Effect of Ground Fissures on Subsidence in Xi'an Metro Line 2

2013 ◽  
Vol 353-356 ◽  
pp. 333-336
Author(s):  
Chao Liu ◽  
Li Jun Su ◽  
Xing Qian Xu
Keyword(s):  
Ground Water ◽  
Land Subsidence ◽  
Ground Subsidence ◽  
Ground Fissures ◽  
Prevention And Treatment ◽  
The Relationship

The subsidence value in fissure site and no fissure site respectively is calculated when ground water is pumped. The relationship between ground fissures and ground subsidence is determined by calculation and then the cause of land subsidence is concluded. This study can solve the problem of ground subsidence in the construction of south section of Xian metro line 2 and it offers theoretic basis of prevention and treatment.

scholarly journals Spatial-Temporal Evolution of Land Subsidence and Rebound over Xi’an in Western China Revealed by SBAS-InSAR Analysis

2020 ◽  
Vol 12 (22) ◽  
pp. 3756
Author(s):  
Wei Shi ◽  
Guan Chen ◽  
Xingmin Meng ◽  
Wanyu Jiang ◽  
Yan Chong ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Groundwater Level ◽  
Surface Deformation ◽  
Western China ◽  
Ground Subsidence ◽  
Underground Space ◽  
Large Area ◽  
Space Utilization ◽  
Rapid Urbanization ◽  
Ground Fissures

Land subsidence is one of the major urban geological hazards, which seriously restricts the development of many cities in the world. As one of the major cities in China, Xi’an has also been experiencing a large area of land subsidence due to excessive exploitation of groundwater. Since the Heihe Water Transfer Project (HWTP) became fully operational in late 2003, the problem of subsidence has been restrained, but other issues, such as ground rebounds, have appeared, and the effect of the underground space utilization on land subsidence remains unsolved. The spatial-temporal pattern of land subsidence and rebound in Xi’an after HWTP and their possible cause have so far not been well understood. In this study, the evolutionary characteristics of land subsidence and rebound in Xi’an city from 2007–2019 was investigated using Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-SAR) technology to process the Advanced Land Observing Satellite (ALOS) and Sentinel-1A SAR datasets, and their cause and the correlation with groundwater level changes and the underground space utilization were discussed. We found that the land subsidence rate in the study area slowed from 2007–2019, and the subsidence area shrank and gradually developed into three relatively independent and isolated subsidence areas primarily. Significant local rebound deformation up to 22 mm/y commenced in the groundwater recharge region during 2015–2019. The magnitude of local rebound was dominated by the rise in groundwater level due to HWTP, whereas tectonic faults and ground fissures control the range of subsidence and the uplift area. The influence of building load on surface deformation became increasingly evident and primarily manifested by slowing the subsidence reduction trend. Additionally, land subsidence caused by the disturbances during the subway construction period was stronger than that in the operational stage. Future land subsidence in Xi’an is predicted to be alleviated overall, and the areas of rebound deformation will continue increasing for a limited time. However, uneven settlement range may extend to the Qujiang and Xixian New District due to the rapid urban construction. Our results could provide a scientific basis for land subsidence hazard mitigation, underground space planning, and groundwater management in Xi’an or similar regions where severe ground subsidence was induced by rapid urbanization.

scholarly journals Activity Characteristics and Safety distance of Gaoliying Ground Fissure in Beijing

2019 ◽  
Vol 79 ◽  
pp. 02009
Author(s):  
Haigang Wang ◽  
Tongchun Qin ◽  
Haipeng Guo ◽  
Juyan Zhu ◽  
Yunlong Wang ◽  
...  
Keyword(s):  
Ground Water ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Hanging Wall ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Rapid Decrease ◽  
Ground Fissure ◽  
Ground Fissures ◽  
Safety Distance

In all ground fissures in Beijing, Gaoliying Ground Fissure has characteristics of highly activity, and it cause serious damages on constructoins. With the distribution as well as the development of land subsidence and the change of the groundwater level, a series of work has been conducted to explain the mechanism of the formation of Gaoliying Ground Fissure. For example, field damage investigations and trench observations were used to define the affected distance of ground fissure; three-dimensional deformation was monitored to determine active characteristic of ground fissure. This paper points out that Gaoliying ground fissure is controlled by Huangzhuang-Gaoliying Fault, which mainly moves in the vertical direction. The rapid decrease of the ground water level greatly increases the development of ground fissure. The distance of damaged zones affected by ground fissure in the hanging-wall of the fault reaches 49.5m, and the distance of damaged zones in the footwall of the fault is 17.5 m. A suggested safety distance of type-one and type-two buildings is 100 m. For type-three buildings, the suggested safety distance is 80 m.

scholarly journals GROUND SUBSIDENCE MONITORING WITH MT-InSAR AND MECHANISM INVERSION OVER XI’AN, CHINA

