Subsidence Features Research Articles

Experimental study on sand production and coupling response of silty hydrate reservoir with different contents of fine clay during depressurization

To further understand the characteristics of clay and sand production (hereafter collectively referred to as sand production) and to provide optimization designs of sand control schemes are critical for gas production from clayey silt natural gas hydrate reservoirs in the South China Sea. Thus-, gas-water-sand production behavoirs and coupling reservoir subsidence characteristics before, during, and after hydrate dissociation of the clayey silt hydrate reservoirs with different clay contents (5%, 10%, 15%, 20%, 25%, and 30%) have been studied through a self-developed experimental system. The results show that with the increase of clay content, the total mass of sand production first increases and then decreases, and it reaches maximum when the clayey content is 20%. The sand production is the lowest before hydrate dissociation and increases significantly during hydrate dissociation, which mainly occurs in the high-speed gas and water production stage at the beginning of hydrate dissociation. After hydrate dissociation, the sand production decreases significantly. During the whole depressurization process, the clay and free sand particles generally move to the sand outlet due to the fluid driving force and overlying stress extrusion. However, for conditions of high clay contents, those particles fail to pass through the sand control screen and gradually accumulate and block the screen by forming a mud cake, which greatly reduce the permeability of the screen and limite sand production as well as gas and water production. Our research lays a foundation for sand production prediction and sand control scheme selection during gas recovery from clayey silty hydrate reservoirs that greatly need to consider a balance between sand control and gas productivity.

Study on land subsidence characteristics and deformation evolution mechanism in Caofeidian New Area, Bohai Bay

Study on land subsidence characteristics and deformation evolution mechanism in Caofeidian New Area, Bohai Bay

Surface Subsidence Characteristics and Causes in Beijing (China) before and after COVID-19 by Sentinel-1A TS-InSAR

Surface subsidence is a serious threat to human life, buildings and traffic in Beijing. Surface subsidence is closely related to human activities, and human activities in Beijing area showed a decreasing trend during the Corona Virus Disease 2019 (COVID-19). To study surface subsidence in Beijing before and after the COVID-19 outbreak and its causes, a total of 51 Sentinel-1A SAR images covering Beijing from January 2018 to April 2022 were selected to derive subsidence information by Time Series Interferometry Synthetic Aperture Radar (TS-InSAR). The results of surface subsidence in Beijing demonstrate that Changping, Chaoyang, Tongzhou and Daxing Districts exhibited the most serious subsidence phenomenon before the COVID-19 outbreak. The four main subsidence areas form an anti-Beijing Bay that surrounds other important urban areas. The maximum subsidence rate reached −57.0 mm/year. After the COVID-19 outbreak, the main subsidence area was separated into three giant subsidence funnels and several small subsidence funnels. During this period, the maximum subsidence rate was reduced to −43.0 mm/year. Human activity decrease with the COVID-19 outbreak. This study effectively analysed the influence of natural factors on surface subsidence after excluding most of the human factors. The following conclusions are obtained from the analysis: (1) Groundwater level changes, Beijing’s geological structure and infrastructure construction are the main reasons for surface subsidence in Beijing. (2) Seasonal changes in rainfall and temperature indirectly affect groundwater level changes, thereby affecting surface subsidence in the area. (3) The COVID-19 outbreak in early 2020 reduced the payload of Beijing’s transportation facilities. It also slowed down the progress of various infrastructure construction projects in Beijing. These scenarios affected the pressure on the soft land base in Beijing and reduced the surface subsidence trend to some extent.

