Average Subsidence Research Articles (Page 1)

As one of the world’s primary energy sources, coal has driven economic development but has also led to severe surface subsidence. Currently, many regions around the world face significant ground deformation risks due to ongoing or legacy mining activities. Accurate monitoring and trend prediction are critical for enhancing subsidence early-warning capabilities and urban resilience. The northern region of Huainan City exhibits a spatial pattern characterized by the coexistence of mining areas, urban areas, and decommissioned mining sites, among which the mining areas show more pronounced surface deformation due to prolonged mining activities. To fully understand the subsidence evolution characteristics and differences across various regions, an LSTM–Transformer prediction model was constructed based on SBAS-InSAR monitoring technology to predict the surface subsidence processes in the three types of areas separately. The results indicated that the subsidence rate and cumulative subsidence in the mining areas were significantly greater than those in the urban and decommissioned areas, demonstrating more intense deformation activity. The average subsidence rates for the mining areas, urban areas, and decommissioned mining sites were −57.42 mm/yr, −5.37 mm/yr, and −3.21 mm/yr, respectively. The model’s prediction results demonstrated good accuracy across different regions, with the root mean square errors (RMSEs) for the mining areas, urban areas, and decommissioned mining sites being 2.16 mm, 1.03 mm, and 0.22 mm, respectively. The study shows that the constructed LSTM–Transformer hybrid model not only possesses strong capability in fitting subsidence trends but will also provide a scientific basis for future monitoring and early warning of surface subsidence hazards.

Abstract To address the insufficient ground deformation monitoring coverage in non-urban areas of the Xiong’an New Area in existing studies, this study employs Distributed Scatterer Interferometric Synthetic Aperture Radar technology to systematically analyze the spatiotemporal characteristics and evolution of ground deformation using 51 ascending Sentinel-1A images acquired between March 2021 and March 2023. The study not only accurately obtained maps of annual average subsidence rates and cumulative deformation amounts, but also delved into the potential driving mechanisms of subsidence. The results reveal significant spatiotemporal heterogeneity in land surface deformation within Xiong’an New Area, with pronounced accelerating subsidence observed in the northeastern and southwestern regions. The maximum deformation rate reaches –22.717 mm/year, and the maximum cumulative subsidence is –58 mm. Further analysis indicates that geomorphological features, shallow groundwater activity, and geothermal resource exploitation are the primary factors controlling the observed subsidence. These findings provide crucial data support for land subsidence monitoring, risk assessment, and management in Xiong’an New Area, offering valuable insights for ensuring the sustainable construction of the new district.

Intensive groundwater extraction and a severe 2021 drought have worsened land subsidence in Taiwan's Choshui Delta, highlighting the need for effective predictive modeling to guide mitigation. In this study, we develop a machine learning framework for subsidence analysis using electricity consumption data from pumping wells as a proxy for groundwater extraction. A long short-term memory (LSTM) neural network is trained to reconstruct missing subsidence records and forecast subsidence trends, while an artificial neural network links well electricity usage to groundwater level fluctuations. Using these tools, we identify groundwater-level decline from pumping as a key driver of subsidence. The LSTM model achieves high accuracy in reproducing historical subsidence and provides reliable predictions of subsidence behavior. Scenario simulations indicate that reducing groundwater pumping, simulated by lowering well electricity use, allows groundwater levels to recover and significantly slows the rate of land subsidence. To assess the effectiveness of pumping reduction strategies, two artificial scenarios were simulated. The average subsidence rate at the Xiutan Elementary School multi-layer compression monitoring well (MLCW) decreased from 2.23 cm/year (observed) to 1.94 cm/year in first scenario and 1.34 cm/year in second scenario, demonstrating the potential of groundwater control in mitigating land subsidence. These findings underscore the importance of integrating groundwater-use indicators into subsidence models and demonstrate that curtailing groundwater extraction can effectively mitigate land subsidence in vulnerable deltaic regions.

3D-printed titanium vertebra in the treatment of cervical spondylotic myelopathy: A comparative analysis of perioperative, radiographic, and clinical outcomes.

