Composite Lining Aseismic Design for Fault-Crossing Tunnel Structures

2014 ◽  
Vol 971-973 ◽  
pp. 30-34
Author(s):  
Chun Lei Xin ◽  
Bo Gao
Keyword(s):  
Active Faults ◽  
Three Dimensional ◽  
Bending Moment ◽  
Simulation Method ◽  
Internal Force ◽  
Great Earthquake ◽  
Underground Structures ◽  
Lining Structure ◽  
Internal Forces ◽  
Composite Lining

Although underground structures have stronger aseismic performance than ground structures, seismic disasters of mountain tunnels were fairly conspicuous in Wenchuan Great Earthquake. On the basis of seismic disaster analysis, a composite lining designfor tunnel structures across active fault was put forward. Three-dimensional numerical simulation method was used to analyze aseismic and damping effect of this structure. The results show that: (1)After setting aseismic and damping structure, the maximum internal forces value in lining the pattern of internal forces will not change. (2)Aseismic and damping structure setting can directly reduce the bending moment value and increase the axial force and stress force value in lining structure. (3) Relative to aseismic and damping structure, grouting region around damping layer can ameliorate internal force condition in lining structure and improve the effect of aseismic and damping structure. The above research results contribute to provide reference for seismic fortification of tunnel structures across active faults.

scholarly journals Mechanical Behavior of Tunnel Lining with Cracks at Different Positions

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 194 ◽  
Author(s):  
Jie Su ◽  
Yinming Jie ◽  
Xiaokai Niu ◽  
Chang Liu ◽  
Xuan Liu
Keyword(s):  
Carrying Capacity ◽  
Three Dimensional ◽  
Side Wall ◽  
Internal Force ◽  
Structural Failure ◽  
Three Dimensional Model ◽  
Lining Structure ◽  
Internal Forces ◽  
Stress And Deformation ◽  
Longitudinal Cracks

Cracks in the lining significantly reduce the safety of a tunnel during operation. It is urgent to figure out the influence of cracks on tunnel carrying capacity. In this paper, three-dimensional model tests were conducted to investigate deformation, internal force, and deterioration laws of the lining with prefabricated cracks at different positions. The main conclusions were obtained as follows: (1) The carrying capacity of the lining structure with prefabricated cracks was reduced, and the deformation of the lining structure increased. The penetration of the vault crown crack accelerated the damage of the lining structure, and structural failure occurred when the crack went through at the left arch spring. (2) The internal force of the lining was greatly affected by the positions of prefabricated cracks. The internal forces of the lining structure decreased with the existence of prefabricated cracks. Whether or not there were prefabricated cracks, tension cracks appeared in the inside fiber of the vault and inverted arch. (3) The deformation of the lining structure with the existence of prefabricated cracks increased. When the prefabricated crack was located at the vault, the deformation was the largest, followed by the arch spring, side wall, and arch shoulder. (4) The analysis shows that prefabricated cracks at the vault are the most damaging under stress and deformation of the lining structure, so longitudinal cracks at the vault should be strengthened.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

scholarly journals Synthesis of numerical methods for the design of segmental tunnel lining

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.

scholarly journals Internal Force Analysis of Buried-boring Piles in the Yuanzishan Landslide

2020 ◽  
Vol 10 (16) ◽  
pp. 5416 ◽  
Author(s):  
Hao Wang ◽  
Zhiying Lv ◽  
Jianwei Zhang ◽  
Jianwei Yue ◽  
Hongyu Qin ◽  
...  
Keyword(s):  
Driving Force ◽  
Limit Equilibrium ◽  
Bending Moment ◽  
Potential Method ◽  
Internal Force ◽  
Distribution Coefficients ◽  
Factors Affecting ◽  
Pile Diameter ◽  
Unstable Slope ◽  
Internal Forces

The Yuanzishan landslide is an unstable slope in Langzhong County, located in northeast Sichuan province, China. The Guangyuan-Nanchong expressway passes through the front edge of the unstable slope, and subgrade excavation has resulted in slope deformation, which threatens the safety of the highway construction. Emergency landslide control requires reduction of the slope disturbance. This study aims to investigate the use of buried-boring piles as a potential method for emergency landslide control. A simplified calculation method was used for the design of the buried-boring piles, according to the limit equilibrium of the soil and the elastic foundation coefficient method. The measured internal force changes of the pile were compared, in order to determine the distribution coefficients of the driving force. A relationship between the driving force of the shared pile ratio and the buried depth ratios was then established. Furthermore, a variety of factors affecting the internal forces of the buried-boring pile and the lateral reaction of the soil were also studied. The results revealed that (1) there was a quadratic relationship between the driving force of the pile-shared ratio and the sliding depth ratios; (2) the maximum bending moment of the pile increased with an increase in the sliding depth ratio of the pile, following a power law relationship; (3) increasing the buried depth of the pile head reduced the influence of the pile diameter on the maximum internal forces; (4) increasing the pile diameter decreased the maximum lateral reaction of the soil. The buried-boring piles can be used in similarly unstable regions for emergency control of deforming slopes.

