scholarly journals Effect of the Location of Fault Fracture Zones on the Stability of Symmetrical Submarine Tunnels

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1111
Author(s):  
Wei Fang ◽  
Gang Wang ◽  
Chang Wang
Keyword(s):  
Safety Factor ◽  
Working Conditions ◽  
Axial Force ◽  
Fracture Zone ◽  
Bending Moment ◽  
Surrounding Rock ◽  
Fracture Zones ◽  
Fault Fracture Zone ◽  
Lining Structure ◽  
The Stability

In this paper, we aim to reveal the influence of fault fracture zones on the stability of submarine tunnels and the surrounding rock under different water and drainage measures. Firstly, four typical working conditions of submarine tunnels intersecting with fault fracture zones were selected. On the basis of the typical cross section of the intersections of submarine tunnels and faults, they were divided into four working conditions. Then, the displacement and plastic zones of the surrounding rock of the tunnel were studied, and the stability of the rock surrounding the submarine tunnel was discussed. This research structure indicates that the bending moment and axial force of the lining structure of the submarine tunnel increase with increasing sealing degree, but the safety factor exhibits a downward trend. When the fault fracture zone goes through the section above the tunnel axis, the bending moment and axial force at the lining vault are greater than the other working conditions, and the displacement of the surrounding rock at the vault and spandrel is prominent. When the fault fracture zone completely passes through the tunnel, the safety factor of the lining structure is at its lowest, and the displacement of the surrounding rock at the arch waist develops laterally. When the fault fracture zone passes through the part below the tunnel axis, the arch foot displacement converges significantly, and the surrounding rock displacement exhibits a downward inclination. In addition, the plastic zone is mainly developed in the arch and the shoulder. These research results provide a reliable reference for tunnel design and excavation support.

Study on the Geological Forecast and Treatment for Water-Bearing Fault of the Qingdao Kiaochow Bay Subsea Tunnel

2013 ◽  
Vol 671-674 ◽  
pp. 1114-1121
Author(s):  
Zhi Peng Li ◽  
Shu Cai Li ◽  
Qing Song Zhang ◽  
De Ming Wang ◽  
Bing Hui ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Surrounding Rock ◽  
Tunnel Excavation ◽  
Bearing Fault ◽  
Grouting Material ◽  
Fault Fracture Zone ◽  
Analysis Of Results ◽  
Subsea Tunnel ◽  
The Stability ◽  
Fissure Water

Water-bearing fault of subsea tunnel has fissure water developed, fractured surrounding rock with low strength, which gets a risk of sudden water inflow and affects the tunnel security. This paper takes the geological forecast and treatment for water-bearing fault of the Qingdao kiaochow bay subsea tunnel for example, according to the water assignment characteristics, using the detect method of TEM and advance borehole to make accurate decision for the position of water-bearing body、the scale of fracture zone and the inflow of water. Through the analysis of results, the grouting form, materials and parameters are chosen and adjusted. The grouting material seals the water flowing fracture, forming water-stopping curtain outside tunnel excavation contour line and strengthening the fault fracture zone to improve the stability of rock.

Effect of a Fault Fracture Zone on the Stability of Tunnel-Surrounding Rock

2017 ◽  
Vol 17 (6) ◽  
pp. 04016135 ◽  
Author(s):  
Yingchao Wang ◽  
Hongwen Jing ◽  
Haijian Su ◽  
Jiangyue Xie
Keyword(s):  
Fracture Zone ◽  
Surrounding Rock ◽  
Fault Fracture Zone ◽  
The Stability

Mechanics Analysis of Grade V Surrounding Rock Primary Support in Maanziliang Tunnel

2012 ◽  
Vol 164 ◽  
pp. 414-417
Author(s):  
Jia Ming Han
Keyword(s):  
Finite Element ◽  
Safety Factor ◽  
Surrounding Rock ◽  
Qinling Mountains ◽  
The Finite Element Method ◽  
Highway Tunnel ◽  
Geological Conditions ◽  
The Stability ◽  
Primary Support ◽  
Rock Section

Commonly used finite element strength reduction to calculate the safety factor of slope，to analyze the stability of the slope[1～3]. Recently it also proposed the methods to evaluate the safety factor for the stability of surrounding rock of underground chambers and supporting structural mechanics[4～6]. For Qinling Mountains of the complex geological conditions in the Maanziliang highway tunnel, this article use the finite element method from the bolt resist tension, bolt length, the force of sprayed layer of concrete to computing gradeⅤsurrounding rock section of primary support safety factor, to give evaluation to support mechanics of the Maanziliang tunnel.