Land subsidence modeling and assessment in the West Pearl River Delta from combined InSAR time series, land use and geological data

West Pearl River Delta (WPRD) is sinking as a result of the jointed effect of natural and anthropogenic factors. Land subsidence has increasingly become a concern because of tremendous population growth and rapid urbanization over this region in the last few decades. In this study, sixty-seven Sentinel-1 images, acquired between 2016 and 2021, were analyzed with the persistent scatterer interferometry technique (PSI), to monitor and reveal the ground subsidence characteristics in the WPRD. It is found that the overall vertical deformation velocities observed in the WPRD ranged between −70 mm/year and 10 mm/year. Three subsidence bowls were found in the study area (Gaolan island of Zhuhai, the junction area of Zhuhai and Zhongshan, and the junction area of Zhongshan and Jiangmen). The spatial–temporal subsidence characteristics have been analyzed. It is discovered that the ground subsidence is mostly dispersed in Quaternary deposits and is highly relevant to the thickness of sediments, indicating that soft soil consolidation is one of the primary causes contributing to land subsidence. Furthermore, land use maps for 2016 and 2021 were generated using Landsat-8 images for the investigation on the relationship between land subsidence and land use. The results obtained from analysis demonstrated that the rapid subsiding areas mainly occurred in the land-use classes as follows: aquaculture, urban land, and agricultural land. The land use conversion pattern with more significant anthropogenic influence usually causes a higher subsidence rate. In addition, based on soft soil thickness, groundwater exploitation, land use, elevation, and strata lithology, a Random Forest Regression (RFR) model was used to predict subsidence rates (R2 = 0.631, RMSE = 2.7 mm/year). The importance of these influencing factors of land subsidence was calculated based on the RFR algorithm. The results indicated that soft soil thickness, elevation, groundwater exploitation, strata lithology, and landcover type are the most significant factors affecting subsidence. The applicability of geological data and land-use history for land subsidence prediction has been demonstrated with the use of the RFR algorithm.

Monitoring Mining Surface Subsidence with Multi-Temporal Three-Dimensional Unmanned Aerial Vehicle Point Cloud

Long-term and high-intensity coal mining has led to the increasingly serious surface subsidence and environmental problems. Surface subsidence monitoring plays an important role in protecting the ecological environment of the mining area and the sustainable development of modern coal mines. The development of surveying technology has promoted the acquisition of high-resolution terrain data. The combination of an unmanned aerial vehicle (UAV) point cloud and the structure from motion (SfM) method has shown the potential of collecting multi-temporal high-resolution terrain data in complex or inaccessible environments. The difference of the DEM (DoD) is the main method to obtain the surface subsidence in mining areas. However, the obtained digital elevation model (DEM) needs to interpolate the point cloud into the grid, and this process may introduce errors in complex natural topographic environments. Therefore, a complete three-dimensional change analysis is required to quantify the surface change in complex natural terrain. In this study, we propose a quantitative analysis method of ground subsidence based on three-dimensional point cloud. Firstly, the Monte Carlo simulation statistical analysis was adopted to indirectly evaluate the performance of direct georeferencing photogrammetric products. After that, the operation of co-registration was carried out to register the multi-temporal UAV dense matching point cloud. Finally, the model-to-model cloud comparison (M3C2) algorithm was used to quantify the surface change and reveal the spatio-temporal characteristics of surface subsidence. In order to evaluate the proposed method, four periods of multi-temporal UAV photogrammetric data and a period of airborne LiDAR point cloud data were collected in the Yangquan mining area, China, from 2020 to 2022. The 3D precision map of a sparse point cloud generated by Monte Carlo simulation shows that the average precision in X, Y and Z directions is 44.80 mm, 45.22 and 63.60 mm, respectively. The standard deviation range of the M3C2 distance calculated by multi-temporal data in the stable area is 0.13–0.19, indicating the consistency of multi-temporal photogrammetric data of UAV. Compared with DoD, the dynamic moving basin obtained by the M3C2 algorithm based on the 3D point cloud obtained more real surface deformation distribution. This method has high potential in monitoring terrain change in remote areas, and can provide a reference for monitoring similar objects such as landslides.

