Population growth leads to increased utilization of water resources.One of these resources is groundwater,which has steadily declined each year.The depletion of these resources brings about various environmental chall...Population growth leads to increased utilization of water resources.One of these resources is groundwater,which has steadily declined each year.The depletion of these resources brings about various environmental challenges.The present study aimed to explore the relationship between groundwater fluctuations and land subsidence in the Malayer Plain,Iran,focusing on quantifying subsidence resulting from groundwater extraction.Using Sentinel-1 satellite data(2014–2019)and monthly piezometric measurements(1996–2018),the analysis revealed an average deformation velocity of–6.3 cm yr–1,with accumulated subsidence of–32 cm over the 2014–2019 period.The maximum subsidence rate reached 10.3 cm yr–1 in areas of intensive agricultural activity.A wavelet-PCA spatiotemporal analysis of groundwater fluctuations identified critical multi-scale patterns strongly correlated with subsidence trends.Regression analysis between subsidence rates and groundwater fluctuations at various wavelet decomposition levels explained 75%of the variance(R2=0.75),indicating that intermediate-scale groundwater declines were the primary drivers of subsidence.Furthermore,land use analysis using Landsat data(1999–2021)revealed a 6230-ha increase in irrigated farmland,contributing to heightened groundwater extraction and subsidence rates.These findings highlight the critical need for sustainable groundwater management to mitigate the risks of continued subsidence in the region.展开更多
The North China Plain is vital hub for agricultural production and urban development.However,decades of excessive groundwater extraction have resulted on significant land subsidence,posing severe threats to the region...The North China Plain is vital hub for agricultural production and urban development.However,decades of excessive groundwater extraction have resulted on significant land subsidence,posing severe threats to the region's socio-economic stability and sustainable development.The relationship between land deformation and groundwater storage Anomalies in this region remains insufficiently understood,and the driving factors behind land subsidence require further exploration.This study employs downscaled GRACE and SBAS InSAR technologies to monitor and analyze land subsidence and groundwater storage Anoma-lies in four representative cities of the North China Plain:Beijing,Tianjin,Cangzhou,and Hengshui.Using geodetector methods,the study investigates the driving factors of land subsidence,incorporating both natu-ral environmental and human activity factors.The results indicate that:(1)Groundwater storage in the North China Plain generally exhibited an overall declining trend from 2002 to 2022,with the rate of decrease weakening from southwest to northeast,showing a clear spatial clustering pattern.(2)While,land subsidence rates in the main urban areas of each city were relatively low,severe subsidence persisted in the surrounding suburban and rural areas.(3)The temporal trends of land subsidence were consistent with changes in groundwater storage across all cities.(4)Groundwater storage Anomalies emerged as the most significant factor influencing the spatial distribution of land subsidence,with a q-value of 0.387,followed by factors such as DEM,evapotranspiration,and rainfall.Seasonal characteristics were evident in land deformation corresponding to groundwater storage Anomalies:During the spring and summer irrigation periods,land subsidence occurred due to groundwater depletion,while in autumn and winter,the surface uplifted with increased groundwater storage.In Cangzhou and Hengshui,excessive deep groundwater extraction caused a lagged response in land subsidence relative to groundwater storage Anomalies.Further-more,interaction among various factors significantly amplified their influence on land subsidence.The interaction between groundwater storage Anomalies and rainfall had the strongest combined effect,under-scoring its critical role in shaping land subsidence in the study area.The findings offer valuable insights for the scientific prevention and management of land subsidence in the North China Plain.展开更多
The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.Thi...The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.This study assessed the land subsidence before and after urban expansion in five areas of Lanzhou by using slope spectrum construction method and gradient expansion intensity measurement that integrated with SBAS-InSAR technology.The results show that construction land on slopes over 20°increased significantly,accounting for 16%of new construction land.The average slope spectrum index was 4.02,with the upper slope limit rising by 8.2°.The land subsidence rate threshold increased by 10 mm/a,and the proportion of pixels experiencing subsidence greater than 5 mm/year rose from 3.63%to 5.24%.Increased construction intensity on slopes caused higher and faster subsidence,which diminished with greater distance from the expansion areas.Areas with slopes between 10°and 25°saw the greatest acceleration in subsidence.Geological composition,building density,groundwater exploitation,and cut-and-fill thickness collectively influence land subsidence rates.This study provides a scientific basis for mitigating geological disaster risks and promoting safe urban development in mountainous cities.展开更多
