Monitoring Data Analysis of Dalian Subway Tunnel and Inversion of Rock Parameters

2011 ◽  
Vol 301-303 ◽  
pp. 559-563
Author(s):  
Liang Yong Wan ◽  
Jun Xiang Wang ◽  
An Nan Jiang ◽  
Zhan Ping Song
Keyword(s):  
Finite Element ◽  
Differential Evolution Algorithm ◽  
Back Analysis ◽  
Feedback System ◽  
Field Monitoring ◽  
Monitoring Data ◽  
Information Feedback ◽  
Analysis Program ◽  
Subway Tunnel ◽  
Displacement Back Analysis

The finite element method combines with differential evolution algorithm to develop the displacement back analysis program. For the field excavation of Dalian subway tunnel, the ground subsidence, crown settlement and convergence displacement are monitoring measurement, then data fitting and regression analysis; Using the independent development program and monitoring data to back analysis so that we can address rock mechanics parameters are not accurate "bottleneck"; According to the inversion parameters, the forward analysis of the finite element numerical simulation, to form a comprehensive monitoring and information feedback system based on the field monitoring - displacement back analysis - being analyzed - field monitoring. The results show that the mechanical parameters of displacement back analysis program are very close to the project survey, while the monitoring and information feedback system has an important theoretical and practical value for safety of surrounding rock and stability of construction process.

Displacement Back Analysis Based on Differential Evolution Algorithm in Metro Station Engineering

2011 ◽  
Vol 55-57 ◽  
pp. 527-532
Author(s):  
An Nan Jiang ◽  
Jun Xiang Wang
Keyword(s):  
Differential Evolution ◽  
Differential Evolution Algorithm ◽  
Back Analysis ◽  
Engineering Practice ◽  
Construction Process ◽  
Analysis Program ◽  
Global Optimization Algorithm ◽  
Metro Station ◽  
Displacement Back Analysis ◽  
Evolution Algorithm

In this paper differential evolution algorithm (DE) which is a new global optimization algorithm is introduced into the displacement back analysis, and the self-developed back analysis program based on DE is used in metro station engineering. The results show that the superiority of DE and the practicability of intelligent displacement back analysis program, more importantly, it is being applied to engineering practice to provide reference and advanced prediction for the construction process.

scholarly journals Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ding Youliang ◽  
Wang Gaoxin
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
High Speed ◽  
Field Monitoring ◽  
Generalized Extreme Value Distribution ◽  
Monitoring Data ◽  
Load Factor ◽  
High Speed Railway ◽  
Arch Bridge ◽  
The Impact

Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF) to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

Monitoring Measurement of Vehicular Tunnels and Finite Element Numerical Simulation Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 2832-2836
Author(s):  
Lei Chen ◽  
Lei Wang ◽  
Lin Zhang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Comparative Analysis ◽  
Linear Regression ◽  
Simulation Analysis ◽  
Field Monitoring ◽  
Monitoring Data ◽  
Finite Element Numerical Simulation ◽  
Simulation Results

The vault settlement, the horizontal convergence of Fangdoushan tunnel are monitored and measured. The changing curves with time are drawn; while the data of convergence measurement is analyzed with linear regression. The whole constructing process is simulated to analyze based on FLAC3D. The results of comparative analysis of the data from field monitoring and the data from numerical simulation shows that the simulation results accord well with the actual monitoring data, which will furthermore optimize both the design and the scientific construction

Intelligent Simulation and Recognition of Metro Station Excavation Based on Differential Evolution and Finite Element

2010 ◽  
Vol 168-170 ◽  
pp. 2641-2647
Author(s):  
An Nan Jiang ◽  
Jun Xiang Wang ◽  
De Hai Yu
Keyword(s):  
Finite Element ◽  
Differential Evolution ◽  
Yield Criterion ◽  
Differential Evolution Algorithm ◽  
Equivalent Plastic Strain ◽  
Back Analysis ◽  
Implicit Integration ◽  
Element Analysis ◽  
Integration Algorithm ◽  
Metro Station

