Subsidence Features Research Articles

Rock strata failure and subsidence characteristics under the mining of short distance thick coal seams: a case in west China

Rock strata failure and subsidence characteristics under the mining of short distance thick coal seams: a case in west China

Field Study on the Law of Surface Subsidence in the High‐Intensity Fully Mechanized Caving Mining Working Face with Shallow Thick Bedrock and Thin Epipedon in Hilly Areas

Shallow and thick coal seams occur extensively in hilly areas in Shanxi Province and Shaanxi Province, China. The surface damage and landslides caused by shallow fully mechanized caving mining have a very serious impact on the environment. To provide a theoretical and reference foundation for mine environmental protection in hilly settings, a research on surface movement of the high‐intensity fully mechanized caving mining working face with shallow thick bedrock and thin epipedon (HIFMCMWFSTBTE) is urgently needed. In this study, using the P2 working face of a mine as the research object, three surface subsidence observation lines were arranged in this working face to analyze the dynamic change characteristics of surface subsidence. Besides, the law of surface movement, mining sufficiency, fracture development and distribution characteristics, subsidence speed, and surface movement duration of HIFMCMWFSTBTE in hilly areas were comparatively studied. The research results reveal that the upper part of the slope slides towards the downhill direction under the action of tensile stress or push stress. As a result, the range of the horizontal movement towards the downhill direction of the slope and the range of surface movement both increase, and the movement angle and boundary angle both decrease compared with the plain. HIFMCMWFSTBTE is prone to serious sudden discontinuous damage. Fractures on the gully region surface develop along the contour, forming a crisscross fracture network, and the fractures are not easy to close after being generated. HIFMCMWFSTBTE in hilly areas can achieve full mining more easily than those of other geological conditions. According to the field measurement, critical full mining can be achieved in P2 working face when the ratio of mining width to mining depth is 1.07. The surface movement duration of HIFMCMWFSTBTE in hilly areas is relatively short. Considerable subsidence will occur in the active stage, and the surface subsidence is sudden and violent. The measured surface stabilization time of the P2 working face is only 20% of the calculated value in the Specification for Coal Pillar Reservation and Coal Mining under Buildings, Water Bodies, Railways, and Main Shafts (hereinafter referred to as the Specification), indicating that the specification′s empirical formula is inapplicable to the calculation of surface stabilization time of the P2 working face.

Integration of Multiband InSAR and Leveling Measurements for Analyzing the Surface Subsidence of Shield Tunneling at Beijing‐Zhangzhou High‐Speed Railway

In modern life, metro and high‐speed rails have become indispensable transportation and have been playing an important role in many areas, especially in cities. The metro and high‐speed rails have varying degrees of impact on the surface and surrounding buildings, which must be carefully understood to minimize the risk of hazards. This work is aimed at investigating the deformation of ground surface and the surrounding structures, caused by the excavation of underground tunnels. Because of the spatiotemporal characteristics of the land subsidence induced by underground tunnel construction, the measurements obtained from InSAR (Synthetic Aperture Radar Interferometry) and leveling techniques are integrated to study the subsidence phenomenon of the ground surface above the shield tunnels and the surrounding buildings. The subsidence‐related parameters, including the advance angles, lag angles, and boundary angles, are derived from the deformation results. This study suggests that leveling and InSAR observations can provide technical support to study the subsidence of dense buildings on the surface of shield tunnel excavation and to protect the surrounding environment.

Special aspects of design and construction of irrigation systems on loess soil

The article describes the problems of construction and design of irrigation and drainage structures on loess subsidence when soaking soils. Irrigation and drainage structures are widely used for laying canals, dams and other water facilities. The difference between these structures from industrial and civil is that water is soaked at the base of irrigation and drainage structures over a very large area. Moreover, depending on the properties of subsidence soils and the thickness of the layer at the base of the structure, subsidence can range from several centimeters to several meters.A large number of accidents were recorded during the design and construction of such structures in natural conditions on the territory of the Republic of Uzbekistan, Kazakhstan, Tajikistan, the Republic of the North Caucasus and in the south of Ukraine, where subsidence loess soils occupy a large area and extend for 10 meters.The article motivates the necessary laboratory and field studies of soils at the stage of research and design. Methods of research on experimental sites are described in detail and the results of the research are presented. It has been established that large subsidence deformations at the base of irrigation and drainage structures begin from a certain depth, which depends on the results of laboratory studies of the characteristics of subsidence properties.The conclusions of the article indicate various factors that determine the occurrence of emergencies at irrigation and drainage facilities and how to predict the operation of such facilities in time, taking into account the results of laboratory and field studies.

