万州驸马长江大桥北锚碇基坑施工安全监测分析
摘要:驸马长江大桥北岸桥位区地表覆盖层厚度较大、强度较低,下伏泥质岩体水敏性较强,边坡天然稳定性较差。为了确保北锚碇基坑施工安全以及进行施工反馈分析,在施工期内开展了系统的安全监测。监测成果综合显示:降雨易诱发坑外地表土体发生浅层变形破坏,导致某些观测点的位移超过了报警值,坑外边坡变形在喷锚防护完成后得到了有效控制。开挖全、强风化地层时,防护桩位移增长较快;开挖中等风化地层时,位移增长相对缓慢,支护结构的地表和深部水平位移都未超过报警值。锚索预应力变化趋势总体平稳,累计变化量远小于报警值。监测结果反映出北锚碇基坑边坡和支护结构处于安全稳定状态,同时验证了工程设计条件和设计参数的合理性,研究成果还可以为类似基坑工程的设计、施工和监测积累经验。
Abstract:The surface soil layer at the north bridge area of Fuma Yangtze River Bridge is characterized of great thickness and low strength,the underlying pelitic rock mass is highly sensitive to water,and thus the stability of the natural slope is relatively poor.In order to ensure the construction safety and perform feedback analysis of the north anchorage foundation pit,systematic safety monitoring had been carried out during the construction period of the foundation pit.Monitoring results showed that,shallow deformation and failure was easily triggered by rainfall in top soil layer at the periphery of the foundation pit,resulting in the displacements of several monitoring points exceeded the alarm value.Fortunately,deformation of peripheral slope had been effectively controlled after the completion of shotcrete-rockbolt protection.Displacement of the retaining pile increased rapidly when the fully and strongly weathered strata were excavated,while the displacement increased slowly when the moderately weathered stratum was excavated.The surficial and deep horizontal displacement of support structure did not exceed the alarm values at last.The prestress of cable changed smoothly during the construction period,and the accumulative variation of the prestress was far less than the alarm value.Monitoring results comprehensively reflect that the side-wall and the support structure of the north anchorage foundation pit were in a state of safe and stable.Meanwhile,the reasonability of the conditions and parameters adopted in the stage of engineering design had been verified.Furtherly,research results in this paper can help accumulate experience for similar excavation engineering in respect of design,construction and monitoring.
中文标题：
万州驸马长江大桥北锚碇基坑施工安全监测分析
Analysis of Monitoring Data over the Construction Period of the North Anchorage Foundation Pit of Fuma Yangtze River Bridge at Wanzhou District,Chongqing City
作者：
冉涛1,2,梅松华3,谭利华4
Ran Tao1,2,Mei Songhua3,Tan Lihua4
作者简介:冉涛,男,1985年生,汉族,四川广元人,博上研究生,主要从事工程地质和岩土工程方而的研究。E-mail:rantaopaul@aliyun.com
通讯地址：
1. 中国科学院地质与地球物理研究所, 北京 100029; 2. 中国科学院大学, 北京 100049; 3. 中国电建集团中南勘测设计研究院有限公司, 湖南长沙 410014; 4. 中交一公局万利万达项目总部驸马长江大桥一分部, 重庆万州 404000
1.InstituteofGeologyandGeophysics,ChineseAcademyofSciences,Beijing100029,China; 2.UniversityofChineseAcademyofSciences,Beijing100049,China; 3.ZhongnanEngineeringCo.,Ltd,Changsha410014,Hunan,China; 4.ChinaFirstHighwayEngineeringCo.,Ltd.HeadquartersofWanzhou-LichuanandWanzhou-DazhouExpresswayProject,FirstDivisionofFumaYangtzeRiverBridge,Wanzhou404000,Chongqing,China
中图分类号:TU196.4
doi:10.3969/j.issn.1007-2993.2017.03.005
出版物：岩土工程技术
收稿日期:2017-02-06
网络出版日期:2021-07-06
关键词:基坑工程,施工监测,地表变形,测斜,锚索预应力
Key words:excavation engineering,construction monitoring,ground surface deformation,inclinometry,prestress of cable
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