The stability of inclined shaft lining structure (ISLS) in complex water-rich strata is affected by many factors, suchas water pressure, joint, soft rock, lining corrosion and so on. The instability of the ISLS will a...The stability of inclined shaft lining structure (ISLS) in complex water-rich strata is affected by many factors, suchas water pressure, joint, soft rock, lining corrosion and so on. The instability of the ISLS will affect the safe andefficient coal mine production. Bathe sed on the geological conditions of the Xiaobaodang coal mine, this papertested the evolution characteristics of concrete composition in long-term water seepage areas and revealed theinfluence mechanism of corrosion weakening of shaft lining (SL) in water-rich strata. Meanwhile, transientelectromagnetic, ground penetrating radar, and infrared monitoring are used to detect the water-rich zones, anddamage zones of surrounding rock and lining water seepage zones, and a three-level safety evaluation model forthe instability risk of ISLS is constructed. Water abundance of the surrounding rock, surrounding rock deterioration, and shaft lining seepage were the specific indicators in the model. The main inclined shaft (MIS) in thestudied coal mine is divided into three levels: non instability risk zone, potential instability risk zone, and highinstability risk zone. According to the evaluation results, comprehensive prevention and control measures of“hydrophobic hole drainage” and “back-lining grouting” are adopted for the water inrush source and the surrounding rock micro-crack water channel. The precise prevention and control of ISLS is realized. The researchresults also provide a reference for the stability evaluation of ISLS and the accurate prevention and control undersimilar conditions.展开更多
1.Objective In the past decade,a group of medium to giant lead-zinc deposits,represented by Huoshaoyun,Sachakou,and Yuanbaoling,have been discovered in the Aksai Chin region of Karakoram,Xinjiang.They are all located ...1.Objective In the past decade,a group of medium to giant lead-zinc deposits,represented by Huoshaoyun,Sachakou,and Yuanbaoling,have been discovered in the Aksai Chin region of Karakoram,Xinjiang.They are all located in the Mesozoic carbonate and clastic rock formations.The Sachakou leadzinc mining area is adjacent to the northwest of the Huoshaoyun lead-zinc mining area and is in the same stratigraphic layer as Huoshaoyun.Although many scholars have been arguing about the type and age of Huoshaoyun lead-zinc mineralization,few scholars have paid attention to the classification of the ore-bearing strata in the area.The stratigraphy of the Lower Permian Shenxianwan Group to the Upper Cretaceous Tielongtan Group is exposed in the Sachakou area of Karakorum,Xinjiang,however,the Late Permian-Early Triassic stratigraphy is missing(Fig.1a).Due to the harsh natural conditions in the area and the low level of work,the stratigraphic delineation is not exhaustive,and the regional lithology is dominated by carbonates and clastic rocks,which makes it difficult to identify the age of the regional lithology and causes problems for the exploration and research of lead-zinc in the area.展开更多
Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thic...Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thickness,an intelligent automatic correlation method of oil-bearing strata based on pattern constraints is formed.We propose to introduce knowledge-driven in automatic correlation of oil-bearing strata,constraining the correlation process by stratigraphic sedimentary patterns and improving the similarity measuring machine and conditional constraint dynamic time warping algorithm to automate the correlation of marker layers and the interfaces of each stratum.The application in Shishen 100 block in the Shinan Oilfield of the Bohai Bay Basin shows that the coincidence rate of the marker layers identified by this method is over 95.00%,and the average coincidence rate of identified oil-bearing strata reaches 90.02% compared to artificial correlation results,which is about 17 percentage points higher than that of the existing automatic correlation methods.The accuracy of the automatic correlation of oil-bearing strata has been effectively improved.展开更多
