基坑最佳开挖方式与变形控制的研究与应用

发布时间：2018-01-17 23:22

本文关键词：基坑最佳开挖方式与变形控制的研究与应用　出处：《昆明理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：近年来,随着我国经济的蓬勃发展,越来越多代表沿海城市发达的高楼大厦,逐步普及到全国范围,深基坑工程成为首要解决的问题。尽管我国目前建筑行业的深基坑工程已经形成一套完整的体系,具备安全妥善处理深基坑工程的能力和技术,并且积累了多年来许多成功案例的工程经验。但基坑事故的发生任未停止。归结原因主要有：(1)设计的因素,设计理论体系还不完善；(2)施工的因素,施工人员技术水平高低不一,对施工工艺和施工组织把握不好。(3)信息化施工的因素。信息化监测施工是完善设计缺陷的重要思想,同时也是施工中及时发现问题,高效制定处理方案的前提。对一些施工困难、开挖较深的基坑及周边环境复杂的基坑,采用信息化施工能够有效控制变形和保证基坑安全。本文拟通过实际的基坑项目,来探讨基坑开挖方式、施工变形控制及信息化施工组织,主要工作有以下几点： (1)总结了目前,基坑开挖采用的主要开挖方式,并对每种开挖方式的优点和缺点做了说明,同时简单介绍了每种开挖方式抑制变形的原理。基坑开挖具有明显的空间效应,如何通过选择恰当的开挖方式来削弱空间效应的影响。 (2)首先,结合实际基坑项目的工程特点,对能适用于该项目的主要开挖方式做对比分析,初步确定拟采用盆式开挖方式进行开挖,把基坑分为盆中部分土体和预留土体部分。其次,1)通过有限元软件MIDAS GTS对基坑盆式开挖后的预留土体部分宽度进行讨论,分别取预留土体宽度为10m、20m、30m、40m建立4个模型模拟开挖工况,最终对比变形位移数据确定出最理想的预留宽度；2)由于盆中部分土体一次开挖完,从模拟数据看基坑和周边环境的变形位移突变较快,因此,对盆中部分土体进一步实施分段开挖。按10m的倍数建立10m、20m、30m、40m分段长度,分析不同分段长度对变形的影响,并确定了最理想的分段长度；针对每一个分段长度建立多个模型讨论大多数可能的分段开挖顺序对变形的影响,并最终确定理想的分段开挖顺序。3)建立多个模型讨论了预留土体的分段开挖方式,包括开挖顺序与分段长度对变形的影响,并最终提出了理想的开挖顺序与分段长度。最终通过MIDAS GTS对各种施工参数的模拟,对比模拟数值可得到对变形影响最小的一种开挖方式,既为最佳开挖方式。 (3)依据有限元软件MIDAS GTS得出的理想开挖方式组织该项目施工,同时结合现场的监测数据,不断的调整施工顺序和检验模型,出现问题及时向上级汇报,达到信息化施工控制变形的目的。 (4)针对该基坑项目具体采用的施工工艺和现场环境,讨论适用于该项目的变形控制措施及可能出现的危害情况,提前编制具体的实施方案和应急处理措施方案,做到事前控制；结合监测数据,动态实施施工过程中的变形控制,把不利情况的苗头及时扼杀。 (5)对比最终的监测数据,分析开挖结论和模型的适用性,通过改变土层参数和改变建模尺寸,对比位移变化情况和监测数据,证明开挖结论对其它基坑工程具有一定的参考价值,同时找到与监测数据最接近的建模尺寸。
[Abstract]:In recent years, with the vigorous development of China's economy, more and more representative of the coastal developed city edifice, gradually spread to the country, to become the primary problem of deep excavation engineering of deep foundation pit engineering. Although China construction industry has formed a complete system, with safety and properly handle the ability and deep foundation pit engineering the technology and engineering experience, accumulated many successful cases in recent years. But the pit accidents was not stopped. Reasons mainly include: (1) design factors, design the theoretical system is not perfect; (2) factors of construction, construction personnel technical level is not a good grasp of the construction process. And the construction organization. (3) factors of information construction. The construction of information monitoring is an important thought of perfecting the design defects, timely detection of problems but also in the construction of efficient treatment scheme. On the premise of developing some application It can effectively control the deformation and guarantee the safety of the foundation pit by means of information construction.
Through the actual foundation pit project, this paper discusses the way of foundation pit excavation, the control of construction deformation and the organization of information construction. The main work is as follows:
(1) summarizes the main methods of excavation, foundation pit excavation is adopted, and for each excavation the advantages and disadvantages are described, and a brief introduction to the principle of each excavation deformation. Inhibition of excavation has obvious spatial effect, how to weaken the space effect of excavation by choosing the right way.
(2) first, combined with the engineering characteristics of the actual excavation project, the main excavation on the comparative analysis can be applied to the project, initially identified by quasi basin excavation of foundation pit excavation, the soil is divided into reservation and part of the soil in the basin. Secondly, 1) on the foundation pit basin excavation after reserved soil the width is discussed by the finite element software MIDAS GTS, were collected from the reserved soil width is 10m, 20m, 30m, 40m 4 models are established to simulate the excavation conditions, the final displacement data obtained for comparison of the ideal width; 2) as part of a soil basin excavation, deformation displacement of foundation pit and surrounding environment the mutation from the simulated data quickly, therefore, further implementation of the soil excavation section in the basin. The establishment of 10m, according to 10m 30m, 40m 20m ratio, segment length, length of analysis of different deformation effects, and to determine the ideal The length of each segment; for each segment length of the establishment of a number of most possible segmentation model to discuss the influence on the deformation of excavation sequence, and ultimately determine the segmented excavation sequence.3 ideal) establish multiple segmentation model excavation reserved soil are discussed, including the excavation sequence and segment length influence on deformation, and finally put forward the excavation sequence and segment length of the ideal.
Finally, through the simulation of various construction parameters by MIDAS GTS, a kind of excavation method which has the smallest influence on the deformation can be obtained by comparing the simulated numerical values. It is the best excavation method.
(3) according to the ideal excavation method obtained by MIDAS GTS, the project is organized. At the same time, combined with on-site monitoring data, we constantly adjust the construction sequence and inspection model, report problems to the higher authorities, and achieve the purpose of information construction control deformation.
(4) the construction process and site specific environment used in the foundation pit project, discuss the harm of deformation control measures for the project and possible, advance preparation of specific implementation plan and emergency measures, so advance control; combining with the monitoring data, the implementation of dynamic deformation control in the construction process, the adverse situation the signs of timely killing.
(5) monitoring data comparison final, applicability analysis and conclusion excavation model, by changing the parameters of soil and the change of modeling size, displacement and comparison of the monitoring data, prove the conclusion of excavation has the certain reference value to other excavation, and find the closest size modeling and monitoring data.

【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU753

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