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1.
太原市地层空间异质性对地面沉降分布的影响 总被引：4，自引：0，他引：4
对比1956～2000年太原市地下水位与地面沉降资料发现,该区地面沉降漏斗与地下水位降落漏斗的空间分布基本相近,但不完全吻合,局部地区存在偏移。通过对黏性土层累计厚度分布、黏性土层与粗颗粒土层的组合特征、不同分区各深度处土的力学特征值与上述偏移的对比分析,认为太原市地层的空间异质性对地面沉降分布有如下影响：（1）与地下水位降落漏斗相比,地面沉降漏斗偏向于黏性土层较厚的一侧;（2）地层组合（黏性土的夹层数、单层厚度等）对地面沉降的空间分布影响较大,沉降多发生在黏性土夹层多、单层厚度较小的地区;（3）土的力学性质的差异是影响沉降分布的重要因素。 相似文献
2.
Characterization of land subsidence induced by groundwater withdrawals in Su-Xi-Chang area, China 总被引：5，自引：0，他引：5
Xiao-Qing Shi Yu-Qun Xue Shu-Jun Ye Ji-Chun Wu Yun Zhang Jun Yu 《Environmental Geology》2007,52(1):27-40
Su-Xi-Chang area is one of the typical regions in China which suffers from severe land subsidence. Various tools of field
monitoring were integrated to study the characteristics and mechanisms of land subsidence in this region. The occurrence and
the development of the land subsidence in this region are strongly related to the groundwater pumping both in time and space.
The main consolidation layers are the soft mud layers; however, the compressibility of the confined sandy layers should not
be ignored. The second and third confined aquifers contributed more than 30% of total subsidence. Meanwhile, irrecoverable
deformations were also observed in the sandy layers. Different sandy layers deform diversely under different stress conditions.
Some have the elastic feature. But the soil strata, including both sandy layers and clayey layers, located in the center of
the groundwater level depression cone exhibited obvious viscous mechanical behavior which caused the common lag phenomenon.
The sand composition (mingled with small clay particles or interbeds) and sand rheology are the two main reasons for the lag
phenomena in sandy layers. A series of laboratory tests for modeling the effective stress changes due to groundwater withdrawals,
were conducted to investigate the mechanism of the lag phenomenon. Based on the test results, the relationship of stress–strain–time
for saturated sands is obtained; and it could be expressed as power functions. The results also showed that the compression
of the sandy layers was time dependent, and its deformation could be remarkable. When establishing land subsidence model,
the deformation for the similar soil formation could be elastic, visco-elastic and even visco-elastic–plastic, because of
the different groundwater level fluctuation experienced. 相似文献
3.
4.
为了分析黄河三角洲地下水动态及其与地面沉降的关系, 利用多年地下水和地面沉降监测数据, 发现黄河三角洲广饶县和东营区的地下水动态变化剧烈且地面沉降严重, 含水层多处于超采状态, 浅、深层地下水降落漏斗先后出现.深层地下水降落漏斗中心水位下降速度达2~3m/a.近年来, 东营和广饶地面沉降漏斗中心沉降量和速率分别为155.1mm、28.2mm/a和356.0mm、64.7mm/a.借助GIS技术及数理统计法, 发现深层地下水降落漏斗与沉降漏斗空间耦合良好, 深层地下水位与地面高程呈线性正相关, 相关系数为0.92, 深层地下水过度开采已成为影响沉降的最根本因素.井灌区第三粘性压缩层成为地面沉降主要贡献层, 且深层地下水降落漏斗中心的地下水位已低于第三承压含水层临界水位, 沉降趋于严重. 相似文献
5.
