Subsidence Monitoring Research Articles

Data-driven and physics-informed Bayesian learning of spatiotemporally varying consolidation settlement from sparse site investigation and settlement monitoring data

A digital twin of a geotechnical project (e.g., a reclamation or ground improvement project) is a virtual model that aims to continuously learn from actual observations (e.g., site investigation and monitoring data) and improve model prediction (e.g., spatiotemporally varying consolidation settlement). However, real geotechnical observation data obtained from a site are often spatially sparse (e.g., site investigation data) and spatiotemporally varying (e.g., settlement monitoring data). The sparse and spatiotemporally varying data pose great challenges for continuous learning of data and improvement in model prediction. To address these challenges, this study proposes a novel data-driven and physics-informed Bayesian learning framework that automatically develops ground models from spatially sparse site investigation data, performs geotechnical analysis, and integrates geotechnical analysis results with limited, but spatiotemporally varying, settlement monitoring data to improve model prediction in a systematic and quantitative manner. The proposed method contains three key components, (1) data-driven ground modeling by Bayesian compressive sampling (BCS) using sparse site investigation data as input, (2) finite element modeling (FEM) of consolidation settlement that incorporates domain knowledge, and (3) Bayesian sparse dictionary learning of settlement monitoring data together with FEM results. The proposed method is illustrated using a real ground improvement project, and the results show that the proposed approach performs well.

Algorithm and Application of Foundation Displacement Monitoring of Railway Cable Bridges Based on Satellite Observation Data

In order to realize real time monitoring of foundation displacement of railway cable bridge based on satellite observation system, reasonable data sources of satellite monitoring and data analysis duration are necessary, and the influence of various errors should be eliminated in the process of satellite signal acquisition. In this paper, the validity of foundation settlement monitoring of bridge tower by satellite is verified through accuracy and stability tests. For eliminating the multipath error and random noise of GNSS signal, a new method is presented by combining stationary wavelet transform and empirical mode decomposition in this study. For improving the observation accuracy of the satellite monitoring system, combing the measured data, the GNSS data are corrected by establishing non-linear mapping between the GNSS data and precise leveling data by BP neural network. Based on that, the accuracy of the presented method is verified by the foundation settlement data of a new railway cable bridge tower.

The Surface Settlement Law of Precipitation in Pile-Beam-Arch Station Adjacent to Pile Foundation

The pile foundations of adjacent buildings can have an impact on the precipitation process in subway stations. In this paper, surface settlement monitoring is carried out by precipitation of horizontal wells in subway stations, and the law of surface settlement change with and without neighboring pile foundations is studied. The influence law of surface settlement in subway stations under different pile depth, different pile spacing and different distance between piles and station boundary is obtained through numerical simulation. Three models of groundwater infiltration in the adjacent pile foundation were established, the principle of pile-soil permeability coefficient equivalence was proposed, and the function relationship between the equivalent soil permeability discount factor and pile parameters was derived. The research results show that the surface settlement is smaller when there are piles in the measured precipitation process than when there are no piles. The greater the pile depth, the smaller the pile spacing and the smaller the pile-station boundary, the stronger the barrier effect and the smaller the final settlement of the ground surface. The accuracy of the formula is also analyzed to show that changing the pile parameters also changes the permeability coefficient of the piles and the soil between the piles. The station surface settlement law is related to the pile parameters, and the study can provide an important theoretical reference for the construction of precipitation with adjacent pile foundations.

Design and implementation of the food supply chain traceability system based on the blockchain

Traditional enterprise-level food supply chain traceability systems are notoriously expensive and complex to set up, but there is a solution that can successfully address both of these problems: the food supply chain traceability system. This study, on the other hand, suggests a blockchain-based food supply chain traceability system business system. The paper is concerned with the food supply chain traceability system. The authentication and authorization procedures, traffic scheduling, and settlement monitoring are examples of some of the operations that make use of the blockchain infrastructure. In the meanwhile, the throughput of the system is increased by making improvements to the consensus method. Users of this system can provide customized service needs for food supply chain traceability systems by using this system. The issue of locking up the system in the food supply chain traceability system is successfully solved by the system, which embodies a great deal of application potential inside the food supply chain traceability system.

