Analysis on Progressive Slipping-Shear Failure Mode of Bedding Slope of Hard Rock with Medium or Large Dip Angle

2013 ◽  
Vol 438-439 ◽  
pp. 1232-1237
Author(s):  
Yu Feng Wei ◽  
De Xin Nei
Keyword(s):  
Failure Mode ◽  
Slope Failure ◽  
Failure Modes ◽  
Shear Failure ◽  
Hard Rock ◽  
Concrete Gravity Dam ◽  
Geologic History ◽  
Deformation And Failure ◽  
The Right ◽  
Bedding Slope

Kala Hydropower Station is located in the midstream of Yalong River in Sichuan Province of China, and the type of dam is concrete gravity dam, with a largest dam height of 129 m, an installed capacity of 1000 MW and a storage capacity of 255.8 million cubic meters. The slope on the right bank of the dam site is mainly composed of hard metasandstone and marbles interbedded with carbonaceous slates and the dip of rock formation is the same as the aspect of slope, so that it is a typical bedding slope. The field survey indicates that the failure of bedding slope of hard rock is not on a common mode of slipping-bending or buckling, but on an uncommon failure mode. The paper introduces a research method that starts with geologic history, analyzes current state and predicts the future failure mode, analyzes the characteristics and phenomenon of slope failure, and adopts the finite element calculation method to analyze the plastic zone resulting from slope deformation. According to the deformation evidence and calculation results, the engineering geologic mechanical theory is used to analyze the deformation and failure mode of slope, and it is indicated that the current and future failure modes of hard rock slope with large thickness are all slipping-shear failure.

Machine learning-based failure mode identification of RCSPSW

2021 ◽  
Author(s):  
Dongqi Jiang ◽  
Shanquan Liu ◽  
Tao Chen ◽  
Gang Bi
Keyword(s):  
Machine Learning ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Tall Buildings ◽  
Shear Walls ◽  
Superior Performance ◽  
Ann Model ◽  
Mode Recognition ◽  
Wide Range

<p>Reinforced concrete – steel plate composite shear walls (RCSPSW) have attracted great interests in the construction of tall buildings. From the perspective of life-cycle maintenance, the failure mode recognition is critical in determining the post-earthquake recovery strategies. This paper presents a comprehensive study on a wide range of existing experimental tests and develops a unique library of 17 parameters that affects RCSPSW’s failure modes. A total of 127 specimens are compiled and three types of failure modes are considered: flexure, shear and flexure-shear failure modes. Various machine learning (ML) techniques such as decision trees, random forests (RF), <i>K</i>-nearest neighbours and artificial neural network (ANN) are adopted to identify the failure mode of RCSPSW. RF and ANN algorithm show superior performance as compared to other ML approaches. In Particular, ANN model with one hidden layer and 10 neurons is sufficient for failure mode recognition of RCSPSW.</p>

Analysis of seismic performance and research of load capacity of steel reinforced high strength concrete columns with rectangular helical hoops

2020 ◽  
pp. 136943322098165
Author(s):  
Jianyang Xue ◽  
Xin Zhang ◽  
Xiaojun Ke
Keyword(s):  
Failure Mode ◽  
Seismic Performance ◽  
Calculation Method ◽  
High Strength Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
High Strength ◽  
Shear Capacity ◽  
Strength Concrete ◽  
Shear Span

This paper mainly focused on the seismic performance and shear calculation method of steel reinforced high-strength concrete (SRHC) columns with rectangular helical hoops. An experimental investigation was performed in this paper. Eleven SRHC columns with rectangular helical hoops and one with ordinary hoops were constructed at the laboratory of Guangxi university. The failure modes, hysteresis loops, envelope curves, characteristic loads and displacements and cumulative damage analysis are presented and investigated. It can be seen from the test results that the failure modes of SRHC columns can be divided into three types with the shear span ratio increased, namely, shear baroclinic failure mode, flexure-shear failure mode and flexure failure mode. In addition, the specimens with rectangular helical hoops have plumper hysteretic loops. Shear span ratio is the main influencing factor of characteristic load; the axial compression ratio and concrete strength have less influence on characteristic load, while stirrup ratio has little effect on the characteristic load. Finally, a calculation method for shear capacity of SRHC columns under shear baroclinic failure and flexure-shear failure mode is proposed.

