Three-Dimensional Analysis of Excavating Face Stability Supported by Pipe Roof

2013 ◽  
Vol 275-277 ◽  
pp. 1257-1263 ◽  
Author(s):  
Xiang Yuan ◽  
Shun Hua Zhou ◽  
Quan Mei Gong
Keyword(s):  
Analytical Solution ◽  
Dimensional Analysis ◽  
Load Transfer ◽  
Three Dimensional ◽  
Subgrade Reaction ◽  
Large Section ◽  
Tunnel Face ◽  
Face Stability ◽  
Tunnel Face Stability ◽  
The Stability

This paper analyzes the load transfer characteristics of pipe roof over the excavating face, and the analytical solution of tunnel face stability is established by the method of three-dimensional analysis. Through the calculation of the load transfer of the pipe roof, it indicates that the released load of excavation is passed to the supporting structure and soil which is not excavated by the effect of the pipe roof, and the magnitude of load and coverage of impact are in connection with excavating footage as well as subgrade reaction. The three-dimensional analytical solution of tunnel face stability is used to analyze a project case of Airport Road underpass in Hangzhou. The results show that the tunnel face stability is not guaranteed when excavated on a large section while the stability is enhanced when excavated on separated pilot headings.

Three-dimensional analysis of tunnel face stability in spatially variable soils

2019 ◽  
Vol 111 ◽  
pp. 76-88 ◽  
Author(s):  
Hongzhan Cheng ◽  
Jian Chen ◽  
Renpeng Chen ◽  
Juehao Huang ◽  
Jianhe Li
Keyword(s):  
Dimensional Analysis ◽  
Three Dimensional ◽  
Tunnel Face ◽  
Face Stability ◽  
Tunnel Face Stability

Three-dimensional undrained tunnel face stability in clay with a linearly increasing shear strength with depth

2017 ◽  
Vol 88 ◽  
pp. 146-151 ◽  
Author(s):  
Boonchai Ukritchon ◽  
Kongkit Yingchaloenkitkhajorn ◽  
Suraparb Keawsawasvong
Keyword(s):  
Shear Strength ◽  
Three Dimensional ◽  
Tunnel Face ◽  
Face Stability ◽  
Tunnel Face Stability

Probabilistic analysis of tunnel face stability considering spatially variable undrained shear strength with linearly increasing mean trend

2020 ◽  
pp. 1748006X2092715
Author(s):  
Hongzhan Cheng
Keyword(s):  
Shear Strength ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Undrained Shear Strength ◽  
Tunnel Face ◽  
Face Stability ◽  
Tunnel Face Stability ◽  
The Stability ◽  
Undrained Shear

The inherent spatial variability of soil properties has been considered as one of the main sources of uncertainties in geotechnical problems. The need for probabilistic analysis of the tunnel face stability that takes into account the variability of soil properties has been acknowledged. This article employed a probabilistic-based method, called random finite difference method, for evaluating the stability of tunnel face under the influence of the variability of undrained shear strength in clays. The two-dimensional spatial variation in soil undrained shear strength is modeled by random fields, which are discretized by the Covariance Matrix Decomposition method. The procedure for random finite difference method is presented. An illustrative example is employed to investigate the effect of soil variability. Particular attention has been paid to the situation that undrained shear strength increases with depth. The results demonstrate that ignoring the variability of undrained shear strength will result in overestimates of the tunnel face stability if the support pressure of the tunnel face exceeds the deterministic value, especially for higher coefficient of variation of soil undrained shear strength. Minor differences in the failure mechanism are observed in comparison to the deterministic case, considering only the global failure of the tunnel face is observed. In addition, ignoring the increase of undrained shear strength with depth will lead to conservative designs. The random finite difference method can provide a practical tool for evaluating the stability of a tunnel face in variable soils.

scholarly journals Probabilistic Analysis of Tunnel Face Stability below River Using Bayesian Framework

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Weiping Liu ◽  
Xiaoyan Luo ◽  
Jinsong Huang ◽  
Lina Hu ◽  
Mingfu Fu
Keyword(s):  
Probabilistic Analysis ◽  
Three Dimensional ◽  
Friction Angle ◽  
Bayesian Framework ◽  
Computational Time ◽  
Support Pressure ◽  
Tunnel Face ◽  
Face Stability ◽  
Mcmc Simulation ◽  
Tunnel Face Stability

A key issue in assessment on tunnel face stability is a reliable evaluation of required support pressure on the tunnel face and its variations during tunnel excavation. In this paper, a Bayesian framework involving Markov Chain Monte Carlo (MCMC) simulation is implemented to estimate the uncertainties of limit support pressure. The probabilistic analysis for the three-dimensional face stability of tunnel below river is presented. The friction angle and cohesion are considered as random variables. The uncertainties of friction angle and cohesion and their effects on tunnel face stability prediction are evaluated using the Bayesian method. The three-dimensional model of tunnel face stability below river is based on the limit equilibrium theory and is adopted for the probabilistic analysis. The results show that the posterior uncertainty bounds of friction angle and cohesion are much narrower than the prior ones, implying that the reduction of uncertainty in cohesion and friction significantly reduces the uncertainty of limit support pressure. The uncertainty encompassed in strength parameters are greatly reduced by the MCMC simulation. By conducting uncertainty analysis, MCMC simulation exhibits powerful capability for improving the reliability and accuracy of computational time and calculations.

scholarly journals Analisis Stabilitas dan Deformasi Terowongan Kereta Cepat Indonesia dengan Pendekatan Numerik Tiga Dimensi