An innovative self-stabilised 3D-printed artificial vertebral body designed for clinical application and comparison with the conventional implants

Fractures are key geological features in hot dry rock structures and fulfill a decisive role in determining productivity and reservoir stability. Adopting the Xudong fault zone in the Songliao Basin as the research object, a multifracture heat extraction model was constructed using COMSOL software to systematically analyze productivity and various field under different numbers and locations of horizontal and vertical fractures. Moreover, the influences of vertical fracture connectivity and the characteristics of seepage and heat transfer between the upper and lower rock layers on the temperature field were evaluated. The findings are as follows: (1) The production flow obtained with nine horizontal fractures is 2.25 to 2.28 times that obtained with four horizontal fractures. Increasing the number of horizontal fractures also increases the production temperature and heat extraction efficiency at the early stages of heat extraction but reduces productivity at the later stages and adversely affects reservoir stability. After 30 years of heat extraction, the production temperature, average subsidence, maximum subsidence, and average in situ stress obtained with nine horizontal fractures are 79.38% and 1.87, 1.61, and 1.45 times, respectively, those obtained with four horizontal fractures. (2) The influence of the number of vertical fractures on the geothermal reservoir characteristics is similar to but slightly smaller than that of horizontal fractures. However, the influences of vertical fractures on the production flow at the early stages and the maximum reservoir temperature at the later stages are opposite to those of horizontal fractures. When vertical fractures are located close to the injection well, productivity is low at the early stages but high at the later stages. The maximum subsidence, average in situ stress, and maximum in situ stress slightly increase, whereas the average subsidence decreases. (3) After 30 years of heat extraction, the average reservoir temperature is highest when seepage and heat transfer between the upper and lower rock layers occur and when vertical fractures do not penetrate the reservoir. When these conditions are reversed, the average temperature is lowest, with the former approximately 0.42°C higher than the latter. The findings of this study provide a reference for the construction of reservoir fracture systems.

Under multiseam mining, the caved strata of upper gob are affected by the lower coal seam mining, and the caved strata of lower gob are affected by the gravity action of the caved strata in the upper gob, resulting in the morphology of caved strata that is more complex than single coal seam mining. In this study, a similar simulation experiment device is used to analyse the morphology, fracture development degree, and subsidence of caved strata in an abandoned gob under multiseam. The physical model of caved strata in an abandoned gob under multiseam is established. Results show that the morphology of caved strata in the abandoned gob is a trapezoid. The caved strata on two sides of the abandoned gob are mainly horizontal fractures, and the middle part is a compacted area. Large number of voids and fractures exist near the start and end mining positions, and they are connected with each other. Because of the influence of the lower coal seam mining, the fracture development degree and subsidence of caved strata in the upper gob increase. The average increase rate of the maximum subsidence and the peak abscission rate is 24·61% and 16·69%, respectively.

Does Stem Design Affect Primary Stability of Splined Tapered Fluted Stems? A Biomechanical Cadaver Study.

ABSTRACTRevealing the response laws of soils under various mining conditions is of significance for the scientific protection of farmland in mining areas. To avoid the interference from the spatial heterogeneity of natural soil on the research results, similar simulation experiments were employed. Two models for soil responses under mining with and without grouting into overburden bed‐separation were designed, and monitoring was conducted for soil quality factors (moisture content, silt and clay content and bulk density) and surface deformation factors (subsidence, inclined and horizontal deformation). The results indicate that it can significantly control surface subsidence in mining with grouting into overburden bed‐separation; the maximum subsidence value was reduced by 66.67%, the average subsidence value of each measuring point in the main section was reduced by 78.92%, and the subsidence area was reduced by 34.68%. The coefficient of variation of soil quality factors in the mining‐affected area was obviously higher than that in the control area and the initial value before mining. Compared with mining without grouting, the coefficient of variation of soil quality factor under mining with grouting was reduced by 2.71%–6.79%. Soil quality factors and surface deformation factors show a significant quadratic function relationship, among which horizontal deformation has the greatest influence on soil quality factors, followed by subsidence and inclination. Therefore, it can effectively control surface subsidence and protect cultivated land when mining with grouting into overburden bed‐separation.