Enhanced Root-MUSIC Algorithm Based on Matrix Reconstruction for Frequency Estimation.

In recent years, frequency-modulated continuous wave (FMCW) radar has been widely used in automatic driving, settlement monitoring and other fields. The range accuracy is determined by the estimation of the signal beat frequency. The existing algorithms are unable to distinguish between signal components with similar frequencies. To address this problem, this study proposed an enhanced root-MUSIC algorithm based on matrix reconstruction. Firstly, based on the sparsity of a singular value vector, a convex optimization problem was formulated to identify a singular value vector. Two algorithms were proposed to solve the convex optimization problem according to whether the standard deviation of noise needed to be estimated, from which an optimized singular value vector was obtained. Then, a signal matrix was reconstructed using an optimized singular value vector, and the Hankel structure of the signal matrix was restored by utilizing the properties of the Hankel matrix. Finally, the conventional root-MUSIC algorithm was utilized to estimate the signal beat frequency. The simulation results showed that the proposed algorithm improved the frequency resolution of multi-frequency signals in a noisy environment, which is beneficial to improve the multi-target range accuracy and resolution capabilities of FMCW radar.

Toward sustainable inland aquaculture: Coastal subsidence monitoring in Taiwan

Inland aquaculture is a major industry that provides fish to reduce the stress of oceans in supplying global protein consumption. Developed and developing nations house their inland aquaculture industries largely in coastal areas, where groundwater is pumped to supply the needed water in a non-sustainable way that leads to coastal land subsidence. This study shows a comprehensive picture of land subsidence in Pingtung, a coastal plain in southern Taiwan, where, after the gradual abandonment of rice cultivation, huge groundwater exploitation has occurred since the 1970s to feed inland aquaculture. Integrated interpretation of multidevice monitoring results has improved knowledge of land subsidence associated with land uses and groundwater pumping. Results indicate a maximum cumulative subsidence of 350 cm from 1972 to 2019 near the aquaculture-rich township of Linbian. Sub-surface displacement measurements using multilayer compaction wells identified the de-watered layers responsible for the land subsidence in four sinking-affected coastal areas, where different groundwater usage patterns lead to different patterns of aquifer-system compactions at varying depths. The use of SAR interferometry with high spatial resolution and frequent revisit times has made it possible to overcome the inherent limitations of ground-based measurement methodologies such as leveling, continuous global navigation satellite system, and multilayer compaction wells, which while very accurate do not allow for adequate monitoring of subsidence in the Pingtung coastland due to the high dynamics and spatial variability of the process. Based on the results of this study, several sustainable aquaculture-related actions are being implemented or have been proposed to reduce the risks of land subsidence, flooding, and salinization in Pingtung. These include the use of InSAR monitoring for conventional sensors to continuously and timely monitor land subsidence.

Seasonal Subsidence and Heave Recorded by Borehole Extensometers in Houston

Seasonal ground movements, particularly subsidence and heave, present a great challenge for the design of roadways, parking lots, underground utility lines, and buried culverts. The US Geological Survey has been operating 13 deep borehole extensometers in Houston, Texas, for land subsidence monitoring since the 1970s and the early 1980s. The half-century extensometer datasets provide direct and continuous measurements of seasonal ground movements in the vertical direction. The Houston global positioning system (GPS) network (HoustonNet) provides independent measures for the timely evaluation of extensometer data. According to this study, shallow expansive soils can induce up to 4 cm (peak-to-trough) seasonal subsidence and heave, and deep sediments can further produce up to 2 cm seasonal subsidence and heave. The latter is primarily caused by the seasonal fluctuations of hydraulic heads in the lower Chicot and upper-Evangeline aquifers, varying considerably over time and space. The results from this study are important for determining potential vertical movement (PVM) for the design of pavements and shallow foundations and for the optimization of groundwater management in the Houston region.

