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Aiming at the problem that the coefficient matrix of multivariate errors-in-variables (MEIV) model contains constant columns, the MEIV model is extended to Partial multivariate errors-in-variables (P-MEIV), and the new algorithm of P-MEIV model is proposed based on the principle of Partial errors-in-variables (PEIV) model and indirect adjustment. The algorithm is simple and easy to implement. An example of coordinate transformation is used for verifying, and the results are compared with the existing MEIV model algorithm, which shows the effectiveness of the proposed algorithm. Finally, the P-MEIV algorithm is applied to the multi-point grey model (MGM(1,N)) of settlement monitoring. The results show that the P-MEIV model proposed in this paper can better consider the influence of monitoring point errors, and the estimated results are in good agreement with the actual situation. [ABSTRACT FROM AUTHOR]

Objective When the sectional tunnel closely under-passes the existing metro station by cutting piles, it has a significant impact on the deformation of the upper station. In order to ensure the safety of construction, it is necessary to take effective measures to control the settlement of metro station. Method Based on the project of a sectional tunnel under-passing the existing metro station, a three-dimensional numerical model is established to analyze the station settlement when being under-passed by cutting piles without settlement control measures. The settlement control effects with measures such as addition of temporary inverted arches, staggered excavation, and grouting reinforcement are studied. A multiple measure combination control scheme is proposed, and its feasibility is verified by the measured engineering data. Result & Conclusion The research results indicate that when the tunnel underpasses the station directly by cutting piles without taking settlement control measures, the maximum settlement of the station will exceed the specified limit. The grouting reinforcement produces the best effect on settlement control with the settlement being reduced by 57.3%. Addition of temporary inverted arches follows next by 40.4%, and staggered excavation has the least effect by 20.8%. The settlement limit can be met by using the multiple measure combination control scheme, which is verified to be feasible by the monitoring data, and can provide reference for similar projects.

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Urban Mass Transit is the property of Urban Mass Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to solve the problems of low reliability and poor prediction accuracy in traditional building structure settlement monitoring, the author proposes a monitoring and analysis of high-rise building settlement deformation status based on nonlinear regression. The author collected and wirelessly transmitted building settlement information through various hardware devices such as sensors and GPRS communication modules. The monitoring data collected by sensors were compared and analyzed to determine the settlement situation of the building. An RBF neural network prediction model was constructed for possible settlement points. Then, the leapfrog algorithm is used to optimize the structural parameters of the RBF neural network. The experimental results show that this method can accurately evaluate the possible settlement of building structures in actual environments, and the prediction error is small, with a maximum relative error of 4.83 %, indicating good warning ability. This method achieved the best actual value fitting curve results, verifying its feasibility in settlement prediction. Subsequently, a more widely applicable settlement detection and prediction system for building complex structures will be established based on the proposed method, in order to promote its large-scale application.

Abstract The settlement is a critical factor in foundation selection. To ensure the safety and stability of a structure, engineers must accurately predict settlement and design the foundation accordingly. However, in cases where the soil stratigraphy is complex, a more detailed analysis is necessary to determine safe and cost-effective solutions for a building's foundation. This paper presents a case study in which settlement monitoring was performed on a 23-story building with spread footings laid on a stiff rock layer of limited thickness overlying more compressible layers of clay and sand. The building was monitored through four construction stages, during which data on vertical displacements and stress distribution on the soil were obtained. To improve the accuracy of the results, a methodology for calibrating the thicknesses of the soil strata was applied, based on the measured settlements, soil-structure interaction, and estimates from semi-empirical methods. Furthermore, a numerical analysis was performed using the finite element method, where more conservative displacements were observed. Finally, the safety of the building was evaluated by verifying angular distortions.

