scholarly journals Some Aspects of Shear Behavior of Soft Soil–Concrete Interfaces and Its Consequences in Pile Shaft Friction Modeling

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2578
Author(s):  
Jakub Konkol ◽  
Kamila Mikina
Keyword(s):  
Shear Strength ◽  
Normal Load ◽  
Soft Soil ◽  
Load Condition ◽  
Initial Stiffness ◽  
Friction Modeling ◽  
Interface Failure ◽  
Friction Behavior ◽  
Constant Normal Load ◽  
Concrete Interface

This paper examines the stiffness degradation and interface failure load on soft soil–concrete interface. The friction behavior and its variability is investigated. The direct shear tests under constant normal load were used to establish parameters to hyperbolic interface model which provided a good approximation of the data from instrumented piles. Four instrumented piles were used to obtain reference soil–concrete interface behavior. It was found that the variability of the friction characteristics is the highest for organic clays and the lowest for organic silts. The intact samples exhibit lower shear strength than reconstituted ones. The adhesion varies significantly depending on interface and soil type, which can result in high scatter of the skin friction prediction. The analysis of parameters variability can be used to determine the upper and lower bound of friction behavior on the interface at constant normal load condition. The backward shearing results in decrease in shear strength up to 40% of the precedent forward phase but higher initial stiffness by a factor of between 2 and 3. Presented research provides basic shear and stiffness parameters for four soft soils (organic clay, organic silt, peat, and silty loam) and gives information about variability of interface characteristics.

Rock joint modeling using a visco-plastic multilaminate model at constant normal load condition

2006 ◽  
Vol 24 (5) ◽  
pp. 1449-1468 ◽  
Author(s):  
Reza Mahin Roosta ◽  
Mohammad Hossein Sadaghiani ◽  
Ali Pak ◽  
Yaser Saleh
Keyword(s):  
Normal Load ◽  
Rock Joint ◽  
Load Condition ◽  
Joint Modeling ◽  
Constant Normal Load ◽  
Constant Normal Load Condition

Lessons Learned From 25 Years of Friction Modeling

2003 ◽  
Author(s):  
Andres Soom
Keyword(s):  
Friction Coefficient ◽  
Scale Effects ◽  
Normal Load ◽  
Constitutive Relations ◽  
Lessons Learned ◽  
Contact Forces ◽  
Friction Modeling ◽  
Friction Behavior ◽  
Primary Means ◽  
The Coefficient Of Friction

We have long known that tangential contact forces and the friction coefficient at a sliding contact arises not due to some “law” but as a result of contact geometric and material properties in combination with physical processes that are not always accessible to direct experimental verification. While tribologists have occasionally sought alternatives to the coefficient of friction as the primary means to quantify tangential forces at sliding contacts, its convenience, simplicity, long history and lack of viable alternatives assure that it will be remain in use for some time to come. Sometimes the coefficient can remain constant with normal load over orders or magnitude. One can be led to believe that the coefficient is a property of the interface or there is a “law” at work. At other times, the coefficient, usually measured, is said to vary with time, sliding distance or some other variable with no explanation as to why the variation occurs. In the present paper we discuss aspects of friction behavior and modeling, focusing on mechanics and the nature of the friction coefficient. The point of departure is a case where the adhesion theory of friction can be used to understand the mechanics of friction. One can then consider a number of situations and concepts that arise as variations of this case including average versus instantaneous friction; cases when Amontons-Coulomb relations do or don’t apply; static versus dynamic friction; scale effects at rough surfaces; limits of applicability of the friction coefficient; friction measurements, thermal and velocity effects; and local versus global friction and constitutive relations.

On the Frictional Behavior of an Incipient-Sliding Contact of Sphere-on-Flat With High Normal Loads

2005 ◽  
Author(s):  
L. Chang
Keyword(s):  
Shear Strength ◽  
Normal Load ◽  
Experimental Results ◽  
Contact Interface ◽  
Friction Behavior ◽  
Key Factor ◽  
Plastic Sphere ◽  
Key Aspects ◽  
Static Coefficient Of Friction ◽  
Limiting Value

