深路堑施工对邻近高架桥的影响研究

发布时间：2018-07-26 14:45

【摘要】：郑州至新郑快速通道改建工程K0+0.000~K1+100.000段,全长1.1Km,路线整体呈南北走向,下穿京广铁路箱涵引道位于上跨京广铁路分离式立交桥东、西两侧,两侧深路堑支护结构近邻桥桩,本研究路段是邻近高架桥和京广线铁路的特殊路段,高架桥桥桩的直径达到2.0米,埋深为55米,属于大直径灌注桩,并且路堑开挖深度达到13.0米,路堑开挖边界距离最近桥桩9米,土质绝大部分为粉土,自立性差,路堑支护结构的设计、施工难度很大。在深路堑支护施工过程中保证高架桥的安全显得非常重要,本文的研究将为类似项目提供一定的工程借鉴。本文依托该邻近高架桥桥桩深路堑支护工程,将深路堑支护结构、近邻高架桥桥桩和土体作为一个整体结构,运用MIDAS/GTS有限元软件数值模拟、理正软件理论计算、现场实测数据相结合的方法,研究了深路堑支护结构、周边土体及邻近高架桥桥桩的受力特征和变形规律等,主要工作如下:1.理论分析大直径灌注桩的承载机理并对其承载力进行计算分析。2.运用理正深基坑计算软件进行路堑支护结构设计。3.分析总结现场监测数据,并对比分析监测结果与理论计算结果差异。4.运用MIDAS/GTS有限元软件建立与实际工程拟合的有限元模型,并对模拟结果(应力、应变等)进行分析,并分析其影响因素。通过以上工作的进行,得出以下主要研究成果:1.在对路堑进行支护设计施工后,桥桩的附加弯矩值降低在10 kN?m以内,起到了保护桥桩的目的。2.随着深路堑土体开挖深度的增加,桩锚支护结构的水平侧移变形增大,最大水平位移发生位置不断下降。桩锚支护结构侧移曲线呈现两头小,中间大的鼓肚子形状。3.得出随着深路堑土体开挖深度的增加,周边影响范围内的地表沉降逐渐增大,距离深路堑土体开挖边界7.5米左右距离处地表沉降量最大,且地表沉降最大位置不变化,在距离深路堑开挖深度3倍以外地表沉降几乎为零。4.得出距离深路堑边界最近桥桩受深路堑施工影响大,随着桥桩距离深路堑边界距离的增大,深路堑开挖对其影响逐渐减小。
[Abstract]:The reconstruction project K0 0.000~K1 100.000 of Zhengzhou to Xinzhou-Xinzheng Expressway has a total length of 1.1 km, and the whole route is in a north-south direction. The underpass of the box culvert of Beijing-Guangzhou Railway is located on the east and west sides of the separated interchange bridge of the Beijing-Guangzhou Railway, on both sides of which the deep cutting supporting structure is close to the bridge pile. This research section is a special section adjacent to the viaduct and the Beijing-Guangzhou railway. The diameter of the viaduct pile is 2.0 meters, the buried depth is 55 meters, which belongs to the large-diameter cast-in-place pile, and the cutting depth reaches 13.0 meters. The cutting excavation boundary is 9 meters away from the nearest bridge pile, the soil is mostly silt, and its independence is poor. The design of cutting support structure is very difficult. It is very important to ensure the safety of viaduct in the process of deep cutting support construction. The research in this paper will provide some reference for similar projects. Based on the deep cutting support engineering of the adjacent viaduct pile, this paper takes the deep cutting support structure, the adjacent viaduct pile and soil as an integral structure, uses the MIDAS/GTS finite element software to simulate, and calculates the theory of straightening software. Based on the field measured data, the stress characteristics and deformation rules of deep cutting support structure, surrounding soil and adjacent viaduct piles are studied. The main work is as follows: 1. The bearing mechanism of large diameter cast-in-place pile is analyzed theoretically and its bearing capacity is calculated and analyzed. Using the calculation software of deep foundation pit of Lizheng to design the cutting support structure. 3. Analyze and summarize the field monitoring data, and compare the monitoring results with the theoretical results. 4. 4. The finite element model fitted to the actual engineering is established by using MIDAS/GTS software. The simulation results (stress, strain, etc.) are analyzed and the influencing factors are analyzed. Through the above work, the following main research results: 1. The additional moment value of the bridge pile is reduced to less than 10 kN?m after the design and construction of the cutting, which plays the purpose of protecting the bridge pile. With the increase of the excavation depth of deep cutting soil, the lateral displacement and deformation of pile-anchor support structure increase, and the position of maximum horizontal displacement decreases continuously. The lateral displacement curve of pile-anchor support structure shows two small, large middle bulging belly shape. 3. It is concluded that with the increase of the excavation depth of deep cutting soil, the surface settlement in the surrounding influence range increases gradually, and the surface settlement is the largest at about 7.5 meters from the excavation boundary of deep cutting soil, and the maximum position of surface settlement does not change. The surface subsidence is almost zero at 3 times the depth of deep cutting excavation. It is concluded that the nearest bridge pile with deep cutting boundary is greatly affected by deep cutting construction. With the increase of the distance between bridge pile and deep cutting boundary, the influence of deep cutting excavation gradually decreases.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.13

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