抽降水对高速铁路桥梁桩基的影响分析

发布时间：2018-03-07 19:16

本文选题：抽降水　切入点：桥梁桩基　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：高铁沿线附近,由于工业用水和民用水的需求开采地下水的情况已经越来越普遍。大量开采地下水将导致地基土的压密沉降,从而引起邻近高速铁路桥梁桩基沉降量的增加,严重时将影响到高速铁路的运营安全。因此,本文对抽降水情况下高速铁路桥梁桩基的工作性状开展研究,主要工作和成果如下： (1)分别建立了井点降水和基坑降水产生的附加荷载简化方法。其中,井点降水产生的附加荷载简化为若干圆形平面锥形分布荷载,基坑降水产生的附加荷载简化为若干矩形平面线性分布荷载。 (2)推导了圆形平面锥形分布荷载以及矩形平面线性分布荷载作用下地基中任意一点的附加应力计算公式。根据公式计算得到圆形平面锥形分布荷载作用下地基中不同位置的附加应力系数,并制成表格以供查阅。 (3)结合荷载传递法和剪切位移法,建立了一种适用于抽降水情况下单桩沉降量计算的理论方法——改进的荷载传递法。利用该方法,以某高速铁路桥墩桩基为例,进行了桩基沉降计算。 (4)推导了抽降水情况下群桩负摩阻力的计算公式,并在此基础上建立了一种适用于抽降水情况下群桩沉降量计算的理论方法——中性点试算法。运用该方法,对某高速铁路桥墩桩基础进行了沉降计算。 (5)利用ABAQUS有限元分析软件,采用定井内水头降深的方式,对抽降水情况下高速铁路桥墩桩基础进行了数值模拟。其中,抽水量根据计算结果提取井壁流速后积分得到。通过假定不同的井内水头降深,最终得到模型抽水量与实际抽水量相符情况下的桩基位移以及桩身受力状况。 (6)对改进的荷载传递法、中性点试算法以及ABAQUS数值模拟的计算结果进行对比分析,认为改进的荷载传递法更适用于单桩沉降计算,中性点试算法更适用于群桩沉降计算,数值模拟法则同时适用于群桩和单桩的沉降计算。图87幅,表16个,参考文献100篇。
[Abstract]:In the vicinity of high-speed railway, the exploitation of groundwater is becoming more and more common because of the demand for industrial and civil water. A large amount of groundwater exploitation will lead to the compaction settlement of foundation soil, which will cause the increase of pile foundation settlement of bridge in the vicinity of high-speed railway. The operation safety of high speed railway will be affected when it is serious. Therefore, the working characteristics of bridge pile foundation of high speed railway under the condition of pumping precipitation are studied in this paper. The main work and results are as follows:. 1) the simplified method of additional load caused by well point dewatering and foundation pit dewatering is established respectively, in which the additional load generated by well point dewatering is simplified to a number of circular plane conical distributed loads. The additional load caused by foundation pit dewatering is simplified to several rectangular plane linear distribution loads. The formulas for calculating the additional stresses at any point in the foundation under the action of circular plane conical load and rectangular plane linear distribution load are derived. According to the formula, the calculation of additional stress in the foundation under circular plane conical distribution load is obtained. Additional stress coefficients at different locations, Forms are made available for inspection. Combined with the load transfer method and the shear displacement method, an improved load transfer method, which is suitable for the calculation of the settlement of the order pile in the case of pumping and dewatering, is established. By using this method, the pile foundation of a bridge pier in a high-speed railway is taken as an example. The settlement of pile foundation is calculated. (4) the formula for calculating the negative friction of pile group under the condition of pumping precipitation is derived, and a theoretical method for calculating the settlement of pile group under the condition of pumping precipitation is established, which is called neutral point test algorithm. The settlement of the pile foundation of a high-speed railway pier is calculated. 5) by using ABAQUS finite element analysis software, the pile foundation of high speed railway bridge pier under the condition of pumping precipitation is numerically simulated by adopting the method of lowering the depth of water head in the fixed well. According to the calculation results, the integral is obtained by extracting the velocity of the well wall. The displacement of the pile foundation and the stress condition of the pile body under the condition that the model pumping quantity is consistent with the actual pumping amount is obtained by assuming the depth of the water head in different wells. The results of the improved load transfer method, neutral point test algorithm and ABAQUS numerical simulation are compared and analyzed. It is concluded that the improved load transfer method is more suitable for the settlement calculation of single pile, and the neutral point test algorithm is more suitable for pile group settlement calculation. The numerical simulation method is applicable to the settlement calculation of both pile groups and single piles. There are 87 figures, 16 tables and 100 references.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.15

【参考文献】