岛状多年冻土地区钻孔灌注桩温度场分析

发布时间：2018-05-04 09:16

本文选题：多年冻土 + 钻孔灌注桩　；参考：《东北林业大学》2015年硕士论文

【摘要】：冻土是多相和多成分的复杂体系,随着温度的变化,其固态冰和液态水之间相互转化,形成复杂的物理力学特性,因此冻土对温度的变化非常敏感。在多年冻土进行钻孔灌注桩的施工时,会随着桩基础施工过程的扰动和桩自身的热量,会给长期稳定的多年冻土冰层带来较大的扰动。特别是在浇筑完混凝土之后,由于混凝土水化热的影响,桩身混凝土的温度会逐渐升高,随着温度的升高,与桩基础接触的多年冻土就会受到桩身混凝土热量传输的影响,温度也会随之提高,随着热量的交换,多年冻土的冰冻状态会发生相应的变化,其本身的物理力学特性也会发生相应的变化,这样就会对桥梁建设带来严重的影响,极易产生冻胀、融沉等不良地质病害。本文依托漠大线林区伴行公路工程,结合该工程所在地(大兴安岭岛状多年冻土区)气温低、温差大等气候条件,研发一套桩基现场温度监测系统,该系统除了可以克服这些气候条件,还可以实时不间断的监测现场的温度,并且可以远程的将温度数据传输给用户端;在K216+746和K205+404两处工程桥梁所在位置建立钻孔灌注试桩,结合本次试验能够观测桩基混凝土灌注后桩-土温度场的变化趋势的目的,给出了试验场温度监测系统平面布置图和纵向测温特征点布置图；依据现场监测的温度数据,绘出了两处试验地桩基内部温度变化曲线图和桩侧lm、2m处不同深度下的温度曲线变化图,从中可以得出桩基混凝土浇筑完后,桩体内部温度场的变化趋势、桩侧土体的温度场变化趋势和混凝土水化热的影响范围；建立桩基础温度场有限元分析模型,利用现场试验的实测数据验证模型的正确性,并根据有限元模型,进一步分析钻孔灌注桩与冻土温度场的分布情况。通过现场实测数据分析的结果和建立在现场实测数据基础上的有限元模拟分析的结果,可以为多年冻土区桩基施工工艺优化和加快施工进度提供数据支撑。
[Abstract]:Permafrost is a complex system of multiphase and multi-component. With the change of temperature, the solid ice and liquid water transform each other to form complex physical and mechanical properties, so the frozen soil is very sensitive to the change of temperature. In the construction of permafrost bored pile, with the disturbance of pile foundation construction process and the heat of pile itself, it will bring great disturbance to the long-term stable permafrost ice layer. Especially after pouring concrete, the temperature of pile body concrete will increase gradually because of the influence of hydration heat of concrete. With the increase of temperature, the permafrost in contact with pile foundation will be affected by the heat transfer of pile body concrete. With the exchange of heat, the frozen state of permafrost will change correspondingly, and the physical and mechanical properties of permafrost will also change accordingly, which will have a serious impact on the bridge construction. It is easy to produce frost heaving, thawing and other bad geological diseases. In this paper, based on the auxiliary highway project in Moda-line forest area and the climate conditions such as low temperature and large temperature difference in the site of the project (the island permafrost region of Daxing'anling), a set of in-situ temperature monitoring system for pile foundation is developed. In addition to overcoming these climatic conditions, the system can monitor the temperature of the site in real time and continuously, and can remotely transmit the temperature data to the user, and establish the bored cast-in-place test pile at the location of two engineering bridges, K216,746 and K205,404. Combined with the purpose of observing the change trend of the pile-soil temperature field after the pile foundation concrete pouring in this experiment, the plane layout map and the longitudinal temperature characteristic point layout map of the temperature monitoring system of the test site are given, and the temperature data of the field monitoring are given. The curves of temperature change inside the pile foundation in two test plots and the temperature curves at different depths at lmm 2 m on the side of the pile are drawn, from which the variation trend of the temperature field inside the pile body after pouring the pile foundation concrete can be obtained. The variation trend of soil temperature field and the influence range of concrete hydration heat on the pile side are analyzed, the finite element analysis model of the temperature field of pile foundation is established, and the correctness of the model is verified by the measured data of field test, and according to the finite element model, The distribution of temperature field between bored pile and frozen soil is further analyzed. Through the analysis of the field measured data and the results of finite element simulation based on the field measured data, the data support can be provided for optimizing the construction technology of pile foundation in permafrost region and speeding up the construction progress.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.15

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