Aquifer thermal energy storage(ATES)system has received attention for heating or cooling buildings.However,it is well known that land subsidence becomes a major environmental concern for ATES projects.Yet,the effect o...Aquifer thermal energy storage(ATES)system has received attention for heating or cooling buildings.However,it is well known that land subsidence becomes a major environmental concern for ATES projects.Yet,the effect of temperature on land subsidence has received practically no attention in the past.This paper presents a thermo-hydro-mechanical(THM)coupled numerical study on an ATES system in Shanghai,China.Four water wells were installed for seasonal heating and cooling of an agriculture greenhouse.The target aquifer at a depth of 74e104.5 m consisted of alternating layers of sand and silty sand and was covered with clay.Groundwater level,temperature,and land subsidence data from 2015 to 2017 were collected using field monitoring instruments.Constrained by data,we constructed a field scale three-dimensional(3D)model using TOUGH(Transport of Unsaturated Groundwater and Heat)and FLAC3D(Fast Lagrangian Analysis of Continua)equipped with a thermo-elastoplastic constitutive model.The effectiveness of the numerical model was validated by field data.The model was used to reproduce groundwater flow,heat transfer,and mechanical responses in porous media over three years and capture the thermo-and pressure-induced land subsidence.The results show that the maximum thermoinduced land subsidence accounts for about 60%of the total subsidence.The thermo-induced subsidence is slightly greater in winter than that in summer,and more pronounced near the cold well area than the hot well area.This study provides some valuable guidelines for controlling land subsidence caused by ATES systems installed in soft soils.展开更多
The implementation of the South-to-North Water Diversion Project (SNWDP) has alleviated groundwater resource pressure in North China to some extent, resulting in a gradual deceleration of land subsidence and even rebo...The implementation of the South-to-North Water Diversion Project (SNWDP) has alleviated groundwater resource pressure in North China to some extent, resulting in a gradual deceleration of land subsidence and even rebound in some areas. To investigate the spatiotemporal evolution characteristics of land subsidence in the eastern plain of Beijing following the SNWDP, this study employs Ascending (ASC) and Descending (DES) InSAR data combined with a Strain Model (SM) to obtain a Three-Dimensional (3-D) deformation field from 2016 to 2018. Through analysis of the 3-D deformation characteristics and spatiotemporal evolution of land subsidence in this region from 2016 to 2018, the results reveal a shift in the distribution of subsiding areas after the South-to-North Water Diversion, with a marked decrease in subsidence rates in certain areas. The maximum subsidence rate in the Beijing area has decreased to 110 mm/yr, accompanied by horizontal deformation at a rate of 12 mm/yr. Additionally, by examining the spatial relationship between major active faults and subsidence deformation in this region, the study further elucidates the influence of fault activity on the spatial distribution of subsidence deformation.展开更多
Numerical simulation modeling is a hotspot in the geological engineering computing field. Tak- ing a fast Langrangian analysis of continua in 3 dimensions （FLAC3D） numerical modeling on com- puting the geo-deformati...Numerical simulation modeling is a hotspot in the geological engineering computing field. Tak- ing a fast Langrangian analysis of continua in 3 dimensions （FLAC3D） numerical modeling on com- puting the geo-deformation information caused by the mining subsidence in a coalmine for example, a new GIS-Excel modeling method is proposed to build geologic strata within the simulation range combined with the coal-seam dip angle of the underground mining working-planes. First of all, the coal-seam model of the numerical computing is built by using the geographic information system （GIS） according to the stripe-through principle and the calculating formula on the size of the model blocks in the paper defined, then the FLAC3D numerical computing model of all geologic strata with- in the simulation range is also built based on the calculating formula of thickness of each stratum and the Excel fast computing advantages. The GIS-Excel method is good at the higher modeling accuracy, seldom making mistakes and consuming less time. The reliability and validity of the method is veri- fied well by its practical applications in the coalmine area.展开更多