STRATA SUBSIDENCE CHARACTERISTICS OF SHIELD TUNNELING IN COASTAL SOFT SOIL AREA

In order to study the subsidence characteristics caused by large diameter shield tunneling in coastal soft soil area, based on the project of North Oujiang shield tunnel in Wenzhou City, the displacement field, seepage field and stress field of surrounding rock during shield tunnel construction process under fluid-solid coupling were analyzed by using finite difference method. The results show that when the shield tunneling passes through the monitoring section of the tunnel, the surrounding rock in a certain range of this section above the tunnel will be uplifted. Shield tail grouting can effectively control the settlement of the ground, and the increasing range of the ground subsidence gradually decreases. With the advance of the shield the pore water pressure increases, and the pore water pressure in the soil layer will rise sharply due to the shield tail grouting. When the shield passes through the monitoring section of the tunnel, the strata stress above the tunnel increases due to uplift extrusion, and the strata stress below the tunnel decreases due to stress releasing. When the grouting at the tail of the shield is completed and gradually moves away from the monitoring section, the stress releasing results in the decrease of the stress in the surrounding stratum and shows a funnel-shaped form.

Land Subsidence Characteristics and Numerical Analysis of the Impact on Major Infrastructure in Ningbo, China

For the construction and safe operation of major infrastructure in coastal cities, the impact of regional land subsidence that has occurred or is slowly proceeding deserves attention. Previous studies have mainly focused on the surrounding land subsidence caused during construction or operation, as well as the superposition effect of land subsidence caused by groundwater extraction. However, research on the different impacts of damage due to land subsidence in the construction and operation of urban infrastructure needs to be carried out according to the actual geological environmental conditions, reflected in parameters such as the soil properties and common loads. Numerical simulation cannot fully reflect the details of reality; however, it can avoid the influence of other conditions to focus on different factors influencing land subsidence and thus highlight the contribution of a single factor influencing land subsidence. Therefore, in this paper, we adopt field measurement data and carry out a numerical simulation analysis of different influencing factors. First, taking the Ningbo Jiangdong subsidence center (now located in Yinzhou District) as an example, area growth, cumulative subsidence and the occurrence and development of the subsidence rate of a typical urban subsidence funnel area are analyzed. Then, taking the Ningbo Chunxiao–Meishan area as an example, based on the physical and mechanical characteristics of the main soil layers in the coastal reclamation area, a numerical analysis of the self-weight/backfill and surcharge consolidation settlement of the soil layer (considering the water permeability/impermeability of the bottom surface) and a numerical analysis of the nonuniform settlement caused by pile foundation engineering are carried out. Finally, the Ximenkou–Gulou area is taken as the analysis object. Numerical simulation of metro tunnel pipeline deformation is carried out considering uniform/nonuniform settlement. The results show that the comprehensive prohibition of groundwater exploitation is beneficial to slow the land subsidence rate, while the sedimentation of silty clay in Layer 4 (muddy clay) is the largest among all the soil layers. Compared with uniform settlement, nonuniform settlement is more likely to cause connection failure between tunnel segments. The above research results can provide references for the prevention and control of land subsidence and thus the safe operation of major infrastructure.

Surface Subsidence Monitoring in Kunming City with Time-Series InSAR and GNSS

Kunming city is located in the middle of Yunnan Province. Due to large-scale groundwater exploitation and urban development in recent years, this area has been affected by surface subsidence. In this paper, Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS) data are used to monitor the surface subsidence in Kunming city area for better analysis and understanding. The study used data of Sentinel-1A from 2018 to 2020 with atmospheric correction based on GACOS to calculate the average annual subsidence rate in Kunming city area, and the results show that the maximum subsidence rate is 48 mm/year. The subsidence obtained by InSAR is compared with the vertical deformation information obtained by eight GNSS stations in continuous operation in the study area. The subsidence rate trend show by the two methods is consistent, which further verifies the validity of InSAR data to reflect the local deformation. Experimental results shown that the eastern and northeastern Dianchi lake areas were affected by underground resources mining, and the induced surface subsidence characteristics were obvious, with the surface subsidence rate reachde 48 mm/year and 37 mm/year respectively. The Kunyang Phosphate Mine also had different degrees of mining subsidence disaster, with the maximum subsidence rate reached 36 mm/year. The subsidence rate of InSAR and GNSS has the same trend on the whole. However, GNSS sites are generally located in stable areas, the settlement amount obtained in the same time period is somewhat different from that of InSAR.

