Failure mechanism and numerical simulation of zonal disintegration around a deep tunnel under high stress

2017 ◽  
Vol 93 ◽  
pp. 344-355 ◽  
Author(s):  
Qiangyong Zhang ◽  
Xutao Zhang ◽  
Zhechao Wang ◽  
Wen Xiang ◽  
Junhua Xue
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
High Stress ◽  
Zonal Disintegration ◽  
Deep Tunnel

scholarly journals Experimental and numerical modeling to investigate the riverbank’s stability

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Asad H. Aldefae ◽  
Rusul A. Alkhafaji
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
High Stress ◽  
Physical Models ◽  
Term Condition ◽  
Tigris River ◽  
Soil Settlement ◽  
Failure Angle ◽  
Dangerous Place ◽  
Type Of Failure

AbstractThe purpose of this paper is to assess the failure mechanism of riverbanks due to stream flow experimentally and numerically to avoid recurring landslides by identifying the most dangerous place and treating them by a suitable method. The experiments and the physical models were carried out to study the failure mechanism of riverbank and evaluation of their stability in two cases: short-term condition and long-term condition flow where three models were tested. The Tigris River (Iraq) is considered as a model in this paper in terms of the applied velocity and modeled soil of the banks it was used at the same characteristics in the prototype scale. Also, a numerical simulation was performed using the FLOW-3D program to determine the velocity distribution and to identify the areas subjected to the high stress levels through the water flow. The obtained results in this paper are inspecting of failure mechanism types that occur under the influence of specific limits of flow velocity, which have shown good compatibility with the type of failure in the prototype scale. In addition to calculating the amount of soil erosion, the failure angle, and the amount of soil settlement at the riverbank model is investigated also. The results of experimental work and numerical simulation were well matched, where the standard error rate for Froude number ranged between (1.8%–6.6%), and the flow depth between (2.7%–6.9%).

Numerical Simulation for Destroy Pattern of Surrounding Rock of Circle Tunnel with M-H Coupling Action

2011 ◽  
Vol 71-78 ◽  
pp. 3572-3576
Author(s):  
An Nan Jiang ◽  
Peng Li
Keyword(s):  
Numerical Simulation ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Rock Fracture ◽  
High Stress ◽  
Surrounding Rock ◽  
Zonal Disintegration ◽  
Affecting Factors ◽  
Tunnel Wall ◽  
Shear Belt

The uniform zonal disintegration of surrounding rock is the peculiar phenomena of deep and high stress field, researching the inner mechanism and affecting factors has important meaning for guaranteeing the safety of deep engineering. The paper adopted strain soft Mohr-Coulomb model and carried out numerical simulation of surrounding rock fracture and excavation. The simulation states that along with the unloading time accumulation, the shear belt produced from tunnel wall and developed to inner rock. The corresponding shear stress concentration zone also spread to inner rock and destroy zone increasing. The pore water pressure increasing will accelerate the shear belt developing and increase the destroy degree.

Study on the Failure Mechanism of Enamel Coatings in HAZ

2011 ◽  
Vol 704-705 ◽  
pp. 700-705
Author(s):  
Han Tao ◽  
Wang Yong ◽  
Wei Liu
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Failure Mechanism ◽  
Base Metal ◽  
Enamel Coating ◽  
High Stress ◽  
Thermal Simulation ◽  
Welding Stress ◽  
Micro Cracks ◽  
Bond Layer

Because the enamel coatings has excellent ageing resistance and anti-corrosion performance, the service life of pipeline with enamel coatings as protective layer can be increased remarkably comparing with the ones with organic coatings. But when the pipeline is welded, the high temperature of welding arc will do harm to the bonding strength of the enamel coating and the base metal because of the differences of thermo-physical properties between them. In order to study the failure mechanism of enamel coating in the heat affected zone, the stress changing process of enamel/steel was studied through numerical simulation and the interface of enamel/steel was studied by welding thermal simulation technology. The results show that the weakness parts of the welded joints are the imperfect normalized zone and overheated zone. In the imperfect normalized zone, the micro-cracks generate at the interface of enamel/steel because high stress occurred and some coatings fused incompletely because of short staying time at high temperature that induced micro-cracks in the enamel coating under high welding stress, so it was one of the dangerous zones of HAZ. Because high tensile stress formed during cooling that was dangerous to the brittle enamel coating, the bond layer of enamel/steel was damaged by high temperature of welding and the pores generated at the interface of enamel/steel, the coatings of overheated zone could be pulled off from the base metal easily that caused the steel exposed to the corrosion medium directly without the protection of enamel coating, so it was another dangerous zone of HAZ. Keywords: enamel coating; numerical simulation; welding thermal simulation; failure mechanism; HAZ

scholarly journals Failure Mechanism and Optimization of Arch-Bolt Composite Support for Underground Mining Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Yuchun Mei ◽  
Weiteng Li ◽  
Ning Yang ◽  
Gang Wang ◽  
Tingchun Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
Underground Mining ◽  
Failure Process ◽  
Pressure Coefficient ◽  
High Stress ◽  
Soft Rock ◽  
Composite Support ◽  
Soft Rock Roadway ◽  
Rock Roadway

