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1.
On June 3, 2010, a series of karst sinkholes occurred at Jili village surrounded by Gui-Bei highway, Wu-Ping highway and Nan-Liu High-Speed Railway in Laibin, Guangxi, China. The straight-line distances from an large sinkhole pit, 85 m in diameter and 38 m in depth, to the above mainlines are 200, 600 and 500 m, respectively. Several investigation methods including geophysical technology, borehole and well drilling, groundwater elevation survey and hydrochemistry analysis of groundwater were used to study the formation mechanisms of these sinkholes. Based on the results, the spatial distribution of the Jili underground river was confirmed with a strike of SN along the middle Carboniferous limestone bedrock and the Quaternary deposits controlled the sinkhole formation. In addition, both historical sinkhole events and analysis of the groundwater–air pressure monitoring data installed in the underlying karst conduit system indicate that sinkholes in this area are more likely induced by extreme weather conditions within typical karst geological settings. Extreme weather conditions in the study area before the sinkhole collapses consisted of a year-long drought followed by continuous precipitation with a daily maximum precipitation of 442 mm between May 31 and June 1, 2010. Typical geological conditions include the Jili underground river overlain by the Quaternary overburden with thick clayey rubble. Especially in the recharge zone of the underground river, a stabilized shallow water table was formed in response to the extreme rainstorm because of the presence of the thick clayey rubble. When the underground conduit was flooded through the cave entrance on the surface, air blasting may have caused the cave roof collapse followed by formation of soil cavities and surface collapses. Borehole monitoring results of the groundwater–air pressure monitoring show that the potential karst sinkhole can pose threats to Shanbei village, the High-Speed Railway and the Wu-Ping highway. Local government needs to be aware of any early indicators of this geohazard so that devastating sinkholes can be prevented in the future. The results also suggest that groundwater–air pressure monitoring data collected both the Quaternary deposits and the bedrock karst system provide useful indicators for potential sinkhole collapses in similar karst areas where sinkholes usually occur during rainy season or karst groundwater level is always under the rockhead. 相似文献
2.
V. Buchignani G. D’Amato Avanzi R. Giannecchini A. Puccinelli 《Environmental Geology》2008,53(5):1037-1044
In 1995 a sinkhole suddenly formed at Camaiore (Tuscany, Italy), causing destruction or heavy damages to several houses and
resulting in the evacuation of many people. To understand the causes, for the formation and evolution of the collapse, surface
and underground geologic features were investigated and reconstructed on the basis of geologic and geognostic surveys. The
sinkhole area is underlain by thick alluvial deposits that cover a bedrock consisting of the Calcare cavernoso formation.
This formation results from hydration and dissolution of Triassic evaporites and has a characteristic spongy and vacuolate
texture. The bedrock contains karst cavities, generally filled by breccia and/or alluvial materials. Thus, the sinkhole disaster
could be ascribed to deep collapse of a cave in the bedrock, and might be considered a distant effect of ancient karst phenomena
in evaporites. 相似文献
3.
以西南某典型岩溶区为例,解析示踪试验在岩溶管道连通性以及获取水文地质参数中的应用。选择落水洞为投放点,分别从落水洞西侧和东侧寻找地下水出露点作为接收点,判别落水洞地下径流的实际去向以及落水洞与接收点之间的水力联系。结合Qtracer2软件对示踪试验成果进行定量解析,确定示踪剂回收率、地下水平均流速、最快流速,估算出岩溶管道结构特征和水文地质参数。结果表明:落水洞与接收点JS01、JS03之间不存在直接水力联系;落水洞与接收点JS02存在水力联系且岩溶管道极为发育,含水介质不均匀,地下水运移路径较为通畅,为典型的紊流流态;落水洞地下径流的主要方向是由西向东,但在丰水期雨量较大期间,接收点JS04能够接收到荧光素钠,说明丰水期水位上涨后两者间会有水力联系,导致部分水量向落水洞西侧排泄。 相似文献
4.
