scholarly journals The competition between folding and faulting in the upper crust based on the maximum strength theorem

2012 ◽  
Vol 468 (2141) ◽  
pp. 1280-1303 ◽  
Author(s):  
G. Kampfer ◽  
Y. M. Leroy
Keyword(s):  
Soil Mechanics ◽  
Surface Friction ◽  
Friction Angle ◽  
Maximum Strength ◽  
Frictional Properties ◽  
Full Development ◽  
Thrust Belts ◽  
Fault Propagation Fold ◽  
Axial Surface ◽  
Kinematic Approach

It is proposed to complement the numerous geometrical constructions of fault-related folds relevant to fold-and-thrust belts by the introduction of mechanical equilibrium and of the rock limited strength to discriminate between various deformation scenarios. The theory used to support this statement is the maximum strength theorem that is related to the kinematic approach of limit analysis known in soil mechanics. The classical geometrical construction of the fault-propagation fold (FPF) is proposed for illustration of our claim. The FPF is composed of a kink fold with migrating axial surfaces ahead of the region where the ramp propagates. These surfaces are assigned frictional properties and their friction angle is found to be small compared with the usual bulk friction angle to ensure the full development of the FPF, a first scenario. For larger values of the axial surface friction angle, this development during overall shortening is arrested by the onset of fault breaking through the front limb, a second scenario. The amount of shortening at the transition from folding to break-through faulting is established.

scholarly journals Experimental study on acidification effect of tailing sand

2021 ◽  
Vol 248 ◽  
pp. 01048
Author(s):  
Wenzhao Chen ◽  
Kai Yang ◽  
Jiaqing Fan ◽  
Xiqi Liu ◽  
Xiaoqing Wei
Keyword(s):  
Fine Particles ◽  
Iron Concentration ◽  
Chemical Properties ◽  
Surface Friction ◽  
Friction Angle ◽  
Immersion Test ◽  
Coarse Particles ◽  
Natural Conditions ◽  
Lead Zinc ◽  
Reaction Processes

Sulfide minerals (mainly FeS2) contained in lead-zinc tailings are easy to be acidified in the air. The acidification mechanism is that the tailing sand generates sulfuric acid and sulfate under the catalysis of oxidant, water and oxygen. The acidic liquid generated by the reaction will continue to react with metal oxides to form an insoluble precipitate.In order to reveal the corresponding changes of chemical properties and physical properties of lead-zinc tailing sand during acidification, a series of reaction processes of tailings under natural conditions were simulated by immersion test in laboratory.It is found through the test that with the deepening of acidification, the coarse particles of tailing sand dissolve, resulting in the decrease of iron concentration in the compound, the increase of fine particles, the increase of specific surface area, the decrease of surface friction and occlusion friction between particles, resulting in the decrease of internal friction angle, and the decrease of the safety of tailings dam. words.

scholarly journals The Friction Angle of the Leiyang Marble Surface after Exposure to High Temperature

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Meng Hong Peng ◽  
Man Huang
Keyword(s):  
Surface Condition ◽  
Surface Friction ◽  
Friction Angle ◽  
Effect Of Temperature ◽  
Tilt Test ◽  
Rock Surface ◽  
Sliding Angle ◽  
Normal Loading ◽  
Basic Friction Angle ◽  
Marble Surface

There is a lack of information about the temperature-dependent nature of the rock surface, which is one of the essential parameters to predict the surface friction. In the present study, we experimentally study the effect of temperature on the basic friction angle of the marble surface through the direct shear test under the low normal loading condition and tilting test (Stimpson/disk tilt test). The basic friction angle gradually decreases with the increase in temperature from 20°C to 600°C for the two kinds of the tilting test. The results indicate that the Stimpson test on samples with the length-to-diameter ratio of 2 can be more reliable to estimate the basic friction angle of the rock surface after exposure to high temperatures. The results illustrate that the sliding angle depends on the surface condition. With the increase in the repetitive measurements, the sliding angle decreases as the marble surface is cleaned, and the parameter increases as the marble surface is not cleaned.

Ecological Highway Slope Stability Analysis by Inversion Method

2011 ◽  
Vol 250-253 ◽  
pp. 2161-2166
Author(s):  
Jun Zhao Gao ◽  
Guo Feng Xiao ◽  
Hai Qiang Miao
Keyword(s):  
Slope Stability ◽  
Soil Mechanics ◽  
Friction Angle ◽  
Inversion Method ◽  
Time Inversion ◽  
Long Time ◽  
Main Factors ◽  
Reinforcement Design ◽  
Rock And Soil

Side slop losing stability is one of the main factors which greatly influences freeway expedite construction, especially after side slop losing stability the determination of rock and soil mechanics parameter may take a long time. Inversion method to analyze slope stability can preferably solve the problem. During the treatment of the ecological freeway landslide, we can not obtain important Parameters due to great disparity of sample Parameters of landslide. However, using inversion method to get cohesion and internal friction Angle, and anglicizing its sensitivity during calculation of stability can identify reliable Parameters. According to slope stability calculus, the ecological reinforcement design scheme come into effect.

