Cause Of Subsidence Research Articles

Monitoring and Analysis of Ground Deformation in Mining Area Based on SBAS Technology

In view of the serious harm and significant economic loss caused by large-scale surface subsidence in Huangling Mining area. Firstly, the surface deformation information was obtained by using the Small Baseline technology during 2007-2009 (ALOS-1) and 2018-2019 (Sentinel-1A), and then the deformation position and magnitude changes were compared in these two different periods, finally, the time series analysis of the surface subsidence funnel in the mining area was performed. The results showed that: (1) The average annual deformation rate respectively reached 360 mm/a and 480 mm/a during 2007-2009 and 2018-2019. It was found that compared with 2007-2009, the deformation position moved up in 2018-2019, and the deformation area and magnitude increased. Combined with the analysis of the mining area data, the Huangling mining area was in the early stage of mining from 2007 to 2009. As the advance of mining working face and the passage of time, the deformation position would move up in 2018-2019. (2) From 2018 to 2019, the most serious surface subsidence in the Huangling mining area was located in the northwest of Shuanglong Town, including Huangling No. 2 Coal Mine. The maximum cumulative subsidence reached 300mm. The results of the study indicated that the main cause of subsidence in this area was underground coal mining. The analysis of the deformation law provides a decision basis for the subsequent rational mining and treatment of the mining area.

Ground Response to Pipe-Roof Tunneling of a Large Underpass in Shanghai Soft Soil

Pipe roof method is an effective way for urban underpassing scheme. Due to the successive jacking of multiple pipes, the characteristics of ground response are distinctly different from single pipe or twin pipes. In this paper, the gradual ground loss by successive pipe-jacking and the causes of settlement are analyzed. The conclusions drawn from this paper show that: (1) The maximum incremental was right above the pipe axis which could be controlled within 1mm. (2) The shield effect of the former pipe on the latter one resulted in a 50% reduction of maximum incremental settlement. (3) The distribution of cumulative settlement curve was reflected by superimposed effect of staged ground settlements. (4) The results of settlement monitoring illustrated that the field measured settlements were basically tally with those of the simulated values, the goodness of fit was more than 85%.

Influence of Subway Shield Tunnel Construction on Ground Settlement

Shield construction has the advantages of stable driving speed, saving manpower, and being able to carry out construction in complex strata, which has been more and more widely used. In the process of shield construction, there is a gap between shield body and segment, which is easy to cause ground settlement when the grouting speed cannot keep up. This paper summarizes the common methods to predict the surface settlement, analyzes the causes of the settlement, and lists an engineering case to illustrate the factors affecting the surface settlement. Finally, it comes to the conclusion that the main causes of the surface settlement caused by shield tunnel construction are formation loss and consolidation settlement, and the use of small cutterhead and composite cutterhead can reduce the surface settlement, It provides a reference for the development of shield construction.

Trends in the settlement of migrant workers in the context of social and economic processes in contemporary Russia

The purpose of the article is to identify the basic trends in the settlement of migrant workers in the Russian Federation. The methodology of the research was based on the humanistic approach, which allowed focusing on the problems of labor migrants’ life activity and their search for value-based orientations. The systemic and comprehensive approach allowed identifying and substantiating the directions of the trends in the settlement of labor migrants by regions and districts of Russia. The comparative analysis of scientific works helped to identify the causes of settlement of labor migrants by place of their labor activity. Two identified opposing trends are the main results of the study. The first is dispersed settlement, which objectively promotes the integration process of representatives of immigrant ethnic groups into the urban environment of the area of residence, at the expense of a simultaneous weakening of intra-ethnic social ties and an increase in the depth and density of contacts with the local population. The second is the opposite trend – the self-isolation of immigrant groups within the framework of compact settlements, leading to the emergence of large ethnic diasporas of migrants in certain areas of the hosting country. The novelty of the study comes from an original approach to the identification and justification of migrants’ settlement trends in the socio-economic conditions of modern Russia.