Utilizing natural expansive clays that are available on-site as sewer trench backfill can cause destructive deformations due to volume changes, which are caused by seasonal climatic changes. Such deformations result in manhole structures protruding from the surface, which cause damage to the surrounding infrastructure and generate potential trip hazards. In this study, mixtures of recycled materials with minor sensitivity to moisture variations and superior compactibility were investigated using geomechanics theories associated with granular materials as an alternative backfill material. Blends of recycled glass (RG), plastic (RP), and tire-derived aggregates (TDA) were mixed on-site, wetted to the required moisture content (MC), and used to backfill excavated trenches around two manhole structures and extended to approximately 11 m along the trench. A benchmark trial was constructed by backfilling with natural soils available on-site according to the normal procedure. The full-scale trial sites were instrumented using settlement plates and MC sensors at various locations and depths for performance monitoring. The results of approximately 17 months of field monitoring showed that settlements over both areas that were backfilled with recycled blends were <20% of those over areas backfilled with site-won soils. Approximately 82% of the settlements in the recycled blends occurred during construction. In contrast, trenches that were backfilled with site-won soils continued to exhibit deformation due to consolidation and swell–shrink cycles. The outcome of this study could contribute to the United Nations' Sustainable Development Goals, in particular, Goal 12, by improving the industry's confidence in the reuse of wastes in geotechnical applications. This study investigated the application of mixtures of RG, RP, and recycled tire when backfilling deep excavated trenches in nontrafficable areas. In deep excavated trenches, quality control of the traditional compaction methods that use the excavator's arm is challenging due to safety restrictions that limit the presence of the testing crew in the trench. The blends that were developed in this study are designed to exhibit self-compacting properties, lower the settlement potential of excavated clay and gravel fill materials, and have less sensitivity to moisture variations. Therefore, they are useful in applications, such as backfilling deep (>1.5 m) excavated trenches. The outcomes of this study could promote sustainable construction approaches through the utilization of recycled materials in earthworks and construction projects. In addition, this would mitigate the challenges associated with waste management, because the substitution of virgin materials with recycled materials or wastes could divert waste from landfills. Furthermore, by improving the strength and deformation properties of backfilled trenches, less damage to the surrounding structures at the surface, such as residential houses, sidewalks and fence lines, is expected. [ABSTRACT FROM AUTHOR]

The construction of airport runways or other infrastructures on soft soil might risk damage and create potential hazards if inappropriate foundation treatments have been conducted. Preloading on soft soil is a commonly used ground improvement method in airport runway construction, owing to the cost efficiency and simplicity of this method. However, the theoretical basis for the design parameter estimation of this method has not been fully understood, for example, preloading height calculation and preloading time determination. In this paper, calculation models of settlement characteristics for soft soil preloading treatment and influence factors of preloading for soft soil are proposed, in accordance with Terzaghi one-dimensional consolidation theory. Preloading is counted as a dynamic process in this theory, and the settlement calculation model is expressed as an integration formula. In addition, a simplified calculation model is proposed in this paper for a specific condition of preloading treatment. Reliability of the models was verified with in situ data from an airport runway construction site in China. Results from multiple analysis reveal that preloading treatment can significantly increase the total settlement and consolidation, and accelerate the settlement rate of soft soil. Sensitivity analysis of the theoretical model found that preloading height is the key parameter affecting the preloading efficiency when ignoring the material type of soft soil. Moreover, the thickness of soft soil is the critical input parameter, as analyzing the factors affects the preloading height, and preloading treatment is a continues process rather than an instantaneous process, as can be noted from analyzing the settlement characteristics of the two loading conditions. The proposed settlement characteristic model provides valuable information for the design of preloading parameters of similar projects. Preloading is a simple and widely used method for improving the strength of soft soil; the design of preloading parameters mainly relies on the construction of a trial site or engineering judgment. The theoretical basis of this method is still weak. Thus, this paper proposes a settlement characteristic model under preloading conditions, which was verified by utilizing in situ data from an airport runway construction site. In addition, the influences of design parameters on such settlement characteristics as preloading height and thickness of backfill soil were analyzed. It was found that preloading height is the key parameter affecting the settlement characteristics of preloading treatment. In addition, sensitivity analysis was conducted on the preloading height design using an analytical model, and the results show that the thickness of soft soil is the critical factor affecting the preloading height. In that case, accurate site investigation is significant for the preloading design of soft soil. [ABSTRACT FROM AUTHOR]