Land subsidence significantly impacts the accuracy of the National Elevation Datum in China.In order to solve this issue,a dynamic and economical way was proposed to update the National Elevation Datum with the assist...Land subsidence significantly impacts the accuracy of the National Elevation Datum in China.In order to solve this issue,a dynamic and economical way was proposed to update the National Elevation Datum with the assistance of InSAR in the North China Plain,which served as the research area.Moreover,the GNSS result was used to correct the InSAR result for the vertical deformation field,which has a relatively unified deformation reference.By integrating the vertical deformation field with the national elevation control point,an analysis and evaluation of changes in the National Elevation Datum were conducted.In addition,a regional remeasurement scheme was formulated to achieve dynamic updates and mainte-nance of the National Elevation Datum on a regional scale.Through data acquisition and processing,we successfully improved reliability within the main subsidence areas for future use.As a result,updating the elevation values utilize a regional update method,and a dynamic and economical technical process to update the National Elevation Datum is shown in the study.展开更多
The Small Baseline Subset InSAR(SBAS-InSAR)and unmanned aerial vehicles(UAVs)as common ocean-land technologies,have been extensively applied in subsidence,glacial movement,surface deformation,and maritime positioning ...The Small Baseline Subset InSAR(SBAS-InSAR)and unmanned aerial vehicles(UAVs)as common ocean-land technologies,have been extensively applied in subsidence,glacial movement,surface deformation,and maritime positioning and navigation.A novel method integrating SBAS-InSAR and UAV photogrammetry is used to analyze ground subsidence deformation in the Gesar gold mine located in Maqu,Northwest China.This approach uses SBAS-InSAR to calculate two-dimensional deformation data for capturing ascending and descending measurements.This method can provide precise information on small-sized deformations within mining regions.The deformation data obtained from UAVs and the vertical deformation data derived from InSAR are integrated to generate comprehensive and accurate ground subsidence data from the mining district.Results demonstrate that using a combined InSAR(vertical)and UAV technique to analyze surface subsidence in mining districts resolves inconsistency between the line-of-sight and deformation orientations.Furthermore,the incoherence issue of InSAR in regions with large deformation gradients is addressed,while the inherent errors of UAV monitoring of mining surface subsidence are mitigated.The genetic algorithm(GA)-backpropagation(BP)neural network algorithm is combined with InSAR data to predict subsidence in collapsed areas.As observed,the GA-BP algorithm has the smallest residual under the same training samples.Therefore,the GA-BP neural network model can effectively predict surface subsidence in mining areas and can be used for subsequent subsidence prediction.展开更多
Morphologies of deltaic strandplains are the result of multiple sedimentary dynamics interacting with climate,neotectonic and anthropic impacts.They record long-term evolution of coastal areas but also reveal past and...Morphologies of deltaic strandplains are the result of multiple sedimentary dynamics interacting with climate,neotectonic and anthropic impacts.They record long-term evolution of coastal areas but also reveal past and present hazards that can be essential to better predict risks in urbanised deltas.This paper aims to identify the effect of a long-term evolution of the prograded plain of the Tiber Delta in using current ground surface variations and geohistorical data.This study applies GIS(Geographic Information System)tools to LiDAR(Light Detection and Ranging)-derived DEM(Digital Elevation Model)data combined with stratigraphical data,aerial photography interpretation and old maps.The main outcome shows areas of subsidence are primarily located in the central part of the Tiber Delta.Lower heights at the river mouth are due to subsidence and specific lower morphologies associated with fast progradation phases,while similar low heights just north in the area of the international airport of Rome are due to subsidence alone.Subsidence under the airport is associated with the compaction of the silty clay infill of the Late Pleistocene Tiber Valley mostly deposited during the Holocene transgressive period.Only observed in the airport area,the presence of washover fans and the large extent of paleolagoons reveal the kind of risks that are increased by this subsidence.This study demonstrates that the densely urbanised central part of the Tiber Delta faces higher risks of marine submersion and coastal flooding considering ongoing relative sea level change.It also contributes to show the importance to better characterise past coastal morphologies to identify areas prone to subsidence.展开更多
