Effect of Time-Varying on Shield Tunnel Lining Structure

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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Synthesis of numerical methods for the design of segmental tunnel lining

MATEC Web of Conferences ◽

10.1051/matecconf/201929503008 ◽

2019 ◽

Vol 295 ◽

pp. 03008

Author(s):

Rim Trad ◽

Hussein Mroueh ◽

Hanbing Bian ◽

Fabrice Cormery

Keyword(s):

Numerical Study ◽

Direct Method ◽

Bending Moment ◽

Experimental Methods ◽

Tunnel Lining ◽

Practical Case ◽

Lining Structure ◽

Water Conveyance ◽

Internal Forces ◽

Water Conveyance Tunnel

This paper presents a numerical study that aims to compare the behavior of the segmental tunnel lining using the direct, indirect and experimental methods. This model is based on a practical case applied in university of Tongji: a project of water conveyance tunnel. A reduction in the bending moment and increasing of the displacement in the tunnel lining is showed in numerical results, when taking into account the effect of the joints. It has been shown that the number of joints in the tunnel-lining structure highly affects the results in terms internal forces and displacements. Furthermore, the internal forces obtained by the continuous method are high compared to the other methods when the effects on segmental joints on tunnel lining behaviour are usually considered. Additionally, the bending moment of the direct method with behaviour of rotation spring linear and experimental method is comparable.

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Numerical Simulation on the Stress and Strain of Lining Structure with Double Shield Tunneling Construction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.605-607.2425 ◽

2012 ◽

Vol 605-607 ◽

pp. 2425-2429

Author(s):

Feng Wang ◽

Tie Jun Cui

Keyword(s):

Ground Surface ◽

Calculation Model ◽

Tunnel Lining ◽

Concrete Lining ◽

Shield Tunnel ◽

Tunnel Construction ◽

Three Dimension ◽

Shield Tunneling ◽

Deformation Law ◽

Lining Structure

This paper takes the Section 201 of shield construction engineering in Dalian Metro Line 2 as an example to analyze the deformation law of surrounding soil and the tunnel lining structure stress during shield tunnel construction. The shield tunnel construction is simulated dynamically by ADINA and the shield tunnel structure model of the concrete lining is established. This model is a three-dimension nonlinear finite element calculation model concerned with the grouting soil and original state soil. Taking the soil lithology in the upper layer and interact influences, we analyzed the dynamic process of shield construction, soil grouting and lining supporting and the stress distribution in difference reinforced concrete supporting segments and the ground settlement characteristics. Through numerical analysis method to study the deformation law of soil surrounding tunnel and the stress in tunnel lining, we get the results to compare with the results of Peck formula under the same condition. After generating the conclusions, we can provide several suggestions for shield tunneling construction, lining segment design and control of the ground surface settlement during the construction.

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Analysis of Structural Response of Subway Shield Tunnel Lining under the Influence of Cavities

Advances in Civil Engineering ◽

10.1155/2021/3326595 ◽

2021 ◽

Vol 2021 ◽

pp. 1-21

Author(s):

Yufeng Shi ◽

Zhaoyang Chen ◽

Duqiang Wei ◽

Tao Zhang ◽

Xuming Zhou ◽

...

Keyword(s):

Structural Response ◽

Bending Moment ◽

Tunnel Lining ◽

Structural Safety ◽

Shield Tunnel ◽

Cavity Depth ◽

Stiffness Reduction ◽

Lining Structure ◽

Reduction Effect ◽

Single Cavity

The existence of cavities behind the shield tunnel lining can cause cracking, broken pieces, water leakage, and other problems, which reduces the durability and safety of the shield tunnel segment structure. In order to clarify the mechanism of cavity damage, a more systematic study of the effects of cavities on the shield tunnel lining structure from the angle, depth, and the number of cavities is carried out using model tests and numerical simulations without considering the effects of the stiffness reduction effect at the tunnel segment joints and groundwater seepage in this paper. The findings show that the bending moment value and the cavity angle value are approximately linear with the increase of single cavity angle, and the bending moment at the vault arch is reversed when the angle of the cavity behind the arch is greater than 30°. With the increase of single cavity depth, the axial force and bending moment at the cavity increase, and the distribution of bending moment remains unchanged, and the bending moment tends to be stable and unchanged beyond a certain depth. With the increase of single cavity angle and depth, the structural safety coefficient of the segment decreases, and the degree of influence is angle value > depth value. The existence of multiple cavities intensifies the influence of each cavity on the segment, especially when there are cavities behind the top and bottom of the vault; the bending moment value of the top of the vault increases by 22.53% compared with that of the single cavity condition.