Study on Stratified Settlement and Weak Reflectivity Fiber Grating Monitoring of Shield Tunnel Crossing Composite Strata

This paper proposes a set of field test technology system for layered settlement of composite strata based on weak reflectivity fiber Bragg grating sensing technology based on the shield project of “Keyuan Station ~ Shenzhen University Station” section of Shenzhen Metro Line 13, and through the comparison and verification of three-dimensional numerical simulation and field monitoring, the law and distribution characteristics of disturbance settlement of ground surface and overlying strata during shield tunneling are systematically analyzed, and the vertical and horizontal zoning (layer) system for the spatial and temporal evolution of layered settlement of composite strata during shield tunneling is constructed. On this basis, the targeted settlement control technical measures and recommendations are proposed. The findings show that the weak reflectivity fiber grating sensing technology can better perceive the evolution law and distribution characteristics of vertical and horizontal settlement of composite strata caused by shield tunneling, which is in good agreement with the numerical simulation results, and has the advantages of automation and high precision, it can be used as a supplement and alternative method for traditional measurement methods. The stratum deformation is small and layered settlement is not obvious in shield approaching stage (−5D~0), after shield crossing and shield tail falling (0~3D), the stratum is the longitudinal main deformation zone of shield tunneling disturbance, and the influence range of the whole tunneling disturbance is about (−1D~3D). Meanwhile, according to the influence degree of shield tunneling disturbance, the overlying strata of the tunnel can be divided into main disturbance layer and secondary disturbance layer, and the main disturbance layer is located in the range of 0.5D above the tunnel. In addition, based on the different stages of shield tunneling and the vertical and horizontal zoning (layers) of existing structures such as buildings (structures), the settlement control measures and suggestions are proposed. The research results demonstrate the feasibility of weak reflectivity fiber grating for distributed and continuous strata monitoring. It has important guiding value for improving the understanding of settlement law produced from shield construction in composite strata and analyzing and predicting potential risks resulting from shield construction. It also provides reference value for future subway design and construction.

Land Subsidence Assessment of an Archipelago Based on the InSAR Time Series Analysis Method

The lack of resources on islands leads to their extremely rapid development, and this can result in frequent geological disasters involving island subsidence. These disasters not only destroy the ecological environment and landscape of islands but also pose massive threats to the safety of residents’ lives and property and can even affect the country’s maritime rights and interests. To meet the demands of island stability and safety monitoring, in this study, we propose a large-area, full-coverage deformation monitoring method using InSAR technology to assess island subsidence based on a comprehensive analysis of conventional monitoring techniques. The working principle and unique advantages of InSAR data are introduced, and the SBAS InSAR key interpretation processing flow are described in detail. The GPU-assisted InSAR processing method is used to improve the processing efficiency. The monitoring results showed that the southern island group of the Miaodao Archipelago was relatively stable overall, with an annual average deformation rate of 3 mm. Only a few areas experienced large-magnitude surface deformation, and the maximum annual deformation magnitude was 45 mm. The time series deformation results of the characteristic points of the five inhabited islands in the southern island group showed that the subsidence trends of the two selected points on Beichangshan Island (P1 and P2) were slowly declining. The P3 point on Nanchangshan Island experienced a large deformation, while the P4 point experienced a relatively small deformation. The selected points (P5, P6 and P7) on Miaodao Island, Xiaoheishan Island and Daheishan Island were stable during the monitoring period. InSAR data can be used to accurately identify the millimetre-scale microdeformations experienced by island groups, thus demonstrating the high-precision deformation monitoring capability of these data. In addition, the accuracy of these data can meet the needs of island and archipelago subsidence monitoring, and the proposed method is an effective means to monitor the spatial deformation of island targets. This study is conducive to further enriching and improving island stability and safety monitoring technology systems in China and to providing data and technical support for identifying and mastering potential island risks, protecting and utilizing islands and preventing and reducing disasters.