To predict the behavior of land subsidence due to groundwater withdrawal, a 3D numerical model is established. The model takes the confined aquifer and soft deposit of Ningbo into account. According to the pumping tes...To predict the behavior of land subsidence due to groundwater withdrawal, a 3D numerical model is established. The model takes the confined aquifer and soft deposit of Ningbo into account. According to the pumping test data, changing regulations of groundwater level, and land subsidence during dewatering are analyzed. Comparison between the calculated value and measured value shows that the 3D model simulates the measured value fairly well. The future behavior of land subsidence during dewatering period provides the scientific basis for the construction of deep foundation.展开更多
Legal boundaries are used for delineating the spatial extent of ownership property’s spaces.In underground environments,these boundaries are defined by referencing physical objects,surveying measurements,or projectio...Legal boundaries are used for delineating the spatial extent of ownership property’s spaces.In underground environments,these boundaries are defined by referencing physical objects,surveying measurements,or projections.However,there is a gap in connecting and managing these boundaries and underground legal spaces,due to a lack of data model.A 3D data model supporting underground land administration(ULA)should define and model these boundaries and the relationships between them and underground ownership spaces.Prominent 3D data models can be enriched to model underground legal boundaries.This research aims to propose a new taxonomy of underground legal boundaries and model them by extending CityGML,which is a widely used 3D data model in the geospatial science domain.We developed,implemented,and tested the model for different types of underground legal boundaries.The implemented prototype showcased the potential benefits of CityGML for managing underground legal boundaries in 3D.The proposed 3D underground model can be used to address current challenges associated with communicating and managing legal boundaries in underground environments.While this data model was specifically developed for Victoria,Australia,the proposed model and approach can be used and replicated in other jurisdictions by adjusting the data requirements for underground legal boundaries.展开更多
Currently,the satellite data used to estimate terrestrial net primary productivity(NPP)in China are predominantly from foreign satellites,and very few studies have based their estimates on data from China’s Fengyun s...Currently,the satellite data used to estimate terrestrial net primary productivity(NPP)in China are predominantly from foreign satellites,and very few studies have based their estimates on data from China’s Fengyun satellites.Moreover,despite their importance,the influence of land cover types and the normalized difference vegetation index(NDVI)on NPP estimation has not been clarified.This study employs the Carnegie–Ames–Stanford approach(CASA)model to compute the fraction of absorbed photosynthetically active radiation and the maximum light use efficiency suitable for the main vegetation types in China in accordance with the finer resolution observation and monitoring-global land cover(FROM-GLC)classification product.Then,the NPP is estimated from the Fengyun-3D(FY-3D)data and compared with the Moderate Resolution Imaging Spectroradiometer(MODIS)NPP product.The FY-3D NPP is also validated with existing research results and historical field-measured NPP data.In addition,the effects of land cover types and the NDVI on NPP estimation are analyzed.The results show that the CASA model and the FY-3D satellite data estimate an average NPP of 441.2 g C m^(−2) yr^(−1) in 2019 for China’s terrestrial vegetation,while the total NPP is 3.19 Pg C yr^(−1).Compared with the MODIS NPP,the FY-3D NPP is overestimated in areas of low vegetation productivity and is underestimated in high-productivity areas.These discrepancies are largely due to the differences between the FY-3D NDVI and MODIS NDVI.Compared with historical field-measured data,the FY-3D NPP estimation results outperformed the MODIS NPP results,although the deviation between the FY-3D NPP estimate and the in-situ measurement was large and may exceed 20%at the pixel scale.The land cover types and the NDVI significantly affected the spatial distribution of NPP and accounted for NPP deviations of 17.0%and 18.1%,respectively.Additionally,the total deviation resulting from the two factors reached 29.5%.These results show that accurate NDVI products and land cover types are important prerequisites for NPP estimation.展开更多
房地不动产具备天然的立体特性,在三维空间中对其进行准确刻画是当前城市地上地下综合开发的关键问题,国内外学者已经提出了各类房地不动产数据模型,旨在解决房地不动产的管理与权利空间的三维表达问题。分析国内外学者的研究成果发现,...房地不动产具备天然的立体特性,在三维空间中对其进行准确刻画是当前城市地上地下综合开发的关键问题,国内外学者已经提出了各类房地不动产数据模型,旨在解决房地不动产的管理与权利空间的三维表达问题。分析国内外学者的研究成果发现,国外学者提出的房地不动产数据模型多以地籍为核心展开,不能完全适用于我国的房地不动产管理;而国内学者虽兼顾了地籍和房产,但忽略了建筑实体、建筑空间与产权空间的关系,无法将房地不动产信息与建筑物信息模型(Building Information Modeling,BIM)整合,不利于房地不动产的精细化管理。针对以上问题,本文提出了基于IFC(Industry Foundation Classes)标准扩展的房地一体化三维不动产数据模型,并通过实例验证了该模型在我国房地不动产管理上是可行的。研究结果表明,本文提出的模型正确表达了各类建筑对象和产权对象,既可以支持业务相关的关联关系的查询,也支持GIS常见拓扑关系的查询和表达,该模型除了能表达符合我国体制的房地不动产对象外,还关联了BIM模型中的建筑构件、建筑空间,为城市建设与运维管理提供技术模型支持。展开更多
基金sponsored by the National Key Research and Development Program of China(Grant No.2020YFC1808102).