Underground coal mining induces significant surface deformation and environmental damage,particularly in deeply buried mining areas with thin bedrock and thick alluvial layers.Based on the case study of the Zhaogu No....Underground coal mining induces significant surface deformation and environmental damage,particularly in deeply buried mining areas with thin bedrock and thick alluvial layers.Based on the case study of the Zhaogu No.2 coal mine in Xinxiang City,Henan Province,China,this study employs a comprehensive research methodology,integrating field investigations,numerical simulations,and theoretical analyses,to explore the surface subsidence features at deeply buried mining areas with thin bedrock and thick alluvial layers,to reveal the effect of alluvial thickness on the surface subsidence characteristics.The findings indicate that the surface subsidence areas span 4.2 km2 with an advanced influence distance of 540 m.The rate of surface subsidence primarily depends on the panel's position and its advancing rate.Moreover,the thickness of the alluvial layer amplifies both the extent and magnitude of surface deformation.The displacement of overlying rock primarily exhibits a two-stage progression:the thin bedrock control stage and the alluvial control stage.In the thin bedrock control stage,surface subsidence initiates with relatively low subsidence values and amplitudes.Subsequently,in the alluvial control stage,surface subsidence accelerates,leading to a rapid increase in both subsidence values and amplitudes.These characteristics of rock formation displacement result in distinct phases of surface subsidence.Furthermore,the paper addresses the utilization of surface subsidence areas and proposes a method for calculating reservoir storage capacity in these areas.According to calculations,the storage capacity amounts to 1.05e7 m^(3).The research findings provide valuable insights into the surface subsidence laws in regions with similar geological conditions and practical implications for the management and utilization of subsided areas.展开更多
0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly ...0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly prominent.China has implemented and completed several largescale land infilling and excavation projects(Figure 1),which have become the main way to increase land resources and expand construction land.展开更多
Based on the characteristics of strata movement of solid backfilling mining technology, the surface subsidence prediction method based on the equivalent mining height theory was proposed, and the parameters selection ...Based on the characteristics of strata movement of solid backfilling mining technology, the surface subsidence prediction method based on the equivalent mining height theory was proposed, and the parameters selection guideline of this method was also described. While comparing the parameters of caving mining with equivalent height, the subsidence efficient can be calculated according to the mining height and bulk factor of sagging zone and fracture zone, the tangent of main influence angle of solid backfilling mining is reduced by 0.2-0.5（while it cannot be less than 1.0）. For sake of safety, offset of the inflection point is set to zero, and other parameters, such as horizontal movement coefficient and main propagation angle are equal to the corresponding parameters of caving mining with equivalent height. In the last part, a case study of solid backfilling mining subsidence prediction was described. The results show the applicability of this method and the difference of the maximum subsidence point between the prediction and the observation is less than 5%.展开更多
Due to the difficulties in obtaining large deformation mining subsidence using differential Interferometric Synthetic Aperture Radar （D-InSAR） alone, a new algorithm was proposed to extract large deformation mining ...Due to the difficulties in obtaining large deformation mining subsidence using differential Interferometric Synthetic Aperture Radar （D-InSAR） alone, a new algorithm was proposed to extract large deformation mining subsidence using D-InSAR technique and probability integral method. The details of the algorithm are as follows：the control points set, containing correct phase unwrapping points on the subsidence basin edge generated by D-InSAR and several observation points （near the maximum subsidence and inflection points）, was established at first; genetic algorithm （GA） was then used to optimize the parameters of probability integral method; at last, the surface subsidence was deduced according to the optimum parameters. The results of the experiment in Huaibei mining area, China, show that the presented method can generate the correct mining subsidence basin with a few surface observations, and the relative error of maximum subsidence point is about 8.3%, which is much better than that of conventional D-InSAR （relative error is 68.0%）.展开更多
In order to monitor large-area mining subsidence accurately, a high-precision global navigation satellite system （GNSS） monitoring network was established based on the nearby international GNSS service （IGS） stati...In order to monitor large-area mining subsidence accurately, a high-precision global navigation satellite system （GNSS） monitoring network was established based on the nearby international GNSS service （IGS） stations taken as reference points. Given the non-linear motions of IGS stations, the robust Kalman filtering （RKF） model was presented to determine the datum of multi-period monitoring network considering the velocity and weekly solution of IGS stations. The theory proposed was applied to monitoring mining subsidence in northern Anhui coal mine in China. According to the case study, the RKF model to establish monitoring datum is better than the prediction method and the weekly solution from IGS analysis centers （ACs）, and the corresponding precision of deformation can reach up to millimeter level with 4 h observation. The research provides an efficient and accurate approach for monitoring large-area mining subsidence.展开更多
