The equivalence of a jointed shield-driven tunnel lining to a continuous ring structure

2001 ◽  
Vol 38 (3) ◽  
pp. 461-483 ◽  
Author(s):  
K M Lee ◽  
X W Ge
Keyword(s):  
Pressure Distribution ◽  
Joint Stiffness ◽  
Earth Pressure ◽  
Horizontal Displacement ◽  
Internal Force ◽  
Ring Structure ◽  
Tunnel Lining ◽  
Bending Rigidity ◽  
Continuous Ring ◽  
Soft Clays

This paper presents a new method of determining the correction factor to approximate a jointed, shield-driven tunnel lining as a continuous ring structure under plane strain conditions. An earth pressure distribution pattern is proposed which is developed based on the long-term behavior of shallow tunnels constructed in soft clays as observed in the field. The "force method" was used to determine the internal forces and displacements of jointed, shield-driven tunnels. Either the vertical or the horizontal displacement of the tunnel lining can be used as a common matching parameter. Factors such as joint stiffness, soil resistance, joint distribution, number of joints, and tunnel geometry can be considered by the proposed method. Simplified design equations for the estimation of equivalence factors are also proposed for the typical tunnel lining geometry of urban subway tunnels. The proposed equivalence method was evaluated by comparing it with the results of laboratory tests.Key words: shield-driven tunnel, jointed segmental lining, effective bending rigidity ratio, equivalence factor, lining internal force, earth pressure distribution.

Field Performance and Analysis of 3-m-Diameter Induced Trench Culvert under a 19.4-m Soil Cover

2008 ◽  
Vol 2045 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Bethanie A. Parker ◽  
Rodney P. McAffee ◽  
Arun J. Valsangkar
Keyword(s):  
Pressure Distribution ◽  
Earth Pressure ◽  
Field Performance ◽  
Overburden Pressure ◽  
Vertical Pressure ◽  
Earth Pressures ◽  
Design Loads ◽  
Horizontal Pressure ◽  
Two Stages

An induced trench installation was instrumented to monitor earth pressures and settlements during construction. Some of the unique features of this case study are as follows: (a) both contact and earth pressure cells were used; (b) part of the culvert is under a new embankment and part was installed in a wide trench within an existing embankment; (c) a large stockpile was temporarily placed over the induced trench; and (d) the compressible material was placed in two stages. The maximum vertical pressure measured in the field at the crown of the culvert was 0.24 times the overburden pressure. The maximum horizontal pressure measured on the side of the culvert at the springline was 0.45 times the overburden pressure. The column of soil directly above the compressible zone settled approximately 40% more than did the adjacent fill. The field results at the crown and springline compared reasonably with those observed with numerical modeling. However, the overall pressure distribution on the pipe was expected to be nonuniform, the average vertical pressure calculated by using numerical analysis on top of the culvert over its full width was 0.61 times the overburden pressure, and the average horizontal pressure calculated on the side of the culvert over its full height was 0.44 times the overburden pressure. When the full pressure distribution on the pipe is considered, the recommended design loads from the Marston–Spangler theory slightly underpredict the maximum loads, and the vertical loads control the design.

scholarly journals Effect of Voids behind Lining on the Failure Behavior of Symmetrical Double-Arch Tunnels

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1321 ◽  
Author(s):  
Zhang ◽  
Ye ◽  
Min ◽  
Xu
Keyword(s):  
Service Life ◽  
Earth Pressure ◽  
Internal Force ◽  
Failure Behavior ◽  
Large Section ◽  
Failure Patterns ◽  
Internal Forces ◽  
Tunnel Safety ◽  
Increasing Demand ◽  
The Impact

The presence of voids behind lining seriously affects the safety of the symmetrical double-arch tunnels during service life. It is essential to find out the impact of voids on tunnel safety due to the increasing demand for the construction and maintenance of symmetrical double-arch tunnels. Model tests and numerical analyses were conducted in this research. The results attained were explored including earth pressure, internal force, and lining failure. Results reveal that the presence of voids has a large influence on the internal force in the lining of symmetrical double-arch tunnels, generally in the form of asymmetrical failure patterns of the lining. The failure patterns of the lining are greatly influenced by the size and location of voids with respect to the symmetrical double-arch tunnel circumference. Significant changes in the lining internal forces were found at the areas in the close vicinity of the void whereas a few changes were found at the bottom of the sidewall, the invert, and the central wall far away from the void. The propagation laws of lining cracks of asymmetrical double-arch tunnels are more complicated than symmetrical tunnels with a void behind the central wall. The location of the initial cracking of symmetrical and asymmetrical double-arch tunnels is the same, while the lining failure of the large-section tunnel is the most complicated.

A Method to Determine Unstable Point and its Impact Estimation in Debris-Blocking Dam Monitoringsurvey Network

2011 ◽  
Vol 55-57 ◽  
pp. 698-703
Author(s):  
Da Bing Huang ◽  
Zhi Qiang Yang ◽  
Zhen Shi
Keyword(s):  
Earth Pressure ◽  
Monitoring Network ◽  
Horizontal Displacement ◽  
Approximate Model ◽  
Deformation Monitoring ◽  
Deformation Model ◽  
Observation Data ◽  
Network Stability ◽  
Other Information ◽  
Dam Deformation

The purpose of this paper is to determine the unstable points of debris-blocking dam deformation network and to lay the foundation for later accurate monitoring and data processing, for the reason that the affection of earth pressure and water-level-fluctuation lead to increased instability to debris-blocking dam. The author signed one horizontal displacement deformation monitoring network, measured two groups data by changing some point’s horizontal displacement with man, judged the point’s stability of the network by the method of mean gap and obtained the deformation model, and analysis the model sensitivity. The results is that the deformation network stability meet the design requirements through application the method in Fengjie Debris-blocking dam which blocked the stones debris for Shirushan tunnel, the actual displacement amount had been proven similar as the result with the method; It is concluded that this method have some practical value in deformation monitoring because it can construct the approximate model by direct observation data, which is smaller rely on other information.