文摘Aquifer thermal energy storage(ATES)system has received attention for heating or cooling buildings.However,it is well known that land subsidence becomes a major environmental concern for ATES projects.Yet,the effect of temperature on land subsidence has received practically no attention in the past.This paper presents a thermo-hydro-mechanical(THM)coupled numerical study on an ATES system in Shanghai,China.Four water wells were installed for seasonal heating and cooling of an agriculture greenhouse.The target aquifer at a depth of 74e104.5 m consisted of alternating layers of sand and silty sand and was covered with clay.Groundwater level,temperature,and land subsidence data from 2015 to 2017 were collected using field monitoring instruments.Constrained by data,we constructed a field scale three-dimensional(3D)model using TOUGH(Transport of Unsaturated Groundwater and Heat)and FLAC3D(Fast Lagrangian Analysis of Continua)equipped with a thermo-elastoplastic constitutive model.The effectiveness of the numerical model was validated by field data.The model was used to reproduce groundwater flow,heat transfer,and mechanical responses in porous media over three years and capture the thermo-and pressure-induced land subsidence.The results show that the maximum thermoinduced land subsidence accounts for about 60%of the total subsidence.The thermo-induced subsidence is slightly greater in winter than that in summer,and more pronounced near the cold well area than the hot well area.This study provides some valuable guidelines for controlling land subsidence caused by ATES systems installed in soft soils.
文摘The implementation of the South-to-North Water Diversion Project (SNWDP) has alleviated groundwater resource pressure in North China to some extent, resulting in a gradual deceleration of land subsidence and even rebound in some areas. To investigate the spatiotemporal evolution characteristics of land subsidence in the eastern plain of Beijing following the SNWDP, this study employs Ascending (ASC) and Descending (DES) InSAR data combined with a Strain Model (SM) to obtain a Three-Dimensional (3-D) deformation field from 2016 to 2018. Through analysis of the 3-D deformation characteristics and spatiotemporal evolution of land subsidence in this region from 2016 to 2018, the results reveal a shift in the distribution of subsiding areas after the South-to-North Water Diversion, with a marked decrease in subsidence rates in certain areas. The maximum subsidence rate in the Beijing area has decreased to 110 mm/yr, accompanied by horizontal deformation at a rate of 12 mm/yr. Additionally, by examining the spatial relationship between major active faults and subsidence deformation in this region, the study further elucidates the influence of fault activity on the spatial distribution of subsidence deformation.
基金Supported by the National Natural Science Foundation of China(No.41271436)
文摘Numerical simulation modeling is a hotspot in the geological engineering computing field. Tak- ing a fast Langrangian analysis of continua in 3 dimensions （FLAC3D） numerical modeling on com- puting the geo-deformation information caused by the mining subsidence in a coalmine for example, a new GIS-Excel modeling method is proposed to build geologic strata within the simulation range combined with the coal-seam dip angle of the underground mining working-planes. First of all, the coal-seam model of the numerical computing is built by using the geographic information system （GIS） according to the stripe-through principle and the calculating formula on the size of the model blocks in the paper defined, then the FLAC3D numerical computing model of all geologic strata with- in the simulation range is also built based on the calculating formula of thickness of each stratum and the Excel fast computing advantages. The GIS-Excel method is good at the higher modeling accuracy, seldom making mistakes and consuming less time. The reliability and validity of the method is veri- fied well by its practical applications in the coalmine area.
文摘To predict the behavior of land subsidence due to groundwater withdrawal, a 3D numerical model is established. The model takes the confined aquifer and soft deposit of Ningbo into account. According to the pumping test data, changing regulations of groundwater level, and land subsidence during dewatering are analyzed. Comparison between the calculated value and measured value shows that the 3D model simulates the measured value fairly well. The future behavior of land subsidence during dewatering period provides the scientific basis for the construction of deep foundation.
