scholarly journals Seismic Stability of Loess Tunnel with Rainfall Seepage

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xuansheng Cheng ◽  
Wanlin Zhang ◽  
Jing Fan ◽  
Xiaoyan Zhang ◽  
Haibo Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Safety Factor ◽  
Calculation Model ◽  
Seismic Stability ◽  
The Finite Element Method ◽  
Infiltration Depth ◽  
Seepage Theory ◽  
The Stability ◽  
Cover Thickness ◽  
Rainfall Seepage

Rainfall seepage changes the mechanical properties of loess masses. Considering fluid-solid coupling, the calculation model of a loess tunnel is established according to the finite element method (FEM). Based on porous media seepage theory and rainfall infiltration depth theory and considering the infiltrated depth of the loess surface for different rainfall intensities over a certain period, the stability of a loess tunnel under different rainfall amounts and loess cover thicknesses is studied using the dynamic finite element static strength reduction method. The results show that under the same rainfall intensity, the safety factor increases with the depth of the tunnel; the safety factor of the loess tunnel with the same loess cover thickness decreases with increasing infiltration depth. The plastic strain is mainly distributed on both sides of the vault and the arch feet. The stability of the loess tunnel is directly related to the loess cover thickness and rainfall seepage.

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.

scholarly journals Analytical and experimental research on stability of large slenderness ratio horizontal hydraulic hoist

2018 ◽  
Vol 10 (10) ◽  
pp. 168781401880347 ◽  
Author(s):  
Ji Zhou ◽  
Duan-Wei Shi ◽  
Zhi-Lin Sun ◽  
Tao Bi ◽  
Xiong-Hao Cheng ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Safety Factor ◽  
Slenderness Ratio ◽  
Hydraulic Cylinder ◽  
Ratio Test ◽  
The Finite Element Method ◽  
Sliding Bearing ◽  
The Stability ◽  
Element Method

Taking the hydraulic cylinder for the miter gate in Dateng Gorges Water Conservancy Project as the object, a large slenderness ratio test hydraulic cylinder was designed based on the similarity theory. The buckling analysis of the test hydraulic cylinder was carried out by the finite element method, considering the friction at the supports, the misalignments between piston rod and cylinder tube, and gravity. The results indicate that the stability safety factor is 10.55. A buckling experimental system was established, and the buckling stability of the test hydraulic cylinder was tested for the sliding bearing support and the rolling bearing support at the piston-rod end, respectively. The stability safety factor is over 9.01 and 6.82 relevantly. The similarities and differences among the results of the finite element method, experimental method, NB/T 35020-2013, and two-sections pressure bar method were analyzed. Experimental and analytical results clearly show that the friction at the supports is a key factor in determining the magnitude of the stability safety for large slenderness ratio horizontal hydraulic hoist and utilizing the sliding bearing can effectively improve the stability safety factor.

scholarly journals Determining the Critical Slip Surface of Three-Dimensional Soil Slopes from the Stress Fields Solved Using the Finite Element Method

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yu-chuan Yang ◽  
Hui-ge Xing ◽  
Xing-guo Yang ◽  
Jia-wen Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Safety Factor ◽  
Slip Surface ◽  
Three Dimensional ◽  
Soil Slope ◽  
Critical Slip Surface ◽  
The Finite Element Method ◽  
The Stability

The slope stability problem is an important issue for the safety of human beings and structures. The stability analysis of the three-dimensional (3D) slope is essential to prevent landslides, but the most important and difficult problem is how to determine the 3D critical slip surface with the minimum factor of safety in earth slopes. Basing on the slope stress field with the finite element method, a stability analysis method is proposed to determine the critical slip surface and the corresponding safety factor of 3D soil slopes. Spherical and ellipsoidal slip surfaces are considered through the analysis. The moment equilibrium is used to compute the safety factor combined with the Mohr-Coulomb criteria and the limit equilibrium principle. Some assumptions are introduced to reduce the search range of center points and the radius of spheres or ellipsoids. The proposed method is validated by a classical 3D benchmark soil slope. Simulated results indicate that the safety factor of the benchmark slope is 2.14 using the spherical slip surface and 2.19 using the ellipsoidal slip surface, which is close to the results of previous methods. The simulated results indicate that the proposed method can be used for the stability analysis of a 3D soil slope.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

scholarly journals Factor of Safety Reduction Factors for Accounting for Progressive Failure for Earthen Levees with Underlying Thin Layers of Sensitive Soils

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Adam J. Lobbestael ◽  
Adda Athanasopoulos-Zekkos ◽  
Josh Colley
Keyword(s):  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Thin Layers ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Limit Equilibrium Methods ◽  
The Stability ◽  
Reduction Factors

The effects of progressive failure on flood embankments with underlying thin layers of soft, sensitive soils are investigated. Finite element analysis allows for investigation of strain-softening effects and progressive failure in soft and sensitive soils. However, limit equilibrium methods for slope stability analysis, widely used in industry, cannot capture these effects and may result in unconservative factors of safety. A parametric analysis was conducted to investigate the effect of thin layers of soft sensitive soils on the stability of flood embankments. A flood embankment was modeled using both the limit equilibrium method and the finite element method. The foundation profile was altered to determine the extent to which varying soft and sensitive soils affected the stability of the embankment, with respect to progressive failure. The results from the two methods were compared to determine reduction factors that can be applied towards factors of safety computed using limit equilibrium methods, in order to capture progressive failure.