Influence of PGV on the Internal Forces of Subway Station

2011 ◽  
Vol 90-93 ◽  
pp. 1987-1991 ◽  
Author(s):  
Hong Bing You
Keyword(s):  
Response Spectrum ◽  
Simulation Method ◽  
Peak Ground Velocity ◽  
Subway Station ◽  
Underground Structures ◽  
Peak Displacement ◽  
Time Histories ◽  
Internal Forces ◽  
Acceleration Response Spectrum

A hybrid simulation method is used to generate two group artificial ground motions that are compatible with the same acceleration response spectrum, same peak displacement and different peak ground velocity (PGV). The influences of PGV on the internal forces of subway station are studied. For the time histories with the same response spectrum and same peak displacement, the larger PGV of input motions may lead to the great plastic deformation of the soil, and then cause the larger internal forces for the most elements of subway station. The influence of PGV should be considered reasonably in determination of design ground motion parameters for underground structures.

Seismic Behavior of Shear Wall-Frame Systems Considering Foundation Stiffness

2017 ◽  
Vol 17 (03) ◽  
pp. 1750041 ◽  
Author(s):  
Bo Di ◽  
Xueyi Fu
Keyword(s):  
Seismic Behavior ◽  
Safety Margin ◽  
Bending Moment ◽  
Shear Wall ◽  
Internal Force ◽  
Shallow Foundation ◽  
Frame Structure ◽  
Base Shear ◽  
Internal Forces ◽  
Frame Systems

In this paper, the influence of foundation stiffness on the seismic behavior of shear wall-frame systems was investigated. First, a basic differential equation was established to account for the interaction between the foundation and superstructure. By solving the equation, the influence of foundation stiffness on the lateral stiffness, inter-story drift, and internal force distribution of the superstructure at the elastic stage was elucidated. Subsequently, the concept and method for determining the range of foundation stiffness suitable for shear wall-frame systems were proposed. By taking a 12-story shear wall-frame structure built on a shallow foundation as an example, a parametric study was performed for various frame-to-wall relative stiffness ratios and foundation stiffnesses. The effect of shallow foundation stiffness on the base shear distribution and energy dissipation of the superstructure was clarified, with results compared with those of the fixed-base model. The analysis results indicated that the degeneration of foundation stiffness due to earthquake damages will result in significant redistribution of internal forces, namely, the internal forces of the walls decrease, while those of the frames increase. In particular, the shear-force and bending moment of the bottom frame columns rise drastically, which may greatly reduce the safety margin and should be considered in practical design.

Mechanical Behavior of Segmented Lining Structure of Tunnel under Acting Ground Fractures in Xi’an Zone

2011 ◽  
Vol 261-263 ◽  
pp. 1778-1783
Author(s):  
Sheng Jun Shao ◽  
Fang Tao She ◽  
Juan Fang
Keyword(s):  
Tensile Stress ◽  
Mechanical Behavior ◽  
Compressive Stress ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Maximum Tensile Stress ◽  
Internal Force ◽  
Subway Tunnel ◽  
Lining Structure ◽  
Pass Through

Xi’an ground fracture, caused by the extraction of groundwater and the movement of fault under soil strata, is a geo-hazard. The movement of ground fracture originates the uneven settlement of upward block and downward block. In Xi’an ground fracture region, the segmented lining structure was adopted in subway tunnel to pass through the ground fracture, so as to adapt for the uneven settlement. Three-dimensional elastic-plastic finite difference method was applied to simulate the initial lining structure, second segmented lining structure, surrounding soils and ground fracture. The horizontal and vertical displacement of segmented lining structure, surrounding soils pressure and internal force of segmented lining structure in subway tunnel were analyzed by the calculation results. The knowledge on mechanical behavior of segmented lining structure passing through an active ground fracture and surrounding soils was shown as following. The relative vertical displacement between segmented lining structure sects beside the ground fracture increases remarkably with the movement of ground fracture, and the segmented lining structure located in upward displaceent block near ground fracture originates notable rotary. Tension or compression deformation occured in the deformation joint between adjacent segmented lining structures near the ground fracture.There was a significant change in the contact pressure of the first sect of lining structure in the upward displace block. Under the same uniform settlement at the bottom of upward diaplacement block, the relativly vertical displacemtn on the surfaceof ground fracture strata without tunnel equals 50cm, but the relativly vertical displacement between adjacent segmented lining structure at ground fracture is 18.2cm on the design level of arch top of lining strcutre. the maximum tensile stress of segmented lining structure is 2.02MPa, the maximum compressive stress of segmented lining is 3.49MPa. In conclusion, segmented lining structure can adapts to the uneven settlement caused by the movement of ground fracture. Though maximum tensile and compressive stress of sengmented lining structure passing through the active ground fracture is bigger than the general lining structure located in soils strata without the ground fracture, the segmented lining structure constructed by the steel fibre concrete can bear with the maximum tensile stress.

