Evaluation of Karst Hazards for Civil and Industrial Buildings

The European part of Russia exhibits highly developed sulphate and carbonate karst. It mostly occurs within river valleys with relatively thin covering deposits. These conditions may induce karst collapses, which appear to be the main danger for civil and industrial buildings. Evolution of karst rocks includes several epochs of karst development, which causes complicated distribution of karst caves in karst rocks and, as the result, irregular distribution of karst caves on the surface. Karst hazards prediction is mostly reliable within the geotechnical system “Karst-Construction”, using probability methods. This approach allows creating 3 types of antikarst protection (alternative design of construction arrangement on a plan, structural protection of a construction and plugging of karst caves beneath construction foundation) and selecting the optimum or the most effective version or their rational combination.

Risk Assessment for Karst Hazards at a Facility in Saudi Arabia—A Case Study

The boom in industrial and infrastructure construction in Saudi Arabia requires in-depth knowledge of the underground conditions to build a sustainable project. This paper gave a practical example of the challenges facing an existing facility built on a karstic limestone formation in 1970’s. Multiple geophysical techniques such as Microgravity, Electrical Resistivity Imaging, Vertical Seismic Velocity Profiling, Cross Hole Seismic Tomography, Ground Penetration Radar, Multi-Channel Analysis of Surface Waves, as well as boreholes and down-hole video imagery, were deployed through the journey of assessing the karst associated hazards of potential sinkholes or general subsidence. This paper described the karst processes, site geology, geophysical and geotechnical exploration program, and characterizes the subsurface karst conditions at the eastern province of Kingdom of Saudi Arabia. Results and findings of preliminary, geotechnical and geophysical investigations have been utilized to identify the major factors influencing the karst formation. Analyses and integration of obtained results to estimate the type and magnitude of risk affected the major components of industrial facility at the project site using well-known statistical approach were presented in this paper. Consequently number of remedial measures implemented to combating the experienced and expected karst hazards at the studied industrial facility placed in karstified landform are given. A model for using integrated geophysical and geotechnical techniques to assess karst-related risks to a facility was further explored herein.

Hazards and Landscape Changes(Degradations) on Hungarian Karst Mountains Due to Natural and Human Effects

In order to study the karstological processes within the karst ecological system,the geohazards and degradation of karst landscapes on the karst areas of the Bakony mountains(Hungary),we investigated the abiotic elements of the environment,soil and cover deposits,erosion soil decay;the changes in the quantity and quality of karst waters:contamination at swallow holes,contamination of karst springs;and the biogenic factors:surface vegetation coverage by the corine land cover method,plant-ecological examinations,qualification of surface waters with the help of biological water labeling.We recognized that the increasing human activities during the past few centuries have had significant impact on the investigated landscapes of karst areas because of their spatial sensitivity.In the scope of our research we concluded that the landscape changes due to natural and human effects can vary strongly on the different karst areas.These differences can arise from the climatic and geomorphologic situation,the coverlayer's qualities,etc.,but primarily from the different utilization of the investigated karst areas(e.g.the intensity,characteristics and territorial extension of utilization).On the spot investigation we detected traces of new and fast geomorphological processes(gully formation,landslides,collapses,new sinkhole development) and landforms(sinkholes,gullies,swallow holes),which are clear evidences of the effect of climatic changes.

贵州省饱和水汽压差时空变化特征与影响因素

饱和水汽压差(VPD)是表示区域大气干燥程度的重要指标,分析贵州省VPD时空变化特征及其影响机制对明晰气候变化规律和农业生产具有重要意义。研究基于中国气象局提供的CN05.1格点化观测数据集,量化并分析了1961—2022年贵州省喀斯特区域和非喀斯特区域VPD及其时空变化特征,采用多元线性回归方法识别了影响VPD变化的主要气象要素并分析了基于VPD的干旱危险性。结果发现:贵州省年际和季节尺度VPD存在显著的升高趋势,其中喀斯特区域和非喀斯特区域春季和夏季VPD空间分布和变化趋势均呈现相反的格局;以VPD为指标的贵州省干旱危险性显著升高,非喀斯特区域速率更快;气温和相对湿度是贵州省年际和季节尺度上VPD变化的主导气象要素,不同区域年和季节尺度上不同气象要素的贡献率稍有差异。

