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The application of TEM to guiding advance exploration drilling of complex geological tunnel |
Sen SHU1, Shu-Dong WANG1, Guang LI2, Zhi-Qiang LV1, Qiang CAO1 |
1. China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, China 2. Headquarters of South Yunnan Railway Construction, Kunming Bureau of Railway, Yuxi 653100, China |
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Abstract Geological conditions in Yunnan mountainous area are complex, and geological hazards such as water and mud inrush often occur in tunnel construction. Tunnel geological prediction is an important way to prevent geological disasters in tunnel construction. The rational layout and implementation of advance exploration drilling can effectively reveal the geological conditions in front of the tunnel face and prevent the occurrence of geological disasters. Nevertheless, for the irregular geological bodies such as karst, the limited 1~2 advance exploration drilling holes sometimes fail to reveal these geological bodies and cause major safety risks to the tunnel construction. It is of great significance to make full use of the advanced geophysical prediction data, especially the TEM which can guide the layout of the advance exploration drilling holes and have the great significance for improving the prediction effect. In this paper, taking the Yangwu tunnel of Yumo railway as an example and based on the analysis of TEM, the authors successfully guided the advance exploration drilling layout, and then compared the results with the drilling and construction excavation results. It is shown that the TEM is effective in predicting and guiding the advance exploration drilling. Some suggestions are given concerning the employment of TME combined with advanced horizontal drilling in the future.
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Received: 29 January 2018
Published: 19 December 2018
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地层岩性及构造 | 地下水类型 | 特点 | 断裂、褶皱 | 构造裂隙水 | 地下水沿断裂及褶皱带分布,发育于张性断裂、储水褶皱与隧道掘进交汇带 | 灰岩、白云岩等可溶岩 | 岩溶水 | 岩溶发育于地下水面附近,处于水平循环带、水平与垂直交替作用的循环贷及季节变动带,形成的大型富水暗河或溶洞 | 可溶岩与非可溶岩接触带 | 岩溶裂隙水 基岩裂隙水 | 在可溶岩及非可溶岩变化接触位置,由于可溶性及风化程度的差异性,形成岩溶或裂隙水通道 | 侵入岩蚀变 | 基岩裂隙水 | 在侵入过程中,热液作用使原岩产生新的物理化学条件,原岩的结构、构造以及成分相应发生改变,导致的围岩物理性质差,差异风化后形成裂隙通道 | 火成岩差异风化 | 基岩裂隙水 | 花岗岩差异风化或玄武岩夹凝灰岩差异风化,致围岩物理性质差,形成裂隙通道 | 相对储水层与隔水层 | 基岩裂隙水 | 如砂岩与泥岩,灰岩与板岩等地层形成的相对储水与隔水层,接触位置形成裂隙通道 |
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方法 | 探测特点 | 优点 | 缺点 | 地震波反射法 | 岩层物理性质,结构面变化 | 对层面异常探测效果较好 | 不能准确判断空间方位 | 电磁波反射法 | 岩层物理性质、结构面变化 | 对在测线范围内层面异常较好 | 不能准确判断空间方位 | 超前钻探 | 岩性及地下水 | 直观、可分析岩性及含水量 | 一孔之见,探测范围受限 | 地质调查 | 岩层地质变化 | 围岩趋势性推测 | 围岩突变或变化频繁时效果差 | 瞬变电磁法 | 岩层含水区域、方向及变化趋势 | 判断含水体方向及变化趋势 | 易受干扰,存在盲区,不能定量 |
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测线 | 线圈中心位置 | A1/(°) | 测点数 | A2/(°) | 1 | 距左边墙3.6 m | 0 | 9 | 15 | 2 | 距左边墙3.6 m | +45 | 9 | 15 | 3 | 距左边墙3.6 m | -45 | 9 | 15 | 4 | 距左边墙7.6 m | 0 | 9 | 15 | 5 | 距左边墙7.6 m | +45 | 9 | 15 | 6 | 距左边墙7.6 m | -45 | 9 | 15 |
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方法 | 里程段落 | 预报结论 | TSP法 | D1K58+690~+756 | 围岩破碎~极破碎,节理裂隙发育~很发育,岩质软,渗水~含水,其中 D1K58+696~+704,D1K58+709~+730段存在软弱夹层或裂隙,局部裂隙水量上升 | 探地雷达法 | D1K58+694.2~+724.2 | 围岩破碎~局部极破碎,节理裂隙发育~很发育,渗水~含水,局部裂隙水量增大,存在较多软弱夹层, D1K58+705~+724.2段存在较大溜塌风险,软弱处裂隙水增大后存在局部突涌风险 | 瞬变电磁法 | D1K58+693~+728 | 围岩破碎~局部极破碎,节理裂隙发育~很发育,含水~局部弱富水,存在较多软弱夹层,溜塌风险较大,D1K58+688~+718段存在局部突涌风险 | 钻探法 | D1K58+690~+720 | 围岩破碎,1#~3#钻孔(图10)无明显异常无水,4#钻孔水量0.76 L/s(4#孔位于掌子面右侧) |
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孔号 | 孔深/m | 立角/(°) | 偏角/(°) | 1# | 30 | 0 | 10 | 2# | 30 | 10 | 20 | 3# | 30 | 15 | 20 | 4# | 30 | 10 | 20 | 1'# | 30 | 15 | 10 | 2'# | 30 | 0 | 0 |
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