The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRT...The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error（RMSE） being 6.35 m in X direction and 11.65 m in Y direction（both in UTM projection）, around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.展开更多
As for the supply chain consisting of a manufacturer and multiple competing retailers, the disruption management decision is considered for the demand disruption that both the investment sensitivity coefficient and th...As for the supply chain consisting of a manufacturer and multiple competing retailers, the disruption management decision is considered for the demand disruption that both the investment sensitivity coefficient and the investment-elasticity are changed simultaneously. Meanwhile, the corresponding solutions are given for different cases of the disruption, and the characteristics of the solutions are analyzed. The production plan is proved to he robustness under certain conditions, and the production plan of the coordination strategy is investigated for the disruption with appropriate contractual arrangement, i. e. , a subside rate schedule. Mutual restraints exist between the changed investment sensitivity coefficient and the investment-elasticity when the coordination mecha- nism is used. And the more the number of the retailers in the system, the more the subside provided by the suppler on the coordinaton strategy.展开更多
Surface subsidence is a typical ground movement due to longwall mining, which causes a series of environmental problems and hazards. In China, intensive coal extractions are commonly operated under dense-populated coa...Surface subsidence is a typical ground movement due to longwall mining, which causes a series of environmental problems and hazards. In China, intensive coal extractions are commonly operated under dense-populated coalfields, which exacerbates the negative subsequences resulted from surface settlement. Therefore, effective approaches to control the ground subsidence are in urgent need for the Chinese coal mining industry. This paper presents a newly developed subsidence control technology: isolated overburden grout injection, including the theory, technique and applications. Relevant procedures such as injection system design, grouting material selection, borehole layout, grout take estimation and injection process design are proposed. The applicability of this technology has been demonstrated through physical modelling, field measurements, and case studies. Since 2009, the technology has been successfully applied to 14 longwall areas in 9 Chinese coal mines. The ultimate surface subsidence factors vary from 0.10 to 0.15. This method has a great potential to be popularized and performed where longwall mining are implemented under villages and ground infrastructures.展开更多
In recent years,field trials of non-pillar longwall mining using complete backfill have been implemented successively in the Chinese coal mining industry.The objective of this paper is to get a scientific understandin...In recent years,field trials of non-pillar longwall mining using complete backfill have been implemented successively in the Chinese coal mining industry.The objective of this paper is to get a scientific understanding of surface subsidence control effect using such techniques.It begins with a brief overview on complete backfill methods primarily used in China,followed by an analysis of collected subsidence factors under mining with complete backfill.It is concluded that non-pillar longwall panel layout cannot protect surface structures against damages at a relatively large mining height,even though complete backfill is conducted.In such cases,separated longwall panel layout should be applied,i.e.,panel width should be subcritical and stable coal pillars should be left between the adjacent panels.The proposed method takes the principles of subcritical extraction and partial extraction;in conjunction with gob backfilling,surface subsidence can be effectively mitigated,thus protecting surface buildings against mining-induced damage.A general design principle and method of separated panel layout have also been proposed.展开更多
文摘Population growth leads to increased utilization of water resources.One of these resources is groundwater,which has steadily declined each year.The depletion of these resources brings about various environmental challenges.The present study aimed to explore the relationship between groundwater fluctuations and land subsidence in the Malayer Plain,Iran,focusing on quantifying subsidence resulting from groundwater extraction.Using Sentinel-1 satellite data(2014–2019)and monthly piezometric measurements(1996–2018),the analysis revealed an average deformation velocity of–6.3 cm yr–1,with accumulated subsidence of–32 cm over the 2014–2019 period.The maximum subsidence rate reached 10.3 cm yr–1 in areas of intensive agricultural activity.A wavelet-PCA spatiotemporal analysis of groundwater fluctuations identified critical multi-scale patterns strongly correlated with subsidence trends.Regression analysis between subsidence rates and groundwater fluctuations at various wavelet decomposition levels explained 75%of the variance(R2=0.75),indicating that intermediate-scale groundwater declines were the primary drivers of subsidence.Furthermore,land use analysis using Landsat data(1999–2021)revealed a 6230-ha increase in irrigated farmland,contributing to heightened groundwater extraction and subsidence rates.These findings highlight the critical need for sustainable groundwater management to mitigate the risks of continued subsidence in the region.