岩溶区地下水数值模拟分析及开采方案比选

数值模拟是解决地下水开采评价问题的有效途径之一。为安全高效开发岩溶塌陷区地下水资源,以山东省临沂市岩溶区为例,根据水文地质调查分析,充分掌握了岩溶区地下水补给规律、运移规律、分布规律,在此基础上,选取合理模拟范围,建立数值模型,开展多方案地下水动态演化数值预测分析,据此来分析评价最优开采方案。研究结果表明:方案一岩溶塌陷危险性较高,数值观测孔水位在第1279 d、第1644 d、第2019 d和第3105 d时,水位降至灰岩顶板标高39.9 m以下,将引发岩溶塌陷风险;方案二则较安全,数值观测枯水期水位接近灰岩顶板标高,既达到地下水开发利用潜力的标准,又可保证生态地质环境安全,因此,建议采用方案二。开采过程中预警区水位应位于基岩顶板标高以下,以避免岩溶塌陷发生。本文研究结果可为类似塌陷区的科学开采提供参考。

水文地质条件极复杂矿井底板岩溶水害强化注浆加固应用与效果分析

为保障矿井安全生产、延长矿井使用寿命、减少生产成本和保护环境。针对水文地质条件极复杂矿井底板岩溶水害治理难题,研究强化注浆加固技术的应用效果。结合121103工作面实际工程,通过对矿井地质构造和水文地质条件的详细分析,制定科学的注浆加固设计方案,采用注浆钻孔布置和井下钻孔探查方法,根据设计要求对奥灰顶部和徐灰进行强化注浆综合治理。并在实施注浆加固工程后,监测注浆终压、钻孔注浆覆盖率、块段吨水注干料数等指标,并通过检查孔和井下物探方法评价改造效果。结果表明,奥灰顶部和徐灰的强化注浆改造均取得显著成效,注浆终压达到预期标准,钻孔注浆覆盖率和块段吨水注干料数达到设计要求,检查孔分析和井下物探结果显示,水害问题得到有效控制,矿井安全生产条件显著改善。

视电阻率法在隐伏岩溶灾害调查中的应用

隐伏岩溶发育引起的地面塌陷和地裂缝等地质灾害频繁发生,提高勘查方法和解译精度在隐伏岩溶区灾害调查中尤为重要。视电阻率法数据处理、反演算法以及综合解译方法的进步为地质灾害调查提供了有力手段。本文引入视电阻率三维模型,结合二维剖面分析,对采集的视电阻率数据进行综合整理,丰富了数据处理方法,提高了数据模块关联性,有效提高了解译精度和地质模型契合度。结合钻探验证情况对泰安市桥沟地区隐伏岩溶塌陷区进行分析研究,通过隐伏岩溶发育区的视电阻率特征,分析岩溶发育范围和成因,为隐伏岩溶区灾害调查提供了良好的地球物理应用和参考价值。

喀斯特地貌区公路岩质边坡地质灾害评估方法研究

作为喀斯特地貌的典型分布区,广西在公路工程中有大量的岩质边坡产生和存在,而岩质边坡稳定性评价亦是公路工程建设项目地质灾害评估最为关注的问题。赤平投影法作为一种常见的定性或半定量分析方法,目前已被应用于部分边坡工程中,但在公路工程地质灾害评估中应用仍不够普及,本文通过赤平投影法进一步丰富地质灾害评估中对于岩质边坡的评价方法,并结合工程实例对此方法进行研究和探讨。

广州市江府-桃源中间风井工程地质条件评价

研究城市地下空间基本地质结构对城市地下交通具有重大意义。本文以广州市江府-桃源中间风井地质勘探为例,开展工程地质条件评价,预测该工程项目可能在施工和完工阶段引发或加剧基坑边坡不稳、地面下沉和岩溶塌陷等地质灾害问题。

Palaeoseismic Events in Karst Terrains along the Northern Bulgarian Black Sea Coast

The study of the palaoseismic events in the karst terrains of the Bulgarian Black Sea coast is a very important up-to-date problem. The investigated region is one of the highest-energy regions in Bulgaria with established and recorded catastrophic historic and contemporary earthquakes. The terrain is subjected to the influence not only of its own earthquake foci but also of those in Romania and Russia. The palaeoearthquakes that caused considerable disturbances in the karst terrains along the Northern Bulgarian Black Sea coast have left significant traces. They caused disturbances in the environment and the relief (rearrangement of the surface and ground water karst basins, partially or entirely collapsed caves, deformed caves, oil, gas and salt intrusions and gravitationally formed caves). The ecological consequences in historic and contemporary aspects were catastrophic. The palaeoseismic dislocations were formed as a result of global, regional and local geodynamic events related with the destruction of the Moezian platform and the regional extension of the Black Sea basin. The time of their display and their spatial interrelations were established as a result of complex investigations accompanied by original documents.

