Study on Mechanism of Slope Instability with Weak Interlayer

2011 ◽  
Vol 71-78 ◽  
pp. 3615-3618 ◽  
Author(s):  
Yun Fei Wang ◽  
Fu Ping Zhong ◽  
Huai Bao Chu ◽  
Li Ping Wang
Keyword(s):  
Stress Field ◽  
Failure Mechanism ◽  
Shear Failure ◽  
Slope Instability ◽  
Tensile Failure ◽  
Cyclic Process ◽  
Research Subject ◽  
Geological Conditions ◽  
Weak Interlayer ◽  
Mass Rock

In the process of the highway building, especially in mountain region the some complex geological conditions often appears. In this paper, using the slope of highway with weak interlayer as the research subject, systematically analyzing the stress field and plastic field during the excavation of the slope, obtained the failure mechanism of the slope with weak interlayer, which is a cyclic process that weak interlayer shear failure led to the tensile failure of its upper mass rock. It has extraordinarily important guiding significance for the protection and reinforcement of similar slope.

Study on Failure of Rock Mass around Deep Tunnel

2011 ◽  
Vol 99-100 ◽  
pp. 370-374 ◽  
Author(s):  
Yue Hong Qian ◽  
Ting Ting Cheng ◽  
Xiang Ming Cao ◽  
Chun Ming Song
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Failure Modes ◽  
Shear Failure ◽  
Simple Function ◽  
Tensile Failure ◽  
Deep Tunnel ◽  
Main Mode

During excavating the problem of unloading is a dynamic one essentially. Assuming the unloading ruled by a simple function and based on the Hamilton principal, the distribution of the stress field nearby the tunnel is obtained. The characteristics of the failure nearby the tunnel are analyzed considering the shear failure and tensile failure. The results show that the main mode of the shear failure, intact and tensile failure occurs from the tunnel. The characteristic of the shear failure, intact and tensile failure are one of the likely failure modes.

scholarly journals Failure Characteristics and Mechanism of Multiface Slopes under Earthquake Load Based on PFC Method

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Tao Yang ◽  
Yunkang Rao ◽  
Huailin Chen ◽  
Bing Yang ◽  
Jiangrong Hou ◽  
...  
Keyword(s):  
Moisture Content ◽  
Failure Mechanism ◽  
Failure Modes ◽  
Shear Failure ◽  
Shaking Table ◽  
Tensile Failure ◽  
Particle Flow Code ◽  
Shear Cracks ◽  
Local Shear ◽  
Shear Slip

Understanding the failure mechanism and failure modes of multiface slopes in the Wenchuan earthquake can provide a scientific guideline for the slope seismic design. In this paper, the two-dimensional particle flow code (PFC2D) and shaking table tests are used to study the failure mechanism of multiface slopes. The results show that the failure modes of slopes with different moisture content are different under seismic loads. The failure modes of slopes with the moisture content of 5%, 8%, and 12% are shattering-shallow slip, tension-shear slip, and shattering-collapse slip, respectively. The failure mechanism of slopes with different water content is different. In the initial stage of vibration, the slope with 5% moisture content produces tensile cracks on the upper surface of the slope; local shear slip occurs at the foot of the slope and develops rapidly; however, a tensile failure finally occurs. In the slope with 8% moisture content, local shear cracks first develop and then are connected into the slip plane, leading to the formation of the unstable slope. A fracture network first forms in the slope with 12% moisture content under the shear action; uneven dislocation then occurs in the slope during vibration; the whole instability failure finally occurs. In the case of low moisture content, the tensile crack plays a leading role in the failure of the slope. But the influence of shear failure becomes greater with the increase of the moisture content.

Effect of Air Position to the Mechanism of Air-Decked Blasting

2011 ◽  
Vol 328-330 ◽  
pp. 1167-1171
Author(s):  
Liang Wu
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Near Field ◽  
Blast Hole ◽  
Tensile Failure ◽  
Detonation Waves ◽  
Affecting Factors ◽  
Concrete Damage ◽  
Failure Properties ◽  
The Media

Based on the JHC model of concrete damage evolution, the dynamic stress characteristics and failure mechanism of blast-hole near-field about different air-decked charge structures are studied by numerical simulation. Result shows that the failure mechanism of typical elements changes from compression-shear failure into shear-tensile failure gradually with the increase of their position in indirect initiation of both top-air-decked and bottom-air-decked charges, because of the affecting factors of the freedom and the loading from the hole. If middle-air-decked charges detonate from the top and bottom at the same time, loading and unloading waves in blasting hole are more influential to the damage of bottom elements than the surface freedom, because detonation waves of both top and bottom meet at the middle hole, so it is conducive to the media failure at the bottom hole, the elements of freedom surface have the same failure properties to top-air-decked charge.

