The principles, methods, technologies and application effects of several electromagnetic methods for the detection of the hidden danger of water gushing at the coal face were introduced. Also, emphasis was laid on exp...The principles, methods, technologies and application effects of several electromagnetic methods for the detection of the hidden danger of water gushing at the coal face were introduced. Also, emphasis was laid on expounding the methods, principles and effects of down-hole detections by electric transmission tomography and transient electromagnetic method. The potential of point power supplied in the underground homogeneous semi-space, as well as the response to a low-resistivity abnormal body in the homogeneous semi-space, was simulated by adopting 3-D finite element method to interpret the basic theory of the electric transmission tomography. The results of actual measurement show that the mine electromagnetic method is sensitive to water-bearing low-resistivity bodies and can play a unique role in detecting the hidden danger of water gushing at the coal face.展开更多
To recognize the presence of the headstream of gushing water in coal mines, the SVM (Support Vector Ma- chine) was proposed to analyze the gushing water based on hydrogeochemical methods. First, the SVM model for head...To recognize the presence of the headstream of gushing water in coal mines, the SVM (Support Vector Ma- chine) was proposed to analyze the gushing water based on hydrogeochemical methods. First, the SVM model for head- stream analysis was trained on the water sample of available headstreams, and then we used this to predict the unknown samples, which were validated in practice by comparing the predicted results with the actual results. The experimental results show that the SVM is a feasible method to differentiate between two headstreams and the H-SVMs (Hierachical SVMs) is a preferable way to deal with the problem of multi-headstreams. Compared with other methods, the SVM is based on a strict mathematical theory with a simple structure and good generalization properties. As well, the support vector W in the decision function can describe the weights of the recognition factors of water samples, which is very important for the analysis of headstreams of gushing water in coal mines.展开更多
Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in ex...Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in extent. Furthermore, due to the different heights of mountains and the lengths of tunnels, the locations of the unfavorable geological sections cannot be fully determined before construction, which increases the risk of water inrush and mud gushing. Based on numerous cases of water inrush and mud gushing in railway tunnels, the paper tries to classify water inrush and mud gushing in railway tunnels in view of the conditions of the surrounding rocks and meteorological factors associated with tunnel excavation. In addition, the causes of water inrush and mud gushing in combination of macroand micromechanisms are summarized, and site-specifc treatment method is put forward. The treatment methods include choosing a method of advance geological forecast according to risk degrees of different sections in the tunnel, determining the items of predictions, and choosing the appropriate methods, i.e. draining-oriented method, blocking-oriented method or draining-and-blocking method. The treatment technologies of railway water inrush and mud gushing are also summarized, including energy relief and pressure relief technology, advance grouting technology, and advance jet grouting technology associated with their key technical features and applicable conditions. The results in terms of treatment methods can provide reference to the prevention and treatment of tunnel water inrush and mud gushing.展开更多
The coastal sedimentary basin in southern Benin consists of monoclinal layers divided into two plateau zones (North and South) which are separated by a longitudinal depression ESE-WNW. The valleys of the main N-S-orie...The coastal sedimentary basin in southern Benin consists of monoclinal layers divided into two plateau zones (North and South) which are separated by a longitudinal depression ESE-WNW. The valleys of the main N-S-oriented rivers (Ouémé, Couffo and Mono) set the bondaries of the different plateau of the BSC (Coastal Sedimentary Basin). The present study, based on geology, hydrochemistry, temperature and log data available on boreholes, makes a physico-chemical characterization of the waters of the gushing aquifers of the coastal sedimentary basin of Benin. The gushing water boreholes are shared between the valleys of the main rivers of the BSC. Some of these boreholes are </span><span style="font-family:Verdana;">thermal with a water temperature between 38 and 69 degrees Celsius. The</span><span style="font-family:Verdana;"> hydrogeological correlations established in the BSC in accordance to the North-</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">South direction in the valleys of the main streams (Couffo and Ouémé) reveal that the captured aquifers are sands, marls and limestones that respond either </span><span style="font-family:Verdana;">in major discordance (northern zone) or above the sedimentation gaps</span><span style="font-family:Verdana;"> (southern zone). Chemical analyses have shown that gushing thermal waters are mineralized in the south with a neutral to basic pH and are highly concentrated with bicarbonate, calcium and magnesium ions. In the North, on the other hand, thermal waters are acidic with a pH ranging from 4.8 to 5.9. The acidic nature of the northern waters is influenced by the crystalline base while the southern neutral to basic waters are influenced by the lithological nature (limestone and marl) of the aquifer. The random distribution of thermal water boreholes in the valleys of the main BSC streams is believed to be related to tectonic events.展开更多
基金Supported by the National Basic Research of China(2006CB202207)the National Natural Science Foundation of China(40674060)
文摘The principles, methods, technologies and application effects of several electromagnetic methods for the detection of the hidden danger of water gushing at the coal face were introduced. Also, emphasis was laid on expounding the methods, principles and effects of down-hole detections by electric transmission tomography and transient electromagnetic method. The potential of point power supplied in the underground homogeneous semi-space, as well as the response to a low-resistivity abnormal body in the homogeneous semi-space, was simulated by adopting 3-D finite element method to interpret the basic theory of the electric transmission tomography. The results of actual measurement show that the mine electromagnetic method is sensitive to water-bearing low-resistivity bodies and can play a unique role in detecting the hidden danger of water gushing at the coal face.