2018 ◽  
Vol XLII-3 ◽  
pp. 1375-1380
Author(s):  
M. M. Peng ◽  
C. Y. Zhao ◽  
Q. Zhang ◽  
J. Zhang ◽  
Y. Y. Liu
Keyword(s):  
Land Subsidence ◽  
Ground Deformation ◽  
Ground Subsidence ◽  
Spatiotemporal Evolution ◽  
Ground Fissure ◽  
Ground Fissures ◽  
The 1960S ◽  
Subsidence Monitoring ◽  
Xi’An City ◽  
Deformation Section

The ancient Xi’an, China, has been suffering severe land subsidence and ground fissure hazards since the 1960s, which has affected the safety of Subways. Multi-sensor SAR data are conducted to monitor the latest complex ground deformation and its influence on subway line No.3 over Xi’an. Annual deformation rates have been retrieved to reveal the spatiotemporal evolution of ground subsidence in Xi’an city from 2013 to 2017. Meanwhile, the correlation between land subsidence and ground fissures are analyzed by retrieving the deformation differences in both sides of the fissures. Besides, the deformation along subway line No. 3 is analyzed, and the fast deformation section is quantitatively studied. Finally, a flat lying sill model with distributed contractions is implemented to model the InSAR deformation over YHZ subsidence center, which manifests that the ground deformation is mainly caused by groundwater withdrawal.

scholarly journals Potential Impacts of Future Climate Change Scenarios on Ground Subsidence

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 219 ◽  
Author(s):  
Antonio-Juan Collados-Lara ◽  
David Pulido-Velazquez ◽  
Rosa María Mateos ◽  
Pablo Ezquerro
Keyword(s):  
Climate Change ◽  
Land Subsidence ◽  
Ground Subsidence ◽  
Lower Percentage ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Fine Grained ◽  
Fine Grained Material ◽  
The Impact

In this work, we developed a new method to assess the impact of climate change (CC) scenarios on land subsidence related to groundwater level depletion in detrital aquifers. The main goal of this work was to propose a parsimonious approach that could be applied for any case study. We also evaluated the methodology in a case study, the Vega de Granada aquifer (southern Spain). Historical subsidence rates were estimated using remote sensing techniques (differential interferometric synthetic aperture radar, DInSAR). Local CC scenarios were generated by applying a bias correction approach. An equifeasible ensemble of the generated projections from different climatic models was also proposed. A simple water balance approach was applied to assess CC impacts on lumped global drawdowns due to future potential rainfall recharge and pumping. CC impacts were propagated to drawdowns within piezometers by applying the global delta change observed with the lumped assessment. Regression models were employed to estimate the impacts of these drawdowns in terms of land subsidence, as well as to analyze the influence of the fine-grained material in the aquifer. The results showed that a more linear behavior was observed for the cases with lower percentage of fine-grained material. The mean increase of the maximum subsidence rates in the considered wells for the future horizon (2016–2045) and the Representative Concentration Pathway (RCP) scenario 8.5 was 54%. The main advantage of the proposed method is its applicability in cases with limited information. It is also appropriate for the study of wide areas to identify potential hot spots where more exhaustive analyses should be performed. The method will allow sustainable adaptation strategies in vulnerable areas during drought-critical periods to be assessed.

Soil Water Characteristic Curve and its Applications in Tunnel

2011 ◽  
Vol 261-263 ◽  
pp. 1039-1043
Author(s):  
Yu You Yang ◽  
Qin Xi Zhang ◽  
Gui He Wang ◽  
Jia Xing Yu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Land Subsidence ◽  
Unsaturated Soil ◽  
Characteristic Curve ◽  
Tunnel Construction ◽  
Coupling Theory ◽  
Engineering Analysis ◽  
Soil Water Characteristic Curve ◽  
The Relationship

A soil water characteristic curve (SWCC) can describe the relationship between unsaturated soil matric suction and water content. By analyzing and researching the test data of the soil water characteristic curve researchers can initially establish the SWCC equation and apply this equation to the actual engineering analysis. In another words, this article is based on the fluid-solid coupling theory of unsaturated soil used to analyze and study the problem of land subsidence caused by tunnel construction. Numerical calculations show that the coupling results agree well with the measured curve works.

scholarly journals Land subsidence and hydrodynamic compaction of sedimentary basins

1998 ◽  
Vol 2 (2/3) ◽  
pp. 159-171 ◽  
Author(s):  
H. Kooi ◽  
J. J. de Vries
Keyword(s):  
Response Time ◽  
Land Subsidence ◽  
Sedimentary Basins ◽  
Sediment Loading ◽  
Dimensional Model ◽  
One Dimensional ◽  
Model Equations ◽  
Sediment Layers ◽  
The Relationship

Abstract. A one-dimensional model is used to investigate the relationship between land subsidence and compaction of basin sediments in response to sediment loading. Analysis of the model equations and numerical experiments demonstrate quasi-linear systems behaviour and show that rates of land subsidence due to compaction: (i) can attain a significant fraction (>40%) of the long-term sedimentation rate; (ii) are hydrodynamically delayed with respect to sediment loading. The delay is controlled by a compaction response time τc that can reach values of 10-5-107 yr for thick shale sequences. Both the behaviour of single sediment layers and multiple-layer systems are analysed. Subsequently the model is applied to the coastal area of the Netherlands to illustrate that lateral variability in compaction-derived land subsidence in sedimentary basins largely reflects the spatial variability in both sediment loading and compaction response time. Typical rates of compaction-derived subsidence predicted by the model are of the order of 0.1 mm/yr but may reach values in excess of 1 mm/yr under favourable conditions.

scholarly journals Blood Pressure Targets for Older Patients—Do Advanced Age and Frailty Really Not Matter?

