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1.
Taiwan High Speed Rail (THSR), which began operations in January 2007, passes through an area in Yunlin County where the largest cumulative subsidence measured during 1992–2006 exceeds 100 cm. Leveling benchmarks, GPS pillars and multi-level monitoring wells were deployed in this area to collect detailed subsidence data from October 2003 to 2006. Leveling is carried out on both ground benchmarks and survey bolts attached to THSR columns. Minimum constraint solutions of leveling networks produce estimated heights accurate to a few mm. Special attention is paid to code smoothing, ionospheric, tropospheric and ocean tidal loading (OTL) effects, so that height estimates from GPS are optimal. Leveling and GPS-derived height changes are consistent to 1 cm, and show that from Stations 210 to 240K of TSHR, the subsidence is bowl shaped. Measurements of sediment compaction in specific depth intervals at three monitoring wells indicate that most of the subsidence is caused by sediment compaction at depths from 50 to 300 m. The major compaction occurs in the interval 220–300 m and is attributed to ground water withdrawal. Large angular deflections as determined from subsidence measurements are detected at some columns, but are below the upper bound (1/1,000) of tolerance specified in the safety code. With the current subsidence and sediment compaction, no significantly reduced loading capacity of the columns is expected to occur. For a safe THSR operation, subsidence and sediment-compaction monitoring should be continued, and current ground water withdrawal in Yunlin must be reduced or stopped.  相似文献   

2.
Review: Regional land subsidence accompanying groundwater extraction   总被引：9，自引：4，他引：5  
The extraction of groundwater can generate land subsidence by causing the compaction of susceptible aquifer systems, typically unconsolidated alluvial or basin-fill aquifer systems comprising aquifers and aquitards. Various ground-based and remotely sensed methods are used to measure and map subsidence. Many areas of subsidence caused by groundwater pumping have been identified and monitored, and corrective measures to slow or halt subsidence have been devised. Two principal means are used to mitigate subsidence caused by groundwater withdrawal??reduction of groundwater withdrawal, and artificial recharge. Analysis and simulation of aquifer-system compaction follow from the basic relations between head, stress, compressibility, and groundwater flow and are addressed primarily using two approaches??one based on conventional groundwater flow theory and one based on linear poroelasticity theory. Research and development to improve the assessment and analysis of aquifer-system compaction, the accompanying subsidence and potential ground ruptures are needed in the topic areas of the hydromechanical behavior of aquitards, the role of horizontal deformation, the application of differential synthetic aperture radar interferometry, and the regional-scale simulation of coupled groundwater flow and aquifer-system deformation to support resource management and hazard mitigation measures.  相似文献   

3.
Subsidence related to multiple natural and human-induced processes affects an increasing number of areas worldwide. Although this phenomenon may involve surface deformation with 3D displacement components, negative vertical movement, either progressive or episodic, tends to dominate. Over the last decades, differential SAR interferometry (DInSAR) has become a very useful remote sensing tool for accurately measuring the spatial and temporal evolution of surface displacements over broad areas. This work discusses the main advantages and limitations of addressing active subsidence phenomena by means of DInSAR techniques from an end-user point of view. Special attention is paid to the spatial and temporal resolution, the precision of the measurements, and the usefulness of the data. The presented analysis is focused on DInSAR results exploitation of various ground subsidence phenomena (groundwater withdrawal, soil compaction, mining subsidence, evaporite dissolution subsidence, and volcanic deformation) with different displacement patterns in a selection of subsidence areas in Spain. Finally, a cost comparative study is performed for the different techniques applied.  相似文献   

