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A 3D sliced-soil-beam model for settlement prediction of tunnelling using the pipe roofing method in soft ground

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Frontiers of Structural and Civil Engineering 2023年第12期17卷 1934-1948页

作者： Yu DIAO Yiming XUE Weiqiang PAN Gang ZHENG Ying ZHANG Dawei ZHANG Haizuo ZHOU Tianqi ZHANG Key Laboratory of Coastal Civil Engineering Structure and Safety of Ministry of Education Tianjin UniversityTianjin 300072China Department of Civil Engineering Tianjin UniversityTianjin 300072China Shanghai Tunnel Engineering Construction Co. Ltd.Shanghai 200032China Tianjin Municipal Engineering Design&Research Institute Tianjin 300392China

The pipe roofing method is widely used in tunnel construction because it can realize a flexible section shape and a large section area of the tunnel,especially under good ground conditions.However,the pipe roofing method has rarely been applied in soft ground,where the prediction and control of the ground settlement play important roles.This study proposes a sliced-soil-beam(SSB)model to predict the settlement of ground due to tunnelling using the pipe roofing method in soft ground.The model comprises a sliced-soil module based on the virtual work principle and a beam module based on structural mechanics.As part of this work,the Peck formula was modified for a square-section tunnel and adopted to construct a deformation mechanism of soft ground.The pipe roofing system was simplified to a threedimensional Winkler beam to consider the interaction between the soil and pipe roofing.The model was verified in a case study conducted in Shanghai,China,in which it provided the efficient and accurate prediction of settlement.Finally,the parameters affecting the ground settlement were analyzed.It was clarified that the stiffness of the excavated soil and the steel support are the key factors in reducing ground settlement.

关键词： pipe roofing method soft ground numerical simulation settlement prediction simplified calculation parametric analysis

settlement prediction of Dredger Fill with the Optimal Combination Model

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Journal of Donghua University(English Edition) 2014年第6期31卷 812-816页

作者：王清闫欢苑晓青牛岑岑张旭东 College of Construction Engineering Jilin University

Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. e., cannot reflect various regulations of settlement at some stages or the entire process). In this study,the correlation coefficient,maximum error values,and other values were obtained according to the fitting and predicted results of a single model. The coefficient of variation was then introduced to determine the weight of each model forming the combination. The proposed model was used to fit and predict for settlement and overcome the issue of utilizing a single model while determining the weight. The fitting predictive effect was also analyzed using the settlement fitting precision results. The fitting precision of optimizing the combination model is high. The predicted data of the post-construction settlement are closer to the calculated value of the settlement monitoring data. Moreover,the proposed model has good practicability,does not require the interval data of settlement,and restricts the model number. Thus,this model can be applied in the engineering field.

关键词： dredger fill settlement prediction combination model coefficient of variation weight

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Shield Excavation Analysis: Ground settlement & Mechanical Responses in Complex Strata

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Structural Durability & Health Monitoring 2024年第3期18卷 341-360页

作者： Baojun Qin Guangwei Zhang Wei Zhang CCCC Rail Transit Branch Beijing101300China School of Civil Engineering Fujian University of TechnologyFuzhou350118China

This study delves into the effects of shield tunneling in complex coastal strata, focusing on how this constructionmethod impacts surface settlement, the mechanical properties of adjacent rock, and the deformation of tunnelsegments. It investigates the impact of shield construction on surface settlement, mechanical characteristics ofnearby rock, and segment deformation in complex coastal strata susceptible to construction disturbances. Utilizingthe Fuzhou Binhai express line as a case study, we developed a comprehensive numerical model using theABAQUS finite element software. The model incorporates factors such as face force, grouting pressure, jack force,and cutterhead torque. Its accuracy is validated against field monitoring data from engineering projects. Simulationswere conducted to analyze ground settlement and mechanical changes in adjacent rock and segments acrossfive soil layers. The results indicate that disturbances are most significant near the excavation zone of the shieldmachine, with a prominent settlement trough forming and stabilizing around 2.0–3.0 D from the excavation. Theexcavation face compresses the soil, inducing lateral expansion. As grouting pressure decreases, the segmentexperiences upward buoyancy. In mixed strata, softer layers witness increased cutting, intensifying disturbancesbut reducing segment floatation. These findings offer valuable insights for predicting settlements, ensuring segmentand rock safety, and optimizing tunneling parameters.