Analysis and Prediction of Regional Land Subsidence with InSAR Technology and Machine Learning Algorithm

As a worldwide environmental and geological disaster, land subsidence may cause serious harm to urban development. Therefore, the prediction of land subsidence is a key scientific problem. Decheng county, Shandong Province in China is taken as the research object. Based on BP neural network (BPNN) and random forest (RF) method, the analysis and prediction of regional land subsidence are carried out by applying multi-source monitoring data, Geographic Information System (GIS), and machine learning algorithm. Combined with Short Baseline Synthetic Aperture Interferometric Radar (SBAS-InSAR) and GIS technology, the spatiotemporal evolution characteristics of land subsidence from 2017 to 2020 are analyzed. The impact of different groundwater levels on land subsidence is quantitatively analyzed by BPNN and RF algorithm. The real-time prediction model of regional land subsidence is established. The results show that: 1) The area with the most serious land subsidence is located in Songguantun town, the maximum annual average subsidence rate is −40.71 mm/yr. 2) Land subsidence is mainly affected by deep groundwater and shallow groundwater in the research area. 3) The accuracy of the prediction results of the BPNN model is higher than that of the RF model when groundwater level change is used to predict land subsidence.

Natural and anthropogenic halite karst subsidence in north Cheshire, UK; comparison of Rostherne Mere, Melchett Mere, Tatton Mere and their surroundings

Most of the north Cheshire (Knutsford Group) of meres (lakes) in the UK formed naturally by dissolution of Triassic halite after the Devensian glaciation. Anthropogenic brine extraction in the 19th and 20th centuries produced further subsidence that enlarged some meres and formed the new lake of Melchett Mere. The characteristic features of three meres, Rostherne, Melchett and Tatton, are compared here by historical surveys, maps, photographs and light detection and ranging (LiDAR) interpretations. These illustrate the similarities of the natural and anthropogenic subsidence features, which can be separated only by temporal evidence of their formation. Rostherne Mere and Tatton Mere are mainly natural, though deepened or made larger by anthropogenic salt dissolution; Melchett Mere is completely anthropogenic and mainly formed between 1927 and 2003. All three meres are surrounded by landslip scars related to the subsidence. Former brine pumping at Northwich, Plumley and possibly Agden is implicated in the formation of Melchett Mere and the reactivation of natural subsidence at Rostherne and Tatton meres plus The Mere along with Tabley, Pickmere and Budworth meres to the SW. The brine run linkages between these abstraction areas and the subsidence cross the route of the proposed HS2 railway.

STRATA SUBSIDENCE CHARACTERISTICS OF SHIELD TUNNELING IN COASTAL SOFT SOIL AREA

In order to study the subsidence characteristics caused by large diameter shield tunneling in coastal soft soil area, based on the project of North Oujiang shield tunnel in Wenzhou City, the displacement field, seepage field and stress field of surrounding rock during shield tunnel construction process under fluid-solid coupling were analyzed by using finite difference method. The results show that when the shield tunneling passes through the monitoring section of the tunnel, the surrounding rock in a certain range of this section above the tunnel will be uplifted. Shield tail grouting can effectively control the settlement of the ground, and the increasing range of the ground subsidence gradually decreases. With the advance of the shield the pore water pressure increases, and the pore water pressure in the soil layer will rise sharply due to the shield tail grouting. When the shield passes through the monitoring section of the tunnel, the strata stress above the tunnel increases due to uplift extrusion, and the strata stress below the tunnel decreases due to stress releasing. When the grouting at the tail of the shield is completed and gradually moves away from the monitoring section, the stress releasing results in the decrease of the stress in the surrounding stratum and shows a funnel-shaped form.