Deformation monitoring of photovoltaic power stations and substations in Yangquan using time-series InSAR

Yangquan is rich in coal resources, and coal mining activities are frequent, which usually causes significant subsidence in the mining area. Substations and power stations around the mining area may be affected by subsidence. In this paper, the time series SAR images of the 25 Sentinel-1A satellite in Yangquan from January to November 2019 are obtained to monitor the deformation of substations and photovoltaic power stations by using the SBAS-InSAR technology. The results show that the deformation range of the study area is between -23.8cm and 11.2cm. In addition, there are multiple subsidence “bowl” due to coal mining. The deformation range of the feature points of the five substations in Wenchi, Niangziguan, Changling, Luhu and Ceshi is between -1cm and 1cm, which are in a stable state. However, there is a continuous linear subsidence phenomenon in Ququcheng photovoltaic power station. Among the Ququcheng three subsidence feature points, the maximum annual subsidence reaches more than 4cm. The main reasons for the subsidence are the gravity component of soil and the increased ground load caused by the power generation device in this area.

Monitoring coal seam fires in Xinjiang using comprehensive thermal infrared and time series InSAR detection

ABSTRACT The combustion of underground coal seams has important effects on the national economy and strategic energy security of countries, and damages the environment, ecology, vegetation, and water resources. Xinjiang, China, is one of the most serious areas of coalfield fires in the world, and it is difficult for any single remote sensing detection method to meet the practical requirements for accurate detection of fire areas. In order to detect coalfield areas in Xinjiang more accurately and reliably, a detection method that integrates thermal infrared and radar remote sensing anomaly is proposed: The mono-window algorithm is used to retrieve the Land Surface Temperature (LST) using images from the Land Remote-Sensing Satellite System (Landsat) 8, the Adaptive Edge Threshold Algorithm (AETA) is used to extract the data characterized by LST anomalies, and Small Baseline Subsets Interferometric Synthetic Aperture Radar (SBAS-InSAR) is used to obtain the land surface subsidence information from Sentinel-1A images. Through the overlay analysis of the above-mentioned LST and subsidence information, the extraction of possible coal fire areas in the Jiangjun Gobi area of Xinjiang is realized. As well as according to the characteristic that underground coal fires melt snow in winter, areas where coal fires are unlikely to occur are excluded using the natural, true-colour images of Landsat 8. Finally, the proposed method is verified using the characteristics of the time series cumulative subsidence of the land surface in areas where coal fires are likely to occur, and by examining the coupling between subsidence velocity and anomalies in LST data. The results show that the proposed method can overcome the shortcomings of single-factor remote sensing detection to a certain extent, and has the ability to detect fire areas more accurately.

Monitoring Subsidence Deformation of Suzhou Subway Using InSAR Timeseries Analysis

Subway subsidence and the consequent geological hazards have become one of the major concerns especially in China's large cities. Large spatial-scale and temporally continuous measurements of surface deformation due to subway subsidence is the basis of the intelligent management for urban transit, as well as the guarantee for the early warning of geological disasters. In this paper, we used persistent scatterer interferometric synthetic aperture radar (PS InSAR) measurements to study and characterize the deformation process resulted from subway-induced subsidence in the construction and operation periods of Suzhou subway using 24-scene high-resolution TerraSAR data (from December 2009 to April 2015) and 19-scene low-resolution Sentinel-1A SAR data (from May 2017 to February 2020). Our results indicate spatially different subsidence rates at different segments along the Suzhou subway lines 1, 2, 3, 4, 5 and 6. TerraSAR data indicate the maximum subsidence rate of -13 mm/yr, while Sentinel-1A data demonstrate the maximum subsidence rate of -20 mm/yr. The decadal-scale subway subsidence deformation is generally characterized by its multistage dynamic processes. The significant subway subsidence is mainly distributed around interchange hubs at the intersection area of railway lines. The Peck function model is used to fit the subway subsidence displacement profiles, which reveals the normal distribution characteristics of the subway surface subsidence. Based on our timeseries analysis in different time periods, the logistic cycle function is used to invert the subway subsidence timing, which reveals four first-order stages during subway subsidence: slow acceleration period, fast acceleration period, decay period and steady-state period.

