Settlement Problems Research Articles

Refined subsidence monitoring and dynamic prediction in narrow and long mining areas based on InSAR and probabilistic integral method

Continuous exploitation in mining areas damages the surrounding environment and has various severe geological impacts. Hence, long-term monitoring of mining areas is crucial to reducing these impacts. Differential interferometric synthetic aperture radar (D-InSAR) is widely applied to monitor the subsidence in mining areas, but it cannot obtain accurate large-gradient subsidence result in the centre of the subsidence basin in mining areas due to the de-coherence phenomenon. The probability integral method (PIM) is a prediction method that can cooperate with D-InSAR (D-InSAR PIM, DPIM) to solve the problem. However, with this method, there is early convergence of the edge subsidence in narrow and long mining areas. Moreover, the PIM can only predict the spatial domain; it cannot achieve dynamic prediction. To address the above problems in the traditional DPIM data processing process, in this study, firstly, the traditional PIM was improved by adjusting the radius of the parameter and constructed an improved DPIM (IDPIM) method. The hybrid algorithm was applied to solve the parameters of the IDPIM method and then acquire subsidence results, thus solving the early convergence of edge subsidence problem characteristic of traditional PIM prediction in mining. Additionally, an area-weighting based fusion method was proposed to integrate the IDPIM results and the D-InSAR results (Area-weighting based fusion of the IDPIM and D-InSAR results, AFID) achieving whole-basin refined subsidence in mining areas. Secondly, based on a summary of subsidence laws in mining areas, the Hossfeld model was introduced and combined with the IDPIM method (IDPIM Hossfeld, IDPIM-H) to construct a subsidence dynamic prediction method. This achieved dynamic prediction of the subsidence in mining areas. A coal mine in Ordos was used as the study area, and the feasibility of the IDPIM method, the AFID method and the DPIM-H method was verified through a comparative analysis of leveling data. The results demonstrated that: (1) The results of the IDPIM method showed 8% and 66% improvement in RMSE along the striking and dip lines, respectively, over the D-InSAR results, improving the early convergence of the DPIM along the dip direction of the mine. (2) The results of the AFID method provide a 69% improvement in whole-basin RMSE over the D-InSAR results, which improves the lack of monitoring capacity in the D-InSAR technology center. (3) The results of the DPIM-H method provide a 35% improvement in basin-wide RMSE over the D-InSAR results, solving the problem of low temporal resolution of the D-InSAR technology and realizing the dynamic prediction with high temporal resolution. These findings provide a theoretical basis for future refined exploration of dynamic subsidence in mining areas

Assessing Potential Groundwater Storage Capacity for Sustainable Groundwater Management in the Transitioning Post‐Subsidence Metropolitan Area

AbstractMany major cities worldwide have inevitably experienced excessive groundwater pumping due to growing demands for freshwater in urban development. To mitigate land subsidence problems during urbanization, various regulations have been adopted to control groundwater usage. This study examines the transition in the post‐subsidence stage, especially in metropolitan areas, to adaptively adjust subsidence prevention strategies for effective groundwater management. Taking the Taipei Basin as an example, historical data reveals significant subsidence of more than 2 m during early urban development, with subsidence hazards largely mitigated over decades. However, the rising groundwater level poses a risk to the stability of engineering excavations. In this study, 29 X‐band Cosmo‐Skymed constellation (CSK) images were utilized with the Persistent Scatterer InSAR (PSInSAR/PSI) technique to monitor surface displacements during the construction of the Mass Rapid Transit system. Correlating groundwater levels helps identify the heterogeneous hydrogeological environment, and the potential groundwater capacity is assessed. PSI time‐series reveal that approximately 2 cm of recoverable land displacements correspond to groundwater fluctuations in the confined aquifer, indicative of the typically elastic behavior of the resilient aquifer system. The estimated groundwater storage variation is about 1.6 million cubic meters, suggesting this potential groundwater capacity could provide available water resources with proper management. Additionally, engineering excavation safety can be ensured with lowered groundwater levels. This study emphasizes the need to balance groundwater resource use with urban development by adjusting subsidence prevention and control strategies to achieve sustainable water management in the post‐subsidence stage.