Geological and Geophysical Study in Udheri Khola Area, Nalgad Hydroelectric Project, Jajarkot District, Lesser Himalaya, Western Nepal

Subsidence in carbonate rock is one of common and challenging action in terms of engineering construction. Geological study and geophysical investigation carried out in the intake area of Nalgad Hydroelectric Project Jajarkot, western Nepal Lesser Himalaya. The main objective was to identify the cause of subsidence in the intake area of Nalgad Hydroelectric Project, Jajarkot. Geological study of the area was carried to understand the lithology, thickness and structure of the area.
 The study area comprises two distinct rock units, namely, Dolomite Unit followed up by the Slate Unit. The Dolomite Unit is composed of light grey to grayish white stromatolitic dolomite which is thrusted over the Slate Unit near to Laikham village and Sepu Khola area. The Slate Unit is made up of grayish black to graphitic slate. A thin prominent calcareous horizon wasconfined between Slate Unit.
 2D-Electric Resistivity Tomography (ERT) measurements were deployed in four different lines to investigate the cause of the subsidence in the carbonate terrain. A concentric very high resistivity patch shown by Tomogram ER-D-01 survey line was identified and interpreted as dry cavity. The result of the 2D- ERT survey was correlated with core log data of geotechnical exploration in the suspicious point to ensure the presence of karst in the Dolomite Unit at right bank of Nalsyagu Khola near dam axis of Nalgad Hydroelectric Project. The 2D – ERT survey together with geotechnical investigation is capable of identifying subsurface karst feature as the cause of surface collapse in the area.

Ground Settlement of High-Permeability Sand Layer Induced by Shield Tunneling: A Case Study under the Guidance of DBN

During the shield construction of Harbin Subway Line No. 3 Project, the average ground settlement exceeds the warning value. In order to find the cause of settlement and improve it, this paper establishes a settlement prediction model to analyse the potential influencing factors based on the Deep Belief Network (DBN) and calculated the correlation degree between influencing factors and settlement through sensitivity analysis. It was found that the permeability coefficients of layer and cutter head torque are the main factors affecting settlement. Then, corresponding muck improvement measures were made according to the analysis of the layer conditions, which successfully reduced the permeability and shear strength of the muck, thereby controlling the surface settlement value within the warning range. The research results in this paper illustrate the applicability and robustness of DBN in tunnel engineering, and the related research ideas can be applied to other projects.

Ground Deformation and Its Causes in Abbottabad City, Pakistan from Sentinel-1A Data and MT-InSAR

Land subsidence, as one of the engineering geological problems in the world, is generally caused by compression of unconsolidated strata due to natural or anthropogenic activities. We employed interferometric point target analysis (IPTA) as a multi-temporal interferometric synthetic aperture radar (MT-InSAR) technique on ascending and descending Sentinel-1A the terrain observation with progressive scans SAR (TOPSAR) images acquired between January 2015 and December 2018 to analyze the spatio-temporal distribution and cause of subsidence in Abbottabad City of Pakistan. The line of sight (LOS) average deformation velocities along ascending and descending orbits were decomposed into vertical velocity fields and compared with geological data, ground water pumping schemes, and precipitation data. The decomposed and averaged vertical velocity results showed significant subsidence in most of the urban areas in the city. The most severe subsidence was observed close to old Karakorum highway, where the subsidence rate varied up to −6.5 cm/year. The subsidence bowl profiles along W–E and S–N transects showed a relationship with the locations of some water pumping stations. The monitored LOS time series histories along an ascending orbit showed a close correlation with the rainfall during the investigation period. Comparative analysis of this uneven prominent subsidence with geological and precipitation data reflected that the subsidence in the Abbottabad city was mainly related to anthropogenic activities, overexploitation of water, and consolidation of soil layer. The study represents the first ever evidence of land subsidence and its causes in the region that will support the local government as well as decision and policy makers for better planning to overcome problems of overflowing drains, sewage system, littered roads/streets, and sinking land in the city.