To explore the applicability of the machine vision-based monitoring system in underground engineering and the settlement variation patterns of underground prefabricated stations, field calibration experiments are conducted and the settlement during the construction and post-construction phases of the underground prefabricated stations is monitored. The field monitoring data is then compared with the finite element calculation results to establish a real-time multi-scale safety level evaluation method. The results show that: (1) When the distance between the camera and the target is less than 60 m, the average measurement error rate is within 3% . This indicates that the system has a high accuracy in monitoring the structural displacements over short distances. (2) The measured data reveal the settlement variations in the stations due to factors such as backfill construction, entrance excavation, and rainfall. (3) During the backfilling phase, the settlement of the prefabricated underground stations is within -7.0 mm, indicating an overall safe condition of the station structure. The measured data obtained from the machine vision-based monitoring system coincide with the settlement variation patterns revealed by the finite element calculation. This demonstrates that the machine vision-based monitoring system can accurately capture and measure the deformations during the construction of underground stations, and it has a good applicability in underground engineering. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Granular pile is one of the proven soil improvement mechanisms applied especially for reinforcement of compressible soils supporting light structures. The improvement performance of granular piles is influenced by various factors including the dimension parameters (length, spacing and diameter of the piles). The influence of these three dimension parameters on deformation response of reinforced weak soil has widely been reported. However, the most influential parameter affecting deformation of the weak soil has not been clearly identified. Apparently, these dimension parameters do not equally influence the performance of stone columns in lessening soil deformation. Hence, comparative analysis was carried out in the current study to find out the dimension parameter to which deformation of stone column reinforced weak ground is most sensitive. Finite element based parametric numerical analysis was conducted to simulate the weak ground reinforced with a group of granular piles supporting light weight building. For the parametric study, five dimensions for each parameter (diameter, spacing and length) were considered. The dimensions were purposely varied by uniform percentage increase. Field settlement monitoring data was used to track deformation response of the site and validate the finite element results. The numerical analysis reveals that the simulation results have good agreement with the field settlement monitoring data. From sensitivity view point, column spacing was found to be the most controlling and influential parameter affecting deformation of the reinforced weak soil. Similarly, column length is the dimension parameter to which ground deformation is least sensitive.

The settlement deformation of the retaining wall, slope top and the soil behind it is an important index for the safety of foundation pit engineering. By analyzing the settlement amount and settlement rate of the structure, scientific guidance can be provided for engineering construction. The average settlement rate and vertical cumulative settlement of the foundation pit group on the south bank of Dalian Bay Subsea Tunnel for two years (from August 29, 2020 to May 27, 2022) were obtained by small baseline set time series Interferometric Radar Technology (SBAS -InSAR). The results show that the maximum settlement in this area is 75.3 mm. The monitoring results were verified using measured leveling data. The verification results show that is feasible to apply this technology to foundation pit monitoring. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During the construction of an ultra-long immersed tube tunnel, the settlement and deformation of the tunnel are monitored by leveling instruments and total stations, which is affected by the complex environmental conditions in the tube construction, thus sometimes resulting in unstable accuracy of the monitored results and bringing great perplexity to the construction decision. Based on the analysis of the deformation monitoring data in each stage of the immersed tunnel construction, the development law of the monitoring error of the settlement and deformation is revealed and the main influencing factors of the settlement and deformation monitoring of the immersed tunnel are grasped. Combined with the construction characteristics of the immersed tube tunnel, by optimizing the monitoring routing, improving the environment inside the tube and reasonably selecting the monitoring period, the influence of the error caused by the settlement and deformation monitoring under the special construction environment is effectively eliminated, to provide accurate and reliable monitoring data for the construction decision-making. [ABSTRACT FROM AUTHOR]

Accurately and dynamically predicting ground settlements during the construction of foundation pits is pivotal to the understanding of the potential risk of foundation pits and, therefore, enables constructors to take timely and effective actions to ensure the construction safety of foundation pits. Existing settlement prediction methods mainly focus on the prediction of the maximum ground settlements based on static influence factors, such as soil properties and the geometry of foundation pits. However, these methods are unable to be applied to the prediction of daily ground settlements in a direct way because daily ground settlements can be affected by many time-dependent influence factors, and an accurate prediction of daily ground settlements should take into consideration such factors. To address this problem, this paper proposes an artificial neural network-based daily ground settlement prediction method, where both static and time-dependent influence factors, as well as previous settlement monitoring data, are considered in the optimum artificial neural network. The proposed method is validated using data collected from a real cut-and-cover highway tunnel project in western Hangzhou, China. The results demonstrate that time-dependent influence factors and previous settlement monitoring data play vital roles in establishing an optimum artificial neural network for the accurate prediction of daily ground settlement. [ABSTRACT FROM AUTHOR]