关键词： Shield construction complex strata finite element method mechanical properties of surrounding rock segment deformation settlement prediction

settlement prediction for Buildings Surrounding Foundation Pits Based on a Stationary Auto-regression Model

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International Journal of Mining Science and Technology 2007年第1期17卷 78-81页

作者： TIAN Lin-ya, HUA Xi-sheng College of Civil Engineering, Hohai University, Nanjing, Jiangsu 210098, China College of Civil Engineering Hohai University Nanjing Jiangsu 210098 China

To ensure the safety of buildings surrounding foundation pits, a study was made on a settlement monitoring and trend prediction method. A statistical testing method for analyzing the stability of a settlement monitoring datum has been discussed. According to a comprehensive survey, data of 16 stages at operating control point, were verified by a standard t test to determine the stability of the operating control point. A stationary auto-regression model, AR(p), used for the observation point settlement prediction has been investigated. Given the 16 stages of the settlement data at an observation point, the applicability of this model was analyzed. settlement of last four stages was predicted using the stationary auto-regression model AR (1); the maximum difference between predicted and measured values was 0.6 mm, indicating good prediction results of the model. Hence, this model can be applied to settlement predictions for buildings surrounding foundation pits.

关键词： foundation pit building settlement monitoring datum stability stationary auto-regression model settlement prediction

A simplified method for prediction of embankment settlement in clays

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第1期6卷 61-66页

作者： Chunlin Li Institute of Civil Engineering Tongling University

The prediction of embankment settlement is a critically important issue for the serviceability of subgrade projects,especially the post-construction settlement.A number of methods have been proposed to predict embankment settlement;however,all of these methods are based on a parameter,i.***.the initial time point.The difference of the initial time point determined by different designers can de?nitely induce errors in prediction of embankment settlement.This paper proposed a concept named"potential settlement"and a simpli?ed method based on the in situ data.The key parameter"b"in the proposed method was veri?ed using theoretical method and?eld data.Finally,an example was used to demonstrate the advantages of the proposed method by comparing with other methods and the observation data.

关键词： Simplified method settlement prediction Embankment Consolidation theory Clayey soil

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Deformation prediction model of concrete face rockfill dams based on an improved random forest model

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Water Science and Engineering 2023年第4期16卷 390-398页

作者： Yan-long Li Qiao-gang Yin Ye Zhang Heng Zhou State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi'an University of TechnologyXi'an 710048China Power China Northwest Engineering Corporation Limited Xi'an 710065China

The unique structure and complex deformation characteristics of concrete face rockfill dams(CFRDs)create safety monitoring challenges.This study developed an improved random forest(IRF)model for dam health monitoring modeling by replacing the decision tree in the random forest(RF)model with a novel M5'model tree algorithm.The factors affecting dam deformation were preliminarily selected using the statistical model,and the grey relational degree theory was utilized to reduce the dimensions of model input variables.Finally,a deformation prediction model of CFRDs was established using the IRF model.The ten-fold cross-validation method was used to quantitatively analyze the parameters affecting the IRF algorithm.The performance of the established model was verified using data from three specific measurement points on the Jishixia dam and compared with other dam deformation prediction models.At point ES-10,the performance evaluation indices of the IRF model were superior to those of the M5'model tree and RF models and the classical support vector regression(SVR)and back propagation(BP)neural network models,indicating the satisfactory performance of the IRF model.The IRF model also outperformed the SVR and BP models in settlement prediction at points ES2-8 and ES4-10,demonstrating its strong anti-interference and generalization capabilities.This study has developed a novel method for forecasting and analyzing dam settlements with practical significance.Moreover,the established IRF model can also provide guidance for modeling health monitoring of other structures.

关键词： Dam health monitoring M5'model tree IRF Monitoring models settlement prediction

Review of research on high-speed railway subgrade settlement in soft soil area

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Railway Engineering Science 2020年第2期28卷 129-145页

作者： Shunhua Zhou Binglong Wang Yao Shan Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 200092China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 200092China

Construction issues of high-speed rail infrastructures have been increasingly concerned worldwide,of which the subgrade settlement in soft soil area becomes a particularly critical problem.Due to the high compressibility and low permeability of soft soil,the post-construction settlement of the subgrade is extremely difficult to control in these regions,which seriously threatens the operation safety of high-speed trains.In this work,the significant issues of high-speed railway subgrades in soft soil regions are discussed.The theoretical and experimental studies on foundation treatment methods for ballasted and ballastless tracks are reviewed.The settlement evolution and the settlement control effect of different treatment methods are highlighted.Control technologies of subgrade differential settlement are subsequently briefly presented.settlement calculation algorithms of foundations reinforced by different treatment methods are discussed in detail.The defects of existing prediction methods and the challenges faced in their practical applications are analyzed.Furthermore,the guidance on future improvement in control theories and technologies of subgrade settlement for high-speed railway lines and the corresponding challenges are provided.

关键词： High-speed railway Subgrade Soft soil foundation Pile-supported embankment Soil arching settlement prediction

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