Water Disaster Research Articles

Experimental Research on Characteristics of Fault Activation and Confined Water Rising

Water inrush due to fault activation in deep coal mining is the main type of water disaster in central and eastern China. This paper analyzed the primary form and mechanism of fault activation that triggers water inrush and derived the critical conditions for fault activation. The WuGou coal mine is used as a geological example, and the characteristics of the fault activation and mechanism of the confined water rising were researched by similar simulation experiments. The results provide the following conclusions. (1) There are three forms of fault activation that trigger water inrush: continuous fault, hidden fault and associated fault activation. (2) Mining causes high abutment pressure in a coal seam; this pressure transfers to the floor, causing damage and failure. The maximum failure depth occurs when the overlying strata is in a critical fractured state. The cracks of the floor gradually close in the goaf. (3) The fault activation causes water inrush and exhibits four stages: fault zone yielding caused by high stress, cracking and extending of the fault zone, movement and slippage of the fault zone, and confined water rising. (4) The influence factors of the confined water rising were analyzed. The experimental results show a negative correlation between the confined water height and distance to the fault zone and a positive correlation among the confined water pressure, fault zone width and confined water height. In addition, a strong–weak–strong change law of the confined water pressure with height is observed.

High-precision Ultrasonic Flowmeter for Mining Applications based on Velocity-area

The flowmeter is widely used in coal mining because of its higher measurement precision and simple installation without channel project modification. In this paper, a flow measurement method based on velocity-area is investigated, and a functional flowmeter for mining applications with higher precision is designed. The two key parameters, the liquid level and flow velocity are required to be obtained for achieving the proposed method. The proposed flowmeter is composed of three main functional modules: (1) flow velocity detection module based on ultrasonic time difference method, (2) liquid level detection module, and (3) mud level detection module based on ultrasonic pulse echo method. All the measured data are transferred to the monitoring station for analysis and displayed in real-time through M-BUS. The flowmeter is designed focusing on mining applications, and has higher benefits for preventing water disasters in coal mines

Groundwater Source Discrimination and Proportion Determination of Mine Inflow Using Ion Analyses: A Case Study from the Longmen Coal Mine, Henan Province, China

Complex hydrogeological conditions in China’s coal mines have contributed to frequent mine water disasters. A simple and effective method to determine water inflow sources and paths is therefore essential. The Longmen Mine, located in Henan Province, in central China was used as a case study. A Piper diagram and cluster analysis were used to screen the characteristic values of 18 water samples from potential aquifers. A comprehensive fuzzy evaluation of the groundwater ions was carried out to determine the main source of the total mine inflow. Then, based on conservation of ionic masses, a matrix function was established to calculate the groundwater recharge composition. Finally, using measured water inflows for the Cambrian limestone aquifer, the calculated and observed results were compared. The results showed that the Carboniferous Taiyuan Formation limestone aquifer (the L7 limestone aquifer) accounts for 60.8% of the total mine inflow, while the Cambrian limestone and roof sandstone aquifers account for 34.8 and 4.4% of the inflow, respectively. The normal mine inflow totals about 19,200 m3/day, of which 6,840 m3/day is from the Cambrian limestone aquifer. This agrees well with the calculated value of 6,720 m3/day. Thus, the method is feasible and reliable.

Overview of goaf water hazards control in China coalmines

Since 1990s, goaf water has become a frequent cause of water disaster in China coalmines, inflicting severe human casualties and huge economic losses. Based on the analysis of the goaf water disaster cases in China coalmines, this article put forward the theoretical and technological system of goaf water control, which include (1) the area and volume of goaf water are reasonably determined due to existence form of goaf water and geophysical prospecting results, (2)retaining sufficient water-resistant coal (rock) pillar to prevent goaf water inrush from adjacent and above, (3)grouting insecure or failure water-resistant coal (rock) pillar, and (4) draining goaf water using “fanned-out” normal drill and long-distance directional drill, and of all, draining goaf water through long-distance drill has been proved to be technically superior in engineering practices. The research results can be of reference to other coal-producing countries in similar geological conditions.

Influential factors and control of water inrush in a coal seam as the main aquifer

In this paper, a combination of field measurement, theoretical analysis and numerical simulation were used to study the main control factors of coal mine water inrush in a main aquifer coal seam and its control scheme. On the basis of revealing and analyzing the coal seam as the main aquifer in western coal mine of Xiao Jihan coal mine, the simulation software of PHASE-2D was applied to analyze the water inflow under different influencing factors. The results showed that water inflow increases logarithmically with the coal seam thickness, increases as a power function with the permeability coefficient of the coal seam, and increases linearly with the coal seam burial depth and the head pressure; The evaluation model for the factors of coal seam water inrush was gained by using nonlinear regression analysis with SPSS. The mine water inrush risk evaluation partition within the scope of the mining field was obtained, through the engineering application in Xiao Jihan coal mine. To ensure the safe and efficient production of the mine, we studied the coal mine water disaster prevention and control measures of a main aquifer coal seam in aspects of roadway driving and coal seam mining.

