【作者】 王波；

【导师】 欧阳治华；

【作者基本信息】 武汉科技大学 ， 土木工程， 2017， 硕士

【摘要】 本文试图通过三轴压缩试验研究深基坑土样特性,利用仿真模拟软Geostudio对深基坑开挖过程进行数值模拟,然后基于改进的最小二乘法模型对支护结构水平位移进行时间序列预测。研究表明,采用三轴随着我国地下空间的开发利用,地下空间结构逐渐向大面积、大深度方向发展,基坑支护结构受到周边复杂环境影响的情况日趋增多,基坑开挖势必对周边的建筑物、构筑物、地下管线等产生影响。减小基坑开挖对周边环境的影响,要求支护体系本身具有一定的可靠性。应用理论知识、技术规范和工程经验设计的支护结构已经无法确保基坑施工过程中周边环境的安全。由于设计不当造成深基坑施工事故频有发生,因此有必要加强支护桩周边土体特性的研究、支护体及周边环境变形预测和数值模拟研究,为以后工程实践提供经验指导施工。能否预测并控制基坑及周围建筑物的安全往往是基坑设计成败的关键。本文以武汉市武昌区某深基坑支护工程为背景,针对深基坑周边的复杂环境,在每个阶段定期对支护结构和周边建筑物的变形进行现场实时监测,并利用室内试验、数值模拟、最小二乘法模型等手段,对深基坑内土样、支护结构及周边变形进行分析研究。压缩剪切试验测定土体抗剪强度可对土体特性指标进行分析,也为仿真模拟提供数据,数值模拟讨论了基坑开挖过程中土压力改变引起支护体应力应变改变的规律,采用改进最小二乘法模型对支护结构水平位移进行时间序列预测且结果与实际监测数据相仿。更多还原

【Abstract】 With the development and utilization of underground space in China,underground structures are being larger and deeper.Hence,there will be more and more cases that foundation pit supporting structure affected by complex surroundings,and the excavation of foundation pit,certainly,will affect its surroundings,like buildings,structures,underground pipelines and so on.Reducing the influence of the excavation needs supporting system with a certain degree of reliable.It is difficult to ensure the safety of surroundings during the excavation that support structure designed merely based on theoretical knowledge,technical specifications and engineering experience.Accident frequently occurred because of improper design,it is very important to strengthen the research on the characteristics of the soil around the supporting pile,to predict and simulate the deformation of the support body and its surroundings,which can provide experience and guidance for the future engineering practice.Predicting and controlling the stress-strain of supporting structures to make sure they can support it is surroundings,which is the key to a successful foundation design.In this paper,a deep foundation pit project in Wuchang district of Wuhan is the background.This paper analyzed the stress-strain of the supporting structures and it is surrounding soil by numerical simulation and least-squares method.The real time stress-strain data of the supporting structures,used in numerical simulation and least-squares method,was collected regularly during every construction stage,aim at the complicated environment.This paper attempts to study the characteristics of deep foundation pit soil by triaxial compression test,Geostudio is used to simulate the excavation process of deep foundation pit,then the time series prediction of the horizontal displacement of the supporting structure is carried out based on the improved least square model.The results show that the soil shear strength can be obtained by triaxial compressive shear test,this can provide basis data for simulation.The simulation is used to discuss the rule of the stress and strain change of the supporting body caused by the change of earth pressure during excavation.Using the improved least squares model to predict the horizontal displacement of the support structure and the results are similar to the actual monitoring data.更多还原