为了准确分析建筑荷载和地下水开采对地面沉降的影响,为吴江盛泽地区科学防控地面沉降提供决策依据,基于比奥固结和地下水渗流理论,建立了建筑荷载和地下水开采与地面沉降三维全耦合有限元数值模型,分别模拟预测了在建筑荷载单独作用、地下水开采单独作用及建筑荷载和地下水开采叠加作用三种情况下,2015-09-01—2030-08-31盛泽地区逐年地面沉降变化趋势。结果表明,建筑荷载对盛泽地区地面沉降的影响大于地下水开采。第Ⅰ黏性土弱含水层和第I承压含水层分别为建筑荷载和地下水开采单独作用下的主压缩层,单层压缩量占比分别为43.04%和54.06%;第Ⅰ承压含水层及其上覆第Ⅰ黏性土弱含水层是二者叠加作用引发土体变形的主压缩层,其压缩量之和占总压缩量的71.30%。建筑荷载和地下水开采单独作用下引发的地面沉降量的线性叠加之和大于二者叠加作用下引发的地面沉降量,建筑荷载和地下水开采叠加作用引发的地面沉降具有耦合效应。 相似文献
6.
Land subsidence and earth fissures due to groundwater withdrawal in the Southern Yangtse Delta,China 总被引：1，自引：0，他引：1
Yun Zhang Yu-Qun Xue Ji-Chun Wu Jun Yu Zi-Xin Wei Qin-Fen Li 《Environmental Geology》2008,55(4):751-762
Excessive extraction of groundwater has caused severe land subsidence and earth fissures in the Southern Yangtse Delta, China.
Based on field data, the temporal and spatial distribution of land subsidence is investigated and the causes for earth fissures
are analyzed. The areal distribution of the land subsidence is closely related to the cones of depression in the main exploited
aquifers. The compaction of a hydrostratigraphic unit depends on its mechanical behavior, thickness, compressibility, and
the piezometric level changing. The primary subsidence layers in Shanghai have been the first aquitard before 1990 and the
third confined aquifer since then. But the second aquitard unit was the primary subsidence layer in Changzhou. Earth fissures,
trending in several directions, occurred in the Husu tectonic zone. They were mainly caused by differential subsidence and
horizontal displacement that resulted from tensile stress and shear stress in units. The majority of fissures in the study
area are tensile. 相似文献
7.
地面沉降通常由于地下水的超采而引发,其发生发展相对于地下水位的变化具有一定滞后性。如何获取准确的地面沉降滞后时间一直是地面沉降研究的重要课题。基于北京平各庄地面沉降监测站2008—2018年地面沉降和地下水位长时间序列的分层监测数据,采用Mann-Kendall趋势检验、连续小波变换、交叉小波变换等方法,分析了不同层位地层形变对地下水位动态的滞后特征。结果表明:中–深层承压水具有1 a左右的主震荡周期,潜水和浅部承压水在大部分时域无显著周期;深部严重沉降层的形变量具有1 a左右的主震荡周期,地下水位与形变量共振周期显著,地层由浅到深形变时滞分别为(16.58±8.91)、(7.16±7.09)和(9.66±6.62) d;浅部弱沉降层中,埋深在32~63 m地层形变量具有1 a左右的主震荡周期,与中层承压水存在显著共振周期,形变时滞为(32.02±9.67) d,其他地层形变量与地下水位无显著周期及相关性。研究成果为构建地面沉降精细化模型、提高地面沉降预测精度以及研究更有效的地面沉降防控措施提供了新的技术思路。 相似文献
8.
Yun Zhang Yu-Qun Xue Ji-Chun Wu Shu-Jun Ye Zi-Xin Wei Qin-Fen Li Jun Yu 《Engineering Geology》2007,90(3-4):160-173
Excessive groundwater pumpage has caused regional cones of depression and severe land subsidence in the Southern Yangtse Delta, China. The characteristics of aquifer system compaction are complex because of the difference in the types, compositions and structures of the soils that the hydrostratigraphic units are composed of, and in the histories of groundwater level change the hydrostratigraphic units have experienced. Based on the data measured from extensometer groups and observation wells, the characteristics of deformation for individual hydrostratigraphic units are analyzed. The results show that different hydrostratigraphic units have different kinds of deformation and that an identical unit may also present different deformation characteristics, such as elasticity, elasto-plasticity, and visco-elasto-plasticity, at different sites of the cone of depression or in different periods. If the groundwater level rises continuously and remains constant later, the aquifers and the aquitard units that consist of hard clay primarily exhibit elastic behaviour, but the aquitard units that consist of soft clay deform plastically and by creep and exhibit visco-elasto-plastic behaviour. If the groundwater level falls but is much higher than the previous lowest value, aquifers and aquitards consisting of hard clay exhibit elasto-plastic behaviour. If the groundwater level falls below the previous lowest value, aquifers and aquitards consisting of hard clay deform plastically and by creep and exhibit visco-elasto-plastic behaviour. 相似文献
9.