Research on prevention and control methods of land subsidence induced by groundwater overexploitation based on three-dimensional fluid solid coupling model—a case study of Guangrao County

Land subsidence is an environmental geological phenomenon with slowly decreasing ground elevation, The North China Plain is one of the areas with the most serious land subsidence in China, and Guangrao County is one of the subsidence centers. This paper is based on the hydrogeological and engineering geological data of Guangrao County, the groundwater monitoring data for many years and the land subsidence monitoring data, systematically analyzes the dynamic characteristics of groundwater, the distribution and evolution of land subsidence, and the correlation between groundwater exploitation and land subsidence development in different layers of this area. Based on Biot porous medium consolidation theory, establishes a three-dimensional fluid solid coupling numerical model of land subsidence in Guangrao County, restores the development process of land subsidence, predicts and analyzes the subsidence evolution law under different groundwater exploitation schemes, and proposes targeted prevention and control measures. The research results show that: the shallow groundwater forms a cone of depression with Guangbei Salt Field as the center, and the deep groundwater forms an elliptical regional cone of depression with the urban area as the center. The ground is gradually formed two small settlement areas with the urban area of Guangrao County and Guangbei Salt Field as the settlement center, and there is a trend of interrelated expansion. The three-dimensional fluid solid coupling model of land subsidence accurately restored the development process of land subsidence in the study area, predicted that under the current groundwater exploitation conditions, by 2040, the settlement of Guangrao urban settlement center will increase to 1,350 mm, forming a large regional funnel centered around the urban area, and gradually developing and expanding around. Prohibition of groundwater exploitation in the main funnel area is a more reasonable and effective exploitation plan to prevent the development of land subsidence.

InSAR time-series analysis and susceptibility mapping for land subsidence in Semarang, Indonesia using convolutional neural network and support vector regression

Global sea-level rise due to climate change is a critical problem for coastal cities. One of the coastal cities in Indonesia, Semarang, is in danger of being submerged by seawater due to flooding, which is exacerbated by land subsidence. Time-series analysis based on persistent scatterer (PS) interferometry usually suffers from sparse measurement points (MP), and thus does not completely cover the study area with low coherence. In this study, we utilized improved combined scatterers interferometry with optimized point scatterers (ICOPS) to increase the MP density. We also compared the optimization of the ICOPS method based on support vector regression (SVR) with convolutional neural network (CNN) algorithms. The ICOPS-CNN showed better model performance and MP density, and was less time-consuming. Further land subsidence analysis was conducted in Semarang using susceptibility mapping. The land subsidence susceptibility map from the standalone deep learning (DL) algorithm (CNN = 0.833) outperformed the standalone machine learning (ML) algorithm (SVR = 0.820). The hybrid DL algorithm with grey wolf optimizer (GWO) (CNN-GWO = 0.907) exhibited the highest accuracy, followed by the hybrid ML algorithm (SVR-GWO = 0.843). The accuracy was consistent with the comparison between the susceptibility maps and the ICOPS measurements, resulting in a susceptibility map based on CNN-GWO with the highest accuracy (0.889). Land subsidence monitoring using ICOPS based on CNN and susceptibility mapping based on a hybrid DL algorithm (CNN-GWO) can be used by local governments to improve urban development planning in Semarang and its surrounding areas.

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.

ADAfinder Tool Applied to EGMS Data for the Structural Health Monitoring of Urban Settlements

The new European Ground Motion Service (EGMS) opens a new prospect in the study of the ground deformation phenomena influencing structures and infrastructures, at regional scale, exploiting the huge archives of Synthetic Aperture Radar (SAR) images acquired from Sentinel-1 satellites. The research is currently oriented toward developing new methodologies to exploit this great volume of data, the management of which is difficult and onerous in terms of time. A new methodology for the monitoring of the deformations of urban settlements, based on the application of the ADAfinder tool to EGMS measure points, is proposed in this work. It targets the semi-automatic extraction of active deformation areas (ADA), given in the form of maps, with the goal to identify the buildings affected by displacements above a given threshold among all the buildings included in the investigated area. This allows a smart selection of the buildings needing insights about their condition through on-site monitoring or inspections, providing real support for the management of the urban areas. The proposed methodology is applied to two different case study areas in the city of Barcelona (Spain): the Eixample, in the heart of the city, and the Zona Franca, an industrial area near to the harbor.

