高速公路桥基荷载作用下溶洞顶板稳定性研究
发布时间：2018-08-18 18:32
【摘要】：我国岩溶地区分布广泛,随着工程建设规模逐步扩大,在岩溶地区修建各类工程设施成为必然,人们也逐渐认识到岩溶地质对结构物的危害性,特别是在桥梁桩基施工过程中遇到埋藏型岩溶地层,一般考虑将桩基作用在溶洞顶板之上。因此,溶洞顶板稳定性研究工作被提到重要议程。本文以益娄高速公路埋藏型岩溶工程特性及处治技术研究项目为依托,开展对岩溶溶洞顶板与桥梁桩基的相互作用机理及其稳定性研究,为后续工程的设计以及安全施工提供一定的借鉴作用,具有很大应用价值。论文所做的主要工作及研究成果如下：(1)本文首先介绍了埋藏型岩溶的特征,通过对模型做出基本的假设,将基桩与顶板的模型进行分类简化,得到了10种熟悉的力学结构模型,在此基础上,采用弹性力学中的薄板理论对溶洞顶板与桥梁桩基荷载系统模型做了详细的受力分析,得出了对应的顶板厚度检验公式。(2)根据建设工程中对基岩洞穴顶板的实际处理经验,分析了溶洞顶板稳定性影响因素,经分析可知：溶洞处于某一埋藏深度时,顶板跨度越大,其允许最小安全厚度越大：而溶洞洞深越深,其最小安全厚度更小；得出顶板跨度是溶洞稳定的非常不利因素,而溶洞的洞深是其稳定的有利因素。(3)从溶洞失稳的原因着手分析了岩溶失稳机理,引入岩石强度理论,建立岩溶失稳模型对其机理进行分析,分析得出,其实岩溶失稳机理即为力学机理：荷载作用导致岩土体强度失效以致失稳。(4)从上述结构模型中选取梁板模型来进行模拟分析,并结合该模型的特点对不同桩径下顶板的稳定性做了抗冲切、抗剪切以及抗弯验算。经验算可知,由基桩和顶板组成的类梁板模型整体呈安全稳定状态,其计算结果能指导工程设计与施工。(5)本文采用数值软件FLAC-3D,对益娄高速公路第10合同段石坝冲大桥位于K81+843和K81+878桥墩下的基桩和溶洞顶板稳定性进行了模拟分析。通过分析,笔者建议采用套筒加固技术对K81+878处的基桩进行加固,研究结论可以作为益娄高速公路桥基工程设计与施工的依据。此外,数值模拟对于此类问题的分析实用可靠,值得更深入研究。
[Abstract]:Karst area is widely distributed in China. With the expansion of engineering construction scale, it is inevitable to build various kinds of engineering facilities in karst area. People also gradually realize the harmfulness of karst geology to structure. Especially in the process of bridge pile foundation construction, when the buried karst strata are encountered, it is generally considered that the pile foundation should be acted on the roof of the karst cave. Therefore, the study of cavern roof stability has been raised to the important agenda. Based on the research project of buried karst engineering characteristics and treatment technology of Yiluo Expressway, the interaction mechanism and stability of karst cave roof and bridge pile foundation are studied in this paper. It can be used for reference for the design and safety construction of the subsequent engineering, and has great application value. The main work and research results are as follows: (1) this paper firstly introduces the characteristics of buried karst and simplifies the model of foundation pile and roof by making the basic assumptions of the model. On the basis of 10 familiar mechanical structural models, the load system model of roof and bridge pile foundation of cavern is analyzed in detail by using thin plate theory in elastic mechanics. The corresponding test formula of roof thickness is obtained. (2) according to the practical treatment experience of bedrock cave roof in construction project, the factors influencing the stability of karst cave roof are analyzed. The analysis shows that the roof span of karst cave is larger when it is in a certain buried depth. The greater the allowable minimum safe thickness is, the deeper the cave is, and the smaller the minimum safe thickness is, the more the roof span is the most disadvantageous factor for the stability of the cave. The cave depth is a favorable factor for its stability. (3) the mechanism of karst instability is analyzed from the reasons of cave instability. The rock strength theory is introduced, and the mechanism of karst instability is analyzed by establishing a karst instability model. In fact, the mechanism of karst instability is mechanical mechanism: the failure of strength of rock and soil caused by load causes instability. (4) the beam and plate model is selected from the above structural model to simulate and analyze. Combined with the characteristics of the model, the stability of the roof under different pile diameter is calculated by anti-punching, shearing and bending. The empirical calculation shows that the beam-like plate model composed of foundation pile and roof is in a safe and stable state as a whole. The calculation results can guide the design and construction of the project. (5) in this paper, the stability of the foundation pile and the roof of the karst cave located under the piers of K81,843 and K81 878 is simulated and analyzed by using the numerical software FLAC-3D in the 10th contract section of Yilu Expressway. Through the analysis, the author suggests that the foundation pile at K81,878 should be strengthened with sleeve reinforcement technology, and the research conclusion can be used as the basis for the design and construction of the bridge foundation of Yiluo Expressway. In addition, the numerical simulation is practical and reliable for the analysis of this kind of problems, which is worthy of further study.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.15