The acceleration of the peat secondary consolidation due to the sorption of bound water with disperse clay

According to observations at the experimental site, the primary consolidation of the 6-6.5 m peat layer completed in 3-5 years after the sandy embankment was filled on. Secondary consolidation of peat caused by the removal of bound water from micropores and channels within vegetation remains is the cause of settlement that has not stabilized for decades. The aim of laboratory research was to evaluate the effects of two methods for peat settlement stabilization at the stage of secondary consolidation – vacuuming and sorption of bound water of disperse clay. Tests were carried out with peat, which has a degree of decomposition of 40-45 %, a density of 0.98–1.12 g/cm3, a void ratio of 11.8–13.8. Samples with a diameter of 87 mm and a height of 30, 50 and 70 mm were set into odometers and maintained under a load of 25, 50 and 100 kPa for 5-6 months, after that experiments to stabilize secondary consolidation were started. In contrast to vacuuming, the use of pre-dried clay with the following properties turned out to be very effective: maximum hygroscopic water content 43%, liquid limit 198%, plastic limit 58%, specific surface area 411 m2/g. The volume of clay was about 20% of the volume of peat samples. Deformations of samples due to water sorption by clay increased within 2-4 days and reached 0.09-0.11 of their initial height. The penetration of clay into the peat can be performed by drilling of boreholes, vibration stamping and other methods.

DOWRY SYSTEM: A BLOT IN SOCIETY

The act of settlement represents a substantial danger to the life of females. Settlement is a well-established practice in Indian culture alluding to property or significant security given by one gathering to another as a thought for marriage. The cause of settlement fundamentally was the commitment of the spouse's family or without anyone else with the goal to support the spouse. This custom of settlement was begun in the archaic period. Ladies were skilled with riches what's more, gems from their folks during her marriage and this filled in as an instrument of monetary freedom for the lady of the hour even after marriage. This hazard is the underlying driver of practically all savagery against a wedded lady. Much of the time, after marriage, the issue of share will emerge. In the event that the spouse can't give all, which her significant other and parents in law request, her life in the lucky man's home becomes hopeless. She will be dealt with cold-bloodedly and at times, she may lose her life.

Evaluating Potential Ground Subsidence Geo-Hazard of Xiamen Xiang’an New Airport on Reclaimed Land by SAR Interferometry

The land reclaimed from the seaside may have a long-term subsidence trend, which poses a potential geohazard in the future land use. Xiamen Xiang’an New Airport (XXNA) is built on reclaimed land since 2016. Based on the spaceborne Sentinel-1 data between January 2018 to April 2019 and the time series interferometric synthetic aperture radar (InSAR) technique, this paper analyzed the reclaimed land subsidence evolution at XXNA in this period. InSAR measurements show that XXNA is suffering from severe subsidence, mainly in three regions because of the earth and sand compacting. By analyzing the spatial subsidence characterizations of the main subsiding areas combined with historical land reclamation and future land use planning, we find the potential threat of subsidence to future land use. Correlation between subsidence and the period of reclamation was found, indicating that the consolidation and compression in dredger fill is the main cause of subsidence. By combining subsidence monitoring results with different land use types and adopting the Expectation (Ex) and Entropy (En) methods, we analyzed the key area with potential subsidence geo-hazard. This work shows that with SAR interferometry, it is possible to find the large area ground subsidence in the airport reclaimed area. The areas with potential subsidence geo-hazards are consistent with the deep reclaimed earth, which means high subsidence risk in the future.

La caminabilidad como estrategia proyectual para las redes peatonales del Borde Urbano

El barrio Sierra Morena se ubica en el borde urbano sur oriental de la ciudad de Bogotá y contiene huellas de un pasado y presente marcados en recorridos veredales que transforman un entorno natural, a causa de asentamientos de comunidades que encontraron en esta, cualidades estratégicas para subsistir. Este proyecto ofrece una nueva perspectiva respecto al papel de la arquitectura en función del espacio colectivo, como respuesta proyectual frente a situaciones de calidad de vida en los recorridos de sectores desestructurados, a partir de la aplicación de un marco investigativo desde la teoría del Nuevo Urbanismo, donde se valida en términos cualitativos de diseño la caminabilidad como estrategia que impacta en la construcción social del borde urbano. Se diseña un proyecto urbano integral, para la re significación del tejido urbano existente que articula los distintos sistemas funcionales y que aúne las prácticas urbanas rurales.