The Rock Failure Mechanism of Air-Decked Blasting in Hole Bottom

2012 ◽  
Vol 201-202 ◽  
pp. 375-378 ◽  
Author(s):  
Liang Wu ◽  
Yong Zhou ◽  
Zhi Hua Guo
Keyword(s):  
Failure Mechanism ◽  
Damage Evolution ◽  
Shear Failure ◽  
Dynamic Stress ◽  
Near Field ◽  
Blast Hole ◽  
Tensile Failure ◽  
Charge Structure ◽  
Concrete Damage ◽  
Bottom Rock

The application of air-decked blasting technology has enabled the efficient use of explosion energy, which proves that the air-decked blasting technology can overcome many disadvantages caused by column charge effectively, getting ideal explosion effect. Based on the JHC model of concrete damage evolution, the dynamic stress characteristics and failure mechanism of blast-hole near-field about bottom-air-decked charge structure is studied by numerical simulation. Result shows that the failure mechanism of typical elements changes from compression-shear failure into shear-tensile failure gradually with the increase of their position, for the effecting factors of the freedom and the loading from the hole. Comparing the dynamic stress characteristics of different detonating manners, indirect initiation can improve the static function intensity and delay the time of detonation gas, so it is easier to destroy the bottom rock of hole.

scholarly journals Study on the Interaction Mechanism of Hydraulic Fracture and Natural Fracture in Shale Formation

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4477 ◽  
Author(s):  
Heng Zheng ◽  
Chunsheng Pu ◽  
CHOE TONG IL
Keyword(s):  
Hydraulic Fracture ◽  
Shear Failure ◽  
Fracture Network ◽  
Tensile Failure ◽  
Natural Fracture ◽  
Natural Fractures ◽  
Propagation Length ◽  
Complex Fracture ◽  
Geological Conditions ◽  
Complex Fracture Network

Hydraulic fracturing is an essential technique for the development of shale gas, due to the low permeability in formation. Abundant natural fractures contained in a formation are indispensable for the development of a fracture network. In this paper, a damage-stress-seepage coupled hydraulic fracture expansion model, based on the extended finite element method, is established. The simulation results show that shear failure occurs when the hydraulic fracture interacts with a frictional natural fracture, while tensile failure occurs when it interacts with a cement natural fracture. Low interaction angles and high tensile strength of the rock are beneficial for the generation of a complex fracture network. Furthermore, under the same geological conditions and injection parameters, frictional natural fractures are more beneficial for the generation of a complex fracture network, when compared with cement natural fractures. This can not only effectively increase the propagation length of the natural fracture, but also effectively reduce its reactive resistance. This research is of great significance for the efficient exploitation of unconventional oil and gas resources.

scholarly journals Dynamic Response Characteristics and Failure Mechanism of Coal Slopes with Weak Intercalated Layers under Blasting Loads

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Guang-wei Liu ◽  
Dan-qing Song ◽  
Zhuo Chen ◽  
Ju-wen Yang
Keyword(s):  
Dynamic Response ◽  
Failure Mechanism ◽  
Natural Frequency ◽  
Shaking Table ◽  
Slope Instability ◽  
Dynamic Loads ◽  
Blasting Operation ◽  
Response Characteristics ◽  
Weak Interlayer ◽  
Dynamic Response Characteristics

Rock slopes with weak intercalated layers could experience disturbance from various deep mining activities; however, their dynamic stability has not been thoroughly investigated. In this paper, the dynamic response characteristics and failure mechanism of the coal slopes with weak intercalated layers under blasting loads were studied by means of numerical analysis, shaking table tests, and field tests. The effects of dynamic loads with different frequencies on the dynamic response of the slope were analyzed, and the natural frequency of the slope was also determined. The results show that the dynamic amplification effect of the slope is smaller than that of the homogeneous slope, and weak layers weaken the wave propagation in the rock mass. Both experimental and field investigation results show that the slope’s natural frequency was approximately 35 Hz. The slope deformation decreased with the distance of the blasting source. Cracks appear along the weak interlayer firstly under the action of horizontal vibration; then, longitudinal cracks occur at the slope crest. With the increase of dynamic loads, cracks continue expanding, deepening, and penetrating in the main controlled weak interlayer; then, the sliding body presents tensile shear failure along the sliding surface. This study could provide insights into the understanding of the coal slope instability and failure mechanism; this could benefit the blasting operation of the coal slope in fields.

scholarly journals Buckling Failure Mechanism of a Rock Dam Foundation Fractured by Gentle Through-Going and Steep Structural Discontinuities

2020 ◽  
Vol 12 (13) ◽  
pp. 5426
Author(s):  
Donghui Chen ◽  
Huie Chen ◽  
Wen Zhang ◽  
Chun Tan ◽  
Zhifa Ma ◽  
...  
Keyword(s):  
Numerical Method ◽  
Failure Mechanism ◽  
Shear Failure ◽  
Distinct Element ◽  
Mechanism Analysis ◽  
Rock Masses ◽  
Dam Foundation ◽  
Deformation Features ◽  
Universal Distinct Element Code ◽  
Distinct Element Code