4.
浊水溪冲积扇为台湾目前最严重的地层下陷区,已设置包括DInSAR、GPS、水准测量、磁环分层式监测井与地下水位井等多元监测系统。大范围监测地层下陷方法中的水准测量有取样性不足之缺点,而DInSAR也易受相位不相关与大气误差影响而致精度降低。本研究利用2006~2008年期间共20幅ENVISAT卫星影像,搭配PSI技术,有效降低DInSAR的误差影响,同时获得107.6像素/km2的取样密度,弥补了水准测量取样密度仅0.2个/km2的取样性不足,透过295个监测点交叉验证,PSI与水准测量的成果显示两者的均方根误差为0.6cm。本研究亦发展了资料融合方法,有效结合水准测量与PSI成果,实验结果显示融合后的成果更能精确展现下陷的范围与下陷中心的变化,同时该成果与水准测量之均方根误差降至0.4cm。  相似文献   

5.
The application of satellite differential synthetic aperture radar (SAR) interferometry, principally coherent (InSAR) and to a lesser extent, persistent-scatterer (PSI) techniques to hydrogeologic studies has improved capabilities to map, monitor, analyze, and simulate groundwater flow, aquifer-system compaction and land subsidence. A number of investigations over the previous decade show how the spatially detailed images of ground displacements measured with InSAR have advanced hydrogeologic understanding, especially when a time series of images is used in conjunction with histories of changes in water levels and management practices. Important advances include: (1) identifying structural or lithostratigraphic boundaries (e.g. faults or transitional facies) of groundwater flow and deformation; (2) defining the material and hydraulic heterogeneity of deforming aquifer-systems; (3) estimating system properties (e.g. storage coefficients and hydraulic conductivities); and (4) constraining numerical models of groundwater flow, aquifer-system compaction, and land subsidence. As a component of an integrated approach to hydrogeologic monitoring and characterization of unconsolidated alluvial groundwater basins differential SAR interferometry contributes unique information that can facilitate improved management of groundwater resources. Future satellite SAR missions specifically designed for differential interferometry will enhance these contributions.  相似文献   

6.

Over-exploitation of groundwater in many evolving urban settings causes ground subsidence and permanent loss of aquifer storage capacity. DInSAR (differential interferometric synthetic aperture radar) time series data from 2016 to 2019 were used to monitor and model the surface deformation around Nairobi, Kenya, where the water demand has exceeded the supply without capacity augmentation for over two decades. The aquifer system constitutes hard rock to semiconfined ash beds in volcanic terrain. The Small Baseline DInSAR technique identified the spatial pattern of subsidence and magnitude (line-of-sight (LOS) velocity), which exceeds 41 mm/year in the semiconfined aquifer towards the western-central part of Nairobi. The spatial distribution of subsidence is consistent with the groundwater level drop and probable compaction modeled using aquifer characteristics for 1950–2015. The Global Navigation Satellite System (GNSS) data at a station from 2007 to 2018 indicate a cumulative 4-cm subsidence which is comparable to ~2.5-cm LOS subsidence from the present study for 2016–2019. The correlation with other hydrological data suggests the aquifer is experiencing inelastic subsidence due to unsustainable groundwater extraction, putting a massive strain on Nairobi’s aquifer system. The present DInSAR based study establishes its effectiveness in the monitoring of groundwater over-exploitation-based subsidence and associated hazard to the aquifer in emerging urban centers.

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7.
The plain of Beijing city in China suffers severe land subsidence owing to groundwater overdraft. The maximum subsidence rate could reach 6 cm/year through the 2000s. An integrated subsidence-monitoring program was designed, including levelling survey, borehole extensometers and multilayer monitoring of groundwater level, with the aim to understand both hydrological and mechanical processes and to characterize the land subsidence. From multilayer compaction monitoring, the major compression layers were identified. The major strata contributing to compression deformation are the second (64.5–82.3 m) and third (102–117 m) aquitards, which contributed around 39 % of the total subsidence. Meanwhile, irrecoverable deformations were also observed in the second (82.3–102 m) and third (117–148 m) confined aquifers; they exhibit elasto-plastic mechanical behavior, which is attributed to the thin beds of silt or silty clay. Stress–strain analysis and oedometer tests were conducted to study the aquifer-system response to pumping　and to estimate the specific storage of the major hydrogeologic units. The results reveal the creep behavior and elasto-plastic, visco-elasto-plastic mechanical behavior of the aquitards at different depths. The compressibility of the aquitards in the inelastic range is about one order of magnitude larger than for the elastic range.  相似文献   