Research on Deformation Law of Deep Excavation Supporting Structures in Beijing Metro Station

2011 ◽  
Vol 243-249 ◽  
pp. 2338-2344
Author(s):  
Qing Yuan Li ◽  
Yang Wang
Keyword(s):  
Horizontal Displacement ◽  
Internal Force ◽  
In Situ Monitoring ◽  
Deep Excavation ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Metro Station ◽  
Deep Foundation Pit ◽  
Deformation Law

Taking deep excavation engineering in North Region of Senlin Park Station of Beijing Olympic Subway branch as engineering background, deformation law of enclosure structure of deep excavation are studied by the in-situ monitoring means .It shows that the maximum horizontal displacement of retaining pile is closely related with excavation depth and time. When the deep foundation pit is excavated to a certain depth, and steel brace hasn’t been erected, horizontal displacement of the pile tops is maximum. The location of the maximum horizontal displacement shifts down with foundation pit excavation and steel brace erection. With steel brace application, steel axis force decrease, so steel brace can effectively control horizontal displacements of retaining pile and internal force of steel in the pile. In addition, temperature has a certain effect to axis force of steel brace.

Research on Horizontal Bearing Behaviors of Circular Section Static Compaction Piles

2013 ◽  
Vol 405-408 ◽  
pp. 111-115
Author(s):  
Qing Guang Yang ◽  
Feng Liu ◽  
Luan Xiao
Keyword(s):  
Bearing Capacity ◽  
Soil Compaction ◽  
Yield Criterion ◽  
Estimation Method ◽  
Earth Pressure ◽  
Horizontal Displacement ◽  
Relative Displacement ◽  
Force Balance ◽  
Circular Section ◽  
Static Compaction

Based on Vesic theory of cavity expansion and Mohr-Coulomb yield criterion,A method was proposed which can be used to calculate earth pressure around circular section static compaction pile.Furthermore, a formula calculating earth pressure around circular section static compaction pile with horizontal displacement was deduced based on hyothesis without relative displacement on pile-soil contact boundary.Finally,according to the research above and force balance condition,an estimation method for horizontal bearing capacity of circular section static compaction pile was gotten.In order to validate the feasibility proposed theory in this paper, a comparative research was carried out.Both experimental and theoretical results indicated that earth pressure on pile-soil contact surface of soil compaction pile was much more than of pile without soil compaction and earth pressure would redistribute with change of horizontal displacement.Moreove,because horizontal bearing capacity calculated by method in this paper accorded with result measured in field very much,the theory in here was feasible.

scholarly journals Impact Pseudostatic Load Equivalent Model and the Maximum Internal Force Solution for Underground Structure of Tunnel Lining

2016 ◽  
Vol 2016 ◽  
pp. 1-16
Author(s):  
Xuan Guo ◽  
Xiao Xin Zhang
Keyword(s):  
Model Test ◽  
Internal Force ◽  
Measured Data ◽  
Tunnel Lining ◽  
Theoretical Solution ◽  
Equivalent Model ◽  
Theoretical Formula ◽  
Circular Tunnel ◽  
Lining Structure ◽  
Force Calculation

The theoretical formula of the maximum internal forces for circular tunnel lining structure under impact loads of the underground is deduced in this paper. The internal force calculation formula under different equivalent forms of impact pseudostatic loads is obtained. Furthermore, by comparing the theoretical solution with the measured data of the top blasting model test of circular formula under different equivalent forms of impact pseudostatic loads are obtained. Furthermore, by comparing the theoretical solution with the measured data of the top blasting model test of circular tunnel, it is found that the proposed theoretical results accord with the experimental values well. The corresponding equivalent impact pseudostatic triangular load is the most realistic pattern of all test equivalent forms. The equivalent impact pseudostatic load model and maximum solution of the internal force for tunnel lining structure are partially verified.

Effect of Time-Varying on Shield Tunnel Lining Structure

2014 ◽  
Vol 580-583 ◽  
pp. 987-990
Author(s):  
Feng Jun Liu ◽  
Jun Fang Chen
Keyword(s):  
Design Theory ◽  
Aging Effect ◽  
Tunnel Lining ◽  
Shield Tunnel ◽  
Time Varying ◽  
Bending Rigidity ◽  
Concrete Shrinkage ◽  
Lining Structure ◽  
Long Time ◽  
Internal Forces

In order to survey the time-varying effect on shield tunnel lining structure, rigidity reduce in the Homogeneous Ring Design Theory is introduced. There are three methods to evaluate the rigidity reduction caused by the aging effect. The first is the bending rigidity analysis method, which considers that the bending rigidity changes with the time-dependent stress and strain. The second is the method named the equivalent moment of inertia; the last is aging coefficient method. With the Homogeneous Ring Design Theory, the internal forces and displacement of the shield tunnel segment lining can be calculated. Based on the preliminary results, using the 1st method, the reduced rigidity and the long-time displacement at different instants of time can be calculated. It is found that the concrete shrinkage and creep effect can’t be ignored in the segment design. The survey is beneficial to monitor the deformation of tunnel lining, and the maintenance of the segments. It will make the tunnel work steadily and safely during the using period.

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