Investigation of the Mechanical Properties of Reinforced Calcareous Sand Using a Permeable Polyurethane Polymer Adhesive.

Calcareous sand has been widely used as a construction material for offshore projects; however, the problem of foundation settlement caused by particle crushing cannot be ignored. Although many methods for reinforcing calcareous sands have been proposed, they are difficult to apply on-site. In this study, a permeable polyurethane polymer adhesive (PPA) was used to reinforce calcareous sands, and its mechanical properties after reinforcement were investigated through compression creep, direct shear, and triaxial shear tests. The reinforcement mechanism was analyzed using optical microscopy, CT tomography, and mercury intrusion porosimetry. The experimental results indicate that there is a critical time during the compression creep process. Once the critical time is surpassed, creep accelerates again, causing failure of the traditional Burgers and Murayama models. The direct shear strength of the fiber- and geogrid-reinforced calcareous sand reinforced by PPA was approximately nine times greater than that without PPA. The influence of normal stress was not significant when the moisture content was less than 10%, but when the moisture content was more than 10%, the shear strength increased with an increase in vertical normal stress. Strain-softening features can be observed in triaxial shear tests under conditions of low confining pressure, and the relationship between the deviatoric stress and strain can be described using the Duncan-Chang model before softening occurs. The moisture content also has a significant influence on the peak strength and cohesive force but has little influence on the internal friction angle and Poisson's ratio. This influence is caused by the different PPA structures among the particles. The higher the moisture content, the greater the number of pores left after grouting PPA.

Subsidence and measures in the polders of the Netherlan ds

AbstractThe Netherlands consists for 65% of polders. Impoldering activities started in the beginning of the 11th century with impoldering of coastal lowlands. In the 13th century, a start was made with reclaiming of lands gained on the sea and since early 16th century with draining of lakes. Up to several metres in depth, soils consist primarily of peat and or clay. Underneath is a thick sandy layer, with lenses of clay. Especially in peat polders, subsidence and oxidation have been significant, up to 5 m, and is still going on. In clay polders, most of the subsidence took place in the first decennia after reclamation. Maximum subsidence in these polders has been 1.25 m. Over centuries, various measures have been taken to cope with the subsidence problems. These measures consist first of all in water management measures related to management not only of the subsidence process, but also of special measures with respect to buildings, structures and infrastructure. The paper presents a review of the subsidence process in the different types of polders, as well as of measures that over the centuries have been taken to cope with the developments in the polders and to cope with subsidence problems.

Contemporary problems of settlement in the ethnic plain villages of the northwestern regions of Azerbaijan (on the example of the Balakan administrative district)

The geographical position of the region, ethnic composition, acceleration of the process of polarization among rural settlements, and other factors increase the relevance of the research. The subject of the research is the study of rural settlement problems, and the object of the research is the villages and ethnic minorities of the Balakan district. The study aims to reveal the modern problems of the settlement of ethnic minorities and the formation of rural agglomerations, to study the causes of the emptying of some villages, and to prepare a rural development model to prevent the problems. To conduct research, the literature and statistical materials were analyzed, as well as cartographic, comparative analysis, SWOT, and modelling methods were used. Moreover, a field investigation was conducted in the research area. It was revealed that although a majority of the rural population settles in villages with a high demographic potential, villages with a weak demographic potential, due to their higher number, play a major role in the settlement system. Moreover, some villages form rural agglomerations, while some of them lose their population due to socioeconomic challenges. Due to the intense migration processes, some villages have turned into endangered villages (Mazimustu, Goyrujuluk), and even some villages are on the brink of extinction (Bayrambina, Mazimchay, Abjit). Studying the regulation of rural settlement in the region is of practical importance in terms of ensuring the equal development of the region, ensuring the security of the borders, and protecting ethnic minorities. However, there is still a need for serious research in this field.