基金supported by the Fundamental Research Funds for Central Public Welfare Research Institutes,CAGS(Project No.KY202302)China Geological Survey Project(DD20230719)China Geological Survey Project(DD20230427)。
文摘The North China Plain is vital hub for agricultural production and urban development.However,decades of excessive groundwater extraction have resulted on significant land subsidence,posing severe threats to the region's socio-economic stability and sustainable development.The relationship between land deformation and groundwater storage Anomalies in this region remains insufficiently understood,and the driving factors behind land subsidence require further exploration.This study employs downscaled GRACE and SBAS InSAR technologies to monitor and analyze land subsidence and groundwater storage Anoma-lies in four representative cities of the North China Plain:Beijing,Tianjin,Cangzhou,and Hengshui.Using geodetector methods,the study investigates the driving factors of land subsidence,incorporating both natu-ral environmental and human activity factors.The results indicate that:(1)Groundwater storage in the North China Plain generally exhibited an overall declining trend from 2002 to 2022,with the rate of decrease weakening from southwest to northeast,showing a clear spatial clustering pattern.(2)While,land subsidence rates in the main urban areas of each city were relatively low,severe subsidence persisted in the surrounding suburban and rural areas.(3)The temporal trends of land subsidence were consistent with changes in groundwater storage across all cities.(4)Groundwater storage Anomalies emerged as the most significant factor influencing the spatial distribution of land subsidence,with a q-value of 0.387,followed by factors such as DEM,evapotranspiration,and rainfall.Seasonal characteristics were evident in land deformation corresponding to groundwater storage Anomalies:During the spring and summer irrigation periods,land subsidence occurred due to groundwater depletion,while in autumn and winter,the surface uplifted with increased groundwater storage.In Cangzhou and Hengshui,excessive deep groundwater extraction caused a lagged response in land subsidence relative to groundwater storage Anomalies.Further-more,interaction among various factors significantly amplified their influence on land subsidence.The interaction between groundwater storage Anomalies and rainfall had the strongest combined effect,under-scoring its critical role in shaping land subsidence in the study area.The findings offer valuable insights for the scientific prevention and management of land subsidence in the North China Plain.
基金National Natural Science Foundation of China(Grant No.42271214)National Key R&D Program of China(Grant No.2022YFC3800700)+1 种基金Key Research Program of Gansu Province(Grant No.23ZDKA0004)Natural Science Foundation of Gansu Province(Grant No.21JR7RA281).
文摘The expansion of construction land on slopes in mountainous cities like Lanzhou has addressed the shortage of flat land but compromised slope stability,leading to uneven land subsidence and risks to infrastructure.This study assessed the land subsidence before and after urban expansion in five areas of Lanzhou by using slope spectrum construction method and gradient expansion intensity measurement that integrated with SBAS-InSAR technology.The results show that construction land on slopes over 20°increased significantly,accounting for 16%of new construction land.The average slope spectrum index was 4.02,with the upper slope limit rising by 8.2°.The land subsidence rate threshold increased by 10 mm/a,and the proportion of pixels experiencing subsidence greater than 5 mm/year rose from 3.63%to 5.24%.Increased construction intensity on slopes caused higher and faster subsidence,which diminished with greater distance from the expansion areas.Areas with slopes between 10°and 25°saw the greatest acceleration in subsidence.Geological composition,building density,groundwater exploitation,and cut-and-fill thickness collectively influence land subsidence rates.This study provides a scientific basis for mitigating geological disaster risks and promoting safe urban development in mountainous cities.