8.
The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the valley, the San Joaquin Valley, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007–2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin Valley. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central Valley Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.  相似文献   

9.
Jakarta is the capital city of Indonesia with a population of about 9.6 million people, inhabiting an area of about 660 square-km. In the last three decades, urban development of Jakarta has grown very rapidly in the sectors of industry, trade, transportation, real estate, and many others. This exponentially increased urban development introduces several environmental problems. Land subsidence is one of them. The resulted land subsidence will also then affect the urban development plan and process. It has been reported for many years that several places in Jakarta are subsiding at different rates. The leveling surveys, GPS survey methods, and InSAR measurements have been used to study land subsidence in Jakarta, over the period of 1982–2010. In general, it was found that the land subsidence exhibits spatial and temporal variations, with the rates of about 1–15 cm/year. A few locations can have the subsidence rates up to about 20–28 cm/year. There are four different types of land subsidence that can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial soil, and tectonic subsidence. It was found that the spatial and temporal variations of land subsidence depend on the corresponding variations of groundwater extraction, coupled with the characteristics of sedimentary layers and building loads above it. In general, there is strong relation between land subsidence and urban development activities in Jakarta.  相似文献   

10.
Land Subsidence of Jakarta (Indonesia) and its Geodetic Monitoring System   总被引：6，自引：2，他引：6  
Abidin  Hasanuddin Z.  Djaja  Rochman  Darmawan  Dudy  Hadi  Samsul  Akbar  Arifin  Rajiyowiryono  H.  Sudibyo  Y.  Meilano  I.  Kasuma  M. A.  Kahar  J.  Subarya  Cecep 《Natural Hazards》2001,23(2-3):365-387
Jakarta is the capital city of Indonesia with a population of about 10 million people, inhabiting an area of about 25 × 25 km. It has been reported for sometime that locations in Jakarta are subsiding at different rates. Up to the present, there has been no comprehensive information about the characteristics and pattern of land subsidence in the Jakarta area. Usually land subsidence in Jakarta is measured using extensometers and ground water level observations, or estimated using geological and hydrological parameters. To give a better picture about land subsidence, geodetic-based monitoring systems utilizing leveling and GPS surveys have also been implemented.The land subsidence characteristics of Jakarta and its surrounding area areinvestigated using data from three repeated leveling surveys performed in1982, 1991, and 1997, and two repeated GPS surveys conducted in 1997and 1999. Leveling surveys detected subsidence up to about 80 cm duringthe period of 1982–1991, and up to about 160 cm during the 1991–1997period; while GPS surveys observed subsidence up to about 20 cm duringthe period of 1997–1999. Comparison with the hydrological data shows thatland subsidence in Jakarta is strongly related to excessive groundwater extraction.  相似文献   

11.
Shanghai, in China, has experienced two periods of rapid land subsidence mainly caused by groundwater exploitation related to economic and population growth. The first period occurred during 1956–1965 and was characterized by an average land subsidence rate of 83 mm/yr, and the second period occurred during 1990–1998 with an average subsidence rate of 16 mm/yr. Owing to the establishment of monitoring networks for groundwater levels and land subsidence, a valuable dataset has been collected since the 1960s and used to develop regional land subsidence models applied to manage groundwater resources and mitigate land subsidence. The previous geomechanical modeling approaches to simulate land subsidence were based on one-dimensional (1D) vertical stress and deformation. In this study, a numerical model of land subsidence is developed to simulate explicitly coupled three-dimensional (3D) groundwater flow and 3D aquifer-system displacements in downtown Shanghai from 30 December 1979 to 30 December 1995. The model is calibrated using piezometric, geodetic-leveling, and borehole extensometer measurements made during the 16-year simulation period. The 3D model satisfactorily reproduces the measured piezometric and deformation observations. For the first time, the capability exists to provide some preliminary estimations on the horizontal displacement field associated with the well-known land subsidence in Shanghai and for which no measurements are available. The simulated horizontal displacements peak at 11 mm, i.e. less than 10 % of the simulated maximum land subsidence, and seems too small to seriously damage infrastructure such as the subways (metro lines) in the center area of Shanghai.  相似文献   