本文编号：2190324
[Abstract]:Karst area is widely distributed in China. With the expansion of engineering construction scale, it is inevitable to build various kinds of engineering facilities in karst area. People also gradually realize the harmfulness of karst geology to structure. Especially in the process of bridge pile foundation construction, when the buried karst strata are encountered, it is generally considered that the pile foundation should be acted on the roof of the karst cave. Therefore, the study of cavern roof stability has been raised to the important agenda. Based on the research project of buried karst engineering characteristics and treatment technology of Yiluo Expressway, the interaction mechanism and stability of karst cave roof and bridge pile foundation are studied in this paper. It can be used for reference for the design and safety construction of the subsequent engineering, and has great application value. The main work and research results are as follows: (1) this paper firstly introduces the characteristics of buried karst and simplifies the model of foundation pile and roof by making the basic assumptions of the model. On the basis of 10 familiar mechanical structural models, the load system model of roof and bridge pile foundation of cavern is analyzed in detail by using thin plate theory in elastic mechanics. The corresponding test formula of roof thickness is obtained. (2) according to the practical treatment experience of bedrock cave roof in construction project, the factors influencing the stability of karst cave roof are analyzed. The analysis shows that the roof span of karst cave is larger when it is in a certain buried depth. The greater the allowable minimum safe thickness is, the deeper the cave is, and the smaller the minimum safe thickness is, the more the roof span is the most disadvantageous factor for the stability of the cave. The cave depth is a favorable factor for its stability. (3) the mechanism of karst instability is analyzed from the reasons of cave instability. The rock strength theory is introduced, and the mechanism of karst instability is analyzed by establishing a karst instability model. In fact, the mechanism of karst instability is mechanical mechanism: the failure of strength of rock and soil caused by load causes instability. (4) the beam and plate model is selected from the above structural model to simulate and analyze. Combined with the characteristics of the model, the stability of the roof under different pile diameter is calculated by anti-punching, shearing and bending. The empirical calculation shows that the beam-like plate model composed of foundation pile and roof is in a safe and stable state as a whole. The calculation results can guide the design and construction of the project. (5) in this paper, the stability of the foundation pile and the roof of the karst cave located under the piers of K81,843 and K81 878 is simulated and analyzed by using the numerical software FLAC-3D in the 10th contract section of Yilu Expressway. Through the analysis, the author suggests that the foundation pile at K81,878 should be strengthened with sleeve reinforcement technology, and the research conclusion can be used as the basis for the design and construction of the bridge foundation of Yiluo Expressway. In addition, the numerical simulation is practical and reliable for the analysis of this kind of problems, which is worthy of further study.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.15
【参考文献】
相关期刊论文 前10条
1 张俊萌;方从启;朱俊峰;;桩基下岩溶顶板稳定性有限元阶段分析[J];工程地质学报;2014年01期
2 金晓文;陈植华;曾斌;张文慧;史婷婷;;岩溶塌陷机理定量研究的初步思考[J];中国岩溶;2013年04期
3 高欣梅;;对规范中铁路桥梁桩基计算方法的补充[J];高速铁路技术;2013年03期
4 任鹏;吴野;;基于模糊理论的溶洞顶板稳定性分析方法研究[J];四川建筑;2012年06期
5 高宏伟;;岩溶桥梁嵌岩桩基础设计及施工技术[J];交通科技;2012年02期
6 骆荣;郑小战;易顺民;;广州花都区赤坭镇岩溶地面塌陷地质灾害现状及防治对策[J];中国地质灾害与防治学报;2012年01期
7 郭柯;刘长成;董鸣;;我国西南喀斯特植物生态适应性与石漠化治理[J];植物生态学报;2011年10期
8 张威;唐文;张卓;韩永昌;;辽宁桓仁地质灾害形成条件及影响因素分析[J];科协论坛(下半月);2011年08期
9 龚先兵;赵明华;张永杰;;桩端下伏溶洞顶板稳定非概率可靠性分析方法[J];湖南大学学报(自然科学版);2011年01期
10 张龙菊;王新刚;李云安;;桥基溶洞顶板稳定性评价与工程治理[J];人民长江;2010年19期
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