岩溶区桥梁基桩及持力层稳定性研究
发布时间：2018-11-04 13:48
【摘要】：在岩溶发育地区,溶洞的形成使得其周围岩体的应力发生了重分布,改变了岩体的力学特征,并严重影响到岩层的承载能力,威胁到桥梁桩基的安全稳定,给设计和施工也带来了很多困难。如何分析和评估溶洞条件下桥基和持力岩层的稳定是工程设计及施工必须面对的关键问题。本论文以广西百色至靖西高速公路BJ-A10合同段的多安大桥为工程依托,分别从理论分析和数值模拟等方面探讨了溶洞顶部持力岩层稳定性验算方法、桥梁基桩及持力岩层力学特征、持力层最小安全厚度的确定等,主要工作包括以下几个方面:(1)对广西境内多条公路干线上的桥梁进行了调研,统计和分析了岩溶区中小跨径桥梁的结构形式和病害特征,发现在岩溶区桩基基础应用最为广泛,上部结构一般首选轻型构件,基础变形破坏是岩溶区中小跨径桥梁的主要病害形式;(2)分析了岩溶区桥梁嵌岩桩的失稳形式及其稳定性的影响因素,讨论了桥梁基桩和持力岩层稳定性的分析方法,得出了不同的持力岩层最小安全厚度计算公式;结合工程实例,采用了多种力学模型分别进行了抗冲切验算、抗剪切验算和抗弯验算的分析,并与数值结果进行了对比,认为实例工程中桥梁基桩持力岩层的受力是较稳定的;(3)采用有限差分程序FLAC3D对不同溶洞形状、尺寸、位置、上部荷载及持力岩层厚度时的基桩及持力层力学特征进行了三维模拟,研究了不同条件下,溶洞对基桩和持力岩层的影响规律,拟合了不同上部荷载时基桩端部竖向位移与持力岩层厚度的函数关系,提出了根据持力岩层塑性区是否贯通和基桩竖向位移是否超过允许范围来确定持力层的最小安全厚度,并结合工程实例验证了其持力岩层厚度满足承载要求。
[Abstract]:In the karst area, the formation of karst cave causes the stress of surrounding rock mass to be redistributed, which changes the mechanical characteristics of rock mass, and seriously affects the bearing capacity of rock layer and threatens the safety and stability of bridge pile foundation. It also brings many difficulties to design and construction. How to analyze and evaluate the stability of bridge foundation and bearing rock is a key problem in engineering design and construction. Based on the Duoan Bridge in the BJ-A10 contract section of Baise to Jingxi Expressway in Guangxi, this paper discusses the method of checking the stability of the rock layer at the top of the karst cave from the aspects of theoretical analysis and numerical simulation. The main work includes the following aspects: (1) the investigation and investigation of the bridges on several main highways in Guangxi, such as the mechanical characteristics of the bridge foundation pile and the bearing rock layer, the determination of the minimum safe thickness of the bearing layer, etc. The structural form and disease characteristics of small and medium span bridges in karst area are statistically analyzed. It is found that the pile foundation in karst area is the most widely used, and the superstructure is generally preferred as light component. Deformation and failure of foundation is the main disease form of medium and small span bridges in karst area. (2) the unstable form of rock-socketed pile and its influencing factors in karst area are analyzed, and the analysis methods of the stability of bridge foundation pile and bearing rock layer are discussed, and different formulas for calculating the minimum safe thickness of bearing rock layer are obtained. Combined with engineering examples, various mechanical models are used to analyze the impact shear calculation, shear resistance checking calculation and bending checking calculation, and the results are compared with the numerical results. It is considered that the bearing force of the bearing rock layer of the bridge foundation pile is relatively stable in the practical engineering. (3) the mechanical characteristics of foundation pile and bearing layer under different shape, size, position, upper load and thickness of bearing rock layer are simulated by finite difference program FLAC3D, and the different conditions are studied. The relationship between vertical displacement at the end of the pile and the thickness of the bearing rock layer under different upper loads is fitted by the influence of the cave on the foundation pile and the bearing rock bed, and the relationship between the vertical displacement of the pile end and the thickness of the bearing rock layer is obtained. The minimum safe thickness of the bearing layer is determined according to whether the plastic zone of the bearing rock layer is through and whether the vertical displacement of the foundation pile exceeds the allowable range.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U443.15