基金Project 40401038 supported by the National Natural Science Foundation of China and 2003047 by the Top 100 Outstanding Doctoral Dissertation Foun-dation of China
文摘To recognize the presence of the headstream of gushing water in coal mines, the SVM (Support Vector Ma- chine) was proposed to analyze the gushing water based on hydrogeochemical methods. First, the SVM model for head- stream analysis was trained on the water sample of available headstreams, and then we used this to predict the unknown samples, which were validated in practice by comparing the predicted results with the actual results. The experimental results show that the SVM is a feasible method to differentiate between two headstreams and the H-SVMs (Hierachical SVMs) is a preferable way to deal with the problem of multi-headstreams. Compared with other methods, the SVM is based on a strict mathematical theory with a simple structure and good generalization properties. As well, the support vector W in the decision function can describe the weights of the recognition factors of water samples, which is very important for the analysis of headstreams of gushing water in coal mines.
文摘Water inrush and mud gushing are one of the biggest hazards in tunnel construction. Unfavorable geological sections can be observed in almost all railway tunnels under construction or to be constructed, and vary in extent. Furthermore, due to the different heights of mountains and the lengths of tunnels, the locations of the unfavorable geological sections cannot be fully determined before construction, which increases the risk of water inrush and mud gushing. Based on numerous cases of water inrush and mud gushing in railway tunnels, the paper tries to classify water inrush and mud gushing in railway tunnels in view of the conditions of the surrounding rocks and meteorological factors associated with tunnel excavation. In addition, the causes of water inrush and mud gushing in combination of macroand micromechanisms are summarized, and site-specifc treatment method is put forward. The treatment methods include choosing a method of advance geological forecast according to risk degrees of different sections in the tunnel, determining the items of predictions, and choosing the appropriate methods, i.e. draining-oriented method, blocking-oriented method or draining-and-blocking method. The treatment technologies of railway water inrush and mud gushing are also summarized, including energy relief and pressure relief technology, advance grouting technology, and advance jet grouting technology associated with their key technical features and applicable conditions. The results in terms of treatment methods can provide reference to the prevention and treatment of tunnel water inrush and mud gushing.
文摘The coastal sedimentary basin in southern Benin consists of monoclinal layers divided into two plateau zones (North and South) which are separated by a longitudinal depression ESE-WNW. The valleys of the main N-S-oriented rivers (Ouémé, Couffo and Mono) set the bondaries of the different plateau of the BSC (Coastal Sedimentary Basin). The present study, based on geology, hydrochemistry, temperature and log data available on boreholes, makes a physico-chemical characterization of the waters of the gushing aquifers of the coastal sedimentary basin of Benin. The gushing water boreholes are shared between the valleys of the main rivers of the BSC. Some of these boreholes are </span><span style="font-family:Verdana;">thermal with a water temperature between 38 and 69 degrees Celsius. The</span><span style="font-family:Verdana;"> hydrogeological correlations established in the BSC in accordance to the North-</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">South direction in the valleys of the main streams (Couffo and Ouémé) reveal that the captured aquifers are sands, marls and limestones that respond either </span><span style="font-family:Verdana;">in major discordance (northern zone) or above the sedimentation gaps</span><span style="font-family:Verdana;"> (southern zone). Chemical analyses have shown that gushing thermal waters are mineralized in the south with a neutral to basic pH and are highly concentrated with bicarbonate, calcium and magnesium ions. In the North, on the other hand, thermal waters are acidic with a pH ranging from 4.8 to 5.9. The acidic nature of the northern waters is influenced by the crystalline base while the southern neutral to basic waters are influenced by the lithological nature (limestone and marl) of the aquifer. The random distribution of thermal water boreholes in the valleys of the main BSC streams is believed to be related to tectonic events.