Numerical simulation tests were performed on the arch-bolt combined supported mining tunnel through an improved numerical simulation approach. The typical soft rock roadway was took as the background, and the influencing factors such as ground stress level, lateral pressure coefficient, and support type and parameters were considered. The failure mechanism of a semicircular roadway with two straight walls was analyzed; results showed that the arch legs’ inward bending deformation and the arch-rock separation are the breakthrough of the global failure of the supporting system, and rock bolts breakage promoted the failure process. The effects of different controlling measures were analyzed including enlarging the bolt diameter, replacing the conventional bolts with energy-absorbing bolts, and setting arch locking bolts on the arch legs. The field test of the concrete-filled steel tube (CFST) arch-bolt composite support scheme was carried out in a high-stress soft rock roadway, and the results indicate the reliability of the main conclusions.

scholarly journals Research on Failure Mechanism and Parameter Sensitivity of Zonal Disintegration in Deep Tunnel

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xutao Zhang ◽  
Qiang Gao ◽  
Shicai Cui ◽  
Changrui Duan
Keyword(s):  
Rock Mass ◽  
Failure Mechanism ◽  
Deformation Modulus ◽  
Morphological Characteristics ◽  
Zonal Disintegration ◽  
Deep Tunnel ◽  
Equilibrium Equations ◽  
Distribution Law ◽  
Deep Rock Mass ◽  
Deep Rock

With the increase of excavation depth, the zonal disintegration phenomenon appears in the deep rock mass, which is quite different from the failure mode of shallow tunnel. In order to analyse the failure mechanism of this phenomenon, an elastoplastic softening damage model was put forward based on the softening damage characteristics of deep rock mass. The constitutive equations, the equilibrium equations, and the failure criterion were deduced. The theoretical solutions of radial displacement and radial stresses and tangential stresses of deep surrounding rock mass were calculated. The distribution law of zonal disintegration in deep tunnel was obtained. The theoretical solutions presented an oscillating mode. The theoretical calculated widths of fracture zones were in good agreement with the in situ test data. Besides, the sensitivity of different parameters to fracture morphology was calculated and analysed. The results show that the relative loading strength has a controlling role in the zonal disintegration morphology, followed by the cohesion force and deformation modulus, and the internal friction angle is the least. This study reveals the morphological characteristics and influencing factors of zonal disintegration, which provides a basis for the prediction and support control of fracture modes.

Numerical Simulation of Factors on Zonal Disintegration in Surrounding Rocks of Deep Roadways

2012 ◽  
Vol 518-523 ◽  
pp. 5935-5938
Author(s):  
Jian Guo Ning ◽  
Xue Sheng Liu ◽  
Hai Tao Li
Keyword(s):  
Numerical Simulation ◽  
Rock Strength ◽  
High Stress ◽  
Mining Area ◽  
Simulation Software ◽  
Zonal Disintegration ◽  
Mining Depth ◽  
Damage Degree ◽  
Mining Conditions ◽  
Weak Structure

At the background of geological and mining conditions of typical roadways in Xinwen mining area, using numerical simulation software FLAC-3D, the effects of mining depth, weak structure and rock strength on the characteristics of zonal disintegration in Deep Roadway was studied. Results show that high stress is the premise to form the phenomenon of zonal disintegration; weak structure in surrounding rocks is the key and surrounding rock strength is the determinants of damage degree and scope of rupture zone in deep surrounding rocks. There are important theoretical and practical significances to explore the formation mechanism of zonal disintegration in surrounding rocks of deep roadways, and to ensure safe mining of deep resources.

Failure Mechanism of Tungsten Heavy Alloy for Mould

2011 ◽  
Vol 341-342 ◽  
pp. 432-435
Author(s):  
Wei Huang ◽  
Ya Feng Li ◽  
Kai Wen Tian ◽  
Fu Jun Shang ◽  
Yong Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
Matrix Composite ◽  
External Load ◽  
High Strength ◽  
Strength Level ◽  
Heavy Alloy ◽  
Theoretical Strength ◽  
Tungsten Heavy Alloy ◽  
The Real

The failure mechanism of tungsten matrix composite was studied with microscale numerical simulation. The results show that high strength tungsten particles are the real loading elements of composite, its strength level embodies the whole property of the composite to some extent. The real stress in tungsten particles is much higher than the external load, so failure may take place when the external load is less than the theoretical strength of tungsten particles.

Sign in / Sign up

Export Citation Format

Share Document