邻近开挖对桥梁桩基变形与内力影响分析
发布时间：2018-07-24 08:20
【摘要】：研究目的:邻近开挖会对桥梁桩基造成不利影响,严重时将影响高速铁路的运营品质与安全。本文通过现场原型试验,获得深厚软土地区3种开挖工况下邻近桩基的工作性状,采用ABAQUS有限元软件对试验过程进行三维数值模拟,通过与试验结果的对比分析,验证计算模型与参数的合理性。基于验证后的计算模型,探讨无支护开挖主要参数(基坑宽度、边缘净距、基坑深度)对桩身变形与内力的影响规律。研究结论:(1)邻近开挖引起的桩身位移与弯矩分布范围约为设计时主动受力桩的2.1~2.8倍,劣化了桩基的工作状态,在高速铁路运营维护中应引起高度重视;(2)基坑宽度大于5倍的边缘净距时,可忽略继续向外侧加宽基坑对邻近桩基的影响;(3)当边缘净距大于30 m(相当于6倍的基坑宽度)时,开挖窄浅基坑(宽度≤5 m且深度≤3 m)对邻近桩基的影响不大;(4)桩顶水平位移、桩身最大弯矩随深宽比增加大致呈指数型增长趋势,且间距越小,其增长速率越大;(5)本研究成果可供高铁桥梁桩基设计、施工、运营维护借鉴。
[Abstract]:Research purpose: the adjacent excavation will have adverse effects on the bridge pile foundation, and will affect the operation quality and safety of the high-speed railway seriously. In this paper, through the field prototype test, the working characteristics of adjacent pile foundation under three excavation conditions in deep soft soil region are obtained. The three-dimensional numerical simulation of the test process is carried out by using ABAQUS finite element software, and the results are compared with the test results. The rationality of the calculation model and parameters is verified. Based on the verified calculation model, the influence of main parameters (width, margin, depth) of unsupported excavation on the deformation and internal force of pile is discussed. The conclusions are as follows: (1) the distribution range of displacement and bending moment of pile caused by adjacent excavation is about 2.1or 2.8 times as much as that of active force pile in design, which results in the deterioration of the working state of pile foundation. High attention should be paid to the operation and maintenance of high-speed railway; (2) when the width of foundation pit is larger than 5 times of the margin net distance, the influence of widening the foundation pit to the adjacent pile foundation can be neglected; (3) when the margin net distance is greater than 30 m (equivalent to 6 times the width of foundation pit), The excavation of narrow and shallow foundation pit (width 鈮，
本文编号：2140788
[Abstract]:Research purpose: the adjacent excavation will have adverse effects on the bridge pile foundation, and will affect the operation quality and safety of the high-speed railway seriously. In this paper, through the field prototype test, the working characteristics of adjacent pile foundation under three excavation conditions in deep soft soil region are obtained. The three-dimensional numerical simulation of the test process is carried out by using ABAQUS finite element software, and the results are compared with the test results. The rationality of the calculation model and parameters is verified. Based on the verified calculation model, the influence of main parameters (width, margin, depth) of unsupported excavation on the deformation and internal force of pile is discussed. The conclusions are as follows: (1) the distribution range of displacement and bending moment of pile caused by adjacent excavation is about 2.1or 2.8 times as much as that of active force pile in design, which results in the deterioration of the working state of pile foundation. High attention should be paid to the operation and maintenance of high-speed railway; (2) when the width of foundation pit is larger than 5 times of the margin net distance, the influence of widening the foundation pit to the adjacent pile foundation can be neglected; (3) when the margin net distance is greater than 30 m (equivalent to 6 times the width of foundation pit), The excavation of narrow and shallow foundation pit (width 鈮，
本文编号：2140788
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