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1.
Shujun Ye Yue Luo Jichun Wu Xuexin Yan Hanmei Wang Xun Jiao Pietro Teatini 《Hydrogeology Journal》2016,24(3):695-709
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
2.
The aquifer system of the Basin of Mexico is the main source of water supply to the Mexico City Metropolitan Zone. Management of the Basin’s water resources requires improved understanding of regional groundwater flow patterns, for which large amounts of data are required. The current study analyses the regional dynamics of the potentiometric groundwater level using a new database called the Basin of Mexico Hydrogeological Database (BMHDB). To foster the development of a regional view of the aquifer system, data on climatological, borehole and runoff variables are part of the BMHDB. The structure and development of the BMHDB are briefly explained and then the database is used to analyze the consequences of groundwater extraction on the aquifer’s confinement conditions using lithology data. The regional analysis shows that the largest drawdown rates are located north of Mexico City, in Ecatepec (a region that has not yet received attention in hydrogeological studies), due to wells that were drilled as a temporary solution to Mexico City’s water-supply problem. It is evident that the aquifer has changed from a confined to an unconfined condition in some areas, a factor that is responsible for the large subsidence rates (40 cm/year) in some regions. 相似文献
3.
地面沉降作为一种常见地质灾害对城市发展造成巨大威胁,有效监测土层的垂向变形过程是地面沉降防治的一项重
要工作。文章采用布里渊光频域分析（BOFDA） 技术,利用室内地面沉降模型,对砂-黏土互层土体在排灌水循环中的垂
向变形进行分布式监测,并结合固结压缩试验对土体的垂向变形进行分析。结果表明：黏土层为地面沉降的主要变形层;
在排灌水循环中,土体也会经历压缩-回弹的循环。此外,BOFDA分布式监测技术可以有效地捕捉砂-黏土互层土体在排
灌水状态下的垂向变形情况,实现对地面沉降发育过程中土体垂向变形的实时监测。研究结果可为实现地面沉降的有效防
治措施提供一定的参考依据。 相似文献
4.
地面沉降作为一种常见地质灾害对城市发展造成巨大威胁，有效监测土层的垂向变形过程是地面沉降防治的一项重
要工作。文章采用布里渊光频域分析（BOFDA） 技术，利用室内地面沉降模型，对砂—黏土互层土体在排灌水循环中的垂
向变形进行分布式监测，并结合固结压缩试验对土体的垂向变形进行分析。结果表明：黏土层为地面沉降的主要变形层；
在排灌水循环中，土体也会经历压缩—回弹的循环。此外，BOFDA分布式监测技术可以有效地捕捉砂—黏土互层土体在排
灌水状态下的垂向变形情况，实现对地面沉降发育过程中土体垂向变形的实时监测。研究结果可为实现地面沉降的有效防
治措施提供一定的参考依据。 相似文献
5.
Jixiong Zhang Qiang Sun Nan Zhou Jiang Haiqiang Deon Germain Sami Abro 《Arabian Journal of Geosciences》2016,9(10):558
In China’s western coal mining area, the traditional room mining technology is facing coal pillar instability, mine earthquake, large-area roof subsidence in the goaf, surface subsidence, water and soil loss, vegetation deterioration, and other environmental problems. To solve the aforementioned problems and to improve coal recovery, the roadway backfill coal mining (RBCM) method was proposed as a solution and its technical principle and key equipment were presented in this paper. In addition, the microstructure and mechanical behavior (strain-stress relation in confined compressive test) of aeolian sand and loess backfill materials were studied for a rational backfill design for underground mines. Further, coal pillar stress, plastic zone change, and surface deformation of the RBCM schemes were studied using the FLAC3D numerical simulation software, and a reasonable mining scheme of “mining 7 m and leaving 3 m” was determined. The engineering application in Changxing Coal Mine shows that the RBCM method with loess and aeolian sand as backfill materials allows a stable recovery of coal pillars with a recovery ratio of more than 70 %. The maximum accumulated surface subsidence and the maximum horizontal deformation were measured to be 15 mm and 0.8 mm/m respectively, indicating that the targeted backfilling effect can help protect the environment and also control surface subsidence. 相似文献
6.