scholarly journals Relation between the Friction Angle of Sand at Triaxial Compression and Triaxial Extension and Plane Strain Conditions

Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 29 ◽  
Author(s):  
Zenon Szypcio
Keyword(s):  
Plane Strain ◽  
Soil Mechanics ◽  
Triaxial Compression ◽  
Deformation Mode ◽  
Friction Angle ◽  
Failure Criteria ◽  
Compression Tests ◽  
Laboratory Test Results ◽  
Experimental Findings ◽  
Triaxial Extension

The strength of sand is usually characterized by the maximum value of the secant friction angle. The friction angle is a function of deformation mode, density, and stress level and is strongly correlated with dilatancy at failure. Most often, the friction angle is evaluated from results of conventional compression tests, and correlation between the friction angle of sand at triaxial compression and triaxial extension and plane strain conditions is a vital problem of soil mechanics. These correlations can be obtained from laboratory test results. The failure criteria for sand presented in literature also give the possibility of finding correlations between friction angles for different deformation modes. The general stress-dilatancy relationship obtained from the frictional state concept, with some additional assumptions, gives the possibility of finding theoretical relationships between the friction angle of sand at triaxial compression and triaxial extension and plane strain conditions. The theoretically obtained relationships presented in the paper are fully consistent with theoretical and experimental findings of soil mechanics.

Yield stress evaluation of Finnish clays based on analytical piezocone penetration test (CPTu) models

2020 ◽  
Vol 57 (11) ◽  
pp. 1623-1638 ◽  
Author(s):  
Bruno Di Buò ◽  
Marco D’Ignazio ◽  
Juha Selänpää ◽  
Tim Länsivaara ◽  
Paul W. Mayne
Keyword(s):  
Yield Stress ◽  
Soil Mechanics ◽  
Friction Angle ◽  
Coefficient Of Determination ◽  
Soil Conditions ◽  
Piezocone Penetration Test ◽  
Bias Factor ◽  
Constant Rate ◽  
Target Values ◽  
Spherical Cavity Expansion

A well-established analytical model based on spherical cavity expansion and critical state soil mechanics theories is applied to piezocone soundings for profiling the yield stress and overconsolidation ratio of five soft sensitive test sites located in Finland. Yield stress is related to three piezocone parameters: net cone resistance, excess porewater pressure, and effective cone resistances. Input geoparameters include the effective stress friction angle, defined at both peak strength and at maximum obliquity, and the model directly provides the operational value of the undrained rigidity index. The piezocone-evaluated profiles compare favorably with results from laboratory constant-rate-of-strain consolidation tests for all the investigated sites. Based on the obtained experimental results, simplified correlations valid for Finnish soil conditions are derived. Their validity is assessed based on the bias factor, coefficient of variation, and coefficient of determination, showing a fairly good agreement between the predicted and the target values.

scholarly journals Influence of Steel Plate Roughness on the Frictional Properties of Cereal Kernels

2018 ◽  
Author(s):  
Zdzisław Kaliniewicz ◽  
Zbigniew Żuk ◽  
Zbigniew Krzysiak
Keyword(s):  
Surface Roughness ◽  
Steel Plate ◽  
Friction Angle ◽  
External Friction ◽  
Adhesive Tape ◽  
Frictional Properties ◽  
Grain Processing ◽  
Experimental Variant ◽  
Optimal Surface ◽  
Friction Plate

The aim of this study was to determine the correlation between the external friction angle of cereal kernels and the roughness of a steel friction plate. The experiment was performed on the kernels of five principal cereals: wheat, rye, barley, oats and triticale. Flat seed units composed of three spaced kernels joined by adhesive tape were analyzed in each experimental variant. The external friction angle of flat seed units was determined on 9 steel friction plates with different roughness. Measurements were performed in 3 replications with a photosensor device which registered the external friction angle of cereal kernels. On friction plates with surface roughness Ra=0.36 to Ra=6.72, the average values of the angle of external friction ranged from 17.56° in rye kernels to 34.01° in oat kernels. The greatest similarities in the angle of external friction were observed between wheat and triticale kernels, whereas the greatest differences were noted between barley and oat kernels and between barley and triticale kernels. Friction plates made of ST3S steel should be characterized by the lowest surface roughness to minimize energy consumption during grain processing. The optimal surface roughness of steel friction plates was determined at Ra=0.9.

scholarly journals Influence of Steel Plate Roughness on the Frictional Properties of Cereal Kernels

2018 ◽  
Author(s):  
Zdzisław Kaliniewicz ◽  
Zbigniew Żuk ◽  
Zbigniew Krzysiak
Keyword(s):  
Surface Roughness ◽  
Steel Plate ◽  
Friction Angle ◽  
External Friction ◽  
Adhesive Tape ◽  
Frictional Properties ◽  
Grain Processing ◽  
Experimental Variant ◽  
Optimal Surface ◽  
Friction Plate