Coupling control on pillar stress concentration and surface cracks in shallow multi-seam mining

In order to ensure safe mining and reduce surface damage in shallow multi-seam mining, the failure characteristics of interburden strata with different coal pillars offset distances between pillars in the upper and lower seams, the distribution characteristics of stress concentration in coal pillars, and the development characteristics of stratum cracks and subsidence were investigated by physical and UDEC2D simulation. Meanwhile, the effect of different coal pillar offset distances on stress concentration of coal pillar and development of stratum cracks were studied. Based on those results, a formula for safe mining and reducing surface damage was established, which provided a theoretical basis for safe and environmentally friendly mining in shallow multi-seam. According to the results, the optimal coal pillar offset distance (the side to side horizontal distance of the upper and lower coal pillars) between the upper and lower coal seams was developed to reduce the stress concentration of coal pillars and surface damage. The results of this study have been applied in Ningtiaota coal mine and have achieved good results in safe and environmentally friendly mining.

Analysis of Land Subsidence Distribution and Influencing Factors in Yan'an New District Based on Time Series InSAR

Objectives The excavation and city in Yan'an New District is the largest geotechnical project in the collapsible loess gully region. Large-scale land creation, engineering construction and complex engineering geological conditions has caused a large number of uneven land subsidence, which is posing an increasing threat to the stability of urban infrastructure and public safety. Methods The ascending Sentinel-1A data stacks obtained during December 2017 to December 2018 were analyzed using the time series interferometric synthetic aperture radar (InSAR) technique, and the distribution characteristics of the post-construction land subsidence of the mountain excavation and city construction in Yan'an New District were obtained. The reliability of the detection results of InSAR technology was demonstrated by field investigation. Finally, based on the deformation monitoring results, the main influencing factors of land subsidence distribution were analyzed. Results (1) The results show that significant uneven land subsidence formed after the mountain excavation and city construction in Yan'an New District is mainly distributed in the filling area, and the maximum deformation rate reaches up to 120.1 mm/a. Field investigation validates the reliability and accuracy of the deformation results. (2)The remodeling of original loess and the change of its physical properties during the filling process is the main intrinsic factors of land subsidence in the filling area. Large-scale land creation determines the distribution of land subsidence, and the thickness of the filling are the main controlling factor of the distribution and size of land subsidence. In addition, human activities and changes in the geo-environment will also accelerate the development of land subsidence. Conclusions In order to achieve the early detection of potential geo-hazards and active risk prevention in the site selection and feasibility study stage of mega engineering projects in the Loess Plateau, the time-series InSAR technology can provide an effective technical that allows for the early detection of potential geo-hazards such as land subsidence and landslides, and provide a scientific basis for further monitoring and warning, planning and construction, geologic disaster prevention.

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

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

Effects and laws analysis for the mining technique of grouting into the overburden bedding separation