This research explores the potential for the evaluation and prediction of earth pressure balance shield performance based on a gray system model.The research focuses on a shield tunnel excavated for Metro Line 2 in Da...This research explores the potential for the evaluation and prediction of earth pressure balance shield performance based on a gray system model.The research focuses on a shield tunnel excavated for Metro Line 2 in Dalian,China.Due to the large error between the initial geological exploration data and real strata,the project construction is extremely difficult.In view of the current situation regarding the project,a quantitative method for evaluating the tunneling efficiency was proposed using cutterhead rotation(R),advance speed(S),total thrust(F)and torque(T).A total of 80 datasets with three input parameters and one output variable(F or T)were collected from this project,and a prediction framework based gray system model was established.Based on the prediction model,five prediction schemes were set up.Through error analysis,the optimal prediction scheme was obtained from the five schemes.The parametric investigation performed indicates that the relationships between F and the three input variables in the gray system model harmonize with the theoretical explanation.The case shows that the shield tunneling performance and efficiency are improved by the tunneling parameter prediction model based on the gray system model.展开更多
The continuously collected cores from the Permo-Carboniferous coal-bearing strata of the eastern Ordos Basin are essential for studying the hydrocarbon potential in this region.This study adopted sedimentological and ...The continuously collected cores from the Permo-Carboniferous coal-bearing strata of the eastern Ordos Basin are essential for studying the hydrocarbon potential in this region.This study adopted sedimentological and geochemical methods to analyze the sedimentary environment,material composition,and geochemical characteristics of the coal-bearing strata.The differences in depositional and paleoclimatic conditions were compared;and the factors influencing the organic matter content of fine-grained sediments were explored.The depositional environment of the Benxi and Jinci formations was lagoon to tidal flat with weakly reduced waters with low salinity and dry-hot paleoclimatic conditions;while that of the Taiyuan Formation was a carbonate platform and shallow water delta front,where the water was highly reductive.The xerothermic climate alternated with the warm and humid climate.The period of maximum transgression in the Permo-Carboniferous has the highest water salinity.The Shanxi Formation was deposited in a shallow water delta front with a brackish and fresh water environment and alternative weak reductiveness.And the paleoclimate condition is dry-hot.The TOC content in fine-grained samples was averaging 1.52%.The main controlling mechanism of organic matter in this area was the input conditions according to the analysis on input and preservation of organic matter.展开更多
Destress blasting(DB)implemented along the perimeter of safety pillars is a special application of destressing in coal longwall mining.The goal is to separate relatively more deformed mined areas from safety pillars,s...Destress blasting(DB)implemented along the perimeter of safety pillars is a special application of destressing in coal longwall mining.The goal is to separate relatively more deformed mined areas from safety pillars,such as shaft pillars or cross-cut pillars,to reduce the transfer of high stresses to the protective pillar.This case study aims to numerically simulate selected destress blasts in the Czech part of the Upper Silesian Coal Basin and examine its impact on stress transfer to the safety pillar area.To separate the area between the protective pillar and the longwall(LW),two fans of five 93-mm blast holes(length of 93e100 m)were drilled from the gate roads into the overburden strata.Each set of blast holes was fired separately in two stages without time delay.The explosive charge(gelatin-type of explosive)of each stage is 3450 kg.The two DB stages were fired when the longwall face was approximately 158 m and 152 m away from the blast.A 3D mine-wide model is built and validated with in situ stress measured with hydrofracturing.Mining and destressing in three 5-m thick coal seams are simulated in the region.Numerical modeling of DB is successfully conducted using a rock fragmentation factor a of 0.05 and a stress reduction/dissipation factor β of 0.95.Buffering of transfer of additional stress from the mining area into the safety pillar is evaluated by comparison of yielding volume before and after DB.It is shown that yielding volume drops after DB by nearly 80%in the area of the destressing panel and near the safety shaft pillar.展开更多