通过对太原市地面沉降资料、气象水文和地质条件以及地下水等大量资料的分析与整理,考虑到太原市各个沉降中心的沉降趋势不尽相同,对太原市吴家堡、西张、万柏林和下元4个沉降中心分别建立BP神经网络模型,并基于训练好的BP神经网络模型,在太原市地下水开采量的规划方案下,预测了在不同降水保证率下2009-2015年地面沉降的趋势,... 相似文献
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11.
《China Geology》2021,4(3):455-462
The Luanhe River Delta is located in the center of the Circum-Bohai Sea Economic Zone. It enjoys rapid economic and social development while suffering relatively water scarcity. The overexploitation of groundwater in the Luanhe River Delta in recent years has caused the continuous drop of groundwater level and serious environmental and geological problems. This study systematically analyzes the evolution characteristics of the population, economy, and groundwater exploitation in the Luanhe River Delta and summarizes the change patterns of the groundwater flow regime in different aquifers in the Luanhe River Delta according to previous water resource assessment data as well as the latest groundwater survey results. Through comparison of major source/sink terms and groundwater resources, the study reveals the impacts of human activities on the groundwater resources and ecological environment in the study area over the past 30 years from 1990 to 2020. The results are as follows. The average annual drop rate of shallow groundwater and the deep groundwater in the centers of depression cones is 0.4 m and 1.64 m, respectively in the Luanhe River Delta in the past 30 years. The depression cones of shallow and deep groundwater in the study area cover an area of 545.32 km2 and 548.79 km2, respectively, accounting for more than 10% of the total area of the Luanhe River Delta. Overexploitation of groundwater has further aggravated land subsidence. As a result, two large-scale subsidence centers have formed, with a maximum subsidence rate of up to 120 mm/a. The drop of groundwater level has induced some ecological problems in the Luanhe River Delta area, such as the zero flow and water quality deterioration of rivers and continuous shrinkage of natural wetlands and water. Meanwhile, the proportion of natural wetland area to the total wetland area has been decreased from 99% to 8% and the water area from 1776 km2 to 263 km2. These results will provide data for groundwater overexploitation control, land subsidence prevention, and ecological restoration in plains and provide services for water resources management and national land space planning.© 2021 China Geology Editorial Office. 相似文献
12.
黏土层和砂土层交替变化的多层土体在强烈开采地下水作用下极易产生压密固结而引发地面沉降灾害。本文针对含水层释水引起地面沉降问题,研制了地面沉降试验装置,进行了排灌水条件下含水层系统的沉降及回弹试验。采用分布式光纤感测技术对土体内部应变分布及含水率变化进行耦合监测,并分析了各分层对水位变化的响应特征。结果表明:黏土层和砂土层均表现出了排水压缩和灌水回弹特点,黏土层变形较砂土层明显。各层变形与含水率变化具有良好的对应关系,表现为砂土层变形和含水率变化基本同步,而黏土层变形略微滞后于含水率变化。黏性土压缩曲线具有明显的分段特征,排水时当含水率低于液限后迅速减小,黏土层压缩速率明显加快;回灌时当含水率高于液限后,回弹速率明显加快。试验结果对研究地面沉降机理、评价地面沉降潜力及地下水利用具有重要意义。 相似文献
13.