Subsidence has been affecting many cities around the world, such as Nagoya (Japan), Venice (Italy), San Joaquin Valley and Long Beach (California), and Houston (Texas). This phenomenon can be caused by natural processes and/or human activities, including but not limited to carbonate dissolution, extraction of material from mines, soil compaction, and fluid withdrawal. Surface deformation has been an ongoing problem in the Houston Metropolitan area because of the city’s location in a passive margin where faulting and subsidence are common. Most of the previous studies attributed the causes of the surface deformation to four major mechanisms: faulting, soil compaction, salt tectonics, and fluid withdrawal (groundwater withdrawal and hydrocarbon extraction). This work assessed the surface deformation in the greater Houston area and their possible relationship with fluid withdrawal. To achieve this goal, data from three complimentary remote sensing techniques Global Positioning System (GPS), Light Detection and Ranging (LiDAR), and Interferometric Synthetic Aperture Radar were used. GPS rates for the last 17 years show a change in surface deformation patterns. High rates of subsidence in the northwestern areas (up to ~4 cm/year) and signs of uplift in the southeast are observed (up to 2 mm\year). High rates of subsidence appear to be decreasing. Contrary to previous studies in which the location of subsidence appeared to be expanding toward the northwest, current results show that the area of subsidence is shrinking and migrating toward the northeast. Digital elevation model generated from airborne LiDAR, revealed changes between salt domes and their surrounding areas. The persistent scatterer interferometry was performed using twenty-five (25) European remote sensing-1/2 scenes. Rates of change in groundwater level and hydrocarbon production were calculated using data from 261 observation wells and 658 hydrocarbon wells. A water level decline of 4 m/year was found in area of highest subsidence, this area also show ~70 million m3/year of hydrocarbon extraction. This study found strong correlation between fluid withdrawals and subsidence. Therefore, both groundwater and hydrocarbon withdrawal in northwest Harris County are considered to be the major drivers of the surface deformation. 相似文献
7.
Some villages and bridges are located on the ground surface of the working district no. 7 in the Wanglou Coal Mine. If longwall mining is adopted, the maximum deformation of the ground surface will exceed the safety value. Strip mining is employed for the working district no. 7 which is widely used to reduce surface subsidence and the consequent damage of buildings on the ground surface. To ensure the safety of coal pillars and improve the recovery coefficient, theoretical analysis and numerical simulation (FLAC 3D) were adopted to determine the coal pillar and mining widths and to discuss the coal pillar stress distribution and surface subsidence for different mining scenarios. The results revealed that the width of coal pillars should be larger than 162 m, and the optimized mining width varies from 150 to 260 m. As the coal seam is exploited, vertical stress is mainly applied on the coal pillar, inducing stress changes on its ribs. The coefficient of mining-induced stress varies from 2.02 to 2.62 for different mining scenarios. The maximum surface subsidence and horizontal movement increase as the mining width increases. However, when the mining width increases to a certain value, increasing the pillar width cannot significantly decrease the maximum subsidence. To ensure the surface subsidence less than 500 mm, the mining width should not be larger than 200 m. Considering the recovery coefficient and safety of the coal pillar, a pillar width of 165 m is suggested. 相似文献
8.
In order to study the dynamic response characteristics of a rock slope with discontinuities under the combined action of earthquakes and rapid water drawdown, a large-scale shaking table test was performed on a rock slope with discontinuous joints. Wenchuan earthquake (WE) seismic records were performed to investigate the horizontal and vertical acceleration response and displacement response. In particular, three-dimensional optical measurement techniques was used to obtain the slope surface displacements. A comparison was made on the seismic response according to the analysis of PGD (peak ground displacement) and M PGA (acceleration amplification coefficient) of the modeled slope. The results show that the experimental slope mainly underwent settlement and horizontal deformation when the WE records were applied in the z and x directions, respectively. The slope was first shaken by the P wave, which caused the differential settlement to occur at the surface slope; then, the slope was shaken more severely by the S wave, which led to a greater horizontal deformation. Moreover, analysis of the ΔPGD (increment of PGD) and ΔM PGA (increment of M PGA) under rapid drawdown suggests that the rapid water drawdown mainly impacts the deformation of the surface slope, particularly between the high and low water levels. The water infiltration through the cracks softened the material of the surface slope, and the rapid drawdown also enhanced the slope deformation. In addition, the damage evolution process of the slope can be identified, mainly including three stages: an elastic stage (<?0.168 g), a plastic stage (0.168–0.336 g), and a failure stage (>?0.336 g). 相似文献
9.