2021 ◽  
Vol 6 (2) ◽  
pp. 111
Author(s):  
Rinaldi Alamsyah ◽  
Indra Noer Hamdhan
Keyword(s):  
Static Analysis ◽  
Safety Factor ◽  
Tunnel Face ◽  
Face Stability ◽  
Level Of Activity ◽  
Tunnel Face Stability ◽  
The Stability ◽  
High Level ◽  
Double Track ◽  
Plaxis 3D

ABSTRAKWilayah perkotaan yang didalamnya terdapat perkantoran dan tempat yang memiliki tingkat kegiatan yang sangat tinggi, menjadikan struktur terowongan bawah tanah sebagai salah satu solusi untuk meningkatkan infrastruktur transportasi secara  optimal. Terowongan kereta cepat Indonesia merupakan salah satu terowongan yang dibangun dan berlokasi di Halim, DKI Jakarta. Terowongan dengan panjang 1.885 m ini memiliki jalur ganda (Double Track Railway). Untuk mengetahui stabilitas dan deformasi terowongan pada saat konstuksi, dilakukan analisis geoteknik. Analisis yang dilakukan yaitu analisis statik dan kondisi longterm dengan analisis dinamik. Tunneling Bore Machine (TBM) dengan sistem perkuatan linning precast dan grouting dipilih sebagai metode konstruksi untuk membangun terowongan. Pemodelan analisis statik menghasilkan deformasi terbesar 0,03056 m dan nilai faktor keamanan 1,869.Kata kunci: terowongan kereta cepat Indonesia, stabilitas, deformasi, faktor keamanan, TBM, PLAXIS 3D, linning, grouting ABSTRACTUrban areas with offices and places that have a very high level of activity make underground tunnel structures one of the solutions to optimally improve transportation infrastructure. The Indonesian fast train tunnel is one of the tunnels built and located at Halim, DKI Jakarta. The tunnel with a length of 1,885 m has a double track (Double Track Railway). To determine the stability and deformation of the tunnel during construction, a geotechnical analysis was performed. The analysis performed is static analysis and longterm conditions with dynamic analysis. Tunneling Bore Machine (TBM) with precast linning reinforcement and grouting system was chosen as the construction method for tunneling. Static analysis modeling produces the largest deformation 0.03056 m and a safety factor value of 1.869.Keywords: tunnel, face stability, deformation, safety factor, TBM, numerical method, PLAXIS 3D, linning, grouting

Influence of laterally loaded sleeved piles and pile groups on slope stability

2001 ◽  
Vol 38 (3) ◽  
pp. 553-566 ◽  
Author(s):  
C WW Ng ◽  
L M Zhang ◽  
K KS Ho
Keyword(s):  
Slope Stability ◽  
Dimensional Analysis ◽  
High Speed ◽  
Slope Failure ◽  
Load Transfer ◽  
Large Diameter ◽  
Three Dimensional ◽  
Pile Groups ◽  
The Stability ◽  
Laterally Loaded

Many high-rise buildings, bridges, and transmission towers are constructed on steep slopes in Hong Kong and are supported by large-diameter piles. These structures may be subjected to large lateral loads, such as those caused by typhoons, earthquakes, and high-speed vehicles. The margin of safety of the slope may decrease as a result of stresses transferred from the piles to the slope. To minimize the transfer of lateral load from the buildings to the shallow depths of the slope, an annulus of compressible material (sleeving) is sometimes formed between the piles and the adjacent soils. In this paper, a three-dimensional analysis is carried out to investigate the effects of unsleeved and sleeved single piles and pile groups on the stability of a cut slope. Mechanisms of load transfer from the piles to the slope are studied. The stability of the slope is evaluated using the strength reduction technique. The evolution of slope failure is examined and the factors of safety for both initiation of instability and global failure of the slope are identified from the numerical analyses. The sleeving technique is found to be capable of significantly reducing the stresses in the shallow depths of the slope in front of the piles, thus improving the local stability of the slope, but offers limited benefit with respect to global stability.Key words: laterally loaded pile and pile group, sleeving, slope stability, three-dimensional analysis, load transfer mechanism, factor of safety.

Analytical Approach for Face Stability Estimate of Tunnel with Pipe Roof Reinforcement

2011 ◽  
Vol 243-249 ◽  
pp. 347-350 ◽  
Author(s):  
Hong Wei Song ◽  
Hai Tao Wang
Keyword(s):  
Three Dimensional ◽  
Stability Estimate ◽  
Test Results ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Tunnel Face ◽  
Face Stability ◽  
Calculation Results ◽  
Tunnel Face Stability ◽  
Centrifugal Model

One of the most popular pre-reinforcement structures in the construction of tunnels through weak grounds would be the pipe roof reinforcement. This composite structure consists on installing, prior to the excavation of a length of tunnel, a series of pipes, either parallel to the tunnel axis or at a certain angle with it. By injecting grout through the pipes, the ground in between the pipes is stiffened and the pipes are connected, creating a kind of ‘umbrella’ above the area to be excavated. In this paper, by modifying the upper bound solution for tunnel face stability, the three-dimensional model for expressing the tunnel face stability with pipe roof reinforcement was established. For a typical example, the solutions computed by the proposed approach were compared with the results given by wedge model, trapezoid wedge model and centrifugal-model test to verify the reasonability of the method. It is shown that the calculation results of limit analysis are in close agreement with test results.

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