Modern total hip arthroplasty (THA) is one of the most common and successful orthopedic procedures performed, utilizing a variety of fixation methods, stem geometry and designs to provide immediate post-operative weight bearing. The purpose of this study was to determine the incidence of intraoperative periprosthetic fractures, subsidence rates and aseptic loosening between collared stems compared with non-collared tapered stems during THA. A retrospective chart review identified 983 THA cases performed by a single surgeon between 2013-2021. The average length of follow up was 1.5 years with an average duration of 533 d between initial and follow radiographs. Intraoperative fractures, subsidence and aseptic loosening were identified through chart review and X-rays. Chi square test, t-test, and descriptive statistics were conducted for both cohorts to determine statistical significance. There were 9 (2.05%) reports of intraoperative fractures in the collarless cohort and 3 (0.55%) reports of intraoperative fractures in the collared cohort. Subsidence values for those who received collarless stems ranged from 0-4.2 mm and had an average value of 0.59 mm. Those who received collared stems had subsidence values that ranged between 0-2.2 mm with an average of 0.23 mm. Patients who received collared stems had fewer incidences of intraoperative fracture within the first two weeks of surgery. Additionally, those who received collared stems had an average subsidence value of 0.23 mm, which was significantly less compared with those who received non-collard tapered stems with an average subsidence value of 0.59 mm. Utilizing cementless collared stems is beneficial in decreasing the rate of intraoperative fracture without increasing the rate of subsidence or loosening.

The bioactive glass-ceramic spacer (BGS)-7, a biosynthetic intervertebral fusion material introduced in 2014, has not been the subject of comparative clinical studies on anterior cervical discectomy and fusion (ACDF) surgery. This study, for the first time, aims to compare the radiological and clinical outcomes of the renewed BGS-7, released in 2019, with those of an allograft spacer. The comparison includes a finite element analysis of the biomechanical properties of each implant, adding a novel dimension to the research. We prospectively followed up on 29 patients who underwent ACDF using BGS-7 as the experimental group. To select a control group for comparison, 253 patients with level 1 ACDF with an allograft spacer between 2012 and 2022 were selected from our hospital. Using propensity score matching, 27 and 54 patients in the BGS-7 and allograft groups, respectively, were selected. The average subsidence length was 1.02 ± 1.44 mm per level in the BGS-7 group and 2.27 ± 2.25 mm per level in the allograft group. Subsidence was observed in 14 of 54 patients (25.9%) in the allograft group and one of 27 patients (3.7%) in the BGS-7 group (p = 0.016). In the allograft group, 16 of the 54 patients (29.6%) monitored for 6 months achieved satisfactory fusion outcomes with grades 4 and 5. Thirty-eight of 54 patients (70.4%) followed up for > 1 year in the allograft group achieved adequate fusion outcomes with grades 4 and 5. In the BGS-7 group, 17 of the 27 patients (63.0%) monitored for 6 months achieved satisfactory fusion results with grades 4 and 5. Twenty-three of the 27 patients (85.2%) followed up for > 1 year obtained adequate fusion outcomes with grades 4 and 5. There was a significant difference in the fusion rates between the two groups at 6 months (p = 0.008). BGS-7 is a reliable instrument for ACDF with no instances of instrumental failure. The BGS-7 group had positive clinical outcomes after surgery without any untoward events, and an early fusion rate with the creation of a bone bridge was noted during the 6-month follow-up period. Our findings not only indicate the safety of BGS-7 but also its practicality as a substitute for allografts in ACDF, instilling confidence in its application.