根据江苏省徐州市睢宁县城区内可压缩土层的类型、空间分布特点及压缩变形等特征,建立了本区地面沉降计算地质模型。利用该模型计算出城区2013年累计地面沉降量3.08~380.60 mm,平均为162.41 mm,最大沉降量发生在城区西北部,该区域可压缩土层、黏性土的累计厚度大,地下水水位下降幅度较大。根据预测2030年地下水位埋深条件,采用地面沉降地质模型计算得出城区累计地面沉降量,在此基础上对区内地面沉降危险性进行分区,从而为地下水开采总量的控制及地面沉降监测控制提供相关建议措施,以避免城区2030年后地面沉降地质灾害逐步发展为特大型地质灾害。 相似文献
10.
Using differential SAR interferometry to map land subsidence: a case study in the Pingtung Plain of SW Taiwan 总被引：3，自引：2，他引：1
Hsieh Chia-Sheng Shih Tian-Yuan Hu Jyr-Ching Tung Hsin Huang Mong-Han Angelier Jacques 《Natural Hazards》2011,58(3):1311-1332
Synthetic aperture radar (SAR) interferometry (InSAR) is a geodetic tool widely applied in the studies of earth-surface deformation.
This technique has the benefits of high spatial resolution and centimetre-scale accuracy. Differential SAR interferometry
(DInSAR) is used to measure ground deformation with repeat-pass SAR images. This study applied DInSAR and persistent scatterers
InSAR (PSInSAR) for detecting land subsidence in the Pingtung Plain, southern Taiwan, between 1995 and 2000. In recent years,
serious land subsidence occurred along coastal regions of Taiwan as a consequence of over-pumping of underground water. Results
of this study revealed that the critical subsidence region is located on the coast near the estuary of Linpien River. It is
also found that subsidence was significantly higher during the dry season than the wet season. The maximum annual subsidence
rate of the dry season is up to −11.51 cm/year in critical subsidence region and the vertical land movement rate is much slower
during the wet season. The average subsidence rates in wet and dry seasons are −0.31 and −3.37 cm/year, respectively. As a
result, the subsidence rate in dry seasons is about 3 cm larger than in wet seasons. 相似文献
11.
We used two semi‐permanent GPS receivers with differential configuration to measure the hydrological subsidence of an aquifer used for water supply, located on a fractured granitic area. The time series of the vertical deformation measurements of the ground surface show a variation of 2 cm between winter and summer. We investigate the relationship between this vertical deformation and hydraulic head variations. We show that this kind of GPS survey allows characterizing part of the hydrological properties of such a heterogeneous aquifer. This is thus a new approach of time continuous monitoring of the deformation related to hydrogeological processes. 相似文献
12.
Numerical simulation of Qiaotou Landslide deformation caused by drawdown of the Three Gorges Reservoir,China 总被引：6，自引：2，他引：4
Jiwei Jiang Dominik Ehret Wei Xiang Joachim Rohn Ling Huang Shaojun Yan Renneng Bi 《Environmental Earth Sciences》2011,62(2):411-419
Landslides located beside reservoirs tend to be unstable or are characterized by large deformation during the drawdown process.
This has been accepted by many experts. In this paper, we use Qiaotou Landslide, which is located beside the Three Gorges
Reservoir (TGR), as a typical case study to investigate and predict the deformation mechanism during the drawdown process
of TGR in detail. According to field investigation, the landslide mass is mainly composed of thick, loose silt and clay mixed
with fragments of rock. Bedrock is mainly composed of silty sandstone. Field and laboratory tests indicate that the landslide
mass has a high permeability coefficient. If the water level declines fast, intense seepage force may result. Based on these
data, we establish a three-dimensional geological model of Qiaotou Landslide by FLAC3D and perform a numerical simulation using the saturated–unsaturated fluid–solid coupling theory. For the simulation, we assume
that the drawdown from 175 to 145 m takes place with a speed of 25 cm/day, which is based on the extreme water level regulation
program of TGR. The simulation shows that this causes a significant deformation in the landslide mass and that the maximum
displacement within the landslide is 24.2 cm. During the drawdown process, the maximum displacement zone is shifting from
the upper part of the landslide where bedrock surface is steeper and thickness of loose deposits is less to the middle part
of the landslide where bedrock surface is less steep and thickness of loose deposits is higher. The deformation mechanism
indicates that in the early stage of the drawdown the deformation of the landslide mass is mainly caused by seepage and in
the later stage mainly by consolidation. 相似文献
13.