The drastic surface displacement and deformation caused by underground mining will have a serious impact on the ecological environment and the personal and property safety, although a broad range of backfill mining techniques has been applied to practical engineering, there is still a lack of effective methods to analyze the effects and laws of these techniques. In this paper, an analysis method for the effects of the mining technique of grouting into the overburden bedding separation (hereafter also referred to as the GOBS) is proposed, this method can be extended to other types of backfill mining techniques as well, and detailed analysis for a grouting mining district in Huaibei mining area, China was carried out by this method. Subsequently, the characteristics of surface subsidence and deformation (hereafter also referred to as the SSD) were summarized, and the relationship between six representative reduction rates of SSD and injection-extraction ratio were investigated, then the modeling verification and analysis were performed. Finally, the advantages and drawbacks of the mining technique of GOBS and other commonly used mining techniques for reduction SSD are compared. The results demonstrate that the mining technique of GOBS is of high cost-effectiveness to reduce the SSD, meanwhile, the reduction rates of SSD with injection-extraction ratio are subject to the Gompertz model very well, and consistent with actual situations. Therefore, they can be used for the design of grouting working faces and the prediction of SSD, and providing a scientific basis for guiding practical mining working in a safe, efficient and clean way.

Surrounding rock deformation and supporting measures on small structure in non-pillar mining with gob-side entry retaining

This study proposes a “large and small structure” concept of cutting cantilever based on the technical principle of gob-side entry retaining in a non-pillar. A mechanical structure model of the “small structure” concept of cutting cantilever is established by analyzing the stress transfer mechanism of the overlying strata in the gob-side entry. The calculation formula of the roof sinking is derived. The deformation law of the surrounding rock and the roof subsidence characteristics in the small structure are studied using a numerical analysis method. Moreover, the surface displacement curve is obtained by combination with the field measurement. The results show that the cutting structural plane generated by pre-splitting blasting effectively changes the stress transfer between the roof of the gob-side entry and the working face, which is beneficial to the rapid formation of the large structure with a self-stabilization bearing. The deformation of the surrounding rock of a “small structure” roadway is significantly controlled and combined with the rigid support system comprising constant-resistance and large-deformation anchor cables, gangue prevention structures, and a pier-beam unit. The gangues in the goaf interact with the large and small structures formed by the surrounding rock of the gob-side entry retaining, thereby forming a synergistic support structure for effectively increasing roadway stability.

Rapid drought-induced land subsidence and its impact on the California aqueduct

The Central Valley in California is characterized by a semi-arid climate prone to droughts, a variable surface water supply, and immense agricultural areas dependent on groundwater irrigation. The groundwater is stored in a complex aquifer system composed of alternating layers of coarse sediments and fine-grained sediments acting as confining materials. Groundwater fluctuations are coupled with both the elastic and inelastic land surface deformation historically observed in the Central Valley. Surface deformation poses a hazard to the California Aqueduct, which supports Central Valley agriculture and large urban populations in Southern California. The risk of reduced aqueduct efficacy and expensive repairs compels water resource managers to carefully monitor land deformation in the Valley.A persistent drought in the region began in 2012, intensified in 2014, and was abruptly alleviated by a wet period from Dec-2016 to Feb-2018. NASA's UAVSAR L-band synthetic aperture radar acquired 31 high resolution radar images between May-2013 and Nov-2018. The interferometric phase difference between acquisitions is used to develop a time series of vertical displacement and identify and track a rapidly forming subsidence feature adjacent to the California Aqueduct. The surface area of the feature that subsided 10 cm or more by the end of the time series reaches 4452 ha and a 10.5+ km segment of the aqueduct. This study also incorporates extensometer measurements, precise leveling surveys, Sentinel-1A displacement, concurrent water elevation data, well construction reports, nearby extensometer measurements, aquifer material characterization, and environmental conditions. Spatiotemporal data availability limits the appropriateness of calculations and models able to be performed for different sites along the aqueduct. We aim to offer insight into heterogeneous subsurface properties and mechanics, estimate the permanent loss of aquifer storage volume, and identify additional data that would aid water management.