DKI Jakarta is one of the provinces experiencing land subsidence problems. Monitoring the rate of land subsidence is very important to mitigate and control environmental impacts. One of the main problems in tracking the rate of land subsidence is the limitation of monitoring tools. Therefore, the Universal Kriging spatial interpolation method can be used to estimate the rate of land subsidence at unsampled locations. This research uses secondary data on the rate of land subsidence in DKI Jakarta Province in 2022. This research aims to produce an estimated value of the land subsidence rate at an unsampled location so that vulnerable areas with unknown land subsidence rates can also be monitored more effectively. Based on the results, the Spherical theoretical semivariogram is the best model because it has the smallest RMSE value compared to other models. The estimation results show that the average subsidence rate is 0.03512 cm/year. The largest subsidence rate is 0.05355 cm/year in Duri Kosambi, and the smallest subsidence rate is 0.03054 cm/year in Tangki. The Universal Kriging method effectively estimates the subsidence rate in unsampled locations. This method can be used as a first step in mitigating, controlling, and preventing the impacts of land subsidence.

Purpose. Determination of foundations subsidence of railways, roads, and other embankments, as well as dams and levees made of soil materials during their design, construction, and operation, is mandatory. At the same time, if the foundation is composed of soils with a small modulus of general deformation (silt, peat, peaty, and similar soils), then not only the average subsidence and its unevenness should be determined, but also determine the profiles of subsidence outside the structures. This is because the subsidence of the foundation has the same order as the height of the embankment (dams, levees); therefore, when determining the additional volume of material required for the construction of an embankment (dams, levees), these deformations must be considered. The purpose of the article was to develop an algorithm for calculating the subsidence profiles of railways, roads, and other embankments, as well as dams and levees made of soil materials. Methodology. Theoretical studies of geomechanical processes using analytical and numerical mathematical methods. Analysis and generalization of theoretical research results. Findings. An algorithm is proposed that allows using simple analytical dependencies to determine those necessary for calculation and design, construction and operation parameters of the system "soil base of dams (levees) and embankments made of soil materials with a trapezoidal cross-section and a rigid core": – the lower limit of the compressed stratum; – subsidence of the foundation within the sole of the base of the dam, levees, or embankment. Originality. It is established that the foundation subsidence on the vertical passing through the center of the dam, levees, or embankment with a symmetrical profile is not less than the subsidence on the calculated verticals passing through any point of the dam, levees, or embankment with an asymmetric profile. Practical value. The main practical result of the work is a more complete (compared to the current regulatory documents) consideration of the features of subsidence of the system "dam, levees (or embankment) made of soil materials – soil base" with a significant reduction in the number of calculations. The results we obtained allow us to determine those necessary for the calculation, design, construction, and operation of dams, levees and embankments made of soil materials characteristics.

The rapid construction of high-speed railways in China has forced more and more routes to pass through slow subsidence zones caused by groundwater extraction or underground mining. It is crucial to carry out deformation monitoring and prediction those areas along high-speed railways to ensure the safe operation. Twenty-nine periods of Sentinel-1A data between Taiyuan South Station and Taigu East Station were first processed using the PS-InSAR technique, and the ground subsidence sequences at ten typical points were selected. Then the Variational modal decomposition (VMD) was combined with the Adaptive Boosting Algorithm (AdaBoost), and the VMD-LSTMAda-LSTMAda model was constructed by combining the long short-term memory (LSTM) model for the prediction of regional ground subsidence along the high-speed railway. The results show that the cumulative subsidence within the 200 m buffer of the line centreline is − 37.58 − 89.19 mm, and the annual average subsidence rate is − 26.57 − 82.63 mm/y. The proposed model can reduce the complexity of the deformation sequence and combines with AdaBoost to improve the prediction accuracy of the LSTM model. It performs well in terms of RMSE, MAE, MAPE, and R2 at the two feature points (3703: RMSE = 0.82 mm, MAE = 0.25 mm, MAPE = 6.31%, and R2 = 0.94; 522: RMSE = 1.32 mm, MAE = 0.46 mm, MAPE = 4.92%, R2 = 0.95). The model improves the accuracy of regional subsidence prediction along the high-speed railway.

