挡土性状的影响,总结了双排桩支护结构的受力特点,得出了对工程实践和理论研究有一定参考价值的结论。1.随着开挖深度的增加,桩背土压力值逐渐减小。基坑开挖面以上桩身所受主动土压力与理论主动土压力值接近,开挖面以下桩身所受土压力介于理论主动土压力与静止土压力之间,并随着深度的增加,逐渐趋近于静止土压力。2.随着开挖深度的增加,桩背土压力值逐渐增加,但与理论被动土压力值相差较大。开挖过程结束时,前排桩在基坑开挖面以下桩身中间部分所受的土压力值最大,开挖面与桩底处较小,呈圆弧状分布。后排桩被动土压力接近静止土压力。因此进行基坑支护结构设计时,主动土压力应予以提高,而被动土压力则应降低。采用本文所述的方法分析了两个双排桩支护的工程实例,验证了计算模型的合理性和适用性。更多还原

【Abstract】 A plane finite element model of high-low double-rowed retaining piles considering the pile-soil interaction is proposed in this paper. In this model, the finite element software ABAQUS is used, and soil nonlinearity is modeled using Modified Cam-clay constitutive relationship. The lateral deformation, the moment and the earth pressure of the pile at any point can be calculated with this model. Some factors which have influences on the retaining character of double-row piles are analyzed, such as the excavation depth, width, the array pitch of the double-row piles, the pile stiffness. Through the comparison of the analysis result, some stress characters of the double-row piles are concluded, and some reference results are summarized for engineering practice and theory study.The main conclusions are the following:1.As the excavation depth is increasing, the positive earth pressure gets smaller and smaller. The positive earth pressure on the pile above the excavation face is almost equal to the academic positive earth pressure. And when under the excavation face, the earth pressure on the pile is between the academic positive earth pressure and the static earth pressure.2.As the excavation depth is increasing, the negative earth pressure gets larger and larger, but it has a big different comparing with the academic negative earth pressure. The negative earth pressure is bigger on the middle of the front pile than on the head and the bottom of the front pile. The negative earth pressure on the back pile is almost equal to the academic static pressure.Through the conclusions above, when design the double-row pile retaining structure, we should enhance the positive earth pressure and reduce the negative earth pressure.Using the method described in this paper, some project cases are analyzed. The rationality and applicability of the model are validated.更多还原