Composite Sand–Clay Infrastructural Soil Fills: Characteristic Consolidation and Hydraulic Properties

In the design construction of infrastructural projects comprised of geotechnical applications, including composite soil fill layers, compacted sand-clay soil fills are widely preferred as barrier layers, particularly in solid waste landfills, to minimize leakage, to prevent leachate from entering into groundwater. When bentonite clay with high water absorption capacity and low hydraulic conductivity is mixed with sand possessing relatively enhanced frictional properties, greater shear strength capacity, an effective fill material exhibiting low sensitivity to frost, and low volume change in case of wetting, drying can be obtained. On the other hand, when montmorillonite clay is loaded, due to highly critical volumetric contraction or dilation characteristics (high compressibility nature of clay), the soil fill composed of sand-clay will significantly consolidate. This situation may cause differential settlement problems of infrastructural fills employed in geotechnical applications. In this regard, the load conditions (mechanical effects) and the environmental conditions (physicochemical effects) in the field control compressibility characteristics and consolidation properties of sand-bentonite clay mixtures. This will ultimately impact the desired stability conditions of sand-clay soil layers built for constructed infrastructural fill, resulting in a deviation from anticipated performance conditions. To this end, in this study, the specimens of sand-bentonite clay mixtures prepared with different contents of sand-bentonite clay were subjected to one-dimensional consolidation tests to investigate the effect of bentonite content used in the mixture on consolidation behavior, hydraulic properties, and effect of sand amount on rate of consolidation and on resulting compressive strength behavior.

Problems of the Post-War Settlement and the Formation of the Yalta-Potsdam System of International Relations

Problems of the Post-War Settlement and the Formation of the Yalta-Potsdam System of International Relations

Feasibility of managing and organizing the problem of informal settlements a field study on informal areas in Najaf Governorate

The research aims to study the problem of informal housing in Najaf Governorate, present strategic scenarios to solve the problem, as well as choosing the low-cost construction strategy as an approved strategy in the research. The study included (9) areas in which informal housing units spread, namely (Al-Radhwiya, Al-Rahma neighborhood, Al-Najaf Sea depression, Al-Shawafi area, behind Al-Quds neighborhood, Al-Jadidah II slums, Al-Jadidah III slums, Tabuk neighborhood, Al-Barakiyah), affiliated to the Najaf Governorate Municipality Directorate. The researchers used the descriptive analysis method based on structured personal interviews in informal areas to identify the problem, in addition to using financial tools by calculating costs (fixed capital, working capital) and revenues to solve the problem by submitting a proposal to establish a low-cost residential complex. The study reached several conclusions, the most important of which is that efforts and procedures can be organized to reach a radical solution by choosing the optimal and fastest scenario, which is building low-cost housing units, and benefiting from the areas on which slums were built. The study recommended a set of recommendations, the most important of which is forming a government working group from the departments concerned with urban planning, the municipality, the Investment Authority, and departments related to infrastructure, to prepare a technical study and an action plan to establish a package of projects distributed across the governorate's areas. These projects are granted to the best investors in establishing low-cost housing units, and forming a subcommittee to evaluate the lands and re-use them in an optimal manner. In a way that achieves benefit for the city, whether by converting them into green spaces, parks, or investment projects that enhance commercial activity in the city.

Effect of cross-correlated hydraulic conductivity and compression index on nonlinear consolidation in randomly heterogeneous highly compressible aquitards

The problem of land subsidence due to groundwater pumping in highly compressible, randomly heterogenous aquitards with stress-dependent parameters is analyzed through one-dimensional Monte Carlo numerical simulations of nonlinear groundwater flow and consolidation. The natural logarithm of hydraulic conductivity (Y) and compression index (Cc) are considered spatially cross-correlated random variables. A stochastic simulation method based on a bivariate normal copula was applied to generate positive, negative, and uncorrelated realizations of the two random variables. The results show that when Y and Cc are correlated random parameters, the ensemble average total settlement is consistently larger (between 13% and 40% for the synthetic cases tested) than the total settlement obtained when the parameters are deterministic (perfectly known). In addition, the results of negative and no correlation between Y and Cc are similar in terms of the ensemble average and variance of total settlement, while positive correlation leads to larger values of total settlement and its variance. The stochastic approach employed here allows incorporating the uncertainty in the parameters in the simulation of the subsidence process, which is relevant for geotechnical engineering, design of structures and groundwater management.