The mining subsidence in the mining area will bring great threats to the safety of surface buildings and personnel. It is of great significance to monitor the time series subsidence of the mining area and provide guidance for the safety of surface buildings. Based on SBAS‐InSAR technology，this paper carried out the time series subsidence monitoring of M mining area in the past five years，determined the subsidence area and annual average subsidence rate of M mining area，and carried out time series analysis on key subsidence areas. In addition，combined with the sentinel data intensity image and GF-1 optical image to interpret the information of the surface buildings in the mining area，combined with the InSAR deformation field to analyze the safety of the main building areas. The results show that the surface subsidence of the third and second mines in the mining area is the most serious，while the subsidence of the first mine is relatively small. Both areas A and B of the mine have a tendency to continue to deepen and expand the scope of influence. Among the surface building complexes in the mining area，the part of the southern part of A1 entering the mining area，and the building complexes A2 and B3 are less safe，with a settlement rate of 30～60mm/a. Follow‐up site exploration is required to do a good job in building safety protection and safety precautions. The settlement rate of A3，A4，and B2 buildings is 0～30mm/a，which is worth paying attention to later. The settlement rate of the B1 building group and the building groups in C～G areas is 0～20mm/a， and their safety is relatively good. [ABSTRACT FROM AUTHOR]

In response to the problem that the measurement noise in the original measurement data of settlement monitoring affects the stability determination of tunnel structure, the classical Kalman filter algorithm and variance compensation adaptive Kalman filter model are presented based on the analysis of Kalman filter algorithm and the application of Kalman filter algorithm in noises reduction of tunnel structure settlement analysis is researched. The analysis results of engineering examples show that the Kalman filter algorithm can well suppress the influence of settlement monitoring noises on tunnel structure deformation analysis, and the results after denoising can more truly represent the subsidence trend. The noises suppression effect of variance compensation adaptive Kalman filter is better than that of classical Kalman filter. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accurately and dynamically predicting ground settlements during the construction of foundation pits is pivotal to the understanding of the potential risk of foundation pits and, therefore, enables constructors to take timely and effective actions to ensure the construction safety of foundation pits. Existing settlement prediction methods mainly focus on the prediction of the maximum ground settlements based on static influence factors, such as soil properties and the geometry of foundation pits. However, these methods are unable to be applied to the prediction of daily ground settlements in a direct way because daily ground settlements can be affected by many time-dependent influence factors, and an accurate prediction of daily ground settlements should take into consideration such factors. To address this problem, this paper proposes an artificial neural network-based daily ground settlement prediction method, where both static and time-dependent influence factors, as well as previous settlement monitoring data, are considered in the optimum artificial neural network. The proposed method is validated using data collected from a real cut-and-cover highway tunnel project in western Hangzhou, China. The results demonstrate that time-dependent influence factors and previous settlement monitoring data play vital roles in establishing an optimum artificial neural network for the accurate prediction of daily ground settlement.