The failure mechanism analysis of dam foundations is key for designing hydropower stations. This study analyses the rock masses in a sluice section, which is an important part of the main dam of the Datengxia Hydropower Station currently built in China. The stability of the sluice rock masses is predominantly affected by gentle through-going soft interlayers and steep structural fractures. Its foundation failure mechanism is investigated by means of a numerical method, i.e., Universal Distinct Element Code (UDEC) and the geomechanical model method. The modeling principle and process, and results for the rock dam foundation are introduced and generated by using the abovementioned two methods. The results indicate that the failure mechanism of the foundation rock masses, as characterized by gentle through-going and steep structural discontinuities, is not a conventional type of shear failure mechanism but a buckling one. This type of failure mechanism is verified by analyzing the deformation features resulting from the overloading of both methods and strength reduction of the numerical method.

scholarly journals Strength and Failure Mechanism of Composite-Steel Adhesive Bond Single Lap Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Kai Wei ◽  
Yiwei Chen ◽  
Maojun Li ◽  
Xujing Yang
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Failure Load ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Adhesive Failure ◽  
Interface Failure ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Structural Adhesive

Carbon fiber-reinforced plastics- (CFRP-) steel single lap joints with regard to tensile loading with two levels of adhesives and four levels of overlap lengths were experimentally analyzed and numerically simulated. Both joint strength and failure mechanism were found to be highly dependent on adhesive type and overlap length. Joints with 7779 structural adhesive were more ductile and produced about 2-3 kN higher failure load than MA830 structural adhesive. Failure load with the two adhesives increased about 147 N and 176 N, respectively, with increasing 1 mm of the overlap length. Cohesion failure was observed in both types of adhesive joints. As the overlap length increased, interface failure appeared solely on the edge of the overlap in 7779 adhesive joints. Finite element analysis (FEA) results revealed that peel and shear stress distributions were nonuniform, which were less severe as overlap length increased. Severe stress concentration was observed on the overlap edge, and shear failure of the adhesive was the main reason for the adhesive failure.

On the Direction of Fatigue Cracks in Polycrystalline Ingot Iron

1952 ◽  
Vol 19 (1) ◽  
pp. 54-56
Author(s):  
F. A. McClintock
Keyword(s):  
Statistical Analysis ◽  
Shear Failure ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Tensile Failure ◽  
Bending Fatigue ◽  
Polycrystalline Iron

Abstract A statistical analysis is developed to show how a microscopic shear failure can result in the apparent tensile failure of polycrystalline iron in rotary bending fatigue tests.

Investigation of the tensile performance and failure mechanism of carbon–aramid hybrid fibers/epoxy sandwich structure laminates using the UV-thermal synergetic curing mechanism: Experimentation and simulation

2018 ◽  
Vol 22 (8) ◽  
pp. 2582-2603
Author(s):  
Jiaojiao Xi ◽  
Xiaoyan Liu ◽  
Zhiqiang Yu
Keyword(s):  
Finite Element ◽  
Failure Mechanism ◽  
Sandwich Structure ◽  
Experimental Results ◽  
Tensile Failure ◽  
Hybrid Fibers ◽  
Pull Out ◽  
Tensile Performance ◽  
Hybrid Laminates ◽  
Curing Agents

The tensile failure mechanism of carbon–aramid hybrid fibers/epoxy sandwich structure laminates was investigated by using experimental and finite element methods. Double curing agents, triarylsulfonium hexafluoroantimonates and triethylene tetramine with a mass ratio of 4:15 were introduced into the laminates. Sandwich structure laminates, with different proportions of hybrid fibers, were cured by UV-initiated anion/cationic dual curing technique. The results showed that the synergetic curing effects of two curing agents were observed under UV irradiation, leading to the better curing of the system, which further plays a positive influence on the mechanical performance. The tensile properties and failure mechanism of the laminates depended on the stacking sequence and fiber volume fractions of the layer structures. The interplay hybrid laminates, containing three alternate plies with fiber contents of 67.7 vol%, presented the optimal tensile performance, and its tensile strength and modulus were 0.82 GPa and 22.09 GPa, respectively. The fracture morphologies revealed that pull-out and debonding of fibers were the main failure mechanism of hybrid laminates. The performance of sandwich structure laminates was determined by the load-carrying capacity of carbon fiber and load-transferring capacity of the aramid fiber and adhesive. The finite element model based on experiments was established to simulate the stress state and failure mechanism of sandwich laminates. The results demonstrated that the stress was better transferred into carbon fibers from the aramid fibers and adhesive, and the relative error rate of maximum stress from finite element analysis and experimental results was less than 5%, which were in reasonable agreement with the experimental results.

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