The longwall method is one of the feasible and efficient underground mining methods for greater depth of workings.Recently,Singareni Collieries Company Limited(SCCL),the largest coal-producing government company in th...The longwall method is one of the feasible and efficient underground mining methods for greater depth of workings.Recently,Singareni Collieries Company Limited(SCCL),the largest coal-producing government company in the Southern part of India,has deployed a high capacity(2×1152T capacity)power support system in its Adriyala Longwall Project(ALP)at a depth of 375 m.There was a concern about the stability of the longwall workings and the protective pillars.Thus,research work was carried out with the geotechnical instruments and numerical modelling tools to analyze the stability while retreating the longwall panels.The outcomes revealed that the convergence in the gate roads increased with the longwall face advancement and the area of exposure.The pressure of the powered support legs on the dip side was less than the rise side legs,which implies a stable roof condition over the longwall face.An abutment zone was identified ahead of the line of extraction up to 10e25 m and presumed from the Factor of Safety(FoS)criterion that within this zone,the longwall pillar possibly will be of better stability at every stage of extraction.The results obtained from this study would be helpful for the mining engineers to understand the behaviour of underground strata in longwall workings.展开更多
Purpose–This paper aims to study the impacts of groundwater seepage on artificial freezing process of gravel strata,the temperature field characteristics of the strata,and the strata process,closure time and thicknes...Purpose–This paper aims to study the impacts of groundwater seepage on artificial freezing process of gravel strata,the temperature field characteristics of the strata,and the strata process,closure time and thickness evolution mechanism of the frozen wall.Design/methodology/approach–In this paper several laboratory model tests were conducted,considering different groundwater seepage rate.Findings–The results show that there is a significant coupling effect between the cold diffusion of artificial freezing pipes and groundwater seepage;when there is no seepage,temperature fields upstream and downstream of the gravel strata are symmetrically distributed,and the thickness of the frozen soil column/frozen wall is consistent during artificial freezing;groundwater seepage causes significant asymmetry in the temperature fields upstream and downstream of the gravel strata,and the greater the seepage rate,the more obvious the asymmetry;the frozen wall closure time increases linearly with the increase in the groundwater seepage rate,and specifically,the time length under seepage rate of 5.00 m d1 is 3.2 times longer than that under no seepage;due to the erosion from groundwater seepage,the thickness of the upstream frozen wall decreases linearly with the seepage velocity,while that of the downstream frozen wall increases linearly,resulting in a saddle-shaped frozen wall.Originality/value–The research results are beneficial to the optimum design and risk control of artificial freezing process in gravel strata.展开更多
基金Financial support for this work was provided by the National Natural Science Foundation of China(52104155)Natural Science Foundation of Beijing(8212032)+2 种基金the Postdoctoral Research Foundation of China(2023M733778)an Open Research Grant of Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining(EC2022012)the Fundamental Research Funds for the Central Universities(2023ZKPYNY03).
文摘The stability of inclined shaft lining structure (ISLS) in complex water-rich strata is affected by many factors, suchas water pressure, joint, soft rock, lining corrosion and so on. The instability of the ISLS will affect the safe andefficient coal mine production. Bathe sed on the geological conditions of the Xiaobaodang coal mine, this papertested the evolution characteristics of concrete composition in long-term water seepage areas and revealed theinfluence mechanism of corrosion weakening of shaft lining (SL) in water-rich strata. Meanwhile, transientelectromagnetic, ground penetrating radar, and infrared monitoring are used to detect the water-rich zones, anddamage zones of surrounding rock and lining water seepage zones, and a three-level safety evaluation model forthe instability risk of ISLS is constructed. Water abundance of the surrounding rock, surrounding rock deterioration, and shaft lining seepage were the specific indicators in the model. The main inclined shaft (MIS) in thestudied coal mine is divided into three levels: non instability risk zone, potential instability risk zone, and highinstability risk zone. According to the evaluation results, comprehensive prevention and control measures of“hydrophobic hole drainage” and “back-lining grouting” are adopted for the water inrush source and the surrounding rock micro-crack water channel. The precise prevention and control of ISLS is realized. The researchresults also provide a reference for the stability evaluation of ISLS and the accurate prevention and control undersimilar conditions.
基金Supported by the Second Tibetan Plateau Scientific Expedition and Research(2021QZKK0303)the Natural Science Basic Research Program of Shaanxi(2020JQ-440 and 2021JQ-327)+1 种基金the Major Science and Technology Project of Xinjiang Uygur Autonomous Region(2021A03001-2)the projects of the China Geological Survey(DD20230333 and DD20230048).