2020 ◽  
Vol 23 (2) ◽  
pp. 205-209
Author(s):  
Amanda Giffin ◽  
Kenneth M. Madden ◽  
David B. Hogan
Keyword(s):  
Blood Pressure ◽  
Risk Assessment ◽  
Older Patients ◽  
Intensive Therapy ◽  
Advanced Age ◽  
Blood Pressure Targets ◽  
Prevention And Treatment ◽  
Treatment Of Hypertension ◽  
The Relationship

In 2017, Hypertension Canada removed advanced age and frailty as considerations for caution when deciding on intensive therapy in their guidelines for the diagnosis, risk assessment, prevention, and treatment of hypertension in adults. Dementia is not mentioned. In this commentary, we review why advanced age and frailty were removed, and examine what is currently known about the relationship between hypertension and both incident and prevalent dementia. We make the case that the presence of frailty (especially when severe) and dementia should be considered when deciding on intensive therapy in future iterations of Hypertension Canada guidelines.

scholarly journals Optimizing Reduction of Groundwater Discharge to Control Land Subsidence (Case study: Nadjafabad Aquifer)

2021 ◽  
Author(s):  
hamid Kardan moghaddam ◽  
Zahra Rahimzadeh kivi ◽  
Fatemeh Javadi ◽  
Mohammad Heydari
Keyword(s):  
Land Subsidence ◽  
Groundwater Resources ◽  
Treatment Strategies ◽  
Flow Simulation ◽  
Maximum Amount ◽  
Water Withdrawal ◽  
Ground Subsidence ◽  
Risk Zoning ◽  
Dry Conditions ◽  
The Impact

Abstract This study evaluates and predicts the ground subsidence that happens due to the haphazard operation of groundwater resources. Also, several strategies have been developed to control this unpleasant phenomenon. For this purpose, groundwater flow simulation has been conducted using MODFLOW numerical model, and subsidence simulation in Najafabad plain has been done using SUB package under three climatic scenarios for future periods. Examination of the simulation results shows that the amount of land subsidence will increase with the aquifer operation's continuation. The maximum amount of subsidence for 6 years in drought conditions will be 23 cm at the aquifer's outlet. According to the land subsidence results at the aquifer, risk zoning of the aquifer operation was done to develop a solution to reduce the withdrawal of groundwater resources to control subsidence. Therefore, risk zoning was performed using land use and the extent of operation of groundwater resources. The results showed that the north-eastern part of the aquifer has the maximum risk of subsidence. According to the obtained results from subsidence risk zoning, scenarios of reduced water withdrawal from the aquifer in its outlet were developed. The treatment strategies results showed that the maximum amount of subsidence in wet, normal and dry conditions will be 10, 14 and 18 cm, respectively. These results indicate a 14% improvement in the quantitative condition of the aquifer in wet conditions, 10% in normal conditions and 7% in dry conditions in the total aquifer of Najafabad. Improvement of conditions by simulation shows the impact of the importance of optimal utilization of groundwater resources.

scholarly journals A biopsychosocial model of violence when sleepwalking: Review and reconceptualisation

BJPsych Open ◽  
2017 ◽  
Vol 3 (2) ◽  
pp. 96-101 ◽  
Author(s):  
Helen M. Stallman ◽  
Andrea Bari
Keyword(s):  
Risk Factors ◽  
Biopsychosocial Model ◽  
Empirical Literature ◽  
Social Risk ◽  
Social Risk Factors ◽  
Violent Behaviour ◽  
Prevention And Treatment ◽  
Serious Injury ◽  
The Relationship ◽  
Consequences Of Violence

SummaryViolence towards others during sleepwalking is relatively uncommon, but can result in serious injury or even death. Much of the research in this field has focused on the forensic consequences of violence during sleepwalking without sufficient attention to an understanding of the risk factors for violence during sleepwalking and the development of prevention and interventions based on these risk factors. This paper reviews the characteristics of impulsive violence in general and reconceptualises violence during sleepwalking as an extension of this prior vulnerability. We propose a biopsychosocial model of the risk for violence during sleepwalking that is supported through a review of empirical literature both within sleepwalking and violent behaviour more generally. Biological, psychological and social risk factors are hypothesised to mediate the relationship between sleepwalking and violence. Implications for prevention and treatment of this potentially fatal problem are discussed.

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