Analysis of Surface Cracking and Fracture Behavior of a Single Thick Main Roof Based on Similar Model Experiments in Western Coal Mine, China

Surface subsidence over coal mines in western China is serious. Collapse pits, step subsidence, surface cracks, among others occur during coal mining. Based on data of surface subsidence in western mining area, this study analyzed the control of key strata on surface subsidence. The breaking mode of the main roof with different thicknesses was discussed based on self-designed simulation test device for the initial breaking of main roof. Through physical experiments, two types of breaking models of the main roof, namely horizontal “X” type and vertical “X” type, were obtained. With the increase in the thickness of the roof, the roof was more prone to sliding instability. Based on Reissner’s thick plate theory, mechanical model of the initial breaking of the main roof was established, and the parameters such as thickness, step distance, Poisson’s ratio, and burial depth were introduced. Through theoretical analysis, the fracture critical condition and breaking mode partition of main roof were obtained. According to the characteristics of surface subsidence of shallow coal seam, the mechanism of strata movement controlled by layered hydraulic fracturing technology was analyzed in the western coal mines of China. This study provides a theoretical reference for the prevention of main roof sliding instability and the control of surface subsidence.

Ground subsidence characteristics caused by construction of shallow-buried tunnel in a sandy soil composite formation

In dry fine sand and medium-coarse sand strata, large surface subsidence and even collapse are common issues related to tunnel excavation. In the Liu-Huo Section of Line 1 of Shijiazhuang Subway, transverse and vertical surface subsidence were examined by analyzing the measured subsidence data. The width coefficient of the settling tank and the loss rate of the sand mixed stratum were determined using the Peck formula. The settlement of the vertical and transverse surface and vault was further analyzed by establishing a three-dimensional numerical model of the tunnel. Results show that the deformation and surface subsidence vary rapidly for the dry sand mixed stratum, and the subsidence trough is “narrow and steep,” which is different from the general clay stratum. In the Peck formula, the ground settlement tank width coefficient is i = 6.55, and the formation loss rate is Vi = 4.81%. Ground settlement increased nonlinearly with the excavation of the pilot tunnels using the double-sided drift method. The settlement caused by the left No. 1 pilot tunnel was the largest, next was the right No. 3 pilot tunnel, the left No. 2 pilot tunnel, and the right No. 4 pilot tunnel. The settlement caused by the middle No. 5 and No. 6 pilot tunnels was smaller. The vertical settlement is divided into three stages: the small settlement stage, rapid stage, and stable stage. The settlement caused by the excavation of the No. 1, No. 2, and No. 3 pilot tunnels was the largest. After excavation of the No. 3 pilot tunnel, the settlement occupied about 78.3% of the final settlement. Monitoring of the No. 1, No. 2, and No. 3 pilot tunnels should be strengthened during the excavation, and the settlement should be strictly controlled.

A New Model for three-dimensional Deformation Extraction with Single-track InSAR Based on Mining Subsidence Characteristics

This paper presents a new model for three-dimensional deformation extraction of single-track interferometric synthetic aperture radar (InSAR) based on mining subsidence characteristics. The model is applied to address the problem of difficult-to-obtain three-dimensional surface deformations in a mining area with high-precision using single-track InSAR. In horizontal or near horizontal coal seam mining regions, land subsidence and horizontal movement are symmetrically distributed along the strike and dip directions of the working face. The proposed method uses this characteristic to calculate the three-dimensional component of surface deformation for the mining area by performing simple addition and subtraction operations on the line-of-sight (LOS) displacement of the symmetric points. Simulations using the developed model show that the root mean square error (RMSE) of the three-dimensional deformations in the vertical, east-west, and north-south directions are 6.9, 5.5 and 8.9 mm, respectively. Experiments were processed using the Sentinel-1A images, and the results show that the vertical displacement generated by the model is consistent with the leveling data. Based on the simulation analysis, it is found that this model can solve the three-dimensional mining deformations, for situations where the strike angle of the coal seam is not perpendicular to the satellite heading.

Temporal evolution of soil deformations around monopile foundations subjected to cyclic lateral loading

Cyclic lateral loading on a monopile in windfarms has been found to cause bed subsidence and convective motions of sediment particles around its foundations. These soil deformations may affect the bearing capacity of the foundation and safety of the structure. This paper presents a 2-dimensional (2D) experimental study on the temporal evolution of bed subsidence and sediment convective-area around vibrating monopiles. The experiments were carried out in a sandbox with a transparent front wall, through which the temporal development of soil deformations around the vibrating monopile can be observed and recorded by using a high definition web camera. The characteristics of the soil subsidence and convective cells are examined with the recorded images, and the influence of the applied force and cyclic loading frequency on the soil deformation process are discussed. The experimental data show that increasing either the force or loading frequency can increase both the temporal development rates and the final size of the subsided bed and convective cells. Empirical equations for depicting the temporal evolution of the subsidence (depth and width) around monopile foundations are proposed.

