湿陷性黄土地区深基坑监测技术研究及应用

发布时间：2018-07-29 19:50

【摘要】：随着国家基础建设的快速发展，黄土地区的工程项目越来越多。黄土的湿陷性问题随即成为施工工程的研究热点。看似稳固的黄土在浸水后，工程特性急剧变化，强度迅速降低。黄土湿陷引发的工程事故中，又以基坑支护结构失稳为主。因此，基坑的变形监测工作越来越重要。但是现行的《建筑基坑工程监测技术规范》（GB50497-2009）明确指出不适合湿陷性黄土地区。而《湿陷性黄土地区建筑规范》（GB50025-2004）与《湿陷性黄土地区建筑基坑工程安全技术规程》（JGJ167-2009）对基坑监测的项目、频率及预警值的规定较为模糊，实际工程中操作难度较大。本文通过对国内外湿陷性黄土和基坑变形监测的研究现状归纳整理后，结合实际工程，主要的研究内容有如下几个方面： 1、系统分析了黄土的分布、成因、微观结构、湿陷机理及工程特性等问题； 2、研究了湿陷性黄土地区常见的基坑支护结构类型特点、适用范围以及不同支护结构机理的监测内容； 3、对现行常规基坑监测项目的施测方法进行归纳分析，并结合规范对湿陷性黄土地区基坑监测的预警值和监测频率确定方法进行研究； 4、结合西安地区一典型湿陷性黄土地层深基坑监测数据，分析不同支护结构在施工期间的变形情况，，并验证本研究提出的制定监测频率和预警值方法的合理性。综上所述，本文较系统的研究了湿陷性黄土地区基坑监测工作的重点内容，针对湿陷性黄土地区提出了基坑监测预警值及监测频率的确定方法，对优化湿陷性黄土地区基坑监测工作效率及经济效益具有理论和现实意义。
[Abstract]:With the rapid development of national infrastructure, there are more and more engineering projects in loess area. The collapsibility of loess becomes the research hotspot of construction engineering. After soaking in water, the seemingly stable loess has a sharp change in engineering properties and a rapid decrease in strength. In the engineering accidents caused by loess collapsibility, the instability of foundation pit support structure is the main factor. Therefore, the deformation monitoring of foundation pit is becoming more and more important. However, the current Technical Code for Monitoring of Foundation Pit Engineering (GB50497-2009) clearly points out that it is not suitable for collapsible loess areas. However, the regulation of frequency and early warning value of foundation pit monitoring items in collapsible loess area (GB50025-2004) and collapsible loess area (JGJ167-2009) is rather fuzzy, and the operation is difficult in practical engineering. After summing up the research status of collapsible loess and foundation pit deformation monitoring at home and abroad and combining with practical engineering, the main research contents are as follows: 1. The distribution and cause of loess are systematically analyzed. The microstructure, collapsing mechanism and engineering characteristics are discussed. 2. The common characteristics of foundation pit supporting structure in collapsible loess area, the applicable scope and the monitoring content of different supporting structure mechanism are studied. 3. Generalize and analyze the current routine foundation pit monitoring project, and study the early warning value and monitoring frequency determination method of foundation pit monitoring in collapsible loess area. 4. Based on the monitoring data of deep foundation pit of a typical collapsible loess stratum in Xi'an area, the deformation of different supporting structures during construction is analyzed, and the rationality of the method of establishing monitoring frequency and early warning value proposed in this study is verified. To sum up, this paper systematically studies the key contents of foundation pit monitoring in collapsible loess area, and puts forward a method to determine the monitoring and warning value and monitoring frequency of foundation pit in collapsible loess area. It is of theoretical and practical significance to optimize the efficiency and economic benefit of foundation pit monitoring in collapsible loess area.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753

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