Jinge Wang Aijun Su Wei Xiang Hsin-Fu Yeh Chengren Xiong Zongxing Zou Cheng Zhong Qingbing Liu 《Landslides》2016,13(4):795-804
The original Badong County, Hubei, China, was mainly below the highest water level of the Three Gorges Reservoir, which is 175 m above sea level. The new downtown of Badong was rebuilt in the Huangtupo area between 1982 and 1991. After detailed geological investigation in the Huangtupo area, four independent landslides were identified, making it one of the largest and most harmful landslide group in the Three Gorges Reservoir area. Since 2003, abundant data have been obtained from the Huangtupo No. 1 sliding mass about rainfall, water level, earth surface deformation and deep deformation. The monitoring data indicate that the earth surface and deep deformation of this landslide is closely related to the seasonal rainfall and water level fluctuation of the reservoir. During increases in the water level, the earth surface deformation velocity decreases, and then increases obviously in the subsequent water level decreasing stage. Because the water level drawdown period overlaps with the rainy season in this area, the earth surface deformation is affected by both rainfall and water level. The deformation velocity of the earth surface caused by rainfall is about 5 mm/month, while that caused by water level decrease is 5–7 mm/month. On the contrary, the deformation velocity of the deep sliding mass accelerates 2 to 3 times faster than average during water level increase. The distinction of surface and deep deformation regulations indicates that the effects of seasonal rainfall and water level fluctuation on the stability of reservoir wading landslides are different. Based on all monitoring data, we also found that the Huangtupo No. 1 riverside sliding mass is creeping seasonally during the seasonal rainfall and periodic reservoir water level fluctuation. The deformation velocities of the east regions of the sliding body indicate acceleration, making these regions even more dangerous. 相似文献
14.
N. Evelpidou D. Melini P. A. Pirazzoli A. Vassilopoulos 《International Journal of Earth Sciences》2014,103(1):381-395
An underwater geomorphological survey along the coasts of six Cycladic islands (Sifnos, Antiparos, Paros, Naxos, Iraklia and Keros) revealed widespread evidence of seven submerged tidal notches. At least seven former shorelines were identified at depths between 280 ± 20 and 30 ± 5 cm below modern sea level. The vertical succession of several submerged notches suggests the occurrence of rapid subsidence events, potentially of seismic origin. Comparison with other sea-level indicators from Naxos and Delos islands indicates that these relative sea-level changes took place after 3300 BP and provides a rough estimate of the time of development of several submerged shorelines. The submergence of the uppermost notch at ?30 ± 5 cm is ascribed to effects of the recent global sea-level rise occurred during the last two centuries and, at least in part, to effects of recent earthquakes. Potential effects of the 1956 Amorgos earthquake with regard to coseismic and post-seismic vertical displacement have been recently investigated using a modellistic approach. According to the above, the lower shorelines should result from repetitive subsidence events and not from gradual subsidence. 相似文献
15.
16.
开采沉陷土体变形与孔隙水压相互作用研究进展 总被引：6，自引：0，他引：6
本文通过实验、实测和理论分析研究了开采沉陷土体变形与孔隙水压力之间的相互作用,结果表明,随着开采的进行,土体的应力变形发生变化造成了超静孔隙水压力的产生和消散,反映在土体变形上出现随开采时间延续而发展的附加压缩和膨胀变形,这种压缩或膨胀在土体的不同部位相互叠加,有时还叠加了底部含水层水位下降引起的地面下沉。这些结果揭示了厚松散含水层地区开采沉陷特殊性的机理,对开采沉陷预测及水体下采煤具有重要意义。 相似文献
17.
结合上海城区某深基坑工程,针对项目特点与场区地质条件,分析了工程建设可能引发的基坑水土突涌、基坑边坡稳定、砂土渗流液化、基坑开挖和降水过程中地基变形和地面沉降等环境地质问题,进行危险性评价,并提出了防治对策措施。 相似文献
18.