An understanding of what influences sinkhole formation and the ability to accurately predict sinkhole hazards is critical
to environmental management efforts in the karst lands of southeastern Minnesota. Based on the distribution of distances to
the nearest sinkhole, sinkhole density, bedrock geology and depth to bedrock in southeastern Minnesota and northwestern Iowa,
a decision tree model has been developed to construct maps of sinkhole probability in Minnesota. The decision tree model was
converted as cartographic models and implemented in ArcGIS to create a preliminary sinkhole probability map in Goodhue, Wabasha,
Olmsted, Fillmore, and Mower Counties. This model quantifies bedrock geology, depth to bedrock, sinkhole density, and neighborhood
effects in southeastern Minnesota but excludes potential controlling factors such as structural control, topographic settings,
human activities and land-use. The sinkhole probability map needs to be verified and updated as more sinkholes are mapped
and more information about sinkhole formation is obtained. 相似文献
5.
为了弄清大龙井岩溶大泉形成机理以及地下水补径排关系。通过调查大龙井地形地貌、补径排关系以及对水化学分析等研究大龙井岩溶大泉的形成机理,通过调查得知:大龙井岩溶大泉是形成于低山－丘陵地区的石灰岩地区。是山盆期和乌江期的强烈岩溶作用以及河谷的不断下切,加上上寨台地地表峰丛之间发育洼地、漏斗,中间区域的落水洞,大气降雨沿着落水洞进入地下,在重力作用下从南向北径流,在这过程中水流逐渐集中,岩溶空间形态也逐步扩大,最终水汇集于龙洞沟呈泉集中排泄出地面,形成大龙井岩溶大泉以及大龙井水系统。 相似文献
6.
线性工程路基岩溶土洞(塌陷)监测技术与方法综述 总被引：4，自引：1，他引：3
土洞(塌陷)的监测预警问题一直是国际上极具挑战性的课题。近年来,随着新技术的发展,特别是光电传感技术的应用,岩溶土洞(塌陷)预警监测已取得可喜的进展。本文通过对地质雷达监测法、剖面沉降监测法、In Sar 监测法、时域反射( TDR)同轴电缆监测法、基于岩溶管道裂隙水(气)压力监测的触发因素监测法、BO TDR及OTDR光纤传感监测法等适合于线性工程岩溶土洞(塌陷)的监测预报方法进行了系统分析比较,结果发现: 单一方法在岩溶土洞(塌陷)的监测预警中都有其局限性; 分布式TDR及BOTDR技术可有效确定岩溶塌陷的空间位置,但在埋设方面需进一步的研究;岩溶土洞(塌陷)的监测预警是一个系统工程,应考虑多种方法的综合运用。 相似文献
7.
The current status of mapping karst areas and availability of public sinkhole-risk resources in karst terrains of the United States 总被引：2，自引：0，他引：2
Subsidence from sinkhole collapse is a common occurrence in areas underlain by water-soluble rocks such as carbonate and evaporite rocks, typical of karst terrain. Almost all 50 States within the United States (excluding Delaware and Rhode Island) have karst areas, with sinkhole damage highest in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania. A conservative estimate of losses to all types of ground subsidence was $125 million per year in 1997. This estimate may now be low, as review of cost reports from the last 15 years indicates that the cost of karst collapses in the United States averages more than $300 million per year. Knowing when a catastrophic event will occur is not possible; however, understanding where such occurrences are likely is possible. The US Geological Survey has developed and maintains national-scale maps of karst areas and areas prone to sinkhole formation. Several States provide additional resources for their citizens; Alabama, Colorado, Florida, Indiana, Iowa, Kentucky, Minnesota, Missouri, Ohio, and Pennsylvania maintain databases of sinkholes or karst features, with Florida, Kentucky, Missouri, and Ohio providing sinkhole reporting mechanisms for the public. 相似文献
8.
