Key Laboratory of Earth Fissures Geological Disaster

Nanjing, China

Key Laboratory of Earth Fissures Geological Disaster

Nanjing, China
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Zhou H.,China University of Mining and Technology | Zhou H.,Key Laboratory of Earth Fissures Geological Disaster | Gong X.,Key Laboratory of Earth Fissures Geological Disaster | Sun Q.,China University of Mining and Technology | And 3 more authors.
Journal of Geophysics and Engineering | Year: 2017

Water seepage in rock and soil is a main inducing factor of accidents in many engineering fields such as tunnel engineering, mineral resource exploitation, and rock slopes. Water migration in rock and soil can lead to abnormal geoelectric fields due to the effects of diffusion, adsorption, filtration, and oxidation. This makes it possible to research the seepage law in porous media by measuring the response of geoelectric fields in this process. In this work, we carry out a physical simulation experiment to study the geoelectric field response occurring in the water-migration process. By analyzing the response of first electric potential, spontaneous potentials, and exciting current, we find that both the spontaneous potential and exciting current can reflect the change of seepage flow during the water-infiltration process. The exciting current and first electric potential is applicable to the seepage research on heterogeneous rock and soil, for they can accurately determine the position and velocity of the seepage. Real-time apparent resistivity not only indicates the infiltration area but also reflects the relative water content, i.e., the seepage reached saturation along with the reduction of the apparent resistivity. © 2017 Sinopec Geophysical Research Institute.

Ge Q.,Key Laboratory of Earth Fissures Geological Disaster | Ge Q.,Wuhan University | Liang X.,Hubei University | Gong X.,Key Laboratory of Earth Fissures Geological Disaster | Liu Y.,Key Laboratory of Earth Fissures Geological Disaster
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2017

The hydraulic conductivity (K) of deposits is one of the important and fundamental properties for solving various problems in the study filed of hydrogeology and geotechenical engineering. However, in the study of clay-rich deposits, the selection of the evaluation method for K is obviously affected by the scale of the site and the degree of deposits disturbance due to the complex deposit structure. Chemical (δ18O as the tracer), laboratory, and empirical formula methods were used to predict the vertical hydraulic conductivity in saturated clay-rich deposits, and their practicability was analyzed. Take the Quaternary thick clay-rich sediments in North Jiangsu coastal plain for example, the estimated hydraulic conductivity of the thick clay-rich sediments was lower than 1×10-11 m/s using δ18O chemical methods. Using laboratory method, that range between 2.61×10-8 and 9×10-12 m/s. The larger predictive values were determined by empirical formula method and higher than that obtained using hydraulic method by several times. Chemical method was applied to display the long-term experimental results under the natural conditions, and the equivalent permeability of the decade meters clay-rich deposits. Besides, the residence time of pore water in the sediments was also predicted. Combined with the laboratory parameters of clay samples, such as liquid and plastic limit, laboratory and empirical formula methods could provide series hydraulic conductivities of the whole profile, in order to show the difference of different permeability coefficient prediction methods in thick clay-rich profile. © 2017, Editorial Department of Earth Science. All right reserved.

Li H.,Nanjing Xiaozhuang University | Li H.,Jilin University | Yu X.,Jilin University | Zhang W.,Jilin University | And 3 more authors.
Exposure and Health | Year: 2017

There is growing evidence of increasing pollution threats to groundwater caused by anthropogenic activities. Risk assessment has proven a useful tool for groundwater management, environmental planning, and decision making in numerous research projects. Based on the origin–pathway–target model, a quantitative evaluation model was established in this study. This study shows that most areas of Suzhou are under medium-to-very high vulnerability to organic pollution, for which the media of the aquifer and the depth of groundwater are responsible. The risk-assessment map shows that the very high-risk areas were mostly distributed in the southeast along with small areas on the northern bank of the river. However, on the groundwater value-weighted risk map, the very high-risk regions were concentrated in the north. Human activities in the industrial area strongly influenced the-risk of organic pollution to groundwater as the areas with very high risks were found mainly in the industrial area. Areas containing very high groundwater value and basic risk class generated a very high value-weighted groundwater contamination risk class. The result of the validation showed that this model was appropriate for groundwater risk assessment for organic pollution in this area. It should be noted that the value-weighted risk map was completely different from the one of the risk map. © 2017 Springer Science+Business Media Dordrecht

Lu X.-R.,Geological Survey of Jiangsu Province | Lu X.-R.,Key Laboratory of Earth Fissures Geological Disaster | Yang L.,Geological Survey of Jiangsu Province | Yang L.,Key Laboratory of Earth Fissures Geological Disaster | And 4 more authors.
Acta Geoscientica Sinica | Year: 2014

Based on an analysis of the distribution of iodine content in phreatic water, soil and hydrogeological conditions and land form, the authors have a new understanding on the control factors of iodine content in groundwater: The previous researchers hold that the iodine content in groundwater is proportional to the organic matter, whereas the authors consider that there is no fixed relationship between the iodine content and organic matter content in groundwater, but the organic matter contributes to the increase of water-soluble iodine content, and they are directly proportional in some areas. Groundwater flow conditions impact significantly the iodine content. The iodine content is often low and in compliance with drinking water standards in hilly land where the runoff conditions are better, whereas the iodine content often exceeds drinking water standards in low-lying areas of poor runoff conditions; The iodine content in groundwater is directly proportional to the content in soil under the same hydrogeological conditions. Another important feature of the iodine concentration in groundwater is that it is very stable and changes very little with time and mining activity.