Solutions for subsidence in the California Delta, USA, an extreme example of organic-soil drainage gone awry

Abstract. The Sacramento-San Joaquin Delta is at the heart of California's water supply system that provides water for irrigation and human consumption. It is also home to subsiding organic soils, decreasing native aquatic species populations, water quality degradation, vulnerable levees (levees are equivalent to dikes) and decreasing agricultural viability. There has been substantial progress in the interdisciplinary understanding and quantification of the nature and effects of subsidence and its mitigation. Because of the need for a drained rootzone, farming of crops such as vegetables, trees, vines, corn and alfalfa, results in an ongoing unsustainable cycle of continuing peat oxidation and deepening of drainage ditches to compensate for elevation loss. Despite substantial evidence for the increasing risks to the State's economy and water supply, the unsustainability of the status quo, and evidence for the benefits of alternatives, there has been limited progress in converting to land uses that can reduce, stop and reverse subsidence. Our overall approach has been to measure land-surface elevation changes; understand, quantify and model subsidence and greenhouse gas emissions from drained organic soil, and evaluate alternate land uses. Subsidence rates vary from less than 0.5 to over 2 cm yr−1, depending primarily on depth to groundwater and soil organic matter content. The primary cause of subsidence is the oxidation of organic matter, which has resulted in elevations of −3 to −9 m on about 100 000 ha. Using the results from micrometeorological measurements and modelling, we estimate that organic-matter oxidation causes an annual emission of over 2×106 t of CO2-equivalent which represents about 21 % of the State's plant-based agricultural emissions. Rewetting of the peat soils is emerging as a viable solution. Rice and wetlands stop and (in the case of wetlands) reverse the effects of subsidence and result in a net greenhouse-gas emission reduction benefit. Wetlands accrete about 3 cm of soil per year, can break the unsustainable subsidence/drainage cycle, reverse the trajectory of increasing hydraulic pressures on levees, reduce the probability of levee failure and seepage onto islands (islands are equivalent to polders), and may provide material for biofuels and animal feed. The recent implementation of a methodology for quantification of the GHG benefit is facilitating land use conversion and participation in the carbon market.

Influence of pore water pressure change on consolidation behavior of saturated poroelastic medium

Abstract. There are many factors causing land subsidence, and groundwater extraction is one of the most important causes of subsidence. A set of coupled partial differential equations are derived in this study by using the poro-elasticity theory and linear stress-strain constitutive relation to describe the one-dimensional consolidation in a saturated porous medium subjected to pore water pressure change due to groundwater table depression. Simultaneously, the closed-form analytical solutions for excess pore water pressure and total settlement are obtained. To illustrate the consolidation behavior of the poroelastic medium, the saturated layer of clay sandwiched between two sand layers is simulated, and the dimensionless pore water pressure changes with depths and the dimensionless total settlement as function of time in the clay layer are examined. The results show that the greater the water level change in the upper and lower sand layers, the greater the pore water pressure change and the total settlement of the clay layer, and the more time it takes to reach the steady state. If the amount of groundwater replenishment is increased, the soil layer will rebound.

Development of GPR Device and Analysis Method to Detect Thickness of Ballast Layer

Insufficient ballast depth and fouled ballast have been pointed to as causes of settlement and track irregularity. Nondestructive testing methods such as Ground Penetrating Radar (GPR) are a preferred alternative to efficiently evaluate thickness and condition of railroad ballast. Data collected using commercial GPR devices show significant noise around and under sleepers. Furthermore, GPR data need attentive preprocessing and filtering of unnecessary noise before main analysis. In this study, to eliminate noise due to the sleeper, a GPR device with a transmitter and a receiver in a separate box is developed. In addition, an algorithm that can automatically detect the thickness of the ballast layer is also proposed. Comparison between data from the developed device and from a conventional device shows that the developed device can effectively eliminate noise. The trial pit measurements show that the proposed algorithm with the developed GPR device can accurately determine the thickness of ballast.