Dynamic Response and Failure Mode Analysis on Light-Weight Steel Columns under Blast Loads

2012 ◽  
Vol 166-169 ◽  
pp. 1489-1497 ◽  
Author(s):  
Shi Yan ◽  
Lei Liu ◽  
Peng Li ◽  
Zhi Qiang Xin ◽  
Bao Xin Qi
Keyword(s):  
Dynamic Response ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Mode Analysis ◽  
Material Strength ◽  
Light Weight ◽  
Blast Loads ◽  
Element Analysis ◽  
Steel Columns

The dynamic response and failure mode of light-weight steel columns under blast loads were studied in this paper by using nonlinear finite element analysis (FEA) software ANSYS/ LS-DYNA, aiming to develop the degree and modes of the excessive plastic deformation during failures of the columns under diverse parameters. The damaged columns with initial blast-induced deformation may evidently influence vertical stability of light-weight steel frame structures. During the numerical simulation, the element of three dimensional solid SOLID164 was used, and the strain rate effect on material strength was included in the material model with Plastic-Kinematic (MAT-03). The main parameters included in the analysis were boundary conditions, scaled distances of explosions, and the vertical compressive load ratios applied on tops of the columns. The results showed that the column with both two fixed ends was the most beneficial to resist blast shock wave, the horizontal displacement at the middle span of the columns were obviously decreasing as increasing of the scaled distances of the explosion, and the axial compression ratio only significantly influenced the column with a sliding end. The failure modes of the developed columns may be summarized as bending failure, direct shear failure, and bending shear combination failure.

scholarly journals Classification of Red-Bed Rock Mass Structures and Slope Failure Modes in South China

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 273 ◽  
Author(s):  
Cuiying Zhou ◽  
Xu Yang ◽  
Yanhao Liang ◽  
Zichun Du ◽  
Zhen Liu ◽  
...  
Keyword(s):  
Rock Mass ◽  
South China ◽  
Slope Failure ◽  
Failure Modes ◽  
Hard Rock ◽  
Soft Rock ◽  
Red Beds ◽  
Rock Falls ◽  
Geological Formation ◽  
Red Bed

Red beds are Meso–Cenozoic continental sedimentary strata that are mainly composed of gravel stone, sandstone, siltstone, mudstone, and shale and occasionally have interlayers of limestone, halite, and gypsum. As a typical rock mass, red beds are widely distributed throughout South China. In a typical tropical and subtropical continental environment, red beds are the product of multiple sedimentary cycles, which have resulted in complicated rock mass structures that play an important role in rock mass stability. It is thus of great significance to investigate the influence of different rock mass structures on the stability of red-bed slopes. In this paper, the geological formation history of red beds in South China is described. The main features of red-bed rock mass slopes in South China are discussed. The main combinations of inner geomechanical structures comprise: (1) mega-thick soft rock structures; (2) mega-thick hard rock structures; (3) thick hard rock structures with weak intercalation; and (4) soft–hard interbedded structures. In addition, the features of slope failure are analyzed, and four common failure modes are identified from the statistical data: (a) weathering spalling and scouring; (b) rock falls; (c) landslides; and (d) tensile dumping.

scholarly journals Experimental Study of the Mechanical Characteristics of a Rock-Like Material Containing a Preexisting Fissure under Loading and Unloading Triaxial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Taoli Xiao ◽  
Mei Huang ◽  
Min Gao
Keyword(s):  
Experimental Study ◽  
Failure Mode ◽  
Mechanical Characteristics ◽  
Failure Modes ◽  
Shear Failure ◽  
Triaxial Compression ◽  
Tensile Failure ◽  
Underground Engineering ◽  
Inclination Angles ◽  
Loading And Unloading