12.
Mechanics of land subsidence due to groundwater pumping   总被引：1，自引：0，他引：1  
This paper presents the formulation of the basic mechanics governing the changes in stress states from groundwater pumping and comparisons among predicted land subsidence from this mechanics with existing analyses and field data. Land subsidence is a growing, global problem caused by petroleum and groundwater withdrawal, mining operations, natural settlement, hydro‐compaction, settlement of collapsible soils, settlement of organic soils and sinkholes. This paper is concerned with the land subsidence due to groundwater level decline by groundwater pumping. It is shown that the stress state consists of asymmetric stresses that are best simulated by a Cosserat rather than a Cauchy continuum. Land subsidence from groundwater level decline consists of vertical compression (consolidation), shear displacement and macro‐rotation. The latter occurs when conditions are favorable (e.g. at a vertical interface) for the micro‐rotation imposed by asymmetric stresses to become macro‐rotation. When the length of the cone of depression is beyond √2 times the thickness of the aquifer, simple shear on vertical planes with rotation is the predominant deformation mode. Otherwise, simple shear on horizontal planes is present. The predicted subsidence using the mechanics developed in this paper compares well with data from satellite‐borne interferometric synthetic aperture radar. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

13.
Land subsidence is a serious problem in Taiwan’s Yunlin area due to groundwater overpumping. There are safety risks in the high-speed railway structures in the areas of Siluo, Huwei, Tuku, and Yuanchang towns that run from north to south in the Yunlin area. Therefore, it is important to increase the groundwater recharge and to remedy the land subsidence in this area. The purpose of this study is to use the stream-flow estimation model (SF) and the groundwater flow numerical software MODFLOW (MF) to estimate the stream infiltration with consideration to the variation of the river water level in the Hsinhuwei River. The Ferris analytical model (FA) and MF are used to estimate the increased stream infiltration after the water level of the river rises. The hydraulic parameters required for each model are obtained from field observations and laboratory experiments. The results indicate that the assessment of the stream infiltration obtained through the SF and MF models are 264.2 × 104 and 170.9 × 104 m3/year, respectively. When the river water level increases by about 2.5 m, the annual stream infiltration obtained through the FA and MF models significantly increases by 31.6 × 104 and 26.4 × 104 m3/year, respectively. Taken together, the stream storages estimated using these two models indicate that an increasing efficiency of groundwater recharge is within the range of 10.0–18.5%.  相似文献   

14.
Land subsidence in China occurs predominantly in 17 provinces (cities) situated in the eastern and middle regions of the country, including Shanghai, Tianjin and Jiangsu, and Hebei provinces. It is primarily caused by groundwater overpumping. One of the areas most severely affected by land subsidence is the Yangtze Delta, most of which consists of Shanghai City, the Su-Xi-Chang area (Suzhou, Wuxi and Changzhou cities) of Jiangsu Province, and the Hang-Jia-Hu area (Hangzhou, Jiaxing and Huzhou cities) of Zhejiang Province. The excessive exploitation of groundwater forms in a large regional cone of depression and, consequently, land subsidence is also regional, currently centered in the Shanghai and Su-Xi-Chang areas. In 2002, the maximum cumulative subsidence of Shanghai, Su-Xi-Chang and Hang-Jia-Hu were 2.63 m, 2.00 and 1.06 m, respectively. The land subsidence area is continuing to expand throughout the Yangtze Delta. To study the characteristics and the pattern of this land subsidence, the government has implemented a monitoring system involving the placement of 37 groups of extensometers (layers marks) and drilling of more than 1000 observation wells. These provide an invaluable historical record of deformation and pore water pressure and facilitate studies on the special features of soil deformation when the groundwater level changes due to pumping. Several measures have been taken in recent years to control the development of the land subsidence in the different areas; these include groundwater injection, prohibition of pumping deep confined groundwater, and an adjustment of the pumping depth and magnitude of the groundwater withdrawn. At present, although the subsidence area is still increasing slowly, the subsidence rate is controlled.  相似文献   