Study on Water Disaster Prevention and Control Technology under Condition of Extra-thick Coal Seam with Slicing Fullmechanized Caving Mining

Some coal seams belong to cretaceous strata in the east of Inner Mongolia, China. There are obvious differences of rock characteristics and mechanical properties between Cretaceous and Carboniferous- Permian strata. The overburden failure characteristics of extra-thick coal seam with slicing full-mechanized caving mining are studied through rock mechanics experiment, field observation and theoretical analysis and so on. Water disaster prevention and control method of roof and goaf is put forward under the condition of extra-thick coal seam with slicing full-mechanized caving mining. The final research results include: (1) The rock of cretaceous strata has low strength and soft characteristic, its stability is very poor, cretaceous rock belongs to weak type; (2) Under the condition of extra-thick coal seam with slicing full-mechanized caving mining, the ratio between caving zone and mining height of field observation result is 4.58～4.74, the observation results of two boreholes are close; (3) It is significantly effective to prevent and control water disaster from goaf through roof hole drainage method, coal and rock safety pillar remain method is used to limit mining height under the Tertiary gravel aquifer, which makes the working face exploit safely.

Discussion on Core Technique and General Software Platform of River Water Resources Regulation in China

Due to the aggravation of human activities and global climate changes in recent decades, catchment water cycle has experienced strong variation. The world is faced with profound water crisis, and water problems are especially severe and water disasters are of high frequency in China. Water problems have become significant obstacle factors for realizing sustainable development, which greatly threatens national economy and ecological safety. Given the scientific background of catchment water cycle evolution and water resources comprehensive regulation, we propose the method of solving water problems through water resources operation based on dualistic water cycle theory and discuss the developing status and existing problems of current water resources operation in China. On this basis, we also put forward the technical framework and key process of water resources regulation, which integrates the six links of monitoring, simulation, evaluation, forecasting, regulation and control. Furthermore, aiming at the background of the second phase of National Water Monitoring Capacity Building Project, we introduce a nationwide general software platform for water resources regulation. This platform will realize business collaboration and information sharing among three-scale platform of Ministry of Water Resources, basin authorities and provincial level, so as to overall improve the ability of water resources regulation and decision-making.

徐庄煤矿主要水害类型及防治措施

徐庄煤矿主要水害类型及防治措施

Multiple tests for identifying hydraulic conductivities of south and north boundary faults at Ganhe field, Huozhou Coal Electricity Group Co., Ltd, China

Hydraulic conductivities of faults influence the mining design and safety of a coalmine badly. Results of field and indoor tests on hydraulic conductivities of the boundary faults in Ganhe coalfield in China are illustrated. According to the drilling engineering, Xiatuanbai fault and F1 fault near north boundary and Xiazhangduan fault near south boundary are all transtensional normal faults. Furthermore, there formed obvious fracture zones in the Ordovician strata of both sides of the faults with respect to its influence and their water conductivities are all obvious. Results of the pumping test show there are obvious hydraulic connectivities between Fengfeng Formation aquifers and Upper Majiagou Formation aquifers on both sides of the three boundary faults. Therefore, they are all partial water-conductive faults. Results of connectivity tests also show there are obvious hydraulic connectivities in the karst aquifers on both sides of Xiatuanbai fault and Xiazhangduan fault and they are both partial conductive faults. Finally, differences on hydrochemical and stable isotope features between both sides of the three faults are all inconspicuous and the same results on the hydraulic conductivities of the three faults are obtained. The above comprehensive conclusions provide a strong basis for water disaster control of Ganhe mine.

Urban Flood Prevention and Early Warning System in Jinan City

The system construction of urban flood control and disaster reduction in China is facing pressure and challenge from new urban water disaster. Under the circumstances that it is difficult to build high standards of flood protection engineering measures in urban areas, it is particularly important to carry out urban flood early warning. In Jinan City, a representative inland area, based on the index system of early warning of flood in Jinan urban area, the method of fuzzy comprehensive evaluation was adopted to evaluate the level of early warning. Based on the cumulative rainfall of 3 hours, the CAflood simulation results based on cellular automaton model of urban flooding were used as evaluation indexes to realize the accuracy and integration of urban flood control early warning.