Towards sustainable development goals: Leveraging multi-data remote sensing fusion for monitoring groundwater-induced bedrock subsidence dynamics in Egypt's Nile Valley

Background: Hip arthroplasty is a common elective surgery worldwide, with rising numbers due to demographic changes and an emphasis on maintaining physical activity in the elderly. The development of new implant designs, especially shorter uncemented stems, has contributed to the advancement of minimally invasive implantation techniques. However, the long-term in vivo behaviour of these implants, particularly regarding subsidence, stability, and stress shielding, remains to be fully understood. Methods: This retrospective, monocentric cohort study analyses the long-term radiographic outcomes of the first 141 patients who underwent total hip arthroplasty with the Fitmore® Hip Stem between June 2007 and December 2008. It focuses on subsidence, stability, varus-valgus alignment, and the influence of patient-related, anatomical, and surgical factors on implant behaviour over a 10-year follow-up period. Results: The average change in varus/valgus alignment was 0.7° into varus and the average subsidence was 1.7 mm over 10 years, with most changes occurring within the first six weeks postoperatively. The varus-valgus alignment and subsidence did not significantly change after the first year, indicating stable osteointegration of the implant. Neither patient factors (gender, age) nor surgical and implant factors (implantation angle, approach, stem family, size, total offset) had a significant influence on the long-term behaviour of the implant. Conclusions: The Fitmore® Hip Stem shows highly reliable long-term stability and integration, unaffected by various patient, surgical, and implant factors, as confirmed by excellent register data. Nevertheless, monitoring of this and other new implants should be continued in order to determine implant behaviour, possible weaknesses, and indication limits at an early stage for the benefit of the patient.

Abstract The landscape and landforms in permafrost regions are transforming due to climate change and permafrost thaw. This study uses optical and radar remote sensing, alongside spatial analysis, to examine thermokarst features and their driving factors in the source region of the Yangtze River (SRYR) on the central Tibetan Plateau. We analyse the distribution, interaction, and key environmental factors influencing thermokarst ponds and ground surface deformation, which are the two widespread and noticeable thermokarst features. Since the 1960s, the number of small water bodies has doubled from approximately ~2 × 104 to ~4 × 104 by the 2020s, with the median size of these water bodies decreasing from 2.3 × 104 m2 to 1.4 × 104 m2. The permafrost terrain has an average subsidence rate of 6.8 mm/a. About 50.9% of the SRYR exhibits evident thermokarst features. Surficial geological factors, especially geomorphology and slope, are primary factors in shaping the spatial distributions of thermokarst features. Both seasonal deformation and long‐term subsidence rates are more pronounced in areas with thermokarst ponds. However, once pond coverage exceeds around 5%, the amplifying effect on long‐term subsidence rates and seasonal deformation diminishes. The investigation further reveals that the relationship between seasonal deformation and long‐term subsidence is not strictly linear and that the combined increase in seasonal deformation and long‐term subsidence applies only to areas with seasonal deformation below approximately 20 mm. Beyond this threshold, the long‐term subsidence rate is no longer exacerbated by increased seasonal deformation.

WITHDRAWN: Characterization of soil response in mining with grouting into overburden bed-separation based on similar material simulation

Surface subsidence hazards in mining areas are common geological disasters involving issues such as vegetation degradation and ground collapse during the mining process, which also raise safety concerns. To address the accuracy issues of traditional prediction models and study methods for predicting subsidence in open-pit mining areas, this study first employed 91 scenes of Sentinel-1A ascending and descending orbits images to monitor long-term deformations of a phosphate mine in Anning City, Yunnan Province, southwestern China. It obtained annual average subsidence rates and cumulative surface deformation values for the study area. Subsequently, a two-dimensional deformation decomposition was conducted using a time-series registration interpolation method to determine the distribution of vertical and east-west deformations. Finally, three prediction models were employed: Back Propagation Neural Network (BPNN), BPNN optimized by Genetic Algorithm (GA-BP), and BPNN optimized by Artificial Bee Colony Algorithm (ABC-BP). These models were used to forecast six selected time series points. The results indicate that the BPNN model had Mean Absolute Errors (MAE) and Root Mean Squared Errors (RMSE) within 7.6 mm, while the GA-BP model errors were within 3.5 mm, and the ABC-BP model errors were within 3.7 mm. Both optimized models demonstrated significantly improved accuracy and good predictive capabilities.

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.