Numerical Analysis on the Influence of Joints Inclination on the Characteristics of Deformation and Stability of Tunnel

2013 ◽  
Vol 790 ◽  
pp. 299-305
Author(s):  
Xiao Song Tang ◽  
Yong Fu Wang ◽  
Ying Ren Zheng
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Calculation Method ◽  
Research Result ◽  
Bending Moment ◽  
Surrounding Rock ◽  
Interface Element ◽  
Tunnel Stability ◽  
Stability Of Surrounding Rock ◽  
The Stability

The paper adopts the interface element to simulate the joints so as to systematically and quantitatively study the deformation around tunnel, the mechanic state of lining and the stability under different inclining angles of joints. The result shows that the deformation around tunnel deteriorates mainly along the joint during the inner convergence effects of surrounding rock. When the inclining angle α=45°, the deformation around the tunnel is most serious, followed by that when α=90°, α=60°, α=30° and α=0°. At the same time, the influence of inclining angle on the distribution of the axial force of lining is comparatively small. But the distribution of bending moment and shear change obviously where the joints penetrate the tunnel. The tunnel stability of surrounding rock is the poorest when α=90° and the tunnel is most stable when α=0°. The stability of surrounding rock changes little when α is between 30° and 60°. The research result provides an effective calculation method for the forecast of deformation, the design of structure and the stability analysis of jointed tunnel. It is also helpful for the monitoring of construction and calculation of jointed tunnel in the future.

scholarly journals Numerical Simulation of Ultra-Shallow Buried Large-Span Double-Arch Tunnel Excavated under an Expressway

2021 ◽  
Vol 12 (1) ◽  
pp. 39
Author(s):  
Jianxiu Wang ◽  
Ansheng Cao ◽  
Zhao Wu ◽  
Zhipeng Sun ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Horizontal Displacement ◽  
Surrounding Rock ◽  
Spatial Effects ◽  
Partition Wall ◽  
Tunnel Support ◽  
Large Span ◽  
Construction Design ◽  
Excavation Process ◽  
Fault Fracture Zone

The temporal and spatial effects of a complicated excavation process are vital for an ultra-shallow buried large-span double-arch tunnel excavated under an expressway in service. Numerical simulations are urgent and necessary to understand the effect of the total construction process. Taking Xiamen Haicang tunnel as a research object, the total excavation process of three pilot tunnels and the three-bench reserved core soil method of an ultra-shallow buried large-span double-arch tunnel with a fault fracture zone under an expressway was simulated using software FLAC3D. The deformation of the surface, surrounding rock, underground pipelines, tunnel support structure and partition wall of the three pilot tunnels and the main tunnel was analyzed, and the dangerous areas and time nodes were obtained. When the tunnel was excavated to the fault fracture zone, the deformation of the surface and surrounding rock increased significantly. The rock and soil within 20 m behind the excavation surface of the pilot tunnel were greatly disturbed by the excavation. During the excavation of the main tunnel, the horizontal displacement of the middle partition wall moved slightly towards the main tunnel excavated first. The research results can provide a reference for the construction design of double-arch tunnels.

The Research on Application of Strength Reduction Finite Element Method in Stability Analysis of Weak Intercalated Rock Tunnel

2011 ◽  
Vol 255-260 ◽  
pp. 1926-1929
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Safety Factor ◽  
Slip Surface ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Element Method

Based on geologic condition of one tunnel surrounding rock mass, systematic numerical tests had been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock by the FEM software ABAQUS and strength reduction finite element method. Some quantificational results about the stability of surrounding rock mass were summarized. And the safety factor and latent slip surface were worked out. The stability of surrounding rock mass was judged by strength reduction finite element method. According to the analysis above, it’s known that the discrepancy of two rules is small; the safety factor is the lowest when weak intercalated rock in vault, and when at bottom, it’s higher than that of in vault. The conclusion can be used to guide the procedure of construction and ensure the safety.

