scholarly journals Test on Rigid-flexible Composite Anti-breaking Measure for Tunnels across Stick-slip Fault

2021 ◽  
Author(s):  
Cui Guang-yao ◽  
Song Bohan
Keyword(s):  
Seismic Intensity ◽  
Structural Safety ◽  
Tunnel Structure ◽  
Test Results ◽  
Tunnel Engineering ◽  
Stick Slip ◽  
Breaking Effect ◽  
Secondary Lining ◽  
Dislocation Layer ◽  
Primary Support

Abstract In this paper, based on the F8 stick-slip fault section of Longxi Tunnel in China, the effect of the anti-breaking measure of rigid-flexible composite (reinforcement of the secondary lining & construction of the reducing dislocation layer between the primary support and the secondary lining) is studied by using the method of indoor model test in order to improve the anti-breaking performance of the tunnel across stick-slip fault in the actual tunnel engineering. The test results show that the anti-breaking effect is limited by adopting structural strengthening measures to resist the influence of stick-slip dislocation on the tunnel structure and the anti-breaking effect is obvious by adopting the measures of reducing dislocation layer only. However, the structural safety of the tunnel with stick-slip fault in the strong seismic intensity area can be greatly improved by adopting the anti-breaking measure of rigid-flexible composite, and the structural safety factor can be significantly improved. The research results of this paper can provide a reference for the anti-breaking design of the tunnel across stick-slip fault in the high seismic intensity area.

scholarly journals Model Test Study on the Antibreaking Technology of Reducing Dislocation Layer for Subway Interval Tunnel of the Stick-Slip Fracture

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Guang-yao Cui ◽  
Xue-lai Wang
Keyword(s):  
Model Test ◽  
Active Fault ◽  
Fault Zones ◽  
Tunnel Engineering ◽  
Stick Slip ◽  
Test Study ◽  
Tunnel Section ◽  
Secondary Lining ◽  
Dislocation Layer ◽  
Primary Support

Based on the background of the Line F2-3 interval tunnel section of Jiujiawan in Urumqi Subway Line 1, this paper carries out the model test research on the antibreaking technology of the reducing dislocation layer in the tunnel section of the stick-slip fracture. The antibreaking effect of different locations and number of reducing dislocation layers in tunnel engineering is analyzed in this paper. The results show that when the double reducing dislocation layer, respectively, set between the surrounding rock and the primary support, and the primary support and the secondary lining, the antibreaking effect is the best. It is recommended to use this scheme for antibreaking design. The research results can provide reference for antibreaking design of traffic tunnels in active fault zones.

scholarly journals Model Tests on the Antibreaking Countermeasures for Tunnel Lining Across Stick-Slip Faults

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Guang-yao Cui ◽  
Xue-lai Wang ◽  
Zheng-zheng Wang ◽  
Dao-yuan Wang
Keyword(s):  
Contact Pressure ◽  
Safety Factor ◽  
Longitudinal Strain ◽  
Operating Conditions ◽  
Structural Safety ◽  
Tunnel Structure ◽  
Stick Slip ◽  
Slip Dislocation ◽  
Dislocation Layer ◽  
Minimum Safety Factor

In order to improve the structural safety and stability of the tunnels crossing stick-slip fault, an indoor model test on the effect of tunnel antibreaking measures under the influence of fault stick-slip movements was conducted. Using contact pressure, longitudinal strain, and safety factor, the antibreaking effect of tunnels was compared and analyzed under 5 kinds of operating conditions, mainly including no measures, structural strengthening, structural strengthening and reducing dislocation layer, structural strengthening and reducing dislocation joint, structural strengthening and reducing dislocation layer, and reducing dislocation joint. The results showed that the longitudinal strain and contact pressure of the tunnel changed markedly (from severe change to more uniform change) when the reducing dislocation measures were adopted in the test, reducing dislocation layer/joint or reducing dislocation layer and reducing dislocation joint. The effect of reducing the fault stick-slip dislocation on the tunnel structure is very limited by only taking structure strengthening measures. The effect of reducing the fault stick-slip dislocation on the tunnel structure is obvious by using the reducing dislocation method, and the minimum safety factor is increased by more than 8 times. The effect of resisting and reducing the fault stick-slip dislocation on the tunnel structure is remarkable by adopting the measures of the structural strengthening and reducing dislocation layer and reducing dislocation joint, and the minimum safety factor is increased by more than 25.45 times. The results can provide reference for the design of antibreaking for the stick-slip fault tunnel in high earthquake intensity and dangerous mountainous areas.

scholarly journals Mechanical and Deformation Characteristics and Optimization of Support Parameters for Superlarge-Span Tunnel: A Case Study from Laohushan Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yanbin Luo ◽  
Jianxun Chen ◽  
Zhou Shi ◽  
Shaoqiang Zhang ◽  
Weiwei Liu ◽  
...  
Keyword(s):  
Stable State ◽  
Structural Safety ◽  
Measuring Point ◽  
Highway Tunnel ◽  
Engineering Economy ◽  
Tunnel Design ◽  
New Construction ◽  
Technical Specifications ◽  
Secondary Lining ◽  
Primary Support