15.
In this paper, we discuss historical and recent land subsidence in the Modern Yellow River Delta. Integrated analysis of leveling and relevant background data, including groundwater level, oil extraction, and geological structure, has revealed that land displacement is driven by natural and induced components acting at various depths. Since the 1950s, intense settlements occurred in the modern estuary delta lobes. Between 2002 and 2008, the subsidence center of Dongying and Guangrao exhibited a typical subsidence area with subsidence rates of 28.2 and 64.7 mm/years, respectively. Higher magnitudes are associated with groundwater withdrawals and oil–gas field exploitations, which induce the compaction of a deep clayey layer. There existed a significant linear positive correlation between groundwater level and elevation in the center of the deep groundwater depression cone. The major contributor of natural subsidence is tectonic movements, while moderate sinking due to the natural consolidation of the recent delta subsoil is still acting.  相似文献   

16.
 Land subsidence due to groundwater withdrawal combined with a global sea level rise creates a serious environmental problem in the coastal region. Groundwater withdrawal results in fluid pressure change in the layers. The pressure change in the layers induces both elastic and inelastic land compaction. The elastic compaction can be recovered if the water level rises again and inelastic compaction becomes permanent. Groundwater response to barometric pressure change is used to estimate the elastic compaction in this study. The storativity, specific storage and other layer and hydrological information are used to estimate the inelastic compaction of the layers due to fluid withdrawal. The discussed methods are applied to estimate and predict the subsidence potentials resulting from overdrafting of the groundwater in the southern New Jersey. The estimated subsidence is about 2–3 cm near the location of monitoring wells in Atlantic, Camden, Cumberland and Cape May Counties over the past 20 years. If the current trend of water-level drop continues, the average subsidence in southern New Jersey in the vicinity of some monitoring wells will be about 3 cm in the next 20 years. The rise of global sea level is about 2 mm/year on average. Because of the very gentle slope in southern NJ, the combination of subsidence and sea level rise will translate into a potentially substantial amount of land loss in the coastal region in each 20 year period. This combination will also accelerate the coastal flooding frequency and the erosion rate of the New Jersey coastal plain, and pose a serious threat to the coastal economy. Received: 15 December 1997 · Accepted: 30 June 1998  相似文献   

17.
It is obvious to anyone working on or dealing with underground mining operations, production gaps have to be opened in the ground during mining. The ground layers just above these gaps collapse toward production lines resulting in horizontal and vertical movements both inside and on the earth's surface. These movements are referred to as mining subsidence which eventually causes technical, economic, social and environmental hazards to natural and cultural structures on the surface. It is substantially crucial to the general and regional characteristics of these subsidence occurrences in the underground mining region so it can be possible to mitigate the subsidence induced damages and problems both in the ground and on the surface. Subsidence observations, thus, are conducted inside and on the ground by employing geodetic, geophysical and geotechnical methods with the aim to determine the characteristics and parameters of subsidence occurrence in a region evaluating these subsidence observations. The Zonguldak Hard Coal Basin and Kozlu Coal Production Region within the basin are places where urbanization and underground mining operations are intensively under way. Therefore it is vitally important to continuously monitor the horizontal and vertical displacements formed due to the underground mining in the basin and to determine the subsidence parameters so that it may be possible to forestall the subsidence induced issues that may occur in the near future. This study yields information and computations about the subsidence parameters determined under the light of three periods of geodetic observations carried out in the region. Using the three periods of GPS and precise leveling observations, the average slope angle values resulting from vertical displacements in the study region were obtained from the adjusted coordinates and height differences, and estimated as 16″.67 in positive (+) direction and 18″.03 in negative (−) direction. The horizontal unit deformation parameters, on the other hand, were computed as 0.28 mm/m for the extension parameter while 0.26 mm/m for compression parameter along the routes chosen in the Kozlu region.  相似文献   