基金supported by the Scientific and Technological Innovation Project of SHASG(SCK2022-01)National Key Research and Development Program of China(2016YFC0803109)。
文摘Land subsidence significantly impacts the accuracy of the National Elevation Datum in China.In order to solve this issue,a dynamic and economical way was proposed to update the National Elevation Datum with the assistance of InSAR in the North China Plain,which served as the research area.Moreover,the GNSS result was used to correct the InSAR result for the vertical deformation field,which has a relatively unified deformation reference.By integrating the vertical deformation field with the national elevation control point,an analysis and evaluation of changes in the National Elevation Datum were conducted.In addition,a regional remeasurement scheme was formulated to achieve dynamic updates and mainte-nance of the National Elevation Datum on a regional scale.Through data acquisition and processing,we successfully improved reliability within the main subsidence areas for future use.As a result,updating the elevation values utilize a regional update method,and a dynamic and economical technical process to update the National Elevation Datum is shown in the study.
基金funded by the Project from the Maqu Branch of Gannan Tibetan Autonomous Prefecture Ecological Environment Bureau,China(No.33412021021)。
文摘The Small Baseline Subset InSAR(SBAS-InSAR)and unmanned aerial vehicles(UAVs)as common ocean-land technologies,have been extensively applied in subsidence,glacial movement,surface deformation,and maritime positioning and navigation.A novel method integrating SBAS-InSAR and UAV photogrammetry is used to analyze ground subsidence deformation in the Gesar gold mine located in Maqu,Northwest China.This approach uses SBAS-InSAR to calculate two-dimensional deformation data for capturing ascending and descending measurements.This method can provide precise information on small-sized deformations within mining regions.The deformation data obtained from UAVs and the vertical deformation data derived from InSAR are integrated to generate comprehensive and accurate ground subsidence data from the mining district.Results demonstrate that using a combined InSAR(vertical)and UAV technique to analyze surface subsidence in mining districts resolves inconsistency between the line-of-sight and deformation orientations.Furthermore,the incoherence issue of InSAR in regions with large deformation gradients is addressed,while the inherent errors of UAV monitoring of mining surface subsidence are mitigated.The genetic algorithm(GA)-backpropagation(BP)neural network algorithm is combined with InSAR data to predict subsidence in collapsed areas.As observed,the GA-BP algorithm has the smallest residual under the same training samples.Therefore,the GA-BP neural network model can effectively predict surface subsidence in mining areas and can be used for subsequent subsidence prediction.
文摘Morphologies of deltaic strandplains are the result of multiple sedimentary dynamics interacting with climate,neotectonic and anthropic impacts.They record long-term evolution of coastal areas but also reveal past and present hazards that can be essential to better predict risks in urbanised deltas.This paper aims to identify the effect of a long-term evolution of the prograded plain of the Tiber Delta in using current ground surface variations and geohistorical data.This study applies GIS(Geographic Information System)tools to LiDAR(Light Detection and Ranging)-derived DEM(Digital Elevation Model)data combined with stratigraphical data,aerial photography interpretation and old maps.The main outcome shows areas of subsidence are primarily located in the central part of the Tiber Delta.Lower heights at the river mouth are due to subsidence and specific lower morphologies associated with fast progradation phases,while similar low heights just north in the area of the international airport of Rome are due to subsidence alone.Subsidence under the airport is associated with the compaction of the silty clay infill of the Late Pleistocene Tiber Valley mostly deposited during the Holocene transgressive period.Only observed in the airport area,the presence of washover fans and the large extent of paleolagoons reveal the kind of risks that are increased by this subsidence.This study demonstrates that the densely urbanised central part of the Tiber Delta faces higher risks of marine submersion and coastal flooding considering ongoing relative sea level change.It also contributes to show the importance to better characterise past coastal morphologies to identify areas prone to subsidence.