Influence of droughts on remote villages in the karst region of Guizhou Province, China: Causes and control

Even though the precipitation is abundant in the Karst region of Guizhou Province, remote villages in this area frequently suffer severe droughts. This paper studied the causes of droughts in this region through field investigation and references collection. Based on the cause analysis, some suggestions were provided for hazard prevention and control from an engineering perspective. Besides occasional extreme weathers, the drought in this area is primarily caused by its unique geological structures of Karst plateau and underdeveloped agricultural techniques. Meanwhile, the vicious cycle between drought and poverty, which causes the deficiency of water conservancy facilities and hazard prevention awareness, is an important reason for the frequent occurrence of agricultural and socioeconomic drought. Considering the social and economic conditions of remote villages, the long-term control of drought can only be realized if current measures are capable of bring immediate effects and benefits. Therefore, the construction of well-planned and designed water conservancy system based on each village's natural and social conditions are the priority for current hazard prevention. Generally, the exploitation of subterranean river should be considered as the first choice to stabilize the water supply for remote villages. Meanwhile, the construction and improvement of micro water conservancy facilities, such as small water tank, small pond and so on, can effectively support the water providence during droughts as well.

Geospatial Modeling for Sinkholes Hazard Map Based on GIS &RS Data

The Kinta Valley is an area of karst in the north-western part of Peninsular Malaysia. Over 30 years of uncontrolled land use and development has led to significant changes in topography and geomorphology, such as the appearance of sinkholes. In this paper, geospatial techniques were utilized to the task of evaluating sinkholes susceptibility map using a spatial multi criteria evaluation approach (SMCE). Sinkhole location and a spatial database were applied to calculate eight inherent causative factors for limestone instability namely: lithology, structure (lineament), soil cover, slope, land use mining, urban area features, ponds and rivers. The preparation of the sinkhole geohazard map involved summing the weighted values for each hazard element, which permits the construction of geohazard model;the results of the analysis were validated using the previous actual sinkholes locations in the study area. The spatial distribution of sinkholes occurrence, urban development, faults distribution and ex-mining ponds are factors that are directly responsible for all sinkholes subsidence hazards. Further, the resulting geo-hazard map shows that 93% of recent sinkholes occur in areas where the model flags as “high” and “very high” potential hazard, located in the urbanized part of the valley, while less-developed areas to the west and southwest suffered less sinkhole development. The results can be used for hazard prevention and land-use planning.

底板岩溶水害治理效果综合评价模型及应用

注浆是解决煤矿底板岩溶突水问题的重要手段,而客观评价注浆效果对煤矿岩溶水害防治具有十分重要的意义。以注浆评价效果为研究目标,结合具体注浆工程,从钻探质量、注浆过程以及效果检验等3个方面,选取了套管质量、固管质量、钻井液质量、平面轨迹偏差、钻孔跟层率、注浆终孔压力、注浆结束泵量、注浆结束稳定时间、注浆材料、浆液性能、压水试验吸水率、P-Q-T动态曲线、岩屑录井和单位吸浆量等14个评价指标。采用模糊数学方法,构建了多指标、多层次注浆效果综合评价模型,通过层次分析法和灰色关联度法确定权重和隶属度。依据评价模型结构,设计、编制了注浆效果综合评价模型程序,应用于顾北南一1煤采区和潘二矿西四采区注浆工程实际,对所选孔组注浆效果进行验证,结果与实际相符。

滕州市岩溶塌陷区地质灾害危险性评价

滕州经济技术开发区位于滕州市城区南部和西部,现已升级为国家级经济技术开发区,其东部为岩溶塌陷发育区域。本文以滕州经济技术开发区为研究区,分析岩溶塌陷发育程度及时空分布规律,然后评估其稳定性,预测项目建设过程中、建成后引发或遭受地质灾害的可能性,明确建设场地的适宜性,并提出地质灾害防治措施,从而服务区域社会经济建设。