文摘1.Objective In the past decade,a group of medium to giant lead-zinc deposits,represented by Huoshaoyun,Sachakou,and Yuanbaoling,have been discovered in the Aksai Chin region of Karakoram,Xinjiang.They are all located in the Mesozoic carbonate and clastic rock formations.The Sachakou leadzinc mining area is adjacent to the northwest of the Huoshaoyun lead-zinc mining area and is in the same stratigraphic layer as Huoshaoyun.Although many scholars have been arguing about the type and age of Huoshaoyun lead-zinc mineralization,few scholars have paid attention to the classification of the ore-bearing strata in the area.The stratigraphy of the Lower Permian Shenxianwan Group to the Upper Cretaceous Tielongtan Group is exposed in the Sachakou area of Karakorum,Xinjiang,however,the Late Permian-Early Triassic stratigraphy is missing(Fig.1a).Due to the harsh natural conditions in the area and the low level of work,the stratigraphic delineation is not exhaustive,and the regional lithology is dominated by carbonates and clastic rocks,which makes it difficult to identify the age of the regional lithology and causes problems for the exploration and research of lead-zinc in the area.
基金Supported by the National Natural Science Foundation of China(42272110)CNPC-China University of Petroleum(Beijing)Strategic Cooperation Project(ZLZX2020-02).
文摘Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thickness,an intelligent automatic correlation method of oil-bearing strata based on pattern constraints is formed.We propose to introduce knowledge-driven in automatic correlation of oil-bearing strata,constraining the correlation process by stratigraphic sedimentary patterns and improving the similarity measuring machine and conditional constraint dynamic time warping algorithm to automate the correlation of marker layers and the interfaces of each stratum.The application in Shishen 100 block in the Shinan Oilfield of the Bohai Bay Basin shows that the coincidence rate of the marker layers identified by this method is over 95.00%,and the average coincidence rate of identified oil-bearing strata reaches 90.02% compared to artificial correlation results,which is about 17 percentage points higher than that of the existing automatic correlation methods.The accuracy of the automatic correlation of oil-bearing strata has been effectively improved.
基金support by the National Natural Science Foundation of China(Grant Nos.52108377,52090084,and 51938008).
文摘This research explores the potential for the evaluation and prediction of earth pressure balance shield performance based on a gray system model.The research focuses on a shield tunnel excavated for Metro Line 2 in Dalian,China.Due to the large error between the initial geological exploration data and real strata,the project construction is extremely difficult.In view of the current situation regarding the project,a quantitative method for evaluating the tunneling efficiency was proposed using cutterhead rotation(R),advance speed(S),total thrust(F)and torque(T).A total of 80 datasets with three input parameters and one output variable(F or T)were collected from this project,and a prediction framework based gray system model was established.Based on the prediction model,five prediction schemes were set up.Through error analysis,the optimal prediction scheme was obtained from the five schemes.The parametric investigation performed indicates that the relationships between F and the three input variables in the gray system model harmonize with the theoretical explanation.The case shows that the shield tunneling performance and efficiency are improved by the tunneling parameter prediction model based on the gray system model.
基金founded by the National Natural Science Foundation of China(Grant No.41772130)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX22_2602)+1 种基金the Graduate Innovation Program of China University of Mining and Technology(Grant No.2022WLKXJ035)the Fundamental Research Program of Shanxi Province(Grant No.202103021223283)。
文摘The continuously collected cores from the Permo-Carboniferous coal-bearing strata of the eastern Ordos Basin are essential for studying the hydrocarbon potential in this region.This study adopted sedimentological and geochemical methods to analyze the sedimentary environment,material composition,and geochemical characteristics of the coal-bearing strata.The differences in depositional and paleoclimatic conditions were compared;and the factors influencing the organic matter content of fine-grained sediments were explored.The depositional environment of the Benxi and Jinci formations was lagoon to tidal flat with weakly reduced waters with low salinity and dry-hot paleoclimatic conditions;while that of the Taiyuan Formation was a carbonate platform and shallow water delta front,where the water was highly reductive.The xerothermic climate alternated with the warm and humid climate.The period of maximum transgression in the Permo-Carboniferous has the highest water salinity.The Shanxi Formation was deposited in a shallow water delta front with a brackish and fresh water environment and alternative weak reductiveness.And the paleoclimate condition is dry-hot.The TOC content in fine-grained samples was averaging 1.52%.The main controlling mechanism of organic matter in this area was the input conditions according to the analysis on input and preservation of organic matter.