An experimental study of a rock-like material containing a preexisting fissure subjected to loading and unloading triaxial compression is carried out, and the results show that the mechanical characteristics of the rock-like specimen depend heavily on the loading paths and the inclination of the fissure. The triaxial loading experiment results show that the failure strength linearly increases, while the residual strength linearly decreases with increasing inclination. Furthermore, specimens subjected to triaxial compression show an “X”-type shear failure mode. The triaxial unloading compression experimental results show that specimens with different inclination angles have various failure modes. Specimens with gentle inclinations show a tensile-shear mix failure mode, specimens with middle inclinations show a shear-sliding failure mode, and specimens with steep inclinations show a tensile failure mode. These findings can be used to forecast excavation-induced instabilities in deep underground engineering rock structures.

Comment on “Plastic deformation and fracture behavior of a Fe-modified Al3Ti-base L12 intermetallic alloy” [J. Mater. Res. 6, 957 (1991)]: The importance of specimen length-to-width ratios and end constraints in compression testing of brittle and semibrittle materials

1992 ◽  
Vol 7 (7) ◽  
pp. 1956-1959 ◽  
Author(s):  
David H. Zeuch
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Compression Tests ◽  
Specimen Length ◽  
End Effects ◽  
Deformation And Failure ◽  
Test Configuration ◽  
Pressure Sensitive ◽  
End Conditions ◽  
Test Pressure

Specimen length-to-diameter ratios and specimen/platen end conditions are important to interpretation of, and comparisons between, uniaxial compression tests on brittle materials. When differing l:d ratios and specimen/platen end conditions are used to test pressure-sensitive materials, observations may not be readily comparable owing to the different and nonuniform triaxial stress states. Specimens of brittle Fe- and Ni-modified Al3Ti intermetallic alloys having relatively low and different l:d ratios were tested in compression by Gengxiang et al. and Turner et al., respectively. Qualitative observations on the macroscopic deformation and failure modes (shear failure and distributed microcracking) indicate that the alloys are pressure-sensitive and that the results were possibly complicated in differing degrees by test configuration. Thus, direct comparison of these results with those obtained earlier for Al3Ti by Yamaguchi et al., who used a significantly greater l:d ratio, may not be altogether useful. Approaches to minimizing end effects are reviewed.

Load and Geometry Effect on Failure Mode Initiation of Composite Sandwich Beams

2006 ◽  
Vol 3-4 ◽  
pp. 173-178
Author(s):  
E.E. Gdoutos ◽  
M.S. Konsta-Gdoutos
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Sandwich Beams ◽  
Compressive Failure ◽  
Honeycomb Core ◽  
Composite Sandwich ◽  
Failure Mode Transition ◽  
Aluminum Honeycomb ◽  
Geometrical Dimensions

Facing compressive failure, facing wrinkling and core shear failure are the most commonly encountered failure modes in sandwich beams with facings made of composite materials. The occurrence and sequence of these failure modes depends on the geometrical dimensions, the form of loading and type of support of the beam. In this paper the above three failure modes in sandwich beams with facings made of carbon/epoxy composites and cores made of aluminum honeycomb and two types of foam have been investigated. Two types of beams, the simply supported and the cantilever have been considered. Loading included concentrated and uniform. It was found that in beams with foam core facing wrinkling and core shear failure occur, whereas in beams with honeycomb core facing compressive failure and core shear crimping take place. Results were obtained for the dependence of failure mode on the geometry of the beam and the type of loading. The critical beam spans for failure mode transition from core shear to wrinkling failure were established. It was found that initiation of a particular failure mode depends on the properties of the facing and core materials, the geometrical configuration and loading of composite sandwich beams.