The Influence of Tangential Roller Pressure on the Stability of Circular Saw Blade

2014 ◽  
Vol 614 ◽  
pp. 32-35 ◽  
Author(s):  
Ming Song Zhang ◽  
Yi Zhang ◽  
Jian Jun Ke ◽  
Xiao Wei Li ◽  
Lian Bing Cheng
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Symmetric Model ◽  
The Finite Element Method ◽  
Circular Saw ◽  
The Face ◽  
Circular Saw Blade ◽  
Cyclic Symmetric ◽  
The Stability ◽  
Saw Blade

The finite element method was used to study tangential roller method impact on the stability of circular saw blade. Using 30 ° cyclic symmetric model is analyzed. The results show that the tension of the saw blade is not the same, and tensioning effect is different, when the tangential roller pressure is not same. At the same time, after tangential roller, the face run out of saw blade is small, which show that the smoothness of tangential roller is better.

Seismic stability of a long unlined circular tunnel in sloping ground

2016 ◽  
Vol 53 (8) ◽  
pp. 1346-1352 ◽  
Author(s):  
Sounik Kumar Banerjee ◽  
Debarghya Chakraborty
Keyword(s):  
Finite Element ◽  
Lower Bound ◽  
Plastic Zone ◽  
Slope Angle ◽  
Seismic Stability ◽  
Circular Tunnel ◽  
Infinite Slope ◽  
Sloping Ground ◽  
The Stability ◽  
Seismic Forces

The stability of an unlined long circular tunnel underneath an infinite slope is examined with the inclusion of seismic body forces. The study is carried out by using the lower bound finite element limit analysis. The values of γH/c are plotted as a function of H/D, [Formula: see text], β, and kh in the form of charts. The magnitude of γH/c is found to decrease consistently with an increase in β and kh. With an increase in the magnitude of β and kh, the plastic zone around the periphery of the tunnel becomes more and more asymmetric. The stability charts presented in this note would be useful for examining the effect of slope angle on the stability of an unsupported circular tunnel under seismic forces.

The Saturated - Unsaturated Seepage Analysis of Hualianshu Landslide on the Condition of Rainfall

2012 ◽  
Vol 594-597 ◽  
pp. 387-390
Author(s):  
Yu Hu ◽  
Qiang Feng
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
The Finite Element Method ◽  
Seepage Field ◽  
Landslide Prediction ◽  
Reservoir Water ◽  
Seepage Analysis ◽  
Seepage Theory ◽  
The Impact ◽  
Unsaturated Seepage

With the saturated - unsaturated seepage theory, Hualianshu landslide is seepage numerical simulated by the finite element method .The changes of Hualianshu landslide seepage are subject to the impact of rainfall and reservoir water level's changes.The formation and variation of the slope seepage field under rainfall infiltration have been come to, providing a basis for analysis of slope stability and landslide prediction.

A Study on the Stability of a Mast Structure for Erecting a Large Crane

2011 ◽  
Vol 110-116 ◽  
pp. 1483-1490
Author(s):  
Hoon Hyung Jung ◽  
Chae Sil Kim
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Analytical Model ◽  
Gantry Crane ◽  
The Finite Element Method ◽  
Analysis Model ◽  
The Stability ◽  
The One ◽  
Two Stages

This paper describes a finite element structural analysis model and determines analysis methods appropriate for determining the stability of the mast of a crane. This analysis model allows various analysis approaches to be applied to the conditions affecting the construction of a large gantry crane in order to ensure the stability of the mast of the crane. The finite element method is used as a way to construct an analytical model that can help ensure the stability of the mast in two stages. The model is used in a two-stage analytical process that takes into account the conditions of the model. In this way, the model can be used to judge the stability of the mast. By allowing variation in the analysis approach used for the crane mast, the analysis model may be changed if the conditions of the one-girder gantry crane require. Designers may apply this method for the active analysis of the stability of a crane mast.

Finite Element Analysis of Quench Propagation Velocity in Bi-2223/Ag Superconducting Multifilamentary Tape

2007 ◽  
Vol 546-549 ◽  
pp. 1931-1934
Author(s):  
Chun Li Wu ◽  
Hai Liang Yang
Keyword(s):  
Finite Element ◽  
Propagation Velocity ◽  
Operating Temperature ◽  
Superconducting Magnet ◽  
Experimental Result ◽  
The Finite Element Method ◽  
Analysis Model ◽  
Element Analysis ◽  
The Stability ◽  
Quench Propagation

Quench propagation velocity is an important parameter to the stability and protection issues of superconducting magnet. In this paper, the finite element method (FEM) numerical simulation of quench propagation velocity has been performed for using the powerful analysis software COSMOS by establishing a suitable thermal analysis model of Bi-2223/Ag superconducting multifilamentary tape. The effects of quench energy and operating temperature on the quench propagation velocity have been studied. The analysis shows that the simulation result basically coincides with the experimental result.

Sign in / Sign up

Export Citation Format

Share Document