基金supported by the National Natural Science Foundation of China(Grant Nos.5193400852374106+5 种基金5220416352404159)China Postdoctoral Science Foundation(Grant no.2024T171006)the Fundamental Research Funds for the Central Universities(Grant Nos.2024ZKPYNY042023ZKPYNY012023YQTD02)。
文摘Underground coal mining induces significant surface deformation and environmental damage,particularly in deeply buried mining areas with thin bedrock and thick alluvial layers.Based on the case study of the Zhaogu No.2 coal mine in Xinxiang City,Henan Province,China,this study employs a comprehensive research methodology,integrating field investigations,numerical simulations,and theoretical analyses,to explore the surface subsidence features at deeply buried mining areas with thin bedrock and thick alluvial layers,to reveal the effect of alluvial thickness on the surface subsidence characteristics.The findings indicate that the surface subsidence areas span 4.2 km2 with an advanced influence distance of 540 m.The rate of surface subsidence primarily depends on the panel's position and its advancing rate.Moreover,the thickness of the alluvial layer amplifies both the extent and magnitude of surface deformation.The displacement of overlying rock primarily exhibits a two-stage progression:the thin bedrock control stage and the alluvial control stage.In the thin bedrock control stage,surface subsidence initiates with relatively low subsidence values and amplitudes.Subsequently,in the alluvial control stage,surface subsidence accelerates,leading to a rapid increase in both subsidence values and amplitudes.These characteristics of rock formation displacement result in distinct phases of surface subsidence.Furthermore,the paper addresses the utilization of surface subsidence areas and proposes a method for calculating reservoir storage capacity in these areas.According to calculations,the storage capacity amounts to 1.05e7 m^(3).The research findings provide valuable insights into the surface subsidence laws in regions with similar geological conditions and practical implications for the management and utilization of subsided areas.
基金funded by the Key Research and Development Program of Shaanxi Province(No.2024SFYBXM-669)the National Natural Science Foundation of China(No.42271078)。
文摘0 INTRODUCTION Due to the rapid population growth and the accelerated urbanization process,the contradiction between the demand for expanding ground space and the limited available land scale is becoming increasingly prominent.China has implemented and completed several largescale land infilling and excavation projects(Figure 1),which have become the main way to increase land resources and expand construction land.
基金Project(2012BAB13B03)supported by the National Scientific and Technical Supporting Programs Funded of ChinaProject(41104011)supported by the National Natural Science Foundation of China+1 种基金Project(2013QNB07)supported by the Natural Science Funds for Young Scholar of China University of Mining and TechnologyProject(2012LWB32)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the characteristics of strata movement of solid backfilling mining technology, the surface subsidence prediction method based on the equivalent mining height theory was proposed, and the parameters selection guideline of this method was also described. While comparing the parameters of caving mining with equivalent height, the subsidence efficient can be calculated according to the mining height and bulk factor of sagging zone and fracture zone, the tangent of main influence angle of solid backfilling mining is reduced by 0.2-0.5（while it cannot be less than 1.0）. For sake of safety, offset of the inflection point is set to zero, and other parameters, such as horizontal movement coefficient and main propagation angle are equal to the corresponding parameters of caving mining with equivalent height. In the last part, a case study of solid backfilling mining subsidence prediction was described. The results show the applicability of this method and the difference of the maximum subsidence point between the prediction and the observation is less than 5%.
基金Project (BK20130174) supported by the Basic Research Project of Jiangsu Province (Natural Science Foundation) Project (1101109C) supported by Jiangsu Planned Projects for Postdoctoral Research Funds,China+1 种基金Project (201325) supported by the Key Laboratory of Geo-informatics of State Bureau of Surveying and Mapping,ChinaProject (SZBF2011-6-B35) supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Due to the difficulties in obtaining large deformation mining subsidence using differential Interferometric Synthetic Aperture Radar （D-InSAR） alone, a new algorithm was proposed to extract large deformation mining subsidence using D-InSAR technique and probability integral method. The details of the algorithm are as follows：the control points set, containing correct phase unwrapping points on the subsidence basin edge generated by D-InSAR and several observation points （near the maximum subsidence and inflection points）, was established at first; genetic algorithm （GA） was then used to optimize the parameters of probability integral method; at last, the surface subsidence was deduced according to the optimum parameters. The results of the experiment in Huaibei mining area, China, show that the presented method can generate the correct mining subsidence basin with a few surface observations, and the relative error of maximum subsidence point is about 8.3%, which is much better than that of conventional D-InSAR （relative error is 68.0%）.