Understanding Land Subsidence Along the Coastal Areas of Guangdong, China, by Analyzing Multi-Track MTInSAR Data

Coastal areas are usually densely populated, economically developed, ecologically dense, and subject to a phenomenon that is becoming increasingly serious, land subsidence. Land subsidence can accelerate the increase in relative sea level, lead to a series of potential hazards, and threaten the stability of the ecological environment and human lives. In this paper, we adopted two commonly used multi-temporal interferometric synthetic aperture radar (MTInSAR) techniques, Small baseline subset (SBAS) and Temporarily coherent point (TCP) InSAR, to monitor the land subsidence along the entire coastline of Guangdong Province. The long-wavelength L-band ALOS/PALSAR-1 dataset collected from 2007 to 2011 is used to generate the average deformation velocity and deformation time series. Linear subsidence rates over 150 mm/yr are observed in the Chaoshan Plain. The spatiotemporal characteristics are analyzed and then compared with land use and geology to infer potential causes of the land subsidence. The results show that (1) subsidence with notable rates (>20 mm/yr) mainly occurs in areas of aquaculture, followed by urban, agricultural, and forest areas, with percentages of 40.8%, 37.1%, 21.5%, and 0.6%, respectively; (2) subsidence is mainly concentrated in the compressible Holocene deposits, and clearly associated with the thickness of the deposits; and (3) groundwater exploitation for aquaculture and agricultural use outside city areas is probably the main cause of subsidence along these coastal areas.

Mechanisms of settlement in municipal solid waste landfills

Settlement prediction of municipal solid waste (MSW) is a key issue in the design, construction, and post-closure development of landfills. As MSW is a highly heterogeneous material with compressible and degradable elements, the factors causing compression and settlement are complex. This paper explores the mechanisms and timescales for the settlement of land-filled MSW, and develops a rational taxonomy and framework of understanding. Conceptual models are reviewed and discussed, and the relative importance of different causes of settlement is assessed with reference to new, high quality, datasets and data from the literature.

Formation of bridge end bumps due to settlement at bridge approaches

The problem of bridge bump has been a major issue for decades. Over the years, a lot of studies have been conducted by various agencies and professionals to investigate and pinpoint the cause of this phenomenon. Majority of researchers agreed that the major cause of the formation of bridge bump is the differential settlement of soil between bridge abutment and bridge approach. However the exact cause of the settlement may vary depending on the site condition. Some of the causes of settlement were discussed in this paper which includes deformation of embankment fill, deformation of foundation soil, poor drainage system in and around the bridge abutment and poor design and construction practices. Besides that, current practices and new development of mitigation and rehabilitation methods were also discussed in this paper. This paper reviews the factors that contribute to the formation of bridge bump while also identifying the available methods that was used to eradicate this problem.

A Model for Complex Subsidence Causality Interpretation Based on PS-InSAR Cross-Heading Orbits Analysis

Urban areas are subject to subsidence due to varying natural and anthropogenic causes. Often, subsidence is interpreted and correlated to a single causal factor; however, subsidence is usually more complex. In this study, we adopt a new model to distinguish different causes of subsidence in urban areas based on complexity. Ascending and descending Sentinel-1 data were analyzed using permanent scatterer interferometry (PS-InSAR) and decomposed to estimate vertical velocity. The estimated velocity is correlated to potential causes of subsidence, and modeled using different weights, to extract the model with the highest correlations among subsidence. The model was tested in Alexandria City, Egypt, based on three potential causes of subsidence: rock type, former lakes and lagoons dewatering (FLLD), and built-up load (BL). Results of experiments on the tested area reveal singular patterns of causal factors of subsidence distributed across the northeast, northwest, central south, and parts of the city center, reflecting the rock type of those areas. Dual causes of subsidence are found in the southwest and some parts of the southeast as a contribution of rock type and FLLD, whereas the most complex causes of subsidence are found in the southeast of the city, as the newly built-up areas interact with the rock type and FLLD to form a complex subsidence regime. Those areas also show the highest subsidence values among all other parts of the city. The accuracy of the final model was confirmed using linear regression analysis, with an R2 value of 0.88.