Research on monitoring and stability evaluation of ground subsidence in gypsum mine goaf

The geological disasters caused by the ground deformation of the goaf have brought huge security risks to the ecological environment and society. Therefore, it is imminent to realize the effective monitoring and stability analysis of the ground deformation of the goaf. In this paper, taking the goaf of the gypsum mine in Diaodao District, Jingmen City as an example, through the investigation of the overall structure and distribution characteristics of the gypsum goaf, combined with the mechanical parameters of the rock mass selected from the site, the InSAR and GNSS technology are used to analyze the ground of the goaf of the gypsum mine. Deformation monitoring is carried out to give full play to the advantages of InSAR monitoring with high vertical accuracy and GNSS monitoring with high horizontal accuracy. Analyzed the thickness conditions of the mined-out area of pillar, roof and overlying rock, established the numerical model of the goaf, and used FLAC (3D) to carry out numerical simulation on this basis to evaluate the stability of the goaf. The research shows that two subsidence areas and three deformation areas were deciphered by DInSAR and time series InSAR, respectively, and the deep buried areas in the goaf were monitored by GNSS. The surface deformation is dominated by horizontal displacement, and the direction of horizontal displacement is the whole points to the goaf. Finally, based on the conclusion that the gob is in different degrees of deformation, the stability of the gob is analyzed, and the area of surface subsidence is obtained by FLAC (3D) simulation.

Monitoring Study of Long-Term Land Subsidence during Subway Operation in High-Density Urban Areas Based on DInSAR-GPS-GIS Technology and Numerical Simulation

During subway operation, various factors will cause long-term land subsidence, such as the vibration subsidence of foundation soil caused by train vibration load, incomplete consolidation deformation of foundation soil during tunnel construction, dense buildings and structures in the vicinity of the tunnel, and changes in water level in the stratum where the tunnel is located. The monitoring of long-term land subsidence during subway operation in high-density urban areas differs from that in low-density urban construction areas. The former is the gathering point of the entire urban population. There are many complex buildings around the project, busy road traffic, high pedestrian flow, and less vegetation cover. Several existing items require monitoring. However, monitoring distance is long, and providing early warning is difficult. This study uses the 2.8 km operation line between Wulin Square station and Ding’an Road station of Hangzhou Subway Line 1 as an example to propose the integrated method of DInSAR-GPS-GIS technology and the key algorithm for long-term land subsidence deformation. Then, it selects multiscene image data to analyze long-term land subsidence of high-density urban areas during subway operation. Results show that long-term land subsidence caused by the operation of Wulin Square station to Ding’an Road station of Hangzhou Subway Line 1 is small, with maximum subsidence of 30.64 mm, and minimum subsidence of 11.45 mm, and average subsidence ranging from 19.27 to 21.33 mm. And FLAC3D software was used to verify the monitoring situation, using the geological conditions of the soil in the study area and the tunnel profile to simulate the settlement under vehicle load, and the simulation results tended to be consistent with the monitoring situation.

A Preliminary Result of Land subsidence Monitoring by Using Low-Cost GNSS in Bandung Basin

Land Subsidence is one of the issues faced by major cities in Indonesia. The need for a land subsidence monitoring station that operates continuously is one of the most important aspects today. The current use of low-cost GNSS (Global Navigation Satellite System) is expected to help in dealing with this problem. This study aims to evaluate Low-Cost GNSS for monitoring land subsidence in Bandung Basin. The Measurement of Low-Cost GNSS using Chip-GNSS U-Blox (single frequency) and the microstrip antenna was assembled itself. The monitoring of land subsidence was carried out at one point(TK01) with an observation period from March 2021 to December 2021. The result of data processing shows the value of the coordinate standard deviation of the TK01 point during the measurement period ranges from ± 1.5 cm. The results of vertical component processing show the standard deviation in the vertical direction is ± 3.5 cm. The rate of land subsidence resulting from linear regression at the point of TK01 from March 2021 to December 2021 in this study was -13.9 cm/year with a standard deviation value of ±0.32 cm/year.

