| 土洞型岩溶塌陷发育过程气体示踪试验研究——以广州金沙洲为例 |
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| 引用本文： | 李卓骏,蒙彦,董志明,贾龙,潘宗源,管振德,周富彪.土洞型岩溶塌陷发育过程气体示踪试验研究——以广州金沙洲为例[J].中国岩溶,2021,40(2):238-245. |
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| 作者姓名： | 李卓骏 蒙彦 董志明 贾龙 潘宗源 管振德 周富彪 |
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| 作者单位： | 1.自然资源部/广西岩溶动力学重点实验室，中国地质调查局岩溶塌陷防治技术创新中心，中国地质科学院岩溶地质研究所/中国地质大学（北京） |
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| 基金项目： | 国家自然科学基金项目（41877300, 41302255）；广西重大科技创新基地建设项目（岩溶动力学重点实验室建设）；社会服务项目（峰丛地貌岩溶区绿色公路特长隧道建设关键技术）；中国地质调查项目（1212011220192，DD20190266）；广西基金项目（2018GXNSFAA294020）；国家基本科研业务项目（川藏铁路长大深埋隧道岩溶及高压岩溶水评估） |
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| 摘 要： | 运用气体示踪进行土洞型岩溶塌陷监测预警是一种比较新的技术方法，其原理是通过气体在不同形状、规模的土体孔隙、裂缝和土洞中的运移规律研究，分析气体特征值与土体变形破坏的关系，进而间接判断土洞的发育情况，实现岩溶塌陷监测预警。本文以广州市金沙洲岩溶塌陷区为例，通过室内物理模型试验再现了土洞发育、形成到地面塌陷的全过程。运用气体示踪技术，按照土洞形成、土洞发育、土洞堵塞、土洞扩大和土洞塌陷五个过程，研究气体浓度、气体聚集时间等参数指标与土洞不同发育阶段的关系。结果表明:①土洞型岩溶塌陷发育程度与示踪气体浓度存在对应关系，气体浓度升高反映了土体变形破坏的进一步发育；②土体变形破坏程度与示踪气体浓度总体呈正相关关系，距离地面塌陷点越近浓度越高；③土体变形破坏程度与示踪气体浓度达到峰值浓度时间存在对应关系，距离地面塌陷点越近，气体浓度达到峰值的时间越快。根据以上试验结果，运用气体示踪技术进行土洞型岩溶塌陷监测预警是可行的，后期应探索预警阈值并进行野外现场实际验证。
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| 关 键 词： | 岩溶塌陷 模型试验 气体示踪 监测预警 广州金沙洲 |
Experimental study of gas tracer simulation of karst collapse development process: An example of Jinshazhou, Guangzhou |
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| LI Zhuojun,MENG Yan,DONG Zhiming,JIA Long,PAN Zongyuan,GUAN Zhende,ZHOU Fubiao.Experimental study of gas tracer simulation of karst collapse development process: An example of Jinshazhou, Guangzhou[J].Carsologica Sinica,2021,40(2):238-245. |
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| Authors: | LI Zhuojun MENG Yan DONG Zhiming JIA Long PAN Zongyuan GUAN Zhende ZHOU Fubiao |
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| Institution: | 1.Institute of Karst Geology，CAGS/Key Laboratory of Karst Dynamics，MNR＆GZAR/China University of Geosciences（Beijing）2.Institute of Karst Geology，CAGS/Key Laboratory of Karst Dynamics，MNR＆GZAR3.Huajie Engineering Consultants， Inc. |
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| Abstract: | Karst collapse is one of main geological hazards in karst areas in China， which can be generally divided into two types: sinkhole and karst collapse. Sinkhole is widely distributed and numerous， and how to monitor them and make an early warning is a focused issue. The primary characteristic of sinkhole development is that under the action of groundwater and other factors， the internal structure of soil is deformed and damaged and then produces cracks and caves. The common monitoring and early warning methods include physical exploration， groundwater dynamic condition monitoring and other nondestructive detection tools. A relatively new technical method in this aspect is to use gas tracer. Its principle is to analyze the relationship between gas characteristic values and soil deformation and damage based on observation to gas transport in soil pores， cracks and holes of different shapes and sizes， and then indirectly judge the development of sinkhole to achieve karst collapse monitoring and early warning. In this work， taking the karst collapse area of Jinshazhou， Guangzhou as an example， the whole process from sinkhole development to ground collapse was reproduced by indoor physical model tests， and then the relationship between gas concentration， gas accumulation time and other parameter indexes and different development stages of karst collapse was studied by using gas tracing technique in five processes of a sinkhole: formation， development， blockage， expansion and collapse. The results show that （1） there is a correspondence between the development of sinkhole and tracer gas concentration， and the increase of gas concentration reflects the further development of soil deformation and damage. （2） There is a positive correlation between the soil deformation and damage and tracer gas concentration in general， and the closer to the ground collapse， relatively higher the concentration. （3） There is a correspondence between the soil deformation and damage and the time of tracer gas concentration reaching peak concentration， and the closer to the ground collapse， the faster the gas concentration reaching the peak. These experimental results demonstrate that it is feasible to use gas tracer technology to conduct monitoring and early warning of karst collapse. Later on we will conduct further research on early warning thresholds and carry out practical verification in the field. |
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