Taking a rail transit elevated section in Songjiang District, Shanghai as the research object, this study analyzed the characteristics and causes of settlement deformation using data on land subsidence, groundwater level change, surrounding engineering impact monitoring, and elevated settlement monitoring. It is pointed out that land subsidence and surrounding engineering construction are the two main influences of elevated deformation. Subsequently, this study attempted to quantify the settlement caused by these two factors. The settlement deformation time of the elevated section was analyzed using monthly monitoring data of the layer benchmark and well. A set of analysis processes of rail transit settlement deformation based on land subsidence was summarized, providing technical support for the safe operation of urban infrastructure such as rail transit. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Geological Hazard & Control is the property of China Institute of Geological Environmental Monitoring (CIGEM) Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Continued settlement monitoring and modeling of landfills are critical for land redevelopment and safety assurance. This paper adopts a MTInSAR technique for time-series monitoring of the Xingfeng landfill (XFL) settlement. A major challenge is that the frequent and significant settlement in the initial stage after the closure of landfills can affect the coherence of interferograms, thus hindering the monitoring of settlement by MTInSAR. We analyzed the factors that can directly affect the temporal decorrelation of landfills and adopted a 3D phase unwrapping approach to correct the phase unwrapping errors caused by such deformation gradient. SAR images from four platforms, including 50 Sentinel-1A, 12 Radarsat-2, 4 ALOS-2, and 2 TerraSAR-X/TanDEM-X images, are collected to measure the settlement and thickness of the landfill. The settlement accuracy is evaluated by a cross-evaluation between Radarsat-2 and Sentinel-1A that have similar temporal coverages. We analyzed the spatial characteristics of settlement and the relationship between the settlement and thickness. Further, we modeled the future settlement of the XFL with a hyperbolic function model. The results showed that the coherence in the initial stage after closure of the XFL is primarily affected by temporal decorrelation caused by considerable deformation gradient compared with spatial decorrelation. Settlement occurs primarily in the forward slope of the XFL, and the maximum line-of-sight (LOS) settlement rate reached 0.808 m/year from August 2018 to May 2020. The correlation between the settlement and thickness is 0.62, indicating an obvious relationship between the two. In addition, the settlement of younger areas is usually greater than that of older areas.

Owing to the pavement cracking of heightening and thickening levees (HTL) caused by differential settlement, it is necessary to study the settlement prediction and differential settlement criterion for HTLs. In this study, an HTL was taken as the study object. First, leveling observation and layered settlement observation were adopted, and a generalized settlement prediction model (GSPM) that can describe both S-shaped and hyperbolic settlement–time curves was proposed. The physical meanings of GSPM parameters were analyzed. Moreover, the effectiveness of the GSPM was verified using field monitoring data. Second, finite element analysis based on a viscoelastic constitutive model was used to reveal the quantitative relationship between the differential settlement and horizontal stress of the pavement. On this basis, the differential settlement criterion was obtained. The results showed that the GSPM can unify the logistic model and hyperbolic model by introducing two morphological change parameters. In addition, the GSPM can be more widely used, more accurate, and more stable than the traditional logistic model and hyperbolic model. When an asphalt concrete pavement (whose ultimate tensile stress is 0.12 MPa) is used, the corresponding differential settlement criterion is approximately 4.3 cm. The research results can provide a reference for reasonable differential settlement control for HTLs in order to prevent pavement cracking. [ABSTRACT FROM AUTHOR]

After the completion of the installation of the immersed pipe, in order to prevent the deviation of the pipe section, it is necessary to carry out the backfill operation on the pipe section in time, in which the locking backfill is a key process after the installation of the immersed pipe. Because the locking backfill is a large volume and a large area of gravel backfill at both sides of the pipe section, the lateral pressure and gravity of the crushed rock during the locking backfill will directly affect the longitudinal and lateral deflection of the immersed pipe and the settlement change. Based on the settlement monitoring before and after the locking backfill of the immersed tube section by the HZMB project, we analyzed the causes of the settlement, expounded the influence of locking backfill on the settlement, which has certain reference significance for the future similar engineering. [ABSTRACT FROM AUTHOR]

• The main challenge of the stress measurement of geotextile is introduced. • OF based intelligent geotextile is developed by implanting OF or FBG sensor. • FRP packaged distributed OF and FBG sensors with small diameter are developed. • The developed geotextile is used to a real high-speed railway subgrade monitoring. Geotextile is one of the important reinforcement materials for high-speed railway subgrade, and its service performance is closely related to subgrade safety. In order to grasp the mechanical properties of geotextile, the OF (optical fiber) based intelligent geotextile by braiding FRP (fiber reinforced polymer) packaged OF sensor into geotextile is developed, and applied for the settlement monitoring of karst cave expansion process in one subgrade model and one high-speed railway subgrade construction. The test and field monitoring data show that the strain data measured by the optical fiber sensor is basically consistent with that measured by the settlement plate which indicates that the developed intelligent geotextile not only has good reinforcement function, but also has good sensing function. [ABSTRACT FROM AUTHOR]

