沈阳地区基坑冻胀量影响因素的研究和数值分析

发布时间：2018-04-12 08:19

本文选题：深基坑 + 冻胀位移　；参考：《沈阳建筑大学》2015年硕士论文

【摘要】：近些年,土木工程进入到了高速发展的时代,随之而来的安全问题也相对增多。其中季节冻胀地区的冻胀安全问题越来越多的受到工程人们的关注。关于永久性工程的土体冻胀问题学者关注较多,例如,水利工程的冻胀问题、地下室的法向冻胀问题、挡土墙的冻胀问题等。虽然暂时性支护结构的冻胀问题学者们关注的相对较少,但暂时性支护结构带来的安全隐患同样也是不能忽视的,如基坑的支护结构的冻胀问题。对于越冬深基坑冻胀力的设计只是按照融土土压力进行考虑,如果基坑越冬,需考虑冻胀的影响,并采取相应的防冻胀措施。但如何考虑冻胀的影响,即冻胀力的如何计算,冻胀力和支护体系的约束作用二者的关系,规范都未介绍,这是我们研究的内容。本文以沈阳地区的某深基坑工程为具体实例。该基坑设计时未考虑冻胀的影响,通过在对冠梁上的监测点进行监测,得到基坑在整个冬期土体发生冻结时的冻胀位移数据。采用FLAC3D模拟软件对整个基坑的开挖、冻胀过程进行数值模拟,通过实际监测值与基坑的模拟值进行比较,确定基坑数值模拟的模型和参数的正确性。之后通过改变基坑土层厚度、土层的含水率、外界的温度场、时间参数的数值,从而得到这些因素对基坑冻胀量变化的影响。最终提出,临时性支护结构的桩顶冻胀位移预测方程。本文主要以模拟的手段对深基坑冻胀位移进行预测,对越冬深基坑工程的设计和施工有一定的参考价值和指导意义。
[Abstract]:In recent years, civil engineering has entered the era of rapid development, followed by a relatively increased safety problems.The problem of frost heaving safety in seasonal frost heaving area is paid more and more attention by engineers.Scholars pay more attention to soil frost heaving in permanent engineering, such as frost heave in hydraulic engineering, normal frost heave in basement, frost heave in retaining wall and so on.Although scholars pay less attention to the frost heave problem of temporary support structure, the hidden danger brought by temporary support structure can not be ignored, such as the frost heave problem of foundation pit support structure.The design of frost heaving force of wintering deep foundation pit is only considered according to the soil thawing pressure. If the foundation pit overwinters, the influence of frost heave should be considered, and corresponding measures should be taken to prevent frost heaving.However, how to consider the influence of frost heave, that is, how to calculate the frost heave force, the relationship between frost heave force and the constraint action of supporting system, is not introduced in the standard, which is the content of our research.This paper takes a deep foundation pit project in Shenyang area as an example.The influence of frost heaving was not considered in the design of the foundation pit. The frost heave displacement data of the foundation pit during the whole winter period was obtained by monitoring the monitoring points on the crown beam.The FLAC3D software is used to simulate the whole excavation and frost heave process of the foundation pit. The correctness of the model and parameters of the numerical simulation of the foundation pit is determined by comparing the actual monitoring value with the simulation value of the foundation pit.Then the influence of these factors on the frost heaving of foundation pit is obtained by changing the thickness of foundation pit soil moisture content outside temperature field and time parameter.Finally, the prediction equation of frost heave displacement of temporary supporting structure is put forward.In this paper, the frost heave displacement of deep foundation pit is predicted by means of simulation, which has certain reference value and guiding significance for the design and construction of wintering deep foundation pit.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU753

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