scholarly journals The Expression of Seismic Surrounding Rock Pressure for a Shallow Tunnel Is Derived Using the Pseudostatic Method

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhengde Wei ◽  
Yanpeng Zhu
Keyword(s):  
Rock Pressure ◽  
Limit Equilibrium ◽  
Seismic Loading ◽  
Surrounding Rock ◽  
Explicit Calculation ◽  
Shallow Tunnel ◽  
Seismic Acceleration ◽  
Acceleration Coefficient ◽  
Shallow Tunnels ◽  
Surrounding Rock Pressure

Terzaghi developed a generalized expression of the vertical surrounding rock pressures of shallow tunnels by considering the limit equilibrium of soil masses. In this paper, based on the Terzaghi failure mode, the pseudostatic method is used to derive this expression under seismic loading conditions. The surrounding rock in the fractured zone of the tunnel side wall is analyzed as an isolated body using the limit equilibrium method to obtain the explicit calculation expressions of the horizontal surrounding rock pressures of a shallow tunnel under seismic loading. Case analysis indicates that the proposed method is feasible. In addition, the influence of the seismic acceleration coefficient on surrounding rock pressures is further discussed. The results show that the horizontal surrounding rock pressure decreases with the increase of seismic acceleration coefficients. The vertical surrounding rock pressure increases as the horizontal seismic acceleration coefficient increases, and it decreases with the increase of the vertical seismic acceleration coefficient, and the effect of the seismic acceleration coefficient on surrounding rock pressure is significant. The study results can provide reference for the seismic safety evaluation and structural seismic design of shallow tunnels.

Study on the Mechanical Behavior of Excavation and Support Construction of Shallow Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 1693-1698
Author(s):  
Zhen Xing Yang ◽  
Liang Song ◽  
Hao Wang ◽  
Yu Yong Jiao ◽  
Shu Cai Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mechanical Behavior ◽  
Rock Pressure ◽  
Simulation Method ◽  
Internal Force ◽  
Surrounding Rock ◽  
Shallow Tunnel ◽  
Maximum Value ◽  
Surrounding Rock Pressure ◽  
Peak Value

In this paper, the mechanical behavior of excavation and support construction of Weishe tunnel, which is a section of the Yangwu expressway, is studied quantitatively using 3D finite difference numerical simulation method. A sequential excavation method is used and the results show that the vault settlement occurs mainly on the phase of upper bench excavation. The convergences of upper and lower sidewalls occur mainly on the phase of lower bench excavation. During the construction, the surrounding rock pressure in the vault and sidewall of the tunnel decrease. Axial force of anchor reaches the maximum value after the finish of second lining. However, the surrounding rock pressure and internal force of steel arch reach the maximum value after completing the upper bench excavation, and then become as smaller as half of the peak value during the lower bench excavation.

Study on the Prediction Method of Tunnel Surrounding Rock Pressure Based on the Theory of Progressive Destruction

2012 ◽  
Vol 446-449 ◽  
pp. 1432-1436
Author(s):  
Suo Wang
Keyword(s):  
Rock Pressure ◽  
Characteristic Curve ◽  
Prediction Method ◽  
Surrounding Rock ◽  
Progressive Damage ◽  
Tunnel Excavation ◽  
Practical Engineering ◽  
Surrounding Rock Pressure ◽  
The Relationship ◽  
Rock Parameters

In order to predict tunnel surrounding rock pressure, this paper puts forward a series of dynamic numerical simulative model on the tunnel excavation. According to the change of rock damage in the construction program, it adjusts dynamically the mechanical material parameters of surrounding rock. So the model achieves the purpose which is controlling and simulating the process of tunnel progressive damage. In accordance with the numerical simulative results, it analyzes the relationship between the rock parameters with the plastic strain, radial displacement. Then this paper proposes a prediction method of tunnel surrounding rock pressure based on the theory of the progressive damage and method of characteristic curve. Finally, it compares the pressure on the numerical simulative models with on the site date, and it proves that the prediction method has practical engineering value.