Differential Evolution (DE) is a new algorithm. Displacement back analysis method based on the algorithm can effectively solve the problems of rock mechanics parameters which are not accurate. Constitutive integration algorithm divided into explicit and implicit integration is the key points of finite element analysis, which affect the convergence and accuracy of the results. Return mapping algorithm avoiding directly solving the equivalent plastic strain is a kind of implicit integration algorithm, which would achieve rapid and accurate for the solution of constitutive equations. This article describes the theoretical framework based on elastic-plastic, von Mises yield criterion conditions, using C + + language to carry out plastic simulation of Dalian metro station CRD excavation and parameter identification based on differential evolution algorithm. The calculated stress, displacement and deformation can determine the surface subsidence and the development of plastic zone, the stability analysis to provide a reference for the construction.

scholarly journals Systematic slope stability assessment through deformation field monitoring

2019 ◽  
Vol 92 ◽  
pp. 18009
Author(s):  
Yukun Wei ◽  
Anders B. Lundberg ◽  
Fredrik Resare
Keyword(s):  
Slope Stability ◽  
Measurement Data ◽  
Back Analysis ◽  
Field Measurements ◽  
Field Monitoring ◽  
Monitoring Data ◽  
Soil Parameters ◽  
Stability Assessment ◽  
Stability Of Slopes ◽  
The Stability

Field monitoring is frequently carried out during excavations and other geotechnical activities and provides additional information during the execution of a construction project. The interpretation of field monitoring data is often obscured by measurement noise and disturbance, and a systematic approach to assess both the quality and implications of the field monitoring data is very helpful in geotechnical practice. The possibility to infer practical conclusions from the field monitoring data depends on the type of field measurements, especially in monitoring of the stability of slopes. Pore pressure measurements can serve as a direct measurement of utilized soil strength for a slope, while deformation measurements are significantly more ambiguous and complicates the interpretation. The assessment of slope stability through field monitoring of deformations requires inverse or back analysis of the soil properties, followed by a forward analysis of the resulting slope stability. Such an inverse or back analysis is frequently influenced by non-uniqueness of the material properties and the stability of the measurement data. Systematic approaches to inverse or back analysis have been demonstrated in the scientific literature, but the practical use of these methods is not entirely straight-forward. The current paper presents a case study of systematic slope stability assessment through field measurements of deformations with a review of the field monitoring programme, numerical simulations of deformations, and a simplified approach to back analysis of the soil parameters. The excavation of a slope in an urban environment including layers of organic clay covered with highly heterogeneous gravel fill is used as an example of geotechnical back analysis. The aim is to elucidate some of the challenges in geotechnical back analysis while providing some practical solutions for practice.

Master S-N Curve-Based Fatigue Life Assessment of Steel Bridges Using Finite Element Model and Field Monitoring Data

2018 ◽  
Vol 19 (01) ◽  
pp. 1940013 ◽  
Author(s):  
X. W. Ye ◽  
Y. H. Su ◽  
T. Jin ◽  
B. Chen ◽  
J. P. Han
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Welded Joint ◽  
Element Model ◽  
Field Monitoring ◽  
Life Assessment ◽  
Monitoring Data ◽  
Steel Bridge ◽  
Structural Stress ◽  
Fatigue Life Assessment

The accuracy of fatigue life assessment for the welded joint in a steel bridge is largely dependent on an appropriate [Formula: see text]-[Formula: see text] curve. In this paper, a master [Formula: see text]-[Formula: see text] curve-based fatigue life assessment approach for the welded joint with an open-rib in orthotropic steel bridge deck is proposed based on the finite element model (FEM) and field monitoring data from structural health monitoring (SHM) system. The case studies on fatigue life assessment by use of finite element analysis (FEA) for constant-amplitude cyclic loading mode and field monitoring data under variable-amplitude cyclic loading mode are addressed. In the case of FEA, the distribution of structural stress at fatigue-prone weld toe is achieved using 4-node shell element model and then transformed into equivalent structural stress by fracture mechanics theory. The fatigue life of the welded joint is estimated with a single master [Formula: see text]-[Formula: see text] curve in the form of equivalent structural stress range versus the cycles to failure. In the case of monitoring data-based fatigue life assessment, the daily history of structural stress at diaphragm to U-rib is derived from the raw strain data measured by the instrumented fiber Bragg grating (FBG) sensors and transformed into equivalent structural stress. The fatigue life of the investigated welded joint is calculated by cyclic counting method and Palmgren–Miner linear damage cumulative rule. The master [Formula: see text]-[Formula: see text] curve method provides an effective fatigue life assessment process, especially when the nominal stress is hard to be defined. A single master [Formula: see text]-[Formula: see text] curve will facilitate to solve the difficulty in choosing a proper [Formula: see text]-[Formula: see text] curve which is required in the traditional fatigue life assessment methods.