SURFACE DEFORMATION MONITORING AND DRIVING FORCE ANALYSIS IN THE YELLOW RIVER DELTA BASED ON PS-INSAR TECHNOLOGY

Abstract. Aiming at the land subsidence in the Yellow River Delta region, based on the Sentinel-1A data of 52 scenes from 2020 to February 2022, Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) were adopted to extract the surface deformation information of the Yellow River Delta region. Firstly, the deformation characteristics of typical subsidence feature points are analyzed, and then the correlation between groundwater, precipitation and land subsidence are analyzed. The result show that the settlement area distribution of the Yellow River Delta is not uniform, mainly distributed in underground brine mining area and oil extraction area, the maximum settlement center is located in Yongan Town, the settlement amount reaches −302.7 mm, the main reason of the settlement is excessive exploitation of underground brine salt. By analyzing the correlation between groundwater, precipitation and land subsidence in the Yellow River Delta, it can be seen that the effect of groundwater content change on land subsidence was the most serious, and the correlation coefficient is 0.875. In general, the subsidence of the Yellow River Delta is mainly caused by the over-exploitation of underground fluids such as fresh water, brine and oil without timely compensation.

Temporal principal component analysis and synthetic aperture radar interference analysis of the spatial and temporal evolution of ground subsidence in the Los Angeles area

The temporal principal component analysis (TPCA) method in the field of geology can extract the temporal and spatial features of spatial-temporal data, and the ground subsidence in the Los Angeles area has typical temporal and spatial features. Based on the ground subsidence data of the Los Angeles area from 2016 to 2019 obtained by small baseline set (SBAS)-InSAR technology, TPCA and wavelet analysis were used to analyze the spatial and temporal evolution characteristics of ground subsidence in the Los Angeles area. Several results were found. First, the first principal component obtained by TPCA analysis reflected the spatial and temporal evolution characteristics of ground subsidence at that time series stage. Second, after wavelet analysis and the temporal trends of the eigenvectors of the second and third principal components, it can be seen that the second and third principal components mainly correspond to the periodic deformation and that the maximum amplitude of the periodic oscillation is 10 mm. Third, the correlation analysis of the eigenvectors of groundwater level, rainfall, and the fourth principal component reveals that there is a time phase delay between deformation and groundwater level change and rainfall.

Spatial and temporal characteristics analysis for land subsidence in Shanghai coastal reclamation area using PS-InSAR method

In recent decades, large-scale reclamation projects have been performed in the intertidal flat area of Shanghai, China. Due to the self-weight consolidation of the foundation and dynamic load caused by human activities, the newly reclamation area will sink within a period of time after the land is formed. Therefore, it is necessary to carry out surface deformation monitoring for taking preventive measures in advance. In this research, the PS-InSAR technology, mostly used for urban subsidence monitoring, was applied to obtain the ground deformation information of Shanghai coastal area based on ENVISAT/ASAR (2007.07-2010.02) and Sentinel-1A (2017.07-2020.02) datasets. The results showed that: 1) Compared with ASAR data, the Sentinel-1A data could distinguish more coherent points and get more comprehensive deformation distribution characteristics. 2) Most high-coherent points were detected in artificial objects, especially airport runways, buildings, roads and seawalls. 3) There was obvious uneven land subsidence in the study area during the two monitoring periods, the PS points with high subsidence rates (<-20 mm/a) mainly distributed around Dishui Lake and artificial seawalls. 4) The ground subsidence velocity of the newly formed land gradually slowed down over times, with the average subsidence rate decreased from -10.45 mm/a to -4.94 mm/a. Our study proved that remote sensing monitoring for ground subsidence in reclaimed land could be realized based on PS-InSAR technology, which could provide the spatial distribution characteristics of subsidence in large-scale and long-term series and help the sustainable development of coastal engineering construction.