Yang L.,Geological Survey of Jiangsu Province | Yang L.,Key Laboratory of Earth Fissures Geological Disaster | Gong X.-L.,Geological Survey of Jiangsu Province | Gong X.-L.,Key Laboratory of Earth Fissures Geological Disaster | And 4 more authors.
Geology in China | Year: 2015

In order to study hydrogeochemistry of the fluoride in groundwater in northern Lianyungang area, the authors analyzed 63 groundwater samples and investigated the distribution and genesis of high-fluoride groundwater. The results show that the concentration of fluoride in groundwater tends to increase with the groundwater flow. The high-fluoride groundwater areas are distributed in low gulf plain and depression. The alkaline water environment with high concentrations of sodium and bicarbonate is the main factor responsible for fluoride enrichment and transfer of fluoride from sediments to groundwater. The formation of high-fluoride groundwater results from prolonged geological and geochemical evolution. The hydrogeochemical processes including mineral dissolution and precipitation, evaporation and concentration, cation exchange and adsorption are the dominant factors for the enrichment of fluoride in groundwater.

Miao Y.,Chinese Academy of Sciences | Song C.,Lanzhou University | Fang X.,CAS Institute of Tibetan Plateau Research | Meng Q.,Lanzhou University | And 3 more authors.
Gondwana Research | Year: 2015

An extinct palynomorph, Fupingopollenites, was used as the basis for a discussion of the late Cenozoic Asian summer monsoon (ASM) evolution and its possible driving forces. Based on the spatial and temporal variations in its percentages across Inner and East Asia, we found that Fupingopollenites mainly occurred in East Asia, with boundaries to the NE of ca. 42°N, 135°E and NW of ca. 36°N, 103°E during the Early Miocene (ca. 23-17. Ma). This region enlarged westwards, reaching the eastern Qaidam Basin (ca. 36°N, 97.5°E) during the Middle Miocene (ca. 17-11. Ma), before noticeably retreating to a region bounded to the NW at ca. 33°N, 105°E during ca. 11-5.3. Ma. The region then shrank further in the Pliocene, with the NE boundary shrinking southwards to about 35°N, 120°E; the area then almost disappeared during the Pleistocene (2.6-0. Ma). The flourishing and subsequent extinction of Fupingopollenites is indicative of a narrow ecological amplitude with a critical dependence on habitat humidity and temperature (most likely mean annual precipitation (MAP) > 1000. mm and mean annual temperature (MAT) > 10. °C). Therefore, the Fupingopollenites geographic distribution can indicate the humid ASM evolution during the late Cenozoic, revealing that the strongest ASM period occurred during the Middle Miocene Climate Optimum (MMCO, ~. 17-14. Ma), after which the ASM weakened coincident with global cooling. We argue that the global cooling played a critical role in the ASM evolution, while the Tibetan Plateau uplifts made a relatively small contribution. © 2015 International Association for Gondwana Research.

Zhang W.,Key Laboratory of Earth Fissures Geological Disaster | Zhang W.,Jilin University | Gao L.,Key Laboratory of Earth Fissures Geological Disaster | Jiao X.,Shanghai Institute of Geological Survey | And 5 more authors.
Geosciences Journal | Year: 2014

Earth fissures in Su-Xi-Chang land subsidence area have induced massive damages to the area. The non-linear characteristic associated with the process of earth fissure formation requires non-linear method for evaluating the occurrence of the hazard. Based on quantification of influence factors on breeding the hazard, GA-ANN method, which integrates artificial neural networks (ANN) with genetic algorithms (GA), is developed for evaluating the occurrence of earth fissure hazard. Six indicators, that include the depth of bedrock burial (DBB), the degree of bedrock relief (DBR), water level (WL) (the II confined aquifer), the gradient of land subsidence (GLS), transmissivity (T) (the II confined aquifer) and the thickness of clay soil (TCS), are selected as the input patterns of the integrated approach, and danger index (DI) as the output pattern. A multilayer back-propagation neural network is trained with 30 sets of data samples including 15 sets of earth fissure samples and 15 sets of safety samples for defining the architecture of ANN. Subsequently, GA is employed by optimizing the initial weights of trained ANN by minimizing the deviation of output. The efficacy of the integrated approach is demonstrated by comparing the deviation of output from ANN and GA-ANN for 5 testing samples and the result shows that the GA-ANN method is more accurate than ANN in identifying the occurrence of earth fissure. The integrated method is applied to the assessment of earth fissure hazard in typical regions of earth fissure. According to the classification of DI, the regions are divided into four zones — danger zone, sub-danger zone, sub-safe zone and safe zone. © 2014, The Association of Korean Geoscience Societies and Springer-Verlag Berlin Heidelberg.

Li J.-P.,Shandong University of Science and Technology | Li J.-P.,Geological Survey of Jiangsu Province | Shang T.-X.,Key Laboratory of Earth Fissures Geological Disaster | Shang T.-X.,Geological Survey of Jiangsu Province | And 2 more authors.
Wutan Huatan Jisuan Jishu | Year: 2014

3D abnormal body daujeeapos;s electromagnetic field with arbitrary shape source multiple locations excitation can be inverted using integral equation and damped least squares. Multiple groups of electromagnetic field data in different excitation and receiving point to be uniform consideration in inversion, a matrix is obtained, distribution of resistivity of underground abnormal body is achieved. Model test shows that inversion of fast convergence speed, less dependent on the initial value, the result is accurate and reliable.

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