电测深法结合地质模型在岩溶探测中的应用

文中采用电测深法对某地铁DK25+748-DK26+952段剖面上的地质体电性情况进行探测,得到各测点地表以下电阻率变化及分布情况,结合前期调查所得地质资料,建立相应岩溶发育地质模型,以此为平台解释电测深等值线图。分析得到的岩溶病害既满足地质体电阻率变化曲线规律,也满足岩溶发育地质规律,从而可以得到比单纯通过电阻率曲线解译岩溶病害更加准确的结果。

不同喀斯特类型区地质灾害敏感性研究

为了解喀斯特内在的岩性特征与地质灾害的关系,选取贵州省3种不同喀斯特类型区作为研究对象,构建地质灾害敏感度评价指标体系。采用层次分析法计算各评价指标的权重,计算出贵州省地质灾害敏感度,确定其地质灾害敏感性。采用统计分析法和格网分析法,研究地质灾害敏感性与不同喀斯特类型区的关联。结果表明,两种方法分析得出的结果一致,地质灾害敏感性与喀斯特类型区存在关联性,这种关联性强弱表现为纯喀斯特>亚喀斯特>非喀斯特,说明喀斯特越典型地质灾害越敏感。

隧道岩溶病害危险性分区在超前地质预报中的应用

针对厦蓉高速公路沙井街隧道岩溶的发育特点,提出了"隧道岩溶病害危险性分区"概念,并应用于超前地质预报工作中;根据中导洞开挖揭露的地质条件,对隧道岩溶病害危险性分区进行了修正,以指导主洞的超前预报工作,从而提高了预报工作的针对性并突出了重点;同时,基于高密度电法对不同介质电阻率的敏感性,在预报方法上将地表高密度电法与洞内地质雷达法相结合,提高了对重大岩溶病害预报的准确性。实际开挖结果显示:超前地质预报结果与实际情况高度吻合。

宜万铁路岩溶地质特征及其发育模式

宜万铁路沿线地形、地质条件复杂,是目前已建和在建铁路中岩溶最发育的工程。宜万铁路全线设计隧道159座,其中全线洞身穿越可溶性岩层的隧道由91座。隧道施工中不可避免的遭遇到岩溶的不利影响,造成隧道突水、泥等岩溶灾害的发生,带来了重大安全危害和经济损失,成为亟待解决的重要问题。本文通过对全线岩溶发育特征、地下岩溶形态的分析,依据典型岩溶隧道实例,对隧道与岩溶的位置关系进行了分类,并探讨了宜万线岩溶隧道的主要岩溶灾害,在此基础上将隧道中的岩溶发育特征概化为四种基本模式,为采取定量分析方法分析岩溶隧道突水、突泥及岩层垮塌机理,得到规律性的认识提供支持。

探地雷达探测潜在喀斯特地面塌陷区的可行性研究

在中国分布很多的喀斯特地区,由岩溶引起的地面塌陷已经成为一种环境灾害。为了探明潜在的喀斯特岩溶塌陷地区,我们引入了探地雷达测量技术。在华中107国道附近的北丰桥地区,使用探地雷达进行的可行性试验表明,探地雷达可以探明地下变形和扰动信号,从而确定出潜在的喀斯特地面塌陷区。

三峡库区巫山县翠屏小区岩溶引起的地质灾害危险性研究

三峡库区移民迁建中发现的岩溶问题是一个重大工程地质问题。巫山县城翠屏小区是较早发现有确切岩溶证据的地方,研究证实小区三叠系嘉陵江组灰岩普遍遭受了强烈的岩溶作用。不同部位具有不同的岩溶特点和强度,在纵向上,从山顶到坡脚岩溶作用有增强的趋势;从地表向深部,有局部强烈岩溶层位。岩溶作用在小区产生了顺坡或顺层延伸的溶洞和深部蜂窝状溶孔。岩溶作用在小区形成了脖颈状溶蚀槽地、槽状谷地、溶蚀台地和与地貌相关的"飞雁状"褶皱、岩溶正断层及帚状密集节理带。岩溶过程中伴随着其他外营力作用,它们的相互耦合形成各种次生岩土体。岩溶轻则引起岩体质量降低,重则可能导致地面不均匀沉降、地裂缝、滑坡、崩塌、泥石流及地面塌陷地质灾害。