Consolidation settlement prediction and monitoring of toll road embankment at STA 23+650 Semarang–Demak Toll Road section

The development of toll road projects in Indonesia is experiencing rapid growth. However, due to the large number of toll roads being constructed over soft soil areas, it is crucial to address the issue of consolidation settlement. This is because settlement can lead to differential or excessive settlement, which potentially damages the structures built on such soil. Unfortunately, consolidation settlement on soft soils is a time-consuming process. Thus, a consolidation acceleration method is needed, one of which is to use a combination of PVD–Preloading. This method can also increase the soil’s bearing capacity, thereby contributing to the preservation and protection of systems that support human activities while maintaining a balance with nature. Therefore, this study aims to investigate consolidation settlement employing PVD–Preloading methods. The analysis focused on a case study conducted at STA 23+650 of the Semarang-Demak Toll Road section. The analysis employed the Asaoka method, integrating field monitoring instruments, along with the Terzaghi method for one-dimensional consolidation. The results showed that the settlement results from the Asaoka and Terzaghi methods correlate with the settlement plate instrumentation in the field.

Understanding the Spatial-Temporal Characteristics of Land Subsidence in Shenzhen under Rapid Urbanization Based on MT-InSAR

Land subsidence is a common geological hazard in urban areas. It can be caused by human activities such as land reclamation and subway construction. However, rapid urbanization can accelerate the progress of these activities. Therefore, spatial-temporal analysis of land subsidence can provide a guarantee for rapid urbanization progress. In this study, Shenzhen, one of the fastest urbanizing cities in China, is selected for continued land subsidence monitoring. We collected 153 Sentinel-1A images from December 2015 to July 2021 and utilized an interferometric point target analysis (IPTA) method to generate the land subsidence in Shenzhen. Additionally, we analyzed the relationship between land subsidence and typical urbanization progress: land reclamation, transportation network, and urban construction. The results show that land subsidence mostly occurs in the western reclamation area, with a maximum rate of -74.9 mm/a in Qianhai Bay. Areas with larger quaternary marine sediment thickness in the range of 10∼20 m are more likely to experience subsidence. Obvious subsidence (<-20 mm/a) along the subway mainly occurred on Lines 11 and Line 5, which is inversely proportional to the distance from the metro. The correlation coefficient is -0.197. Areas with low road densities have a high probability of experiencing great subsidence. A relationship between land subsidence and building construction in the Guangming district is found. Obvious subsidence (<-20 mm/a) mainly occurred in the building areas, with a percentage of 43.48%.

Deformation Analysis of the Cable Reinforcement System of Large Section Box Culvert Roof Entry and Downward Penetration

For the underpass railway large-section box culvert jacking and pipe jacking project, the key to ensuring the normal operation of the existing railway is to maintain the smoothness and stability of the track, railway settlement monitoring and line reinforcement, and box culvert and pipe culvert attitude control are the keys to solving this problem. Taking the Beijing-Harbin high-speed railway project under a city road in Beijing as an example, the law of railway track settlement during the implementation of box culvert jacking was analyzed according to real-time monitoring data. The monitoring results show that accelerating the pouring of the bedding and grouting and strengthening the railway subgrade on both sides of the foundation pit can effectively control the settlement of the railway subgrade and reduce the impact of subsequent construction on the railway, and the line renovation and secondary grouting reinforcement can effectively improve the smoothness of the railway. Combined with the comparative analysis of numerical simulation results, the necessity of line refurbishment and rail fastening combination reinforcement in actual construction is verified.

Application of Spot Quality Evaluation in Subgrade Settlement Monitoring and Measurement System

Application of Spot Quality Evaluation in Subgrade Settlement Monitoring and Measurement System