Seismic uplift capacity of inclined strip anchors

2005 ◽  
Vol 42 (1) ◽  
pp. 263-271 ◽  
Author(s):  
Deepankar Choudhury ◽  
K S Subba Rao
Keyword(s):  
Limit Equilibrium ◽  
Ground Surface ◽  
Failure Surface ◽  
Friction Angle ◽  
Uplift Capacity ◽  
Principle Of Superposition ◽  
Seismic Acceleration ◽  
Acceleration Coefficient ◽  
Angle Of Internal Friction ◽  
Seismic Forces

Uplift capacities of inclined strip anchors in soil with a horizontal ground surface are obtained under seismic conditions. Limit equilibrium approaches with a logarithm-spiral failure surface and pseudostatic seismic forces are adopted in the analysis. The results are presented in the form of seismic uplift capacity factors as functions of anchor inclination, embedment ratio, angle of internal friction of the soil, and horizontal and vertical seismic acceleration coefficients. The uplift capacity factors are worked out separately for cohesion, surcharge, and density components. Use of the principle of superposition for calculating anchor uplift capacity is validated. The vertical seismic acceleration coefficient always reduces the uplift capacity, whereas the horizontal seismic acceleration coefficient reduces the uplift capacity in most cases. The roles of anchor embedment ratio, soil friction angle, and anchor inclination in determination of the seismic uplift capacity are also discussed. Comparisons of the proposed method with available theories in the seismic case are also presented. The present study gives the minimum seismic uplift capacity factors compared with the existing theory.Key words: seismic uplift capacity factors, inclined strip anchors, limit equilibrium, pseudostatic, c–ϕ soil.

FBG Earth Pressure Sensors Applied in Surrounding Rock Pressure of Tunnel

2013 ◽  
Vol 351-352 ◽  
pp. 1173-1178
Author(s):  
Zhou Chun Cai ◽  
Chuan Li ◽  
Yuan Yu Guan ◽  
Wu Fen Chen ◽  
Li Jun Guo ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Rock Pressure ◽  
Pressure Sensors ◽  
Earth Pressure ◽  
Surrounding Rock ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Stress Changes ◽  
Surrounding Rock Pressure

During the period of tunnel excavation, shoring, forming and long-term operation, stress changes of tunnel surrounding rock are complex, the real-time monitoring of surrounding rock pressure is the key factor in ensuring long-term stability in tunnel. Fiber Bragg grating earth pressure sensors apply in surrounding rock pressure of tunnel which can change the pressure of the surrounding rock into fiber Bragg grating wavelength shift. According to the feature of pressure and temperature in Tian Xin Tunnel, 40 earth pressure sensors are embedded in 20 representative sections and one earth pressure sensor is embedded in each arch shoulder. In addition, one temperature compensation sensor is embedded in each arch crown. During the 235 monitoring days, the biggest daily change of surrounding rock pressure reaches 800 KPa. In 3 months of the sensor installation, the average monthly variation is within 50 KPa. The long-term measurement results indicate that the changes of surrounding rock pressure are different in different locations. When the surrounding rock is close to the excavated and blasted surface the surrounding rock pressure changes largely.

Surrounding rock pressure of shallow-buried bilateral bias tunnels under earthquake

2015 ◽  
Vol 9 (4) ◽  
pp. 427-445 ◽  
Author(s):  
Xin-Rong Liu ◽  
Dong-Liang Li ◽  
Jun-Bao Wang ◽  
Zhen Wang
Keyword(s):  
Rock Pressure ◽  
Surrounding Rock ◽  
Surrounding Rock Pressure

scholarly journals Calculation of Surrounding Rock Pressure of Undercut Subway Station Based on Multi-Factor Affecting Pressure Arch Theory

Engineering ◽  
2020 ◽  
Vol 12 (02) ◽  
pp. 59-70
Author(s):  
Bin Shang ◽  
Xiaoguang Jin ◽  
Guiyong Ao ◽  
Qiao Chen ◽  
Qiong Qiu
Keyword(s):  
Rock Pressure ◽  
Surrounding Rock ◽  
Subway Station ◽  
Surrounding Rock Pressure
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