湖南宁乡大成桥充水矿山疏干区岩溶系统水气压力监测及突变特征 总被引：5，自引：4，他引：1
湖南煤炭坝煤矿是我国著名的大水矿山,开采标高已降至-400 m,每小时排水量11 000 m3。长期的疏干排水,已形成面积达219.19 km2的地下水降落漏斗。以往的调查资料表明,矿山疏干诱发的岩溶塌陷主要发生在疏干开始、地下水位下降到基岩面附近、矿坑发生突水突泥灾害等3个阶段,在疏干区应该无诱发因素导致岩溶塌陷的发生。但近年来煤炭坝煤矿疏干区大成桥的岩溶塌陷特征表明,尽管相关部门采取了一系列处置措施,但岩溶塌陷仍然频繁发生。为了进一步揭示该地区岩溶塌陷发育规律,使处置决策更加科学化,作者所在团队选择大成桥为典型区,通过岩溶系统地下水气压力监测,分析诱发岩溶塌陷的动力来源及其变化规律。结果表明,疏干区岩溶管道裂隙系统中水气压力突变现象极为明显,年最大变幅达54.72 m,瞬时水气压力变化速率最大为70.6 cm/min,造成这一现象的主要原因是气爆、地下洞穴（溶洞、土洞）垮塌。 相似文献
9.
Management and mitigation of sinkholes on karst lands: an overview of practical applications 总被引：2，自引：0，他引：2
When karst lands are developed for residential or commercial purposes, sinkholes are to be properly managed or mitigated.
This paper discusses various types of sinkholes and their possible formation mechanisms, presents some guidelines for sinkhole
management, and summarizes several engineering measures for sinkhole remediation. Because a sinkhole is often not an isolated
feature but a component of an integrated groundwater and surface water system, knowledge of the sinkhole geology and hydrology
is essential in selection of the proper management tools and remediation options. Adverse effects including flooding, additional
sinkholes, and groundwater contamination can result from poorly managed or improperly repaired sinkholes. 相似文献
10.
岩溶塌陷研究现状及趋势分析 总被引：2，自引：1，他引：1
为全面掌握当前国际岩溶塌陷研究动态,促进岩溶塌陷综合防治水平提升,重点从成因机制、识别评价和监测预警三个方面总结了当前国内外岩溶塌陷研究现状,以此为基础,综合运用文献和项目数据对国内外岩溶塌陷研究趋势进行了分析。结果显示:人类工程活动与岩溶环境相互作用关系是当前国际岩溶塌陷研究的热点;成因机理定量化、隐患识别快速化、监测预警精细化和风险防控时效化将是未来的重点攻关方向。 相似文献
11.
I. Nouioua Aek. Rouabhia Ch. Fehdi M. L. Boukelloul L. Gadri D. Chabou R. Mouici 《Environmental Earth Sciences》2013,68(6):1661-1672
Sinkhole collapse is one of the main limitations in the development of karst areas, especially where bedrock is covered by unconsolidated material. Studies of sinkhole formation have shown that sinkholes are likely to develop in cutter (enlarged joint) zones as a result of subterranean erosion by flowing groundwater. Ground-penetrating radar (GPR) and electrical resistivity imaging or tomography (RESTOM) are well suited to mapping sinkholes because of the ability of these two techniques for detecting voids and discriminating subtle resistivity variations. Nine GPR profiles and two-dimensional electrical resistivity tomography have been applied, with relative success, to locate paleo-collapses and cavities, and to detect and characterize karst at two sinkhole sites near Cheria City where limestone is covered by about 10 m of clayey soils. The survey results suggest that GPR and RESTOM are ideal geophysical tools to aid in the detection and monitoring of sinkholes and other subsurface cavities. 相似文献
12.
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。 相似文献
13.
Sinkhole distribution in a rapidly developing urban environment: Hillsborough County, Tampa Bay area, Florida 总被引：4，自引：1，他引：3
Sinkhole formation in Florida is a common event. The Florida karst plain is significantly altered by human development and sinkholes cause considerable property damage throughout much of the state. We present in this paper a morphometric analysis of karst depressions in the Tampa Bay area, and the relation with the known distribution of sinkholes. We selected the Tampa Bay area because it is particularly susceptible to the evolution of karst depressions in relation with development of the built-up environment. Karst depressions were mapped from the 1:24,000 USGS topographic maps and a morphometric analysis was performed by using parameters such as shape, circularity index, perimeter, area, length, width, and orientation. Maps showing the distribution of depression density, and the sectors with greatest areas of karst depression were produced using a GIS. These results were compared with data compiled from the database of sinkhole occurrences in Florida maintained by the Florida Geological Survey. Our analysis demonstrates that the distribution of new sinkhole occurrences differs from the distribution of existing sinkholes, indicating that there are processes acting today that are influencing karst landscape formation that are different from those acting in the past. 相似文献
14.