In the new construction or reconstruction of expressway projects, the number of highway twin tunnels with eight lanes is increasing. However, there are no corresponding design support parameters and measures in the current technical specifications for tunnel design and construction in China. In Laohushan superlarge-span highway tunnel with single hole and four lanes, the deformation behavior and mechanical characteristics of support structures are measured and analyzed. The monitoring results indicated that the deformation of tunnel structure mainly experienced three stages: rapid deformation, slow deformation, and stable deformation, and finally reached a relatively stable state; the structure stress of primary support and secondary lining increases sharply at first and then tends to be stable gradually with the gradual construction of each excavation part in the tunnel; the stress of each measuring point at the steel rib is less than the yield limit of steel rib (235 MPa), and the support structure is safe and stable in the process of tunnel construction. Then, the structure safety of primary support under different support parameters is simulated and calculated by numerical simulation with Grade IV rock mass, and the reasonable support parameters for Laohushan highway tunnel are studied considering the structural safety and engineering economy. It is suggested to use the H175-type steel sets with a distance of 80 cm and C25 shotcrete with a thickness of 26 cm. The results could provide reference for similar tunnel projects and provide a basis for the design specification and construction standards for superlarge-span tunnels.

Effect of Cross Passage Construction on the Structural Safety of Collapse Reinforcement Segment of Existing Tunnel

2013 ◽  
Vol 779-780 ◽  
pp. 538-543 ◽  
Author(s):  
Kong Jian Shen ◽  
Shui Wan ◽  
Xiao Chun Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Reference Value ◽  
Element Model ◽  
Surrounding Rock ◽  
Practical Significance ◽  
Structural Safety ◽  
Tunnel Structure ◽  
Tunnel Engineering ◽  
Supporting Structure

On the basis of the engineering background of cross passage construction in the Chen Yu Tunnel project, the collapse section above the intersection of the existing tunnel is selected to establish finite element model. Considering the effect of cross passage construction and the local weakening area of surrounding rock on the safety of existing tunnel structure, the strength of the shotcrete supporting structure of existing tunnel intersection is checked, and the security of the existing tunnel is evaluated. This research is of great practical significance and a certain reference value for the plan and design upon the construction of tunnel engineering.

Long-Term Safety Analysis of Tunnel Structure Based on the Performing Degree of Support Strength

2011 ◽  
Vol 261-263 ◽  
pp. 1220-1224
Author(s):  
Jin Xing Lai ◽  
Xiao Wei Liu ◽  
Fei Zhou
Keyword(s):  
Safety Analysis ◽  
Internal Force ◽  
Tunnel Structure ◽  
Load Bearing ◽  
Geological Conditions ◽  
Temporary Support ◽  
Tunnel Design ◽  
Secondary Lining ◽  
Primary Support

At present, the new Austrian tunneling method is basically used as the theoretical guidance for domestic tunnel design, which shows that the primary support is not progressed by durability design in the light of service life in the practical work generally acting as the temporary support structure during the period of construction. After the long-term tunnel operation, owing to the erosion of groundwater and the changes of internal stress and external load of surrounding rock, the reinforced of primary support system will be rusted; the bolt, grille arch frame and I-beam will be partially invalidated; the stress of tunnel structure system will be readjusted gradually from the original load-bearing state with dominant position of primary support into the load-bearing state by secondary lining. The Long-term safety analysis refers to the analysis of secondary lining internal force and safety coefficient by load structure model, and the long-term safety analysis of Qingshashan tunnel which is in season frozen zone with complex geological conditions is very necessary.

scholarly journals Study on the Mechanical Behavior of Double Primary Support of Soft Rock Tunnel under High Ground Stresses and Large Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhe Liu
Keyword(s):  
Mechanical Behavior ◽  
Large Deformation ◽  
Design Method ◽  
Characteristic Curve ◽  
Soft Rock ◽  
Support Design ◽  
Deformation Amount ◽  
Secondary Lining ◽  
Rock Tunnels ◽  
Primary Support

Double primary support structures could effectively solve the problem of large deformation of surrounding rock for soft rock tunnels. However, the mechanical behavior of this new support structure is still incomplete, and the design method should be revised. Based on the theory of energy conversion, this paper analyzes the support characteristic curve of double primary support and puts forward the dynamic design method of double primary support. Considering that the secondary lining can be set after monitoring the deformation amount and deformation rate of the first primary support, its support parameters can be dynamically adjusted according to the actual situation. By applying the double primary support design method in the Maoxian tunnel of Chenglan Railway, the field monitoring results show that the double primary support has a significant effect on the energy release of surrounding rocks, greatly reducing the load acting on the secondary lining and ensuring the safety and reliability of the tunnel structure.