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Fluid-solid coupling response of shield tunnel lining structure under high water pressure

Marine Georesources and Geotechnology ◽

10.1080/1064119x.2021.1971805 ◽

2021 ◽

pp. 1-11

Author(s):

Xuansheng Cheng ◽

Shanglong Zhang ◽

Lei Qi ◽

Xinhai Zhou

Keyword(s):

Water Pressure ◽

High Water ◽

Tunnel Lining ◽

Shield Tunnel ◽

Lining Structure ◽

High Water Pressure

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Numerical Investigation on Crack Propagation and Fatigue Life Estimation of Shield Lining under Train Vibration Load

Shock and Vibration ◽

10.1155/2021/6926452 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Long-gang Tian ◽

Zi-ling Cheng ◽

Zhi-qiang Hu

Keyword(s):

Fatigue Life ◽

Crack Propagation ◽

Tunnel Lining ◽

Shield Tunnel ◽

Vibration Load ◽

Life Estimation ◽

Fatigue Life Estimation ◽

Lining Structure ◽

Train Speed ◽

Train Vibration

Dynamic loads such as the train vibration load usually act on the shield tunnel lining in the long term, which could make the initial flaws in shield segment propagate and gradually weaken the robustness of the tunnel structure. In this paper, a three-dimensional numerical model of shield tunnel lining structure with the initial defect is built to study its dynamic reaction and fatigue crack propagation under the train vibration load. Furthermore, the damage to intact shield segment caused by train vibration load is studied by employing the rain-flow counting method and the Miner damage theory, and a rational fatigue life estimation for the concrete shield tunnel lining is finally made. Results show that crack propagation is influenced by both the train speed and train axle, the higher the train speed, the longer the final crack, and train axle has a larger influence than train speed on the crack propagation in shield tunnel segment. The shield tunnel lining structure of Nanjing Metro Line 5 can meet the demand of working for a hundred years under the current working conditions.

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Transverse Response of Underwater Shield Tunnel to Incident P Waves

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.90-93.1602 ◽

2011 ◽

Vol 90-93 ◽

pp. 1602-1609

Author(s):

Hong Wei Ma ◽

Wen Hua Chen

Keyword(s):

Seismic Response ◽

Water Depth ◽

Exact Analytical Solution ◽

Incident Angle ◽

Expansion Method ◽

Tunnel Lining ◽

Shield Tunnel ◽

P Waves ◽

Lining Structure ◽

Underwater Tunnel

In this paper, the seismic response of underwater shield tunnel to incident P waves is investigated by using the Fourier-Bessel series expansion method. On the basis of the exact analytical solution, it is studied that the seismic response of the system which is made up of tunnel lining structure, underwater soil and water. The influence that water depth and buried depth of shield tunnel put on the seismic response of tunnel lining is given. The analytical result shows that the seismic response of tunnel lining unobvious varies with water depth change when incident P waves have a small incident angle, nevertheless, opposite conclusion appears when oblique incident P waves have a big incident angle. At a certain incident angle, the seismic response of tunnel increases with the increasing of the water depth; and the seismic response decreases with the increasing of the buried depth of underwater tunnel.

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Computational Model of Outer Circle and Inner Ellipse Shield Tunnel Lining Structure

Advances in Civil Engineering ◽

10.1155/2021/2303140 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Shuancheng Gu ◽

Guanlin Sun ◽

Peili Su

Keyword(s):

Calculation Model ◽

Tunnel Lining ◽

Shield Tunnel ◽

Internal Space ◽

Design Elements ◽

Outer Circle ◽

Force Method ◽

Lining Structure ◽

Tunnel Lining Design ◽

Subway Tunnels

Subway tunnels are mostly located in strata with an uneven pressure. This uneven pressure is usually manifested by lateral pressure coefficients less than 1. To adapt to the unevenness of the stratum load, in this study, we propose a new shield tunnel lining structure—outer circle and inner ellipse shield tunnel lining structure—whose outer contour remains circular and the inner contour shape of the structure is designed according to the load conditions. We used the stiffness step discounting method to obtain the calculation coefficients used in the force method formulas and established the calculation model of the outer circle and inner ellipse shield tunnel linings. The force method was then used to determine the force distribution characteristics of the outer circle and inner ellipse shield tunnel lining structure. During the verification, it was sufficient to analyze whether the waist structure rigidity met the safety conditions. This simplifies the design elements. The internal space area of our proposed design is expanded by 0.86 m2 compared to the internal space area of the equal stiffness shield tunnel lining design.

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RESEARCH ON PREPARATION OF&NBSP; GAMMA ORYZANOL ANTI-AGING CREAM

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2017.6.2 ◽

2017 ◽

pp. 15-21

Author(s):

Thi Minh Nguyet Le ◽

Thi Kim Lien Phan

Keyword(s):

Product Quality ◽

Rice Bran ◽

Rice Bran Oil ◽

Aging Effect ◽

Triterpene Alcohols ◽

Beneficial Effects ◽

Long Time ◽

Formulation Parameters ◽

Rice Water ◽

Gamma Oryzanol

Background and Objectives: For a long time, Asian women have known to use rice water, rice bran for skin care, lightening dark spots and slowing down the aging process. Gamma Oryzanol, an ester mixture of trans-ferulic acid with phytosterols and triterpene alcohols extracted from rice bran oil, has been shown to have beneficial effects on the skin, especially its antioxidant and anti-aging effect. The aims of this research were to formulate Gamma Oryzanol-loaded anti-aging cream and to evaluate the product quality. Materials and Methods: Gamma Oryzanol was imported from Japan. Some formulation parameters such as emulsifi-ers, performance modifiers were investigated and the product quality was evaluated according to the criteria of drugs and cosmetics. Results: The excipients were chosen including 1% (w/w) of Lunamer with 3% (w/w) of Prolipid as emulsifiers and 8% (w/w) of mango seed butter as a state modifier in the formulation of Gamma Oryzanol anti-aging cream. The cream is ivory-white, thick, smooth, fragrant-smelling and satisfied all criteria of developed specification. Conclusion: The study was successful in the preparation of Gamma Oryzanol anti-aging cream. Key words: Gamma Oryzanol, anti-aging cream, Franz cells.

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