Owing to the pavement cracking of heightening and thickening levees (HTL) caused by differential settlement, it is necessary to study the settlement prediction and differential settlement criterion for HTLs. In this study, an HTL was taken as the study object. First, leveling observation and layered settlement observation were adopted, and a generalized settlement prediction model (GSPM) that can describe both S-shaped and hyperbolic settlement⁻time curves was proposed. The physical meanings of GSPM parameters were analyzed. Moreover, the effectiveness of the GSPM was verified using field monitoring data. Second, finite element analysis based on a viscoelastic constitutive model was used to reveal the quantitative relationship between the differential settlement and horizontal stress of the pavement. On this basis, the differential settlement criterion was obtained. The results showed that the GSPM can unify the logistic model and hyperbolic model by introducing two morphological change parameters. In addition, the GSPM can be more widely used, more accurate, and more stable than the traditional logistic model and hyperbolic model. When an asphalt concrete pavement (whose ultimate tensile stress is 0.12 MPa) is used, the corresponding differential settlement criterion is approximately 4.3 cm. The research results can provide a reference for reasonable differential settlement control for HTLs in order to prevent pavement cracking.

In the field of time-frequency decomposition,the Local Mean Decomposition( LMD) method is applied in settlement monitoring, hut the phenomenon of mode mixing can appear during the appli­cation. which results in inaccurate deformation signal extraction . The Ensemble Local Mean Decom­position KLMD) method can he used to improve the mode of mixing the local mean decomposition by adding auxiliary noise to the original signal* and also can use the statistical characteristics of auxiliary noise to remove the mode mixing. This paper uses simulation data to analyze the model error in the ELMD method and presents a parallel combination prediction method based on ELMD. In the case of high speed railway bridge monitoring data, it divides a series of discrete nonlinear and unstable signal into three product function(PF) components and one remaining component. The method takes advan­tage of the support vector machine and Kalman filter algorithms to predict these components, and ana­lyses the superiority of ELMD in the case of mode mixing and overall feasibility empirically. The re­sults indicate that: the parallel combination model, based on ensemble local mean decomposition (ELMD).can eliminate the mode mixing problem in the local mean decomposition (LMD) method ver- y well and extracts the deformation signal accurately. In terms of prediction precision, the mean rela­tive error can reach 8. 3% .and may provide areference for prediction of deformation monitoring. [ABSTRACT FROM AUTHOR]

The settlement monitoring of subway runs through the entire construction stage of subway. It is very important to predict the accurate settlement value for construction safety of subway. In this paper, the wavelet transform is used to denoise the settlement data. The auxiliary wavelet neural network, embedded wavelet neural network and single BP neural network are applied to predict the settlement of Tianjin subway. Compared with single BP neural network and auxiliary wavelet neural network, the embedded wavelet neural network model has a higher accuracy and better prediction effect. The embedded wavelet neural network is more valuable than the BP neural network model so it can be used in the prediction of subway settlement. [ABSTRACT FROM AUTHOR]

Settlement is one of the most important deformation characteristics of high concrete faced rockfill dams (CFRDs, >100 m). High CFRDs safety would pose a great threat to the security of people's lives and property downstream if this kind of deformation were not to be measured correctly, as traditional monitoring approaches have limitations in terms of durability, coverage, and efficiency. It has become urgent to develop new monitoring techniques to complement or replace traditional monitoring approaches for monitoring the safety and operation status of high CFRDs. This study examines the Shuibuya Dam (up to 233.5 m in height) in China, which is currently the highest CFRD in the world. We used space-borne Interferometric Synthetic Aperture Radar (InSAR) time series to monitor the surface deformation of the Shuibuya Dam. Twenty-one ALOS PALSAR images that span the period from 28 February 2007 to 11 March 2011 were used to map the spatial and temporal deformation of the dam. A high correlation of 0.93 between the InSAR and the in-situ monitoring results confirmed the reliability of the InSAR method; the deformation history derived from InSAR is also consistent with the in-situ settlement monitoring system. In addition, the InSAR results allow continuous investigation of dam deformation over a wide area that includes the entire dam surface as well as the surrounding area, offering a clear picture continuously of the dam deformation. [ABSTRACT FROM AUTHOR]