Geophysical investigation of a sinkhole in the northern Harz foreland (North Germany) 总被引：2，自引：0，他引：2
The creek Jerstedter Bach is part of the Ringelheimer Mulde along the northern rim of the Harz Mountains in Northern Germany,
a trough structure comprising steeply dipping limestones. The limestones are well karstified and drain parts of the region
efficiently via sub-surface flow. As the entire region is intensively used by agriculture, contamination of the fast-flowing
karst aquifer is a potential problem. During 2006, a small sinkhole (Windmühlenweg) developed alongside the Jerstedter Bach
close to the city of Goslar. The sinkhole enlarged rapidly, with a small cave within the gravel cover diverting part of the
creek to the subsurface karst catchment. Geophysical methods (gravimetry, geoelectrics) were used around the sinkhole to determine
its extent and possible evolution. A negative Bouguer anomaly was found over the sinkhole, indicating more voids further downstream.
The geoelectric survey helped to identify the old meandering course of the small river, which was straightened during the
cultural land reform in the twentieth century. 相似文献
15.
Poroelastic analysis of cover-collapse sinkhole formation by piezometric surface drawdown 总被引：1，自引：0，他引：1
T. Tharp 《Environmental Geology》2002,42(5):447-456
Where the water table is above the soil-rock contact in karst regions, cover-collapse sinkholes in the soil and soft sediment above the rock commonly occur as a result of drawdown of the piezometric surface in the karst aquifer. Transient stresses and pore pressures around soil voids at the soil-rock contact can cause hydraulic fracturing of the soil near the wall of the void. After the first such fracture, successive sloughing of soil propagates the soil void rapidly to the surface, resulting in a cover-collapse sinkhole. Sinkhole formation by this mechanism should be strongly a function of rate and magnitude of piezometric surface drawdown, permeability and tensile strength of the soil, and the size, depth, and geometry of the initial soil void. Large soil voids and those with walls that are partly planar or of low curvature are most susceptible to hydraulic fracture and the resulting progression to sinkhole formation. 相似文献
16.
Phillip Kemmerly 《Environmental Geology》1981,3(5):281-292
Soluble rock terrains pose increased flood hazards because of a demographic shift from the upper Middle West and metropolitan
Northeast to the “Sun Belt.” Approximately one-half of the soluble rock terrains in the continental United States occur in
the Sun Belt. Urbanization of karst terrains generally increases the frequency and magnitude of sinkhole flooding and the
probability of collapse. Soil erosion attendant with urbanization results in silt deposition in depressions, reducing sinkhole
runoff storage capacity and regolith hydraulic conductivity.
A new flood-hazard designation termed the sinkhole flood-plain is advocated for use by federal mortgage agencies in karst
terrains so that sinkhole-related flooding can be minimized. A four-phase methodology for assessing sinkhole flood hazards
in a rapidly urbanizing karst terrain is developed, using examples from central Tennessee and southern Kentucky. 相似文献
17.