Back Analysis on Tunnel Rheological Parameters

2013 ◽  
Vol 405-408 ◽  
pp. 1227-1230
Author(s):  
Qiang Huang
Keyword(s):  
Neural Network ◽  
Strain Field ◽  
Back Analysis ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Monitoring Data ◽  
Rheological Parameters ◽  
Tunnel Excavation ◽  
Highway Tunnel ◽  
The Difference

The surrounding rock strain field monitoring have been done during a highway tunnel excavation. The rock rheological parameters was inversed by neural network based the field monitoring data. The predicted value and the field monitoring data have been compared, the result shows that the difference is 12%, the predicted value is credible.

Finite Element Modeling of a Mechanically Stabilized Earth Trial Wall

2021 ◽  
pp. 036119812110164
Author(s):  
Andrew Lees ◽  
Michael Dobie
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Retaining Wall ◽  
Back Analysis ◽  
Soil Parameters ◽  
Failure Behavior ◽  
Valuable Insight ◽  
Deformation And Failure ◽  
First Case ◽  
Soil Shear Strength

Polymer geogrid reinforced soil retaining walls have become commonplace, with routine design generally carried out by limiting equilibrium methods. Finite element analysis (FEA) is becoming more widely used to assess the likely deformation behavior of these structures, although in many cases such analyses over-predict deformation compared with monitored structures. Back-analysis of unit tests and instrumented walls improves the techniques and models used in FEA to represent the soil fill, reinforcement and composite behavior caused by the stabilization effect of the geogrid apertures on the soil particles. This composite behavior is most representatively modeled as enhanced soil shear strength. The back-analysis of two test cases provides valuable insight into the benefits of this approach. In the first case, a unit cell was set up such that one side could yield thereby reaching the active earth pressure state. Using FEA a test without geogrid was modeled to help establish appropriate soil parameters. These parameters were then used to back-analyze a test with geogrid present. Simply using the tensile properties of the geogrid over-predicted the yield pressure but using an enhanced soil shear strength gave a satisfactory comparison with the measured result. In the second case a trial retaining wall was back-analyzed to investigate both deformation and failure, the failure induced by cutting the geogrid after construction using heated wires. The closest fit to the actual deformation and failure behavior was provided by using enhanced fill shear strength.

scholarly journals Tunnel Back Analysis Based on Differential Evolution Using Stress and Displacement

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Joon-Sang An ◽  
Kyung-Nam Kang ◽  
Ju-Young Choi ◽  
Won-Suh Sung ◽  
Vathna Suy ◽  
...  
Keyword(s):  
Differential Evolution ◽  
Differential Evolution Algorithm ◽  
Back Analysis ◽  
Friction Angle ◽  
Internal Displacement ◽  
Average Error ◽  
Analysis Algorithm ◽  
Evolution Algorithm ◽  
Displacement Based ◽  
The Stability

The stability of tunnels has mainly been evaluated based on displacement. Because displacement due to the excavation process is significant, back analysis of the structure and ground can be performed easily. Recently, the length of a segment-lined tunnel driven by the mechanized tunneling method is increasing. Because the internal displacement of a segment-lined tunnel is trivial, it is difficult to analyze the stability of segment-lined tunnels using the conventional method. This paper proposes a back analysis method using stress and displacement information for a segment-lined tunnel. A differential evolution algorithm was adopted for tunnel back analysis. Back analysis based on the differential evolution algorithm using stress and displacement was established and performed using the finite difference code, FLAC3D, and built-in FISH language. Detailed flowcharts of back analysis based on DEA using both monitored displacement stresses were also suggested. As a preliminary study, the target variables of the back analysis adopted in this study were the elastic modulus, cohesion, and friction angle of the ground. The back analysis based on the monitored displacement is useful when the displacement is significant due to excavation. However, the conventional displacement-based back analysis is unsuitable for a segment-lined tunnel after construction because of its trivial internal displacement since the average error is greater than 32% and the evolutionary calculation is finalized due to the maximum iteration criteria. The average error obtained from the proposed back analysis algorithm using both stress and displacement ranged within approximately 6–8%. This also confirms that the proposed back analysis algorithm is suitable for a segment-lined tunnel.

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