The transition sections from E1-S3 to E4-S3 of the west island of the Hongkong-Zhuhai-Macao Bridge are deep mud, it used sand compaction piles and stack preloading as treatments, in which, sand compaction piles was used as a drainage channel. In order to ensure the foundation treatment results meeting the design requirements of degree of consolidation, settlement monitoring need to do in the loading period, such to obtain the consolidation settlement and residual settlement during loading. Based on the engineering characteristics, in the stack preloading area of transition section, the total settlement during foundation reinforcement process would be known through the surface settlement monitoring of composite foundation, then we analyzed the final settlement and residual settlement of composite foundation, and calculated the average degree of consolidation, determined the unloading time, and evaluated the strengthening effect of foundation. [ABSTRACT FROM AUTHOR]

• Guiyang Metro in China is located in a special karst landform. • A new special metro station construction scheme is proposed. • Design deformation monitoring technology of special terrain tunnel construction. • Analysis of tunnel deformation and mechanical behavior. • The feasibility and application achieved using this technology are discussed. The Huo-Sha Tunnel of the Guiyang Metro Line 1 in China runs from the Guiyang Railway Station to the Shachong road station, and it passes close to the railway station platform. The minimum distance between the crown and pile foundation is only 2.19 m, and the settlements of existing buildings are strictly controlled, such as pile foundations. Existing comprehensive measures, such as super pipe shed support, surrounding rock reinforcement, inverted arch grouting, and lining strengthening, are stringently adopted to prevent the influence of construction on the operation of station buildings and in-service railways, high-speed railways, and other buildings. In this study, the changing laws related to existing building subsidence, subgrade settlement, station longitudinal displacement variation, and the development trends of lining safety, stability, eccentricity, compression types, and internal force of the lining are analyzed. The following results are presented. The Huo-Sha Tunnel was gradually excavated. The roadbed settlement of the Guiyang Railway Station platform gradually increased, but it did not exceed the existing railway deformation control standards for the subsurface excavation section. The longitudinal distribution of the existing railway settlement is approximately a normal curve after the construction of the secondary lining. The outcome is consistent with the law of the surface settlement trough proposed by Peck, and the range is −50 to 50 m. The stress of the lining is primarily concentrated at the arch waist and crown, the compression types include large and small eccentricities, and the axial force value gradually increases symmetrically from the crown to the arch footing, while the maximum axial force appears at the arch footing, and all control indicators meet the corresponding control standards. The subgrade settlement of the skew section adheres to the deformation control standards of the existing railway of subsurface excavation sections after the stabilization of the secondary lining deformation. [ABSTRACT FROM AUTHOR]

Excessive and unexpected settlement of supertall buildings during the construction stage may affect structural safety. Floor settlement monitoring is imperative during the structural construction. The current practice is to measure floor settlement within a specific time frame and then compensate for the elevation error in the next construction stage. This posterior manner is inaccurate because it does not take account of measurement error and the real settlement in the next construction stage. This paper presents a Kalman filter based settlement monitoring approach with the aid of forward construction stage analysis. The settlement of floors in the next stage is predicted with the forward construction stage analysis. Consequently the elevation of the floor to be constructed can be pre-determined. The proposed method is demonstrated through construction settlement monitoring of the 632-m tall Shanghai Tower. The structure will be the tallest supertall building of China upon completed in 2014. It shows that this method can improve the accuracy of pre-determined elevation of supertall buildings. [ABSTRACT FROM AUTHOR]

A new measurement technique is used to determine the settlement of bridge pile foundation and the thickness of deep compressed soft layer. The finite element Plaxis 3D foundation program is used in the analysis with a proposed empirical equation to modify the input parameters represented by the soil compression modulus. The results of the numerical analysis using the proposed empirical equation provide insight to the settlement analysis of pile groups in soft clayey soils; consequently, the finite element Plaxis 3D program can be a useful tool for numerical analysis. The numerical analysis is modified by adjusting the calculation of compression modulus from those obtained under pressure between 100-200 kPa by which the results of the settlement are modified and thus matching the realistic measurements. The absolute error is 3 mm which is accepted compared with the last researches. This scenario can be applied for the similar problems in the theoretical applications of deep foundations. [ABSTRACT FROM AUTHOR]