超固结地层发生地面沉降需要一个大于超固结应力的起始附加应力来驱动。依据有效应力原则,临界水位与超固结应力之间存在线性相关关系,则超固结地层垂向形变机理亦可通过临界水位描述为：当人为开采地下水引起的起始水位降深大于临界水位时,地面沉降将明显发生。西安南郊地质技校钻孔埋深100-300m内土样试验资料分析及计算结果表明：该地层普遍呈现超固结特性;第一、二承压含水组的临界水位值分别为63.44m及73.76m;将“临界水位”作为控制地面沉降与最大限度开采地下水资源的主控指标来考虑,是地面沉降的有效防治措施。 相似文献
19.
In view of the construction technology and formation deformation of the existing rivers under the subway shield interval tunnel, relying on Zhengzhou rail transit line 17 shield tunnel through the south-north water transfer channel project, using the trial tunneling method of shield tunnel test section to optimize all kinds of construction parameters, and the formation analysis and calculation of the determined digging pressure, noting the final parameters that are determined by comparison between the extractive parameters such as pulp pressure, and they are used in MIDAS GTS/NX finite unit analysis software for numerical simulation analysis, combined with on-site testing, to study the variation of different depth formation subsidence values and horizontal displacement values when passing through the south-north water transfer canal under water conditions, and put forward the reinforcement scheme of shield tunneling through the general river bed and hole. The results show that the maximum subsidence of the trunk canal shield through the bottom is 11.3 mm, and the verification parameters are reasonable and feasible. The horizontal subsidence trough of the soil above the over-soil layer at the top of the main canal embankment is distributed by Gauss. The sinking distribution can be estimated using the Peck formula, the middle of the layer subsidence trough is distributed horizontally, and the soil subsidence trough below it is inverted hump-like distribution, with the peak point directly above the center line of the two tunnels, and the vertical zero horizontal displacement surface is located in the middle line position between the two tunnels, and the horizontal zero horizontal displacement surface is located. The horizontal displacement curve of the soil layer above the soil layer is inverted S-type, the maximum displacement appears at the anti-bending point of the surface sedimentation trough curve, the horizontal displacement curve of the soil layer on the horizontal zero horizontal displacement surface is zero, and the lower soil layer curve is double-inverted S-shaped. In the construction, we should pay attention to the monitoring of the vertical subsidence and horizontal displacement of the deep soil, adjust the shield parameters and reduce the horizontal and vertical shearing effect of the deep soil on the surrounding pipeline, inner pile base and other structures during the construction of the shield.
相似文献20.
Anthropogenic subsidence in the Mexicali Valley,Baja California,Mexico, and slip on the Saltillo fault 总被引：2，自引：1，他引：1
Ewa Glowacka Olga Sarychikhina Francisco Suárez F. Alejandro Nava Robert Mellors 《Environmental Earth Sciences》2010,59(7):1515-1524
Deep fluid extraction in the Cerro Prieto geothermal field (CPGF) has caused subsidence and induced slip on tectonic faults
in the Mexicali Valley (Baja California, Mexico). The Mexicali Valley is located in the southern part of the Salton Trough,
at the boundary between the Pacific and North American plates. The Valley is characterized by being a zone of continuous tectonic
deformation, geothermal activity, and seismicity. Within the Cerro Prieto pull-apart basin, seismicity is concentrated mainly
in swarms, while strong earthquakes have occurred in the Imperial and Cerro Prieto transform faults, that are the eastern
and western bound of the basin. Since 1973, fluid extraction at the CPGF has influenced deformation in the area, accelerating
the subsidence and causing rupture (frequently as vertical slip or creep) on the surface traces of tectonic faults. Both subsidence
and fault slip are causing damage to infrastructure like roads, railroad tracks, irrigation channels, and agricultural fields.
Currently, accelerated extraction in the eastern part of CPGF has shifted eastwards the area of most pronounced subsidence
rate; this accelerated subsidence can be observed at the Saltillo fault, a southern branch of the Imperial fault in the Mexicali
Valley. Published leveling data, together with field data from geological surveys, geotechnical instruments, and new InSAR
images were used to model the observed deformation in the area in terms of fluid extraction. Since the electricity production
in the CPGF is an indispensable part of Baja California economy, extraction is sure to continue and may probably increase,
so that the problem of damages caused by subsidence will likely increase in the future. 相似文献