18.
The Upper Rhine graben is a north–northeast trending rift system, which belongs to the European Cenozoic rift system. Today, the southern part of the graben is seismically still active. Earthquakes of magnitude 5 have a recurrence time of approximately 30 years. In order to monitor and to determine the displacements in the study area, GPS measurements have been carried out in two campaigns (1999 and 2000), and observations of the available permanent stations have been processed in 2002. Owing to the small size of deformations expected, high accuracy requirements must be met by the GPS processing. In order to achieve these requirements, precise antenna modeling has been introduced into the processing. As expected the short time span has not enabled to detect significant displacements from the GPS measurements. The deformation analysis shows that the horizontal displacement rates do not exceed 1 mm/year, which is compatible with the geological information. Owing to the fact that the accuracy of positioning with GPS for the vertical coordinates is lower than for the horizontal coordinates, the determination of vertical displacements has been carried out using the leveling technique. In the area of Freiburg, first-order and second-order leveling lines have been chosen for the detection of local displacements on the Weinstetten, on the Lehen-Schönberg and on the Main Border Fault (MBF). Some sections of these faults are still active today. Significant vertical displacements have been observed at the Weinstetten fault in the area of Bad Krozingen and on the MBF in Freiburg. The displacement rates (1925–1984) are 0.17±0.01 mm/year and 0.25±0.02 mm/year respectively. The results agree very well with the results of seismotectonic investigations, and show that ongoing displacements can be found on the northern part of the Lehen-Schönberg fault in the vicinity of Eichstetten, and on the MBF in the vicinity of Freiburg.  相似文献   

19.
Land subsidence was first observed in Shanghai nearly a century ago, in 1921. Land subsidence attributed to groundwater extraction has been severe in China and is still occurring. Recent subsidence and associated earth fissures occurring since 2000 in three principal regions—the North China Plain, Fenwei Basin and Yangtze Delta—are introduced, and historical subsidence in these areas is briefly summarized. The subsidence-affected area in these regions with cumulative subsidence greater than or equal to 200 mm is more than 90,000 km2 and covers 22 provinces (cities), which include intensively developed and densely populated areas. Earth fissures accompanying the subsidence create significant geohazards; more than 1,000 earth fissures have been identified in the North China Plain, Fenwei Basin and Yangtze Delta. Effective land-subsidence-monitoring networks, that include continuous global positioning system (GPS) stations, repeat GPS and leveling surveys of geodetic benchmarks, InSAR, borehole extensometers, and groundwater observation wells, have been established in these three subsidence-affected areas. Mitigation measures and administrative means have been implemented in some areas, with good results in the Yangtze Delta area.  相似文献   

20.
Information on the distribution of subsurface temperature and hydraulic heads at 24 observation wells in and around the Tokyo Lowland, the eastern part of the Tokyo Metropolitan area, were examined to make clear the relationship between groundwater and the subsurface thermal environment in the urban area. Minimums in temperature–depth logs due to subsurface temperature increasing at shallow parts were recognized in 21 wells. This fact shows subsurface temperature is affected by ground surface warming in almost all of this area. Deeper than minimums, where the effects of surface warming became relatively small, regional variation is observed as follows: high temperatures are shown in the central part to the southern part, and low temperatures shown in the inland to eastern part. The high temperature area corresponds to an area where the lower boundary of groundwater flow is relatively shallow. This area corresponds also to an area with severe land subsidence resulting from excessive groundwater pumping. It is considered that this high temperature area is formed by the effects of upward groundwater flow affected by hydrogeological conditions and pumping. On the other hand, a comparison between past data (1956–1967) and present data (2001–2003) revealed widespread decreasing temperature in the inland area. This is explained by downward groundwater flow based on an analysis of temperature–depth logs. This fact suggests that subsurface temperature is not only increasing from the effects of surface warming but also decreasing from the effects of groundwater environment change due to pumping.  相似文献   

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