Analysis on Causes of Deformation and Failure of Large Scale Underground Powerhouse

2011 ◽  
Vol 71-78 ◽  
pp. 644-650 ◽  
Author(s):  
Jin Yu Dong ◽  
Ji Hong Yang ◽  
Guo Xiang Yang ◽  
Fa Quan Wu
Keyword(s):  
Large Scale ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Concrete Cracking ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Underground Caverns ◽  
Geological Conditions ◽  
The Right

Jinoping No.1 is a dominant reservoir cascade hydropower station which locates at the downstream of Yalong river. The underground powerhouse locates at the right bank of the dam, lithology is marble that belongs to the second member of Zagunao group. It is constructed at region with very complicated geological conditions and high geo-stress. Concrete cracking, spalling and steel buckling and bending occurred at the downstream crown after supporting. This paper analysed the causes of deformation and failure through geological analysis and numerical simulation, and concluded that deformation and failure mainly occurred at the region where the quality of surrounding rock belongs to Ⅲ1 and had nothing to do with the unstable block cut by cracks; stress field of surrounding rock varied continueously with the proceeding of successive excavation of underground powerhouse, so the compressive stress and shear stress concentration occurred which caused the compression and shear failure of downstream crown and made it bending to the free face. It is significant to the further enforcement of this project and to the research on other similar underground caverns theoretically and practically.

Experimental Investigation on Compressive Properties for 3D Four-Directional Braided Composites

2010 ◽  
Vol 160-162 ◽  
pp. 1744-1748 ◽  
Author(s):  
Bao Lai Wang ◽  
Zhen Qing Wang ◽  
Guo Dong Fang ◽  
Jun Liang ◽  
Li Min Zhou
Keyword(s):  
Experimental Investigation ◽  
Compressive Stress ◽  
Failure Mode ◽  
Epoxy Matrix ◽  
Failure Modes ◽  
Shear Failure ◽  
Shear Direction ◽  
Compressive Properties ◽  
Braided Composites ◽  
Stress Strain

Based on changing the braid angle and geometrical sizes, the compressive experiment of 3D braided four-directional Carbon/Epoxy braided composites is researched. It is found that failure of the braided composites exhibits compressive and shear failure mode. The failure crack propagates mainly in one or two 45º shear direction. Epoxy matrix among braid yarns of the braided composites is squeezed out to form epoxy band. The stress-strain relations of the braided composites with 45º and 30º braid angles all appear nonlinear apparently. Meanwhile the correlation of failure modes and constitutive relation with geometrical sizes of the braided composites is obtained. The compressive stress-strain relations of the braided composites are not great affected by the geometrical sizes. The compressive strengths with great discrete behaviors do not have obvious rules with height of the braided composites.

scholarly journals Particle Flow Simulation of the Strength and Failure Characteristics of a Layered Composite Rock-Like Sample with a Single Hole

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1132
Author(s):  
Guozhu Wang ◽  
Yu Wang ◽  
Lei Song ◽  
Hao Shi ◽  
Mingwei Zhang ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Surrounding Rock ◽  
Tensile Failure ◽  
Practical Significance ◽  
Rock Masses ◽  
Engineering Structures ◽  
Layered Rock

Layered rock masses with holes are common in nature. Their mechanical behavior plays an important role in the safety and stability of engineering structures. However, previous studies have concentrated on a single lithological layer, and few studies have reported on the mechanical behavior of layered rock masses with holes. Based on the concept of symmetry, uniaxial compression tests and numerical simulations were performed on rock-like specimens with three layers and a hole in the interlayer. The hole was in the center of the sample and was symmetrical up and down. The influence of the thickness and strength of the interlayer on the mechanical behavior and failure processes of the layered rock masses with holes was investigated. The results show that the peak strength and elastic modulus were associated with the thickness and strength of the interlayer. Three failure modes were observed in the specimens, which were not only related to the thickness and strength of the interlayer, but also affected by the presence of the hole. When the thickness of the interlayer is small, mainly a single failure mode was observed (tensile failure or shear failure). However, when the interlayer was thick, the failure mode was tension-shear mixed failure. The failure mechanism of the specimens was primarily crack propagation at the edge of the hole. These research results can provide a basis for site selection, and the design of surrounding rock protection and support parameters, and thus have important practical significance for improving surrounding rock stability and ensuring construction safety.

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