Prediction method and research on characteristics of surface subsidence due to mining deeply buried Jurassic coal seams

Prediction method and research on characteristics of surface subsidence due to mining deeply buried Jurassic coal seams

Analysis of Mining Subsidence Characteristics and Deformation Prediction considering Size Parameters and Mechanical Parameters

Crushing and caving of roof strata in goaf is an important factor affecting surface subsidence. In order to study the influence law of mining under thick loose layer, overburden size parameters, and initial mechanical parameters of collapse zone on surface subsidence, the law of surface subsidence was analyzed through measured data. On this basis, with the help of FLAC3D numerical simulation software, the surface subsidence was simulated by changing the above factors, and the evolution characteristics of the maximum surface subsidence under the influence of various factors were analyzed. Based on the grey relational analysis, the relational degree between each factor and the maximum surface subsidence value is analyzed, and through multiple nonlinear regression, the prediction model of mining subsidence deformation under thick loose layer considering the influence of seven factors is established. The results show that the mining thickness has the greatest influence on the surface subsidence, and cohesion has the least influence on surface subsidence. The rationality of the subsidence prediction model is verified by an example.

Numerical Simulation of Crack Evolution Mechanism and Subsidence Characteristics Effected by Rock Mass Structure in Block Caving Mining

In the block caving mining, the significant rock mass deformation and surface subsidence will be formed with the continuous extraction of ore. However, the internal crack evolution mechanisms in rock mass and associated subsidence characteristics present one of the key issues in rock mining engineering. Although block caving method has been used for many years, current knowledge of the crack evolution mechanisms, the subsidence characteristics under the influence of rock mass structure and subsidence prediction capabilities are limited. Based on the rock mechanics model provided by CEMI (Centre for Excellence in Mining Innovation), crack evolution mechanisms and subsidence characteristics effected by the rock mass structure in block caving are numerically investigated using RFPA 2D, a numerical code based on FEM (Finite Element Method). Crack formation, propagation and coalescence in the overlying strata and the stress-balancing arch evolution in the stress field are represented visually during the whole process of extraction. The numerically obtained crack evolution shows that the stress-balancing arch has a significant influence on the fracture development of rock mass, and directly determines the slump form and rate of the rock mass. After understanding of the crack evolution mechanism in rock mass, the characteristics of surface subsidence are analyzed. Numerical experiments emphasize the geometrical configuration of joints and faults about mechanisms of subsidence development, including joints orientation, faults location and inclination, which can provide significantly meaningful guides for investigation of subsidence mechanisms and implementation of remedial measures.

Calculation Model for Progressive Residual Surface Subsidence above Mined-Out Areas Based on Logistic Time Function

The exploitation of underground coal resources has stepped up local economic and social development significantly. However, it was inevitable that time-dependent surface settlement would occur above the mined-out voids. Subsidence associated with local geo-mining can last from several months to scores of years and can seriously impact infrastructure, city planning, and underground space utilization. This paper addresses the problems in predicting progressive residual surface subsidence. The subsidence process was divided into three phases: a duration period, a residual subsidence period, and a long-term subsidence period. Then, a novel mathematical model calculating surface progressive residual subsidence was proposed based on the logistic time function. After the duration period, the residual subsidence period was extrapolated according to the threshold of the surface sinking rate. The validation for the proposed model was estimated in light of observed in situ data. The results demonstrate that the logistic time function is an ideal time function reflecting surface subsidence features from downward movement, subsidence rate, and sinking acceleration. The surface residual subsidence coefficient, which plays a crucial role in calculating surface settling, varies directly with model parameters and inversely with time. The influence of the amount of in situ data on predicted values is pronounced. Observation time for surface subsidence must extend beyond the active period. Thus back-calculated parameters with in situ measurement data can be reliable. Conversely, the deviation between predictive values and field-based ones is significant. The conclusions in this study can guide the project design of surface subsidence measurement resulting from longwall coal operation. The study affords insights valuable to land reutilization, city planning, and stabilization estimation of foundation above an abandoned workface.