• An innovative spring-shaped fiber-optic displacement sensor (SSFODS) based on OTDR for settlement monitoring is proposed. • The SSFODS shows high linearity with the R2 of 0.985, large measurement range of 90 mm, minimum displacement resolution of 0.173 mm, maximum hysteresis error of 2.81% and maximum repeatability error of 8.42%, respectively. • Several SSFODSs can be connected in series on one optical link to realize quasi-distributed sensing monitoring. In this paper an innovative spring-shaped fiber-optic displacement sensor (SSFODS) based on optical time domain reflectometer (OTDR) technology with simple construction and cheap cost was proposed for subgrade settlement monitoring. The sensor incorporated a simple spring-shaped fiber bending modulation that increased its sensitivity in bending, light source and detector. The sensing principle between the measured external displacement and bending loss of optical fiber was theoretically explained and its expression was also derived. Sensor calibration was conducted, which showed that the SSFODS was characterized by a large measurement range of 90 mm, minimum displacement resolution of 0.173 mm, maximum hysteresis error of 2.81% and maximum repeatability error of 8.42%, respectively. A soil drainage model test with the SSFODS was performed to study its performance in determining compression deformation of the soil. At last, a simple field monitoring application with two SSFODSs connected in series was conducted and the progressive compaction behavior of the fill slope was accurately captured by two SSFODSs. Additionally, it is possible to connect these SSFODSs in series on one optical link to realize quasi-distributed sensing monitoring. This capability supports a promising application of the sensor in geotechnical engineering for real-time monitoring of the stability of fill slopes, foundation pits and so on. [ABSTRACT FROM AUTHOR]

Because of several unforeseen actions such as the deep excavation and long-term consolidation of ground, the settlement and lateral displacement have become important parameters for shield tunnel. Due to lack of distributed characteristic, the traditional monitoring methods based on manual observation on some preset uniformly spaced points, probably ignore some local settlements or lateral displacements which may occur anywhere along a shield tunnel. According to an improved conjugated beam method (ICBM) which uses the distributed fiber optic sensors to monitor the deflection of statically indeterminate structure with a finite number of supports, this paper first extends the ICBM to monitor distributed deflection of statically indeterminate structure with infinite number of supports. Then a settlement and lateral displacement monitoring method for shield tunnels is proposed. Two experiments including a scale-down longitudinal concrete model and a long steel tube model are carried out to verify the monitoring accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract: The method of preloading associated with prefabricated vertical drains was used to accelerate the consolidation process and anticipate the long-term settlements of the foundation soil of two cylindrical oil tanks founded on an alluvial deposit mainly consisting of silty clays. In-situ investigations, including boreholes and cone penetration tests (CPTs), and laboratory tests were carried out to define the geotechnical profile of the construction site and the soil mechanical properties. Dissipation tests were also carried out during the CPTs and allowed evaluating the horizontal consolidation and permeability coefficients through several procedures. An extensive field monitoring of the site was carried out during the embankment construction, the preloading period and, after the embankment removal, during the hydraulic leakage test of the tanks. Differential settlements and angular distortions of the tank foundation evaluated from the measured settlement profiles were compared with expected profile shapes for tanks overlying homogeneous compressible soil layers and with available empirical relationships. A general fair agreement was observed even if the heterogeneity of the alluvial soil deposit affects the tank response. Observed absolute and differential settlements and distortions are consistent with the allowable limits provided by the literature and with the design prescriptions, thus confirming the effectiveness of the preloading and drainage technique adopted in the project and envisaging a satisfactory performance of the tank under service conditions. [Copyright &y& Elsevier]

In order to analyse embankment dam settlement survey data during construction and describe the relationship between the settlement and fill, the grey model has been considered because of its excellence. Two kinds effective factors of embankment settlement during construction stage were obtained based on the correlated settlement calculation methods. There are fill height and equivalent fill height effecive factor. GM (1,h) model is used to establish the equation between settlement and construction process to describe and forecast the settlement's disciplinarian. The example shows that the settlement-fill monitoring model fits the settlement regulation and reflects the relationship between them very well. [ABSTRACT FROM AUTHOR]