Dynamic Behavior of a Clamped Plastic Beam With Cracks at Supporting Ends Under Impact

1999 ◽  
Vol 121 (4) ◽  
pp. 406-412 ◽  
Author(s):  
F. L. Chen ◽  
T. X. Yu
Keyword(s):  
Axial Force ◽  
Complete Solution ◽  
Bending Moment ◽  
Deformation Energy ◽  
Failure Behavior ◽  
J Integral ◽  
Rigid Plastic ◽  
The Stability ◽  
Complementary Equation ◽  
Initial Cracks

This paper examines a projectile impact on a rigid-plastic beam with cracks at the fully clamped ends. By assuming the cracked sections yield immediately after impact, a three-hinge/two-hinge mechanism for the response process is constructed so that a complete solution considering the interaction between bending moment M and axial force N is derived. The key of the formulation is to find a complementary equation concerning the axial force N. To predict accurately the stability of the initial cracks, the J-integral criterion is extended to involve the contribution of the axial force. All the governing equations are nondimensionalized and rearranged, ready for Runge-Kutta integration procedure. The numerical results demonstrate that the mass ratio and the axial force have significant influence on the final deformation, energy partition, and the value of J-integral near the crack tip. The J-integral is not very sensitive to the depth of the initial cracks, but the presence of initial cracks in a beam may alter the failure behavior of the beam after impact, that is, from a strength-type failure to a fracture-type failure.

Research on the Mechnical Characteristics of Primary Supports in Guanjiao Tunnel Fault Fracture Zone and its Influence Zone by Field Tests

2011 ◽  
Vol 105-107 ◽  
pp. 1203-1210 ◽  
Author(s):  
Da Li ◽  
Zhan Fu Luo ◽  
Yong Sheng Li
Keyword(s):  
Fracture Zone ◽  
Field Tests ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Railway Tunnel ◽  
Influence Zone ◽  
Geological Conditions ◽  
Fault Fracture Zone ◽  
Under Construction ◽  
Primary Support

The tunnel which excavated through the fault fracture zone is still one of the difficulties in the current tunnel construction. Guanjiao tunnel is the longest high-altitude tunnel in the world, and also the longest railway tunnel which is under construction in China. The 9# shaft which located in Erlang fault fracture zone with several faults, complicated geological conditions is difficult to excavate. In the representative section of F3 fault and its influence zone, F22 fault fracture zone, the monitoring tests on contact pressure between surrounding rock and primary support and stress of steel arch is conducted. According to the above monitoring results，the project recommendations are proposed to ensure the smooth construction of tunnel.

scholarly journals Quantitative Study on Empirical Strength Parameters of Extremely Fractured Phyllite Based on Fractal Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yongbin Xie ◽  
Xiaoyu Yang ◽  
Jianhua Dong ◽  
Guosheng Liu
Keyword(s):  
Fractal Dimension ◽  
Fracture Zone ◽  
Shear Test ◽  
Fractal Theory ◽  
Surrounding Rock ◽  
Strength Parameter ◽  
Strength Parameters ◽  
Significant Difference ◽  
Fault Fracture Zone ◽  
Fractal Description

Extremely broken phyllite is widely distributed and is easily seen in engineering construction. Aiming at the problem that the empirical strength parameters of extremely broken surrounding rock have intense subjectivity and significant difference, based on the characteristics of the existence of particle group state in the highly broken surrounding rock, the fractal theory and large-scale direct shear test are used, the fractal description of polar broken phyllite samples with different pile numbers in fault fracture zone of Qinyu Tunnel is carried out, and the fractal dimensions and empirical strength parameters of each sample are determined. Based on a fractal description and large shear test, the functional relationship between fractal dimension and empirical strength parameter of extremely broken phyllite in fault fracture zone is established, and the quantitative value method of empirical strength parameter determined by fractal dimension of extremely broken phyllite is given, which provides ideas for the quantitative value of empirical strength parameter of the similar extremely broken surrounding rock.

Sign in / Sign up

Export Citation Format

Share Document