The aim of this study was to determine the correlation between the external friction angle of cereal kernels and the roughness of a steel friction plate. The experiment was performed on the kernels of five principal cereals: wheat, rye, barley, oats and triticale. Flat seed units composed of three spaced kernels joined by adhesive tape were analyzed in each experimental variant. The external friction angle of flat seed units was determined on 9 steel friction plates with different roughness. Measurements were performed in 3 replications with a photosensor device which registered the external friction angle of cereal kernels. On friction plates with surface roughness Ra=0.36 to Ra=6.72, the average values of the angle of external friction ranged from 17.56° in rye kernels to 34.01° in oat kernels. The greatest similarities in the angle of external friction were observed between wheat and triticale kernels, whereas the greatest differences were noted between barley and oat kernels and between barley and triticale kernels. Friction plates made of ST3S steel should be characterized by the lowest surface roughness to minimize energy consumption during grain processing. The optimal surface roughness of steel friction plates was determined at Ra=0.9.

Efficacy of Resinous Polypropylene (PP) Fibers on Strength Behavior of Reinforced Soils

2013 ◽  
Vol 787 ◽  
pp. 75-80 ◽  
Author(s):  
Shahriar Shahrokhabadi ◽  
Najme Nazeryzadeh
Keyword(s):  
Friction Angle ◽  
Weight Percent ◽  
Maximum Strength ◽  
Silty Sand ◽  
Compression Tests ◽  
Constant Length ◽  
Constant Weight ◽  
Strain Behavior ◽  
Strength Tests ◽  
Study Laboratory

In the current study, Laboratory uniaxial compression tests are carried out in order to determine the strength and mechanical behavior of silty sand reinforced with randomly distributed short resinous Polypropylene (PP) fibers. The stress-strain behavior of composite materials is investigated through varying the number and length of PP fibers. In order to study the effects of the length and weight percent of fibers on the results of the uniaxial compressive strength, tests were accomplished on specimens with three different lengths and weight percentages of fibers. The results demonstrate increasing weight percent of fibers, in a constant length, leads to increase the maximum strength. Meanwhile, increasing the length of fibers, in a constant weight percent, reduces the maximum strength. Moisture absorbency of fibers which was about 120% at first, however, could be reduced to just 9% by using the epoxy polyamide resin. Moreover, the resin causes more interaction between sand aggregates and fibers leading to a higher internal friction angle.

Research on Foundation Stability of Building Based on Foundation Bearing Capacity

2014 ◽  
Vol 624 ◽  
pp. 661-664
Author(s):  
Han Rui Pei
Keyword(s):  
Bearing Capacity ◽  
Soil Mechanics ◽  
Physical And Mechanical Properties ◽  
Friction Angle ◽  
Simulation Method ◽  
Influential Factors ◽  
Structural Members ◽  
Geological Conditions ◽  
Foundation Base ◽  
Properties Of Soil

Foundation stability can ensure the building is safe and reliable. Reliability of the building depends not only on the reliability of structural members and the entire structure of the system. In this paper, there is the aspect of soil to make the analysis of the reliability and stability of the foundation of the issues involved temporarily upper structure. The paper takes subsidence areas as the engineering background, combines with its mining geological conditions and applies comprehensively soil mechanics, probability integration method, and numerical simulation method and so on. According to the theoretical calculating formula of ground bearing capacity in the soil mechanics theory, analyze the major influential factors of building ground bearing capacity in subsidence areas, and they are internal friction angle, cohesive, and foundation base buried depth, especially physical and mechanical properties of soil.

Active pressure on gravity walls supporting purely frictional soils

2012 ◽  
Vol 49 (1) ◽  
pp. 78-97 ◽  
Author(s):  
D. Loukidis ◽  
R. Salgado
Keyword(s):  
Critical State ◽  
Soil Mechanics ◽  
Retaining Wall ◽  
Pressure Coefficient ◽  
Earth Pressure ◽  
Friction Angle ◽  
Soil Mass ◽  
Active Earth Pressure ◽  
Foundation Soil ◽  
Surface Plasticity

The active earth pressure used in the design of gravity walls is calculated based on the internal friction angle of the retained soil or backfill. However, the friction angle of a soil changes during the deformation process. For drained loading, the mobilized friction angle varies between the peak and critical-state friction angles, depending on the level of shear strain in the retained soil. Consequently, there is not a single value of friction angle for the retained soil mass, and the active earth pressure coefficient changes as the wall moves away from the backfill and plastic shear strains in the backfill increase. In this paper, the finite element method is used to study the evolution of the active earth pressure behind a gravity retaining wall, as well as the shear patterns developing in the backfill and foundation soil. The analyses relied on use of a two-surface plasticity constitutive model for sands, which is based on critical-state soil mechanics.

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