The Structural Safety Test Research for 300 MW PWR Control Rod Driver Machine Pressured Shell

2005 ◽  
Author(s):  
Weiming Sun ◽  
Xing Ren ◽  
Kangda Zhang
Keyword(s):  
Safety Margin ◽  
Operating Mode ◽  
Structural Safety ◽  
Test Results ◽  
Load Bearing ◽  
Control Rod ◽  
Safety Test ◽  
Inner Pressure ◽  
Asme Code ◽  
Analyze Structure

The safety analysis and test research are done to inspect the safety of 300MW control rod drive machine (CRDM) pressured shell structure in a systematic way. The test result agrees accords with FEA result. In actual operating mode (300 °C) inner-pressure fatigue simulative test, the axial and hoop pre-cracks are made, and the fatigue crack growth is observed. The load-bearing capability and deformation are tested in shell-burst test. Based on test research, this paper analyses theoretical load-bearing capability and safety margin in accordance with ASME CODE Sec. III design is calculated. Elastic-plastic fracture mechanics theory and GEGB.R6 method is used to analyze structure safety. The test results show pressure shell’s safety allowance is large enough.

Study on Optimized Mix-Proportion and Crack Resistance of Modern Secondary Lining Concrete for High-Speed Railway Tunnel

2010 ◽  
Vol 168-170 ◽  
pp. 106-110 ◽  
Author(s):  
Li Ping Guo ◽  
Wei Sun ◽  
Qing Yu Cao ◽  
Jin Yu Zong
Keyword(s):  
Crack Resistance ◽  
High Speed ◽  
Test Results ◽  
Railway Tunnel ◽  
Curing Conditions ◽  
Air Voids ◽  
Mix Proportion ◽  
Surrounding Rock Pressure ◽  
Secondary Lining ◽  
Fine Organic

Cracking is the most common damage in the secondary lining concrete because of its continuous thin-walled structure, potential surrounding rock pressure and poor curing conditions. In order to improve the crack resistance of concrete and to reduce the responding costs, seven series modern concretes including ultra-fine pozzolanic powder and different organic fibers are prepared and investigated. The optimized modern secondary lining concrete is determined as the concrete including 0.08% or 0.1% volume fractions of ultra-fine organic fiber (UF), based on the test results of segregation, air voids parameters, primary strengths and multi-factorial crack resistance. The spacing factor and average chord length of concretes including UF are less than 0.1mm, which is positive for mixing UF to enhance the crack resistance of concrete at micro- and meso-scale.

Influence of Cavity above Tunnel on Stratum Deformation and Failure in Urban Tunnelling

2012 ◽  
Vol 170-173 ◽  
pp. 1810-1815
Author(s):  
Yanan Zhang ◽  
Cheng Ping Zhang ◽  
Qian Qian Li ◽  
Zheng Li ◽  
Yi Cai
Keyword(s):  
Failure Process ◽  
Test Method ◽  
Test Results ◽  
Tunnel Engineering ◽  
Deformation And Failure ◽  
Tunnel Section ◽  
Section Size ◽  
Ground Cavity ◽  
Stratum Deformation ◽  
Beijing Subway

In order to study the influence of cavity above the tunnel on stratum deformation and failure in urban tunnelling, the model test method was adopted based on the parameters of the stratum and tunnel section size in Beijing subway. The stratum responses were obtained under the conditions without ground cavity and with ground cavity above the tunnel. The responses include the stratum stress distribution, stratum settlement law and stratum failure process. It was concluded that the existence of ground cavity above the tunnel worsened the stratum condition and accelerated the progress of stratum deformation and failure. Furthermore, the failure began from the cavity and the damage scope was bigger than that under the condition without cavity according to the test results. The research results can be referenced for the similar tunnel engineering.

Seismic Fragility Analysis of MRFs with PR Bolted Connections Using IDA Approach

2018 ◽  
Vol 763 ◽  
pp. 678-685 ◽  
Author(s):  
Emanuele Brunesi ◽  
Roberto Nascimbene ◽  
Gian Andrea Rassati
Keyword(s):  
Three Dimensional ◽  
Seismic Intensity ◽  
Structural Safety ◽  
Damage State ◽  
Steel Moment Resisting Frames ◽  
Existing Structures ◽  
Moment Resisting ◽  
Damage States ◽  
Structure Height ◽  
Partially Restrained

Partially restrained (PR) bolted beam-to-column connections are a promising typology of connection in modern steel moment resisting frames (MRFs). Both high-fidelity three-dimensional solid models and mechanics-based idealisations have been extensively explored in order to investigate the behaviour of this attractive solution, applicable both to new construction and to retrofitting of existing structures. Despite this, structural safety has been probabilistically assessed and controlled in a relatively few cases, thus neglecting characterisation, modelling and propagation of uncertainties. As such, this paper moves from a deterministic to a probabilistic framework, proposing fragility models at multiple damage states for low-and medium-rise MRF structures with T-stub and top-and-seat angle connections which may be applied for seismic risk assessment and management. After validation against past experimental data, use was made of component-based modelling to reproduce the seismic response of these PR bolted connection systems within planar MRFs designed for earthquake resistance in accordance with current European rules. A set of 44 records scaled at increasing seismic intensity was considered to perform a series of incremental dynamic analyses (IDAs). Fragility functions for each damage state of interest were then derived and compared. The analysis results show the influence of connection typology and structure height.

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