Threat of land subsidence in and around Kolkata City and East Kolkata Wetlands,West Bengal,India 总被引：4，自引：0，他引：4
This paper attempts to estimate the possible rate of land subsidence of Kolkata City including Salt Lake City and the adjoining
East Kolkata Wetlands located at the lower part of the deltaic alluvial plain of South Bengal basin. Demand of groundwater
for drinking, agricultural and industrial purposes has increased due to rapid urbanization. The subsurface geology consists
of Quaternary sediments comprising a succession of clay, silty clay and sand of various grades. Groundwater occurs mostly
under confined condition except in those places where the top aquitard has been obliterated due to the scouring action of
past channels. Currently, the piezometric head shows a falling trend and it may be accelerated due to further over-withdrawal
of groundwater resulting in land subsidence. The estimated mean land subsidence rate is 13.53 mm/year and for 1 m drop in
the piezometric head, the mean subsidence is 3.28 cm. The surface expression of the estimated land subsidence is however,
cryptic because of a time lag between the settlement of the thick low-permeable aquitard at the top and its surface expression.
Therefore, groundwater of the cities and wetland areas should be developed cautiously based on the groundwater potential to
minimize the threat of land subsidence. 相似文献
14.
During the process of urbanization and industrialization, groundwater has been extensively overexploited, with the direct result of continuously decreasing groundwater level, followed by the appearance of large scale of depression cones, which is furthermore followed by land subsidence, seawater intrusion, and increasing difficulties in subsequent groundwater exploitation. This paper makes an analysis on the geological disasters caused by overexploitation of groundwater. The consumption and overexploitation status of groundwater in representative regions in China is discussed first, with the distribution and development of depression cones elaborated the next. And the problems of land subsidence, seawater intrusion, and increasing difficulties caused by overexploitation of groundwater are analyzed at last. Results show that overexploitation of groundwater is positively related to economic development. Moreover, geological disasters such as land subsidence and seawater intrusion caused by long term of overexploitation also aggregate, posing threats, and losses to people’s lives and production. According to the analysis, the fundamental resolution for overexploitation of groundwater as well as consequential geological damages is to properly control city size and to utilize groundwater rationally and efficiently. 相似文献
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16.
Jichun Wu Xiaoqing Shi Yuqun Xue Yun Zhang Zixin Wei Jun Yu 《Environmental Geology》2008,55(8):1725-1735
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
17.
地面沉降是北京平原区主要地质灾害之一。文中采用永久散射体差分干涉测量(PS-InSAR)技术获取平原区地面沉降空间分布特征,基于GIS空间分析平台,将多种地面沉降影响因素分别与PS-InSAR获取的地面沉降场形变信息进行耦合研究,查明地面沉降与多种影响因素之间的响应关系。研究发现:(1)北京市地面沉降发育较为严重的地区主要出现在平原区东部、北部以及南部等地,存在多个沉降中心,最大沉降速率达到152mm/a,区域不均匀沉降现象明显,并且有连成一片的趋势。(2)地面沉降分布具有明显的构造控制特性,沉降区多位于几大活动断裂交接部位的沉积凹陷地区,与第四纪沉积凹陷十分吻合。地面沉降的发展趋势与活动断裂的走向具有明显的对应关系,在有活动断裂通过的区域,地面沉降剖面线上表现出明显的转折或突变,断裂两侧区域不均匀沉降十分明显。(3)地面沉降分层沉降量与对应层位上黏性土占比呈正比例关系,其空间分布特征及变化趋势与平原区的地层结构及可压缩黏性土层厚度具有很好的一致性,沉降范围整体由北西向的单一结构区向南东方向的多层结构区扩张。沉降速率大于50 mm/a的沉降区大多分布在黏性土层厚度大于100 m的地区,几大沉降中心与黏性土层厚度较大地区吻合较好。(4)第二承压含水层(顶底板埋深100~180 m)地下水开采对地面沉降影响最大,沉降中心与该层位地下水位降落漏斗区高度吻合,是地面沉降的主要贡献层位。 相似文献
18.