Effect of Ground Improvement on Settlement Problems of Lignite Spoil Heaps Using Numerical Modelling

Effect of Ground Improvement on Settlement Problems of Lignite Spoil Heaps Using Numerical Modelling

Exponential qubit reduction in optimization for financial transaction settlement

We extend the qubit-efficient encoding presented in (Tan et al. in Quantum 5:454, 2021) and apply it to instances of the financial transaction settlement problem constructed from data provided by a regulated financial exchange. Our methods are directly applicable to any QUBO problem with linear inequality constraints. Our extension of previously proposed methods consists of a simplification in varying the number of qubits used to encode correlations as well as a new class of variational circuits which incorporate symmetries thereby reducing sampling overhead, improving numerical stability and recovering the expression of the cost objective as a Hermitian observable. We also propose optimality-preserving methods to reduce variance in real-world data and substitute continuous slack variables. We benchmark our methods against standard QAOA for problems consisting of 16 transactions and obtain competitive results. Our newly proposed variational ansatz performs best overall. We demonstrate tackling problems with 128 transactions on real quantum hardware, exceeding previous results bounded by NISQ hardware by almost two orders of magnitude.

STRATEGI KOMUNIKASI KONTROL JEJARING KEBIJAKAN DALAM GERAKAN BERSAMA RAKYAT ATASI KAWASAN PADAT KUMUH DAN MISKIN (GEBRAK PAKUMIS) DI KABUPATEN TANGERANG

Housing and settlements have a very fundamental role in the life of the Indonesian people considering the problem that often occurs is the level of housing needs that is not balanced with the level of regional capacity in providing habitable housing. As a result, a residential area will receive a load that exceeds the carrying capacity of its environment and tends to become slum. The problem of settlements is a serious problem because it is feared that it will cause fatal pockets of poverty and then cause various social problems beyond the government's ability to handle and monitor them. The Tangerang Regency government tries to clean up uninhabitable houses through the GEBRAK PAKUMIS Program. The main focus of this program is to improve the water and sanitation sector with a focal point on improving the quality of houses because a poor sanitation system is a major factor in the formation of slum areas. This study aims to analyze and find theoretical answers to the principles of policy networks and obtain new concepts about policy networks. This research uses descriptive qualitative methods, data collection techniques by means of interviews, observation, and documentation. One of the problems that is the basis for the failure of this program is the long procedure. This is something that is feared by residents, because it is considered difficult to be realized. Based on the problems faced by residents as recipients of house renovation assistance, environmental development and community empowerment, the correct communication strategy is a solution to communicate the benefits of the program to the beneficiary residents. Therefore, the communication strategy solution offered in this study is as a stimulant for local government to provide populist socialization to residents in order to bring citizens to ease in taking procedures in this program.

Что удалось сделать в сельском Татарстане за десять лет реализации системы самообложения населения

The budget deficit in municipalities of the Republic of Tatarstan forces local authorities to search for additional sources of funding to solve the problems of rural settlements. One of the ways was the participation of rural municipalities in the development of a system of self-taxation for citizens. It has been implemented in Tatarstan since 2013. The article sets the task of assessing the effects of the self-taxation system in rural settlements of the republic, accumulated over 10 years of its operation. By analyzing the legislative framework of the Russian Federation and the Republic of Tatarstan, the author reveals the basic concepts and provisions used in the system of self-taxation of citizens. Using interviews he conducted in municipalities of the Republic of Tatarstan with heads, deputies, and activists of rural settlements, the experience of using and features of public participation in the self-taxation system over the past ten years was examined. It was revealed that the results of the implementation of the self-taxation system are expressed in an increased level of trust in it on the part of villagers, in almost one hundred percent collection of contributions, in the involvement of village residents in the formation of municipal budget plans, in increasing the civic responsibility of representatives of rural communities of Tatarstan. The “external” effect of the self-taxation system is expressed in the number of solved problems of local importance: repair and construction of rural roads, water supply, street lighting, improvement of cemeteries, monuments and obelisks, sites for garbage containers, sidewalks, embankments, springs, parks and public gardens. This list of work of conducted works, which is far from complete, using the villagers’ self-taxation system and through co-financing from the government bodies of Tatarstan, has significantly increased the level and quality of rural life in the republic.