scholarly journals Numerical analysis of symmetrical and asymmetrical reinforced concrete flat slabs - an integrated slab/ column analysis

2016 ◽  
Vol 9 (3) ◽  
pp. 306-356
Author(s):  
A. Puel ◽  
D. D. Loriggio
Keyword(s):  
Numerical Analysis ◽  
Axial Force ◽  
Three Dimensional ◽  
Bending Moment ◽  
Bending Moments ◽  
Flat Slabs ◽  
Distributed Load ◽  
Significant Difference ◽  
Local Support ◽  
Internal Forces

ABSTRACT This paper studies the modeling of symmetric and asymmetric flat slabs, presenting alternatives to the problem of singularity encountered when the slab is modeled considering columns as local support. A model that includes the integrated slab x column analysis was proposed, distributing the column reactions under the slab. The procedure used transforms the bending moment and column axial force in a distributed load, which will be applied to the slab in the opposite direction of gravitational loads. Thus, the bending moment diagram gets smooth in the punching region with a considerable reduction of values, being very little sensible to the variation of used mesh. About the column, it was not seen any significant difference in the axial force, although the same haven't occurred with the bending moments results. The final part of the work uses geoprocessing programs for a three-dimensional view of bending moments, allowing a new comprehension the behavior of these internal forces in the entire slab.

scholarly journals Optimized Partition Scheme for Prefabricated Underpass with Large Cross Section

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhiyi Jin ◽  
Taiyue Qi ◽  
Xiao Liang ◽  
Bo Lei
Keyword(s):  
Cross Section ◽  
Underground Structure ◽  
Bending Moment ◽  
Internal Force ◽  
Optimal Partition ◽  
Large Cross Section ◽  
Underground Structures ◽  
Cross Sectional ◽  
Partition Scheme ◽  
Urbanization In China

With the acceleration of urbanization in China, more underpasses will be constructed in big cities to alleviate the great traffic pressure. The prefabricated and assembly construction method has been introduced to replace the traditional cast-in-place method to achieve quick construction. However, for a fully prefabricated and assembled underground structure (PAUS) with large cross section, the structure must be cut into segments in transverse direction to reduce the size and weight for easy transportation and assembly. Therefore, how to develop an optimal partition scheme is a new problem to be studied. Firstly, three preliminary partition schemes were proposed based on the internal force distribution and completed engineering practices. Then, the three schemes were compared in terms of bending moment, shear force, and axial force. The construction efficiencies were also compared with special emphasis on difference of the build period. Finally, an optimal partition scheme was determined and successfully applied in the real project. Furthermore, the construction period of this partition scheme was 1/3 of the traditional cast-in-place method. The results of the current paper can provide some design guidance to large cross-sectional underpasses and other underground structures in the partition stage.

Analysis on Seismic Pounding of Curved Bridge

2011 ◽  
Vol 90-93 ◽  
pp. 800-804
Author(s):  
Qiang Xu ◽  
Xing Jun Qi
Keyword(s):  
Three Dimensional ◽  
Time History ◽  
Bending Moment ◽  
Relative Displacement ◽  
Internal Force ◽  
Curved Bridge ◽  
Reference Base ◽  
History Analysis ◽  
Seismic Pounding ◽  
The Impact

Based on the impact phenomenon between the end of the beam and the bridge abutment of the curved continuous bridge during earthquakes, a spatial finite element calculating model with collision element is presented. The law of collision is studied by the nonlinear contact time history analysis method under two three-dimensional ground motions. The variation laws of relative displacement and the internal force at the bottoms of piers are researched. In addition the changing of displacement and internal force at the end diaphragm are studied. The results show that the pounding action can easily lead to significant collision forces between the end beam and the abutment of the curved bridge which increases the axial force of girder evidently. The collision forces and longitudinal displacements from the inner to outer of the diaphragm generally are showed by an increasing trend, and the pounding action is more fierce under Elcentro ground motion than that under Tianjin ground motion.There is no relative displacement of consolided pier, bending moment and shear force of the consolided pier are greater than that of the mobile pier.The conclusions from the present study may serve as a reference base for seismic design of continuous curved bridges.

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