Quantitative sinkhole hazard assessments in karst areas allow calculation of the potential sinkhole risk and the performance
of cost-benefit analyses. These estimations are of practical interest for planning, engineering, and insurance purposes. The
sinkhole hazard assessments should include two components: the probability of occurrence of sinkholes (sinkholes/km2 year) and the severity of the sinkholes, which mainly refers to the subsidence mechanisms (progressive passive bending or
catastrophic collapse) and the size of the sinkholes at the time of formation; a critical engineering design parameter. This
requires the compilation of an exhaustive database on recent sinkholes, including information on the: (1) location, (2) chronology
(precise date or age range), (3) size, and (4) subsidence mechanisms and rate. This work presents a hazard assessment from
an alluvial evaporite karst area (0.81 km2) located in the periphery of the city of Zaragoza (Ebro River valley, NE Spain). Five sinkholes and four locations with features
attributable to karstic subsidence where identified in an initial investigation phase providing a preliminary probability
of occurrence of 0.14 sinkholes/km2 year (11.34% in annual probability). A trenching program conducted in a subsequent investigation phase allowed us to rule
out the four probable sinkholes, reducing the probability of occurrence to 0.079 sinkholes/km2 year (6.4% in annual probability). The information on the severity indicates that collapse sinkholes 10–15 m in diameter
may occur in the area. A detailed study of the deposits and deformational structures exposed by trenching in one of the sinkholes
allowed us to infer a modern collapse sinkhole approximately 12 m in diameter and with a vertical throw of 8 m. This collapse
structure is superimposed on a subsidence sinkhole around 80 m across that records at least 1.7 m of synsedimentary subsidence.
Trenching, in combination with dating techniques, is proposed as a useful methodology to elucidate the origin of depressions
with uncertain diagnosis and to gather practical information with predictive utility about particular sinkholes in alluvial
karst settings: precise location, subsidence mechanisms and magnitude, and timing and rate of the subsidence episodes. 相似文献
18.
This paper describes seismic velocity tomography applied to the investigation and assessment of karst collapse hazards to facilitate accurate characterization of geological conditions of karst sinkhole formation. In the survey areas of Xiamao, Guangzhou, China, and Huangchi, Foshan, China, seismic velocity tomography was used to explore the structures of rock and soil associated with karst collapse. The results show that sand intercalated with clay or clay intercalated with soft soil dominates the cover of these two areas. The overburden is 20–33 m thick and underlain by Carboniferous limestone. In the limestone, there are well-developed karst caves and cracks as well as highly fluctuating bedrock surfaces. The seismic velocities are less than 2500 m/s in the cover, 2500–4500 m/s in the karst fracture zones and caves of Xiamao, and 1500–2000 m/s in the Huangchi collapse area. The karst fracture zones, relief of bedrock surfaces, and variations of soil thicknesses revealed by seismic velocity tomography are well constrained and in agreement with those in the drilling borehole profiles. This paper demonstrates that seismic velocity tomography can delineate anomalies of rock and soil with the advantages of speed, intuitive images, and high resolution. 相似文献
19.
根据岩溶土洞(塌陷)变形演化特点,分析土体与传感光纤之间的力学关系,简化塌陷力学模型,加工塌陷模拟试验装置并进行试验。首先通过对光纤加载和卸载来模拟土洞形成过程顶板荷载的变化及分析传感光纤相应的变形和轴向应变特点,然后研究了土洞规模变化对光纤传感监测的影响。研究表明:在土洞形成过程中,因土洞规模和上覆土层荷载不一而导致的应力场的分布变化,以及不同光缆对应力场变化响应灵敏性的差异,是影响分布式光纤传感技术在岩溶土洞中应用的关键因子。文中所标定的光纤传感试验装置能较好地显示岩溶土洞形成演化过程中的应变变化特征,说明分布式光纤传感技术可应用于岩溶土洞的监测预警。 相似文献
20.
基于武汉市易发生的29处岩溶塌陷,从岩溶、覆盖层和地下水3方面分析了岩溶塌陷的内部结构;通过现场监测和数值模拟,分析了降雨、钻探和桩基施工的输入作用,并探讨了武汉市岩溶塌陷的演化机理。结果表明:（1）“上黏下砂”的盖层结构、浅部岩溶发育、孔隙水与岩溶水具良好水力联系是塌陷形成的基础条件;（2）自然环境下开口岩溶上方土洞扩展存在水力潜蚀和应力集中破坏两个演化阶段;（3）钻探和桩基施工联通孔隙水和岩溶水的瞬间,孔壁周边松散砂土快速进入临界水力梯度而破坏。桩基施工在覆盖层内的振动荷载和超孔隙水压力,易造成覆盖层整体破坏。在岩溶区施工产生的冲击作用可使岩溶水和孔隙水形成不同步波动,两者存在高水头差,致使覆盖层内砂层在压力差作用下破坏。 相似文献