Mechanism of Land Subsidence of Plateau Lakeside Kunming City Cluster (China) by MT-InSAR and Leveling Survey

Li, S.M.; Wang, Z.M.; Yuan, L.W.; Li, X.X.; Huang, Y.Z., and Guo, R., 2020. Mechanism of land subsidence of plateau lakeside Kunming city cluster (China) by MT-InSAR and leveling survey. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 666-675. Coconut Creek (Florida), ISSN 0749-0208.The Kunming city cluster (KCC) is located around the lakeside of Dianchi Lake, a plateau lake in Kunming Basin southwest of China, which is of complex geological structures and evolutionary history, and belongs to an earthquake fault depression area, where faults are developed and crustal stability is poor. Influenced by regional uplift and continuous subsidence of lakeside areas, the land subsidence characteristics of KCC are quite complex. The subsidence mechanism shows multi-inducement and multi-source property. In this paper, the land subsidence ranges, subsidence rate and subsidence spatio-temporal variation pattern of KCC were analyzed, mainly based on multi-temporal interferometry synthetic aperture radar (MT-InSAR), supplemented by leveling survey data, from 1986 to 2018. The effects of various controlling factors on land subsidence were studied respectively, such as geological structure, stratigraphic distribution, groundwater exploitation, and loads on the ground due to infrastructure construction and human activities, and the internal mechanism and response relation between the subsidence and the factors were studied too. The controlling factors and variation pattern of land subsidence in KCC were identified. The results have shown that the land subsidence of KCC is mainly affected by the tectonic activity in this area, fault basin landform sediments provide conditions for the development and speed up of land subsidence, and the previous land subsidence areas were closely related to the excessive exploitation of groundwater. However, in recent years, the subsidence areas expand continuously due to increases of loads from human activities. By analyzing the controlling factors and spatio-temporal variation pattern of land subsidence in the study areas, this paper has preliminarily revealed the land subsidence mechanism, which will provide reasonable theoretical reference and practical guidance for identifying and eliminating the potential land subsidence hazards and urban development planning in the plateau lakeside city cluster.

Spatial-temporal characteristics of land subsidence in Tianjin city based on leveling data

Spatial-temporal characteristics of land subsidence in Tianjin city based on leveling data

Time-Series Analysis of Subsidence in Nanning, China, Based on Sentinel-1A Data by the SBAS InSAR Method

Recent research has demonstrated that the Sentinel-1 constellation can be used for continuous tracking of ground deformation phenomena. In this study, the spatial–temporal subsidence characteristics in Nanning were investigated with 18 Sentinel-1A TOPS synthetic aperture radar (SAR) images acquired from 25 June 2015 to 16 December 2016 based on the small baseline subset interferometric SAR (SBAS InSAR) technique. The results showed that the annual average surface deformation rates in Nanning ranged from − 48 mm/year to 20 mm/year, and the maximum deformation was detected in the Langdong area. The SBAS-derived results were validated by Nanning continuously operating reference station (CORS) and levelling measurement data. The correlation coefficient and root-mean-square error (RMSE) between SBAS-derived and levelling-derived mean deformation rates were 0.79 and 2 mm/year, respectively. The maximum discrepancy and the RMSE amounted to 7 mm/year and 4 mm/year comparing the SBAS time-series with the CORS-measured displacement. The verification using levelling and CORS implied high reliability and precision of surface subsidence derived by SBAS InSAR. Our analysis revealed that surface subsidence in Nanning was mainly caused by large-scale urban construction, which should be paid enough attention to avoid further aggravation. With the help of the meteorological data, we also found that the subsidence in Nanning was closely related to climatic anomalies in 2015. This research work will provide important theoretical and practical reference value for urban planning and construction in Nanning.