Assessments of Land Subsidence in the Tehran Metropolitan Using Satellite Radar Interferometry Technique

Background and objective Many cities in the world have land subsidence problems because of environmental issues related to urban development. The arid and semi-arid climatic conditions prevailing in most of the interior regions of Iran and the need for the increasing industrial, agricultural, and drinking water exploitation from underground water resources, as well as urban development, have increased the occurrence of land subsidence in Iran, especially in the metropolis of Tehran. This study aims to assess land subsidence in Tehran, Iran, using the satellite radar interferometry (InSAR) technique. Method In this research, 31 images of Sentinel-1 were processed using the time series of persistent scatter interferometry (PSI) in 2022, and a map of the average annual rate of land subsidence in Tehran metropolis was prepared. Finally, after validating the results of interferometry with GPS station observations, the relationship between land subsidence and exploitation of underground water resources was examined as the most important factor in ground surface changes in the study area. Results The findings showed a decreasing trend in land subsidence from plain to urban areas. The highest land subsidence, with a rate of -43 mm per year occurred in the southern and southwestern parts of Tehran. Districts 10, 11, 12, 16, 17, 18, 19, and 20, which comprise about 26% of Tehran’s population, were experiencing land subsidence. The drop in the water level of observation wells was considerable in the areas where the highest rate of land subsidence occurred. Another finding of the research was the decrease of the underground water level from the north to the south of Tehran, indicating that the water depth in the southern areas of Tehran decreased due to human activities such as water pumping. Conclusion There is an increasing pressure in the aquifer through pumping water from wells in the study area for various industrial, agricultural and drinking water uses which has led to the increase in the occurrence of land subsidence.

Soil-structure interaction issues in integral abutment bridges

Integral Abutment Bridges (IABs) are constructed without expansion joints and bearings, connecting the bridge deck monolithically to the end abutments. Therefore, the construction and maintenance costs of IABs are low compared to conventional bridges with bearings and joints. However, the soil-structure interaction issues are more complex for IABs due to the transfer of deck movements to the foundations through the abutments. Hence abutments of these bridges play an important role in the performance of the substructure and consequently the design approach for the substructure. In this paper, soil-structure interaction issues are investigated for the deck movements due to cyclic thermal loading, which occurs as a combination of daily and seasonal temperature changes. The development of a physical model facility to simulate the problem is described with scaling laws and material properties. The settlement problem at the bridge approach and stress ratcheting phenomena observed at the abutment soil interface are discussed using results from model tests. For the prediction of lateral earth pressure distribution behind abutments, currently available methods are discussed, and modifications are proposed. Finally, the effectiveness of Expanded Polystyrene (EPS) geofoam as an inclusion is discussed to mitigate approach settlement and stress ratcheting problems due to cyclic thermal loading. The results of this study confirm that EPS geofoam is a highly effective material to minimise adverse soil-structure interaction issues in integral bridge abutments.

The change of physical properties of calcium carbonate nanomaterials cured soil in road substrates

The utilization of appropriate materials to enhance road subgrade’s physical characteristics is crucial for current transportation construction and maintenance. This study proposes a curing method that employs calcium carbonate nanomaterials to address the problem of soil displacement and settlement in roadway subgrades. A method was developed during the study to explore the optimal curing material ratio. Additionally, this study developed a method for testing and analyzing the mechanical properties of soils cured with nanomaterials, including measures of tensile stress, triaxial shear stress, and Moore’s damage envelope. The study demonstrated that the unconfined compressive strength of the soil treated with calcium carbonate nanomaterials was 0.40 MPa after 7 days of curing with a 6% doping of the curing agent. Increasing the doping to 18% resulted in a breaking load of the soil reaching 0.100 kN. Furthermore, the triaxial shear stress–strain curve of the soil exhibited a slope of 264.47 during the linear phase when the curing agent was dosed at 6%. The slope of the linear phase of the stress–strain curve for triaxial shear at 6% curing agent doping was found to be 264.47. The cured soil molar pack line exhibited an internal friction angle of 22.66 degrees at the same curing agent dosage. The displacement analysis of the replacement roadbed with cured soil revealed a maximum observed displacement of only 377 mm after filling the embankment using the study method. The experimental results provide support for the hypothesis of the study, which suggests that the application of calcium carbonate nanoparticles can significantly enhance the physical characteristics of road subgrade.