文摘Destress blasting(DB)implemented along the perimeter of safety pillars is a special application of destressing in coal longwall mining.The goal is to separate relatively more deformed mined areas from safety pillars,such as shaft pillars or cross-cut pillars,to reduce the transfer of high stresses to the protective pillar.This case study aims to numerically simulate selected destress blasts in the Czech part of the Upper Silesian Coal Basin and examine its impact on stress transfer to the safety pillar area.To separate the area between the protective pillar and the longwall(LW),two fans of five 93-mm blast holes(length of 93e100 m)were drilled from the gate roads into the overburden strata.Each set of blast holes was fired separately in two stages without time delay.The explosive charge(gelatin-type of explosive)of each stage is 3450 kg.The two DB stages were fired when the longwall face was approximately 158 m and 152 m away from the blast.A 3D mine-wide model is built and validated with in situ stress measured with hydrofracturing.Mining and destressing in three 5-m thick coal seams are simulated in the region.Numerical modeling of DB is successfully conducted using a rock fragmentation factor a of 0.05 and a stress reduction/dissipation factor β of 0.95.Buffering of transfer of additional stress from the mining area into the safety pillar is evaluated by comparison of yielding volume before and after DB.It is shown that yielding volume drops after DB by nearly 80%in the area of the destressing panel and near the safety shaft pillar.
文摘The longwall method is one of the feasible and efficient underground mining methods for greater depth of workings.Recently,Singareni Collieries Company Limited(SCCL),the largest coal-producing government company in the Southern part of India,has deployed a high capacity(2×1152T capacity)power support system in its Adriyala Longwall Project(ALP)at a depth of 375 m.There was a concern about the stability of the longwall workings and the protective pillars.Thus,research work was carried out with the geotechnical instruments and numerical modelling tools to analyze the stability while retreating the longwall panels.The outcomes revealed that the convergence in the gate roads increased with the longwall face advancement and the area of exposure.The pressure of the powered support legs on the dip side was less than the rise side legs,which implies a stable roof condition over the longwall face.An abutment zone was identified ahead of the line of extraction up to 10e25 m and presumed from the Factor of Safety(FoS)criterion that within this zone,the longwall pillar possibly will be of better stability at every stage of extraction.The results obtained from this study would be helpful for the mining engineers to understand the behaviour of underground strata in longwall workings.
基金supported by the National Natural Science Foundation of China(Grant No.51978426)the NSFC Young Scientists Fund(Grant No.41801277)+1 种基金the Science and Technology Research Program of Hebei Education Department(Grant No.QN2018072)the Program for High-level Talent Fund of Hebei Province(Grant No.A201903010).
文摘Purpose–This paper aims to study the impacts of groundwater seepage on artificial freezing process of gravel strata,the temperature field characteristics of the strata,and the strata process,closure time and thickness evolution mechanism of the frozen wall.Design/methodology/approach–In this paper several laboratory model tests were conducted,considering different groundwater seepage rate.Findings–The results show that there is a significant coupling effect between the cold diffusion of artificial freezing pipes and groundwater seepage;when there is no seepage,temperature fields upstream and downstream of the gravel strata are symmetrically distributed,and the thickness of the frozen soil column/frozen wall is consistent during artificial freezing;groundwater seepage causes significant asymmetry in the temperature fields upstream and downstream of the gravel strata,and the greater the seepage rate,the more obvious the asymmetry;the frozen wall closure time increases linearly with the increase in the groundwater seepage rate,and specifically,the time length under seepage rate of 5.00 m d1 is 3.2 times longer than that under no seepage;due to the erosion from groundwater seepage,the thickness of the upstream frozen wall decreases linearly with the seepage velocity,while that of the downstream frozen wall increases linearly,resulting in a saddle-shaped frozen wall.Originality/value–The research results are beneficial to the optimum design and risk control of artificial freezing process in gravel strata.