基金supported by Australian Research Council(Grant No.DE220100094).
文摘Legal boundaries are used for delineating the spatial extent of ownership property’s spaces.In underground environments,these boundaries are defined by referencing physical objects,surveying measurements,or projections.However,there is a gap in connecting and managing these boundaries and underground legal spaces,due to a lack of data model.A 3D data model supporting underground land administration(ULA)should define and model these boundaries and the relationships between them and underground ownership spaces.Prominent 3D data models can be enriched to model underground legal boundaries.This research aims to propose a new taxonomy of underground legal boundaries and model them by extending CityGML,which is a widely used 3D data model in the geospatial science domain.We developed,implemented,and tested the model for different types of underground legal boundaries.The implemented prototype showcased the potential benefits of CityGML for managing underground legal boundaries in 3D.The proposed 3D underground model can be used to address current challenges associated with communicating and managing legal boundaries in underground environments.While this data model was specifically developed for Victoria,Australia,the proposed model and approach can be used and replicated in other jurisdictions by adjusting the data requirements for underground legal boundaries.
基金Supported by the National Key Research and Development Program of China(2018YFC1506500)Natural Science Program of China(U2142212)National Natural Science Foundation of China(41871028).
文摘Currently,the satellite data used to estimate terrestrial net primary productivity(NPP)in China are predominantly from foreign satellites,and very few studies have based their estimates on data from China’s Fengyun satellites.Moreover,despite their importance,the influence of land cover types and the normalized difference vegetation index(NDVI)on NPP estimation has not been clarified.This study employs the Carnegie–Ames–Stanford approach(CASA)model to compute the fraction of absorbed photosynthetically active radiation and the maximum light use efficiency suitable for the main vegetation types in China in accordance with the finer resolution observation and monitoring-global land cover(FROM-GLC)classification product.Then,the NPP is estimated from the Fengyun-3D(FY-3D)data and compared with the Moderate Resolution Imaging Spectroradiometer(MODIS)NPP product.The FY-3D NPP is also validated with existing research results and historical field-measured NPP data.In addition,the effects of land cover types and the NDVI on NPP estimation are analyzed.The results show that the CASA model and the FY-3D satellite data estimate an average NPP of 441.2 g C m^(−2) yr^(−1) in 2019 for China’s terrestrial vegetation,while the total NPP is 3.19 Pg C yr^(−1).Compared with the MODIS NPP,the FY-3D NPP is overestimated in areas of low vegetation productivity and is underestimated in high-productivity areas.These discrepancies are largely due to the differences between the FY-3D NDVI and MODIS NDVI.Compared with historical field-measured data,the FY-3D NPP estimation results outperformed the MODIS NPP results,although the deviation between the FY-3D NPP estimate and the in-situ measurement was large and may exceed 20%at the pixel scale.The land cover types and the NDVI significantly affected the spatial distribution of NPP and accounted for NPP deviations of 17.0%and 18.1%,respectively.Additionally,the total deviation resulting from the two factors reached 29.5%.These results show that accurate NDVI products and land cover types are important prerequisites for NPP estimation.
文摘房地不动产具备天然的立体特性,在三维空间中对其进行准确刻画是当前城市地上地下综合开发的关键问题,国内外学者已经提出了各类房地不动产数据模型,旨在解决房地不动产的管理与权利空间的三维表达问题。分析国内外学者的研究成果发现,国外学者提出的房地不动产数据模型多以地籍为核心展开,不能完全适用于我国的房地不动产管理;而国内学者虽兼顾了地籍和房产,但忽略了建筑实体、建筑空间与产权空间的关系,无法将房地不动产信息与建筑物信息模型(Building Information Modeling,BIM)整合,不利于房地不动产的精细化管理。针对以上问题,本文提出了基于IFC(Industry Foundation Classes)标准扩展的房地一体化三维不动产数据模型,并通过实例验证了该模型在我国房地不动产管理上是可行的。研究结果表明,本文提出的模型正确表达了各类建筑对象和产权对象,既可以支持业务相关的关联关系的查询,也支持GIS常见拓扑关系的查询和表达,该模型除了能表达符合我国体制的房地不动产对象外,还关联了BIM模型中的建筑构件、建筑空间,为城市建设与运维管理提供技术模型支持。