Characterization of regional land subsidence in Yangtze Delta, China: the example of Su-Xi-Chang area and the city of Shanghai 总被引：5，自引：1，他引：4
Xiaoqing Shi Yuqun Xue Jichun Wu Shujun Ye Yun Zhang Zixin Wei Jun Yu 《Hydrogeology Journal》2008,16(3):593-607
Su-Xi-Chang area and the city of Shanghai, located in the south of Yangtze Delta, China, has subsided due to groundwater overpumping. Because of the regional scale of the groundwater exploitation, cone of depression and land subsidence at present, Su-Xi-Chang area and Shanghai are treated as a single area for a land subsidence study, which could more clearly elaborate the relationships between the deformation features of hydrostratigraphic units and the different sites of the cone of depression. All hydrostratigraphic units in the study area were discussed throughout. Based on the field data, including data on compression of individual strata from groups of extensometers and groundwater levels from observation wells, the relationship between the deformation and the groundwater level was analyzed. The results indicate that the deformation features of the hydrogeologic units are greatly related to hydrogeologic properties and groundwater-level variations. An identical hydrogeologic unit may exhibit different deformation features in different locations such as along the periphery and in the center of the cone of depression. In addition, in the same location, a hydrogeologic unit also exhibits different features in different periods because of different groundwater level variations. The delay phenomenon of the sandy aquifer is not specific but occurs widely. 相似文献
19.
The microscopic characteristics of Shanghai soft clay and its effect on soil body deformation and land subsidence 总被引：5，自引：0，他引：5
Compaction of the 40-m-thick, upper Shanghai soft clay contributes to land subsidence in the Shanghai region. The upper clay,
a marine deposit, continuously subsides at rate of 3 mm/years despite mitigation strategies designed to control land subsidence.
These strategies include the artificial injection of water into the subsurface. Data describing the particle-size distribution,
pore-size distribution, microstructure, mineralogical composition, pore-solution composition, and cation-exchange capacity
indicate that the clay is semidispersed, substable, and susceptible to compaction. An evaluation of soil body deformation
caused by artificial injection of dilute water into a marine clay suggests that depression of the electrostatic double 1ayer
in the marine clays may be responsible for the observed compaction and resulting subsidence. A decrease in the swelling pressure
of the marine clays might result from a reduction in the concentration of dissolved sodium in pore fluids when calcium-bicarbonate
water is injected. Thus, ironically, the strategy designed to mitigate land subsidence could be contributing to it. Increasing
the concentration of dissolved salts in the injection water may prevent the collapse of the clay structure and halt or reverse
the subsidence process. The analysis results indicate the deformation of soft clay by consolidation is subject to its microscopic
physical and chemical features, rather than the fluctuation of groundwater level. This continuous compression contributes
as a major part to the land subsidence in Shanghai.
Supported by Programmer of Excellent Young Scientists of the Ministry of Land and Resources People’s Republic of China, No.2002-18. 相似文献
20.
天津滨海新区地面沉降层位的精准识别与沉降过程重建 总被引：1，自引：0，他引：1
塘沽地区地面沉降是新生代松散沉积物多层位沉降叠加的结果,精准识别各层位的沉降贡献是该区地面沉降防控的关键。利用塘沽G2地面沉降分层标组2011—2014年观测数据,对新生代沉积物不同层位的地面沉降进行了精准识别;结合以前的分层标观测资料,重建了1960年以来不同层位的地面沉降过程。结果显示,在1960—1970年地下水开发初期,地面沉降主要层位是浅部粘性土自然固结和第二含水组地下水开采;1970—1980年深层地下水开采高峰期,主沉降层位由二组逐渐加深到三、四组;1985年以后实施了地面沉降控制措施后,第四系地下水开采引起的地面沉降逐渐减小;2000年之后,随着滨海新区的成立和大规模的城市建设,城市建设引起的建筑基础沉降逐渐成为主要的沉降层。通过对不同时期主要地面沉降层位的转换过程分析,提出地面沉降精准防治新思路。 相似文献