本文编号：2310002
[Abstract]:In the karst area, the formation of karst cave causes the stress of surrounding rock mass to be redistributed, which changes the mechanical characteristics of rock mass, and seriously affects the bearing capacity of rock layer and threatens the safety and stability of bridge pile foundation. It also brings many difficulties to design and construction. How to analyze and evaluate the stability of bridge foundation and bearing rock is a key problem in engineering design and construction. Based on the Duoan Bridge in the BJ-A10 contract section of Baise to Jingxi Expressway in Guangxi, this paper discusses the method of checking the stability of the rock layer at the top of the karst cave from the aspects of theoretical analysis and numerical simulation. The main work includes the following aspects: (1) the investigation and investigation of the bridges on several main highways in Guangxi, such as the mechanical characteristics of the bridge foundation pile and the bearing rock layer, the determination of the minimum safe thickness of the bearing layer, etc. The structural form and disease characteristics of small and medium span bridges in karst area are statistically analyzed. It is found that the pile foundation in karst area is the most widely used, and the superstructure is generally preferred as light component. Deformation and failure of foundation is the main disease form of medium and small span bridges in karst area. (2) the unstable form of rock-socketed pile and its influencing factors in karst area are analyzed, and the analysis methods of the stability of bridge foundation pile and bearing rock layer are discussed, and different formulas for calculating the minimum safe thickness of bearing rock layer are obtained. Combined with engineering examples, various mechanical models are used to analyze the impact shear calculation, shear resistance checking calculation and bending checking calculation, and the results are compared with the numerical results. It is considered that the bearing force of the bearing rock layer of the bridge foundation pile is relatively stable in the practical engineering. (3) the mechanical characteristics of foundation pile and bearing layer under different shape, size, position, upper load and thickness of bearing rock layer are simulated by finite difference program FLAC3D, and the different conditions are studied. The relationship between vertical displacement at the end of the pile and the thickness of the bearing rock layer under different upper loads is fitted by the influence of the cave on the foundation pile and the bearing rock bed, and the relationship between the vertical displacement of the pile end and the thickness of the bearing rock layer is obtained. The minimum safe thickness of the bearing layer is determined according to whether the plastic zone of the bearing rock layer is through and whether the vertical displacement of the foundation pile exceeds the allowable range.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U443.15
【参考文献】
相关期刊论文 前10条
1 许国平;;岩溶区中小跨径桥梁结构形式及存在问题分析[J];西部交通科技;2016年01期
2 张秉旭;;岩溶地区桥梁基础设计与施工[J];辽宁省交通高等专科学校学报;2014年01期
3 穆川川;;溶洞区桥梁钻孔灌注桩施工控制技术[J];交通世界(建养.机械);2013年10期
4 曹文贵;李媛;翟友成;;基于Info-Gap理论的基桩下伏岩溶顶板稳定性的主动分析方法[J];岩石力学与工程学报;2013年02期
5 龚先兵;赵明华;杨明辉;吴立坚;;岩溶区桥梁基桩极限承载力的突变求解方法[J];公路交通科技;2012年11期
6 刘伟龙;;岩溶区某桥梁桩基稳定性分析[J];公路工程;2012年05期
7 孙映霞;张智浩;王金安;;岩溶区桩基破坏模式研究及稳定性分析[J];工业建筑;2012年09期
8 韩淑朋;严新泺;;广西岩溶塌陷类型、影响因素、成因机制及其防治措施[J];资源调查与环境;2012年02期
9 王晓楠;张燕奇;王建良;;桥梁基桩下伏溶洞围岩应力状态分析[J];科学技术与工程;2012年14期
10 高军;;武广铁路岩溶地区桥梁钻孔桩施工要点探析[J];铁道技术监督;2011年01期
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