Land Subsidence Monitoring Method in Regions of Variable Radar Reflection Characteristics by Integrating PS-InSAR and SBAS-InSAR Techniques

In the InSAR solution, the uneven distribution of permanent scatterer candidates (PSCs) or slowly decoherent filtering phase (SDFP) pixel density in a region of variable radar reflection feature can cause local low accuracy in single interferometry. PSCs with higher-order coherence in Permanent Scatter InSAR (PS-InSAR) are generally distributed in those point targets of urban built-up areas, and SDFP pixels in Small Baseline Subset InSAR (SBAS-InSAR) are generally distributed in those distributed targets of countryside vegetation areas. According to the respective reliability of PS-InSAR and SBAS-InSAR for different radar reflection features, a new land subsidence monitoring method is proposed, which combines PS-SBAS InSAR by data fusion of different interferometry in different radar reflection regions. Density-based spatial clustering of applications with noise (DBSCAN) clustering analysis is carried out on the density of PSCs with higher-order coherence in PS-InSAR processing to zone the region of variable radar reflection features for acquiring the boundary of data fusion. The vector monitoring data of PS-InSAR is retained in the dense region of PSCs with higher-order coherence, and the vector monitoring data of SBAS-InSAR is used in the sparse region of PSCs with higher-order coherence. The vertical displacements from PS-InSAR and SBAS-InSAR are integrated to obtain the optimal land subsidence. The verification case of 38 SAR images acquired by the Sentinel-1A in Suzhou city indicates that the proposed method can automatically choose a matched interferometry technique according to the variability of radar reflection features in the region and improve the accuracy of using a single interferometry method. The integrated method of the combined field is more representative of overall subsidence characteristics than the PS-InSAR-only or SBAS-InSAR-only results, and it is better suited for the assessment of the impact of land subsidence over the study area. The research results of this paper can provide a useful comprehensive reference for city planning and help decrease land subsidence in Suzhou.

Analysis of Temporal and Spatial Evolution Characteristics of Land Subsidence in Western Songnen Plain Using Multisource Remote Sensing

Abstract The exploitation of underground fluid is an important factor leading to land subsidence. The effects of mining depth, frequency, and mode on land subsidence are also different. The objective of this study was to develop a multisource method—including optical remote sensing interpretation, Interferometric Synthetic Aperture Radar (InSAR) technology, and unmanned aerial vehicle (UAV)—to reveal the long-term temporal and spatial evolution law of subsidence characteristics driven by groundwater and oil extraction, as well as to reveal the formation mechanism and seasonal response law of land subsidence under the action of different driving factors. In this paper, we select the western region of Jilin Province located in Songnen Plain as the study area. The subsidence funnels in the study area are distributed in a porphyritic manner, and the distribution of the subsidence funnels has a certain correlation with the distribution of the pumping wells. In farmland areas, the subsidence is mainly caused by pumping groundwater. The annual land subsidence rate in the study area is -3.14 mm/a, and the maximum deformation rate in the study area is -22.05 mm/a. The subsidence is affected by the season, shown by the fact that it rises in the dry season and decreases in the rainy season. The subsidence in the west of Songnen Plain is caused by oil pumping and groundwater pumping, and groundwater pumping is dominant. The exploitation of underground fluid transfers the pressure borne by water or oil to the soil skeleton so as to increase and consolidate the effective stress of the soil layer and lead to land subsidence. The continuous observation of the surface in the western area of Songnen Plain is helpful to guide the safe production of agriculture and industry and ensure the smooth development of local industry and agriculture.