基金Projects(51174206,41204011)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPDSA1102),China
文摘In order to monitor large-area mining subsidence accurately, a high-precision global navigation satellite system （GNSS） monitoring network was established based on the nearby international GNSS service （IGS） stations taken as reference points. Given the non-linear motions of IGS stations, the robust Kalman filtering （RKF） model was presented to determine the datum of multi-period monitoring network considering the velocity and weekly solution of IGS stations. The theory proposed was applied to monitoring mining subsidence in northern Anhui coal mine in China. According to the case study, the RKF model to establish monitoring datum is better than the prediction method and the weekly solution from IGS analysis centers （ACs）, and the corresponding precision of deformation can reach up to millimeter level with 4 h observation. The research provides an efficient and accurate approach for monitoring large-area mining subsidence.
基金Project(51174191)supported by the National Natural Science Foundation of ChinaProject(2013CB227904)supported by the National Basic Research Program of ChinaProject(2012QNB09)supported by Fundamental Research Funds for the Central Universities,China
文摘The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error（RMSE） being 6.35 m in X direction and 11.65 m in Y direction（both in UTM projection）, around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.
基金Supported by the Scientific Research Foundation for Young Faulty of Nanjing University of Aeronautics & Astronautics(S0670-082)~~
文摘As for the supply chain consisting of a manufacturer and multiple competing retailers, the disruption management decision is considered for the demand disruption that both the investment sensitivity coefficient and the investment-elasticity are changed simultaneously. Meanwhile, the corresponding solutions are given for different cases of the disruption, and the characteristics of the solutions are analyzed. The production plan is proved to he robustness under certain conditions, and the production plan of the coordination strategy is investigated for the disruption with appropriate contractual arrangement, i. e. , a subside rate schedule. Mutual restraints exist between the changed investment sensitivity coefficient and the investment-elasticity when the coordination mecha- nism is used. And the more the number of the retailers in the system, the more the subside provided by the suppler on the coordinaton strategy.
基金financial support provided by the National Natural Science Foundation of China(51604258)is greatly appreciated
文摘Surface subsidence is a typical ground movement due to longwall mining, which causes a series of environmental problems and hazards. In China, intensive coal extractions are commonly operated under dense-populated coalfields, which exacerbates the negative subsequences resulted from surface settlement. Therefore, effective approaches to control the ground subsidence are in urgent need for the Chinese coal mining industry. This paper presents a newly developed subsidence control technology: isolated overburden grout injection, including the theory, technique and applications. Relevant procedures such as injection system design, grouting material selection, borehole layout, grout take estimation and injection process design are proposed. The applicability of this technology has been demonstrated through physical modelling, field measurements, and case studies. Since 2009, the technology has been successfully applied to 14 longwall areas in 9 Chinese coal mines. The ultimate surface subsidence factors vary from 0.10 to 0.15. This method has a great potential to be popularized and performed where longwall mining are implemented under villages and ground infrastructures.
文摘In recent years,field trials of non-pillar longwall mining using complete backfill have been implemented successively in the Chinese coal mining industry.The objective of this paper is to get a scientific understanding of surface subsidence control effect using such techniques.It begins with a brief overview on complete backfill methods primarily used in China,followed by an analysis of collected subsidence factors under mining with complete backfill.It is concluded that non-pillar longwall panel layout cannot protect surface structures against damages at a relatively large mining height,even though complete backfill is conducted.In such cases,separated longwall panel layout should be applied,i.e.,panel width should be subcritical and stable coal pillars should be left between the adjacent panels.The proposed method takes the principles of subcritical extraction and partial extraction;in conjunction with gob backfilling,surface subsidence can be effectively mitigated,thus protecting surface buildings against mining-induced damage.A general design principle and method of separated panel layout have also been proposed.