City growth and its impact on residential problems: A case study in the city of Jakarta

This study aims to examine housing and settlement problems, especially in the Jakarta area as a result of population growth which has caused a very large population by identifying the number of housing needs and housing deficits. This study takes the object of the city of Jakarta as a case study and focuses on the housing sector which includes 2731 residential neighborhoods (RW) where the city occupies an area of 664.01 km2. Studies show the cause of the problem is caused by relatively stable city growth with a growth rate of around 1% over the past 20 years, which is reflected in the number of families, which amount to 3,627,111 families, with a housing density of 5462 families/km2, living in 2,242,163 housing units. The findings show that another cause is the spread of slum settlements in the city, which total 445 RWs, which means 16.30% of the total RWs. The results of the research show that so far, the problem has not been resolved.

Analysis of subsidence zone of the village access road in Jatirunggo, Semarang Regency using microtremor data

The rehabilitation of the subsidence phenomenon in Jatikurung sub-village, Jatirunggo village, Pringapus Subdistrict, Semarang Regency, Central Java, has been carried out for a long time however, it has never been successful. Every time an embankment is made, it is only a matter of time before another subsidence occurs. This research aims to investigate the subsurface structure of the subsidence sites. It is proposed to be used as a reference for structural planning in the treatment of road subsidence. Subsurface information is very useful in addressing the subsidence problem more effectively and precisely. The method used was by recording microtremor data and analyzing shear wave velocity and Poisson ratio as parameters to determine the type of subsurface layer. The obtained results are in the form of clay layers to bedrock layers at a depth of 35m. The movement occurred because of the soft or loose soil below and at the edge of the road above the impermeable clay layer. In addition, to the north side of the collapse point is a fairly deep cliff, which is a burden on the bedrock. When it was raining, the soil filled with water and there was even a flow of water in the soil deposits (piping) resulting in the ground movement toward the lower part.

Research on the analysis and management measures of land subsidence caused by groundwater exploitation in Tianjin, China

Since the 20th century, there has been an increasing reliance on groundwater due to the rapid development of agriculture and industry. This has resulted in the exploitation of groundwater in large quantities, leading to global land subsidence problems. Tianjin is one of the cities where this problem first emerged, but few studies and surveys have been conducted. As a result, the lack of management of groundwater extraction has caused the issue of land subsidence to become more prominent in recent years. By investigating and collating global research on land subsidence problems caused by groundwater extraction, it is concluded that mathematical and numerical methods, global information systems, remote sensing, and other technologies can be utilized to monitor and predict groundwater levels. Regional management measures can then be developed based on simulation results. However, the application of such technology in Tianjin is insufficient, and there is a need to strengthen the connection between management measures and research data analysis results.

Shear Strength of Soft Soil Reinforced with Singular Bottom Ash Column

Structures construct on soft clays are often affected by stability and settlement problems due to high compressibility, low shear strength and low permeability of soft clay which will lead to bearing capacity failure and excessive settlement. The soft clay samples had the dimensions of 50 mm diameter and 100 mm in height. The bottom ash column had two (2) different area replacement ratios which were 4% and 9% (10 mm and 15 mm diameters respectively) with the bottom ash column penetration ratio of 0.3, 0.7 and 1.0. The results of the unconfined compression test show that there is an improvement in shear strength of soft kaolin clay when reinforced with bottom ash column. For samples with area replacement ratio 4%, the results show the increment of 25%, 37.5% and 50% at height penetrating ratio of 0.3, 0.7 and 1.0, respectively in shear strength. Meanwhile, for samples of 9% area replacement ratio, the shear strength of the soft kaolin clay increased about 14.29, 28.57 and 57.14%, respectively. It can be concluded that by reinforcing the soft clay using singular bottom ash column, the shear strength of the soils increases and become more significant as the area replacement ratios and the column penetration ratios increase.