盐井煤矿水文地质特征与水灾防治措施研究

为了满足盐井矿区高效安全生产的需要，我们对矿井水文地质特征进行了研究，并在结合大量地质水文资料综合研究的基础上，分析得出该矿区的水文地质特征、主要充水因素及矿井水灾的主要预防措施。该研究成果对矿井水害的防治和煤矿的安全生产具有积极的指导意义，可以为该矿的合理开采提供一定的技术帮助，从而提高煤矿的开采效率。 According to the needs of safe production of coal mine, through the study on the hydrogeological characteristics of coal mine and based on the comprehensive research of numerous materials of coal geology and hydrogeological characteristics, the hydrogeological characteristics and main factors of water-filling and primary disaster controlling measures have been made. The research results have a positive significance of on water disaster controlling and safe production of coal mine and provide some technical support for the reasonable exploitation so as to improve the efficiency of coal mining.

A Mechanical Model of the Overlying Rock Masses in Undersea Coal Mining and a Stress‐Seepage Coupling Numerical Simulation

The water inrush of a working face is the main hidden danger to the safe mining of underwater coal seams. It is known that the development of water‐flowing fractured zones in overlying strata is the basic path which causes water inrushes in working faces. In the engineering background of the underwater mining in the Longkou Mining Area, the analysis model and judgment method of crack propagation were created on the basis of the Mohr–Coulomb criterion. Fish language was used to couple the extension model into the FLAC3d software, in order to simulate the mining process of the underwater coal seam, as well as to analyze the initiation evolutionary characteristics and seepage laws of the fractured zones in the overlying strata during the advancing processes of the working face. The results showed that, during the coal seam mining process, the mining fractured zones which had been caused by the compression‐shear and tension‐shear were mainly concentrated in the overlying strata of the working face. Also, the open‐off cut and mining working face were the key sections of the water inrush in the rock mass. The condition of the water disaster was the formation of a water inrush channel. The possible water inrush channels in underwater coal mining are mainly composed of water‐flowing fractured zones which are formed during the excavation processes. The numerical simulation results were validated through the practical engineering of field observations on the height of water‐flowing fractured zone, which displayed a favorable adaptability.

Experimental simulation of water-inrush disaster from the floor of mine and its mechanism investigation

Mine water inrush is very common in China and can cause hysteretic and severe damages to the safety production of coal mines. Essentially, water inrush from coal floor can be attributed to the connection of cracks and the formation of water channel in floor rocks under the interaction of stress field and seepage field. In this paper, the interaction between cracks, stress field, and seepage field in floor rocks was studied by physical simulation; the evolution law of water inrush from floor cracks was obtained under the fluid-solid coupling effect, and the monitoring of rock stress and seepage pressure was realized by virtue of soil pressure and pore-pressure sensors. The results indicated that the permeability of floor rocks had regional and temporal characteristics due to the cyclical variation of in-situ floor stress. The high-permeability zone occurred under the early mining stress area, and gradually extended and connected inside the floor. As a result, more confined water could flood into the connected cracks and thus changed the seepage field in front of working face. This work provides new approaches and knowledge for researching coal floor water inrush and has important significances for the prevention of coal water disasters.

Economics.

A review of literature in calendar year 2016 on topics relating to environmental policies and sustainable development, and economic policies. This review is divided into these sub-sections: sustainable development, irrigation, economics and water management, climate change and disaster risk management, economic growth, water supply policies, water consumption and water access, and water price regulation and water value.

Climate Change-Related Water Disasters' Impact on Population Health.

Rising global temperatures have resulted in an increased frequency and severity of cyclones, hurricanes, and flooding in many parts of the world. These climate change-related water disasters (CCRWDs) have a devastating impact on communities and the health of residents. Clinicians and policymakers require a substantive body of evidence on which to base planning, prevention, and disaster response to these events. The purpose of this study was to conduct a systematic review of the literature concerning the impact of CCRWDs on public health in order to identify factors in these events that are amenable to preparedness and mitigation. Ultimately, this evidence could be used by nurses to advocate for greater preparedness initiatives and inform national and international disaster policy. A systematic literature review of publications identified through a comprehensive search of five relevant databases (PubMed, Cumulative Index to Nursing and Allied Health Literature [CINAHL], Embase, Scopus, and Web of Science) was conducted using a modified Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach in January 2017 to describe major themes and associated factors of the impact of CCRWDs on population health. Three major themes emerged: environmental disruption resulting in exposure to toxins, population susceptibility, and health systems infrastructure (failure to plan-prepare-mitigate, inadequate response, and lack of infrastructure). Direct health impact was characterized by four major categories: weather-related morbidity and mortality, waterborne diseases/water-related illness, vector-borne and zoonotic diseases, and psychiatric/mental health effects. Scope and duration of the event are factors that exacerbate the impact of CCRWDs. Discussion of specific factors amenable to mitigation was limited. Flooding as an event was overrepresented in this analysis (60%), and the majority of the research reviewed was conducted in high-income or upper middle-/high-income countries (62%), despite the fact that low-income countries bear a disproportionate share of the burden on morbidity and mortality from CCRWDs. Empirical evidence related to CCRWDs is predominately descriptive in nature, characterizing the cascade of climatic shifts leading to major environmental disruption and exposure to toxins, and their resultant morbidity and mortality. There is inadequate representation of research exploring potentially modifiable factors associated with CCRWDs and their impact on population health. This review lays the foundation for a wide array of further areas of analysis to explore the negative health impacts of CCRWDs and for nurses to take a leadership role in identifying and advocating for evidence-based policies to plan, prevent, or mitigate these effects. Nurses comprise the largest global healthcare workforce and are in a position to advocate for disaster preparedness for CCRWDs, develop more robust environmental health policies, and work towards mitigating exposure to environmental toxins that may threaten human health.