Remotely sensing large- and small-scale ground subsidence: A case study of the Guangdong–Hong Kong–Macao Greater Bay Area of China

As the world's largest city cluster, the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is vulnerable to significant subsidence. The widely distributed sediments and rapid urbanization in the GBA result in the concurrence of large- and small-scale subsidence. Mono-sensor synthetic aperture radar (SAR) images usually suffer from the limitation of either low resolution or small coverage, and thus, are not applicable to completely monitoring the GBA. In this study, we used Sentinel-1 (S1), COSMO-SkyMed (CSK) and TerraSAR-X (TSX) images jointly to reveal multi-scale subsidence of the GBA. The overall subsidence ranged from 0 to 112.3 mm/yr derived from the 2015–2017 S1 images. Three regional subsidence bowls (Zhuhai–Zhongshan, Jiangmen, and Guangzhou–Zhongshan) formed in the western alluvial plain. The high correlation between regional subsidence and Quaternary sediments confirms that sediment consolidation is the main cause of subsidence. The land use and numerical modeling results suggest that groundwater extraction and artificial loading are the triggering factors. Two representative local subsidence cases were analyzed using high-resolution images: reclamation settlement at the Hong Kong International Airport (HKIA) and sinkhole subsidence due to the excavation of the Shenzhen Wenbo skyscraper foundation pit. The validation at the HKIA showed that the measurements from the CSK and S1 data both agreed well with the leveling data. However, CSK outperformed S1 in the sense that it increased the point density by a factor of 5, improved the height precision by a factor of 4, and showed fewer false alarms. CSK is therefore more applicable to monitoring the local subsidence of key infrastructures. The cross-heading tracks of TSX and CSK images detected precursory subsidence before the sinkhole collapse from two sides, indicating that the cross-heading tracks benefit the comprehensive monitoring of local subsidence in high-rise and high-density built environments. In summary, the synergistic use of multi-sensor SAR images demonstrates the practicability of the operational surveillance of multi-scale subsidence from regional surveying to the fine monitoring of local areas in the GBA.

Uplift Evidences Related to the Recession of Groundwater Abstraction in a Pyroclastic-Alluvial Aquifer of Southern Italy

Aquifer mismanagement is a common anthropogenic cause of subsidence and uplift phenomena in alluvial plains, representing one of the main natural hazards in urban areas due to related damage to urban structures and infrastructures. In this work, the groundwater rebound phenomenon that occurred in the last decades of the 20th century in the Lufrano area (Metropolitan area of Naples, Southern Italy) has been studied by integrating geological data, hydrogeological continuous monitoring and spaceborne SAR information derived from ERS-1/2 and ENVISAT satellites. In the period of 1989–2006, the Lufrano area, which hosts an important well field made up of 180 wells extracting groundwater for drinking use, suffered an initial over-exploitation of the aquifer which was followed by a sudden and severe decrease of the volume abstraction, resulting this last in a rapid ground uplift. The coupled analysis of hydrogeological and DInSAR data have shown a correspondence between piezometric level rise (up to 15 m) and ground uplift (up to 50 mm) trends in the period 1989–2006. In order to examine the spatio-temporal evolution of the phenomena and the cause-effect relationships, showing the link between the two phenomena and their rates, longitudinal cross-sections were carried out and comparisons between piezometric level rise and time-series of displacements were reconstructed. The obtained results represent an initial contribution to the definition of ground deformation related to groundwater level rise phenomena, providing a basis for future studies focused on the modelling of the hydro-mechanical properties of the aquifer.