2015年4月上第44卷第7期
DOI:10. 7672/sgjs2015070055
施工技术
CONSTRUCTION TECHNOLOGY
综合物探技术在跨地铁建筑场地地基勘察中的应用
占文锋"，王强"贺学海
（1.北京工业职业技术学院建筑工程系，北京100042；2.北京时信基业岩土科技有限公司，北京100142）【摘要】拟建办公楼临近及上跨北京地铁4号线，为查明场地地基土特性、地下管线分布、地铁隧道的位置和埋深等情况，采用多种物探手段开展综合探测。运用高密度电法和地质雷达获取地铁隧道的位置、埋深和宽度等数据，两种方法的探测结果具有一致性，但在反演深度时均存在误差，而引起误差的原因则各不相同：以管线探测仪为主，地质雷达为辅，结合现场调查，绘制出场地内地下管线分布图。运用微动测试获得不同时段、不同位置的场地特征周期和振动幅值，分析表明地铁运行对拟建场地具有影响。运用剪切波速测试计算出相应的等效剪切波速
度，对场地土层和场地类型进行了分类，并从场地土特性角度探讨了振动在介质中的传播规律。【关键词］地铁；隧道；地基；勘察；雷达；探测
［中图分类号］TU412
【文献标识码］A
[文章编号】1002-8498（2015)07-0055-05
ApplicationofComprehensiveGeophysicalProspectinginthe
BuildingFoundationAboveMetro Zhan Wenfeng',Wang Qiang',He Xuehai
(1. Department of Architectural Engineering, Bejing Polytechnic College, Beijing 100042, China ;
2.Beijing Shield Geosciences Technology Co. ,Lid., Beijing100142, China)
Abstract: The planned building is closed to or over spanned Metro Line 4 of Beijing. To find out the characteristics of foundation soil, the distribution of underground pipelines, the metro tunnel location and buried depth, etc, the comprehensive geophysical techniques were used. The high-density resistivity method and ground penetrating radar (GPR)were used to detect the metro tunnel location,buried depth and width, both obtained the similar results, but there was error during inversing the buried depth, and the causes of the error were different. Based on pipeline detector, and combined with the GPR and field investigation, the distribution maps of the underground pipelines were drew. The pulsation measurement technology was used to obtain the predominant period and the amplitude at different positions and depth during different times, the comparative analysis showed that the metro running evoked the dynamic response on the foundation. The shear wave velocity measurement was used and calculated the equivalent shear wave velocity, the foundation soil layers and the foundation type were classed, and the rule of the vibration transmitted in the foundation was discussed.
Key words:subways; tunnels; foundations; investigation; radar; detection
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引言
工程地质勘察中常会遇到场地地基评价、地下管线分布、岩溶或空洞探测等问题。传统的钻探、原位测试等方法虽然可靠，但工作周期长、成本高，且只能进行单点勘察1。物探方法因速度快、费用低、手段及信息丰富等优点，对传统方法的不足进行了有益补充。但物探方法实际应用时也存在地
*北京市教育委员会科技计划面上资助项目（KM201310853004）[作者简介］占文锋，博士，副教授，E-mail;cumth515@163.com【收稿日期］2014-02-24
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质现象多解性及方法自身偏重性的问题，且易受周围环境的影响。加之近地表地层复杂多变，空间延续性差，透镜体、地层尖灭现象发育[2]，造成单一物探方法无法满足察任务的要求。
因此，在面临复杂工程地质问题时，不仅需要结合已知地质资料，还需要运用综合物探方法，利用各地层的不同物性参数差异，多参数、全方位综合分析，分别从不同侧面、部分或全面地解决工程地质问题，消除单一物探方法因方法本身的局限性或多解性等引起的误差，以便于更加客观真实地再