東京東部低地(ゼロメートル地帯)における水災害の歴史とその特性に関する研究(1)

東京東部低地(ゼロメートル地帯)における水災害の歴史とその特性に関する研究(1)

A Review of Geophysical Exploration Technology for Mine Water Disaster in China: Applications and Trends

Geophysical exploration can be effective in detecting and monitoring potential sources of coal mine water in-rushes and underground watercourses. Generally, in-mine seismic, DC resistivity, and transient electromagnetic methods are used for such purposes in China. However, such technologies can be influenced by many factors, such as roadways, fissures in the surrounding rocks, and various secondary conditions. Our review of current geophysical methods and tools concludes that further basic research should be carried out on geophysical field propagation in the whole space, data collection methods, and inversion methods appropriate for the special environment of coal mines. Moreover, borehole and roadway space should be designed to incorporate effective geophysical drilling, cross-hole exploration, drilling–roadway exploration, and roadway–roadway exploration. Future hydrogeophysical exploration research should focus on comprehensive geophysical methods combining multi-field synergistic observations with multi-field data integration and automatic monitoring as well as early warning systems for mine water disasters combining real-time processing and analysis of exploration equipment with Internet of Things technology.

Discussion on Sponge City Construction under the Circumstance of Urban Waterlogging

Urban waterlogging caused by flooding hazards is becoming a severe phenomenon for the urbanization of society. To address the challenging problem of urban waterlogging, the strategy of Sponge City (SPC) was put forward. Based on the discussion of Sponge City development, this paper analyzed the Sponge City construction in Shanghai. The analysis indicates that SPC construction is helpful to improve the resilience of Northern cities to flooding disasters, with two potential associated issues: drought disaster and urban waterlogging. Sponge city can absorb rainwater during heavy rainfalls and reuse the useful water to resist drought disasters. For cities which have intensive river systems, taking advantage of river systems to quickly discharge rainwater is an effective way in the process of SPC construction. SPC construction is a long-term complicated process at the system-level. The construction of Sponge City projects should formulate and adjust specific measures to local urban conditions, rather than formulating the uniform strategy. Vigorous and effective strategies should be developed and implemented to cope with the unfavorable situations of aggravating water disasters in urban areas in China.

The Forest and the Trees: How Population-Level Health Protections Sometimes Fail the Individual

The Forest and the Trees: How Population-Level Health Protections Sometimes Fail the Individual

In Situ Investigations on Failure Evolution of Overlying Strata Induced by Mining Multiple Coal Seams

Accurate evaluation of the failure evolution of the overlying strata after multiple mining actions is of great importance both for the prevention of water disasters and the mining designs. To ensure the safety of mining multiple coal seams, the fracture criterions of overlying strata after mining actions were established on the basis of beam theory as well as the influences of coal seam spacing, face size, and lithology on the increased heights of failure zones after each consecutive mining sequence. A newly developed device, named electric controlled water flow detector, and its detecting procedure, was introduced. In situ investigations were performed in the Gaojialiang and Jinhuagong Mines, China. Results showed that the mining of a lower coal seam does not change the failure evolution of the roof strata of the upper coal seam when the coal seam spacing is large. The larger the mining height of the lower coal seam is, the more fractures the overlying strata of the upper coal seam have, and the larger the height of the failure zone. In addition, the failure extent of overlying strata caused by coal face mining increased with their hardness. It was found that the electric controlled water flow detector can effectively detect the failure evolution during multiple mining actions, with high water plugging effectiveness and detection accuracy.