Levinson et al [1] present experimental results that show a steep reduction in the static coefficient of friction of a dry sphere-on-flat contact as the normal load increases. The experiments cover a range of loading conditions from elastic contact to contact with significant plastic deformation. A theoretical analysis is carried out in this study using a contact model of an elastic-plastic sphere on a rigid flat. The shear strength of the contact interface is assumed to be proportional to the contact pressure until it reaches a limiting value that is below the bulk shear strength of the sphere. The theory predicts a friction behavior that is consistent with that from the experimental results in [1] in all key aspects. The analysis reveals that a relatively low limiting shear strength in the contact interface is likely the key factor leading to the dramatic reduction in the friction coefficient and the negligible junction growth obtained in the experiments.

scholarly journals Thermal effects on mechanical behaviour of soil–structure interface

2020 ◽  
Vol 57 (1) ◽  
pp. 32-47 ◽  
Author(s):  
Soheib Maghsoodi ◽  
Olivier Cuisinier ◽  
Farimah Masrouri
Keyword(s):  
Shear Strength ◽  
Mechanical Behaviour ◽  
Soil Structure ◽  
Clayey Soil ◽  
Normal Load ◽  
Shear Characteristics ◽  
Constant Normal Stiffness ◽  
Constant Normal Load ◽  
Dense State ◽  
Interface Behaviour

Mechanical behaviour of the soil–structure interface plays a major role in the shear characteristics and bearing capacity of foundations. In thermoactive structures, due to nonisothermal conditions, the interface behaviour becomes more complex. The objective of this study is to investigate the effects of temperature variations on the mechanical behaviour of soils and the soil–structure interface. Constant normal load (CNL) and constant normal stiffness (CNS) tests were performed on the soil and soil–structure interface in a direct shear device at temperatures of 5, 22, and 60 °C. Fontainebleau sand and kaolin clay were used as proxies for sandy and clayey soils. The sandy soil was prepared in a dense state and the clayey soil was prepared in a normally consolidated state. Results show that the applied thermal variations have a negligible effect on the shear strength of the sand and sand–structure interface under CNL and CNS conditions, and the soil and soil–structure interface behaviour could be considered thermally independent. In clay samples, an increase in the temperature increased the cohesion and consequently the shear strength, due to thermal contraction during heating. The temperature rise had less impact on the shear strength in the case of the clay–structure interface than in the clay samples. The adhesion of the clay–structure interface is less than the cohesion of the clay samples.

scholarly journals A Study on Shear Strength under Constant Normal Load Conditions by Using 3DEC

2014 ◽  
Vol 24 (1) ◽  
pp. 46-54
Author(s):  
Young-Mok Noh ◽  
Hong-Ju Mun ◽  
Ki-Ho Kim ◽  
Won-Yil Jang
Keyword(s):  
Shear Strength ◽  
Normal Load ◽  
Constant Normal Load ◽  
Load Conditions

scholarly journals Thermo-mechanical behaviour of clay-structure interface

2019 ◽  
Vol 92 ◽  
pp. 10002 ◽  
Author(s):  
Soheib Maghsoodi ◽  
Olivier Cuisinier ◽  
Farimah Masrouri
Keyword(s):  
Shear Strength ◽  
Mechanical Behaviour ◽  
Soil Structure ◽  
Normal Load ◽  
Active Structures ◽  
Shear Characteristics ◽  
Constant Normal Stiffness ◽  
Constant Normal Load ◽  
Effects Of Temperature ◽  
Interface Behaviour

The mechanical behaviour of the soil-structure interface plays a major role in the shear characteristics and bearing capacity of foundations. In thermo-active structures, due to non-isothermal conditions, the interface behaviour becomes more complex. The objective of this study is to investigate the effects of temperature variations on the mechanical behaviour of soils and soil-structure interface. Constant normal load (CNL) and constant normal stiffness (CNS) tests were performed on soil and soil-structure interface in a direct shear device at temperatures of 5, 22 and 60 °C. Kaolin clay was used as proxy for clayey soils. The results showed that, in clay samples the temperature increase, increased the cohesion and consequently the shear strength, due to thermal contraction during heating. The temperature rise had less impact on the shear strength in the case of the clay-structure interface than in the clay samples. The adhesion of the clay-structure interface, is less than the cohesion of the clay samples.

scholarly journals Friction of Metals: A Review of Microstructural Evolution and Nanoscale Phenomena in Shearing Contacts

2021 ◽  
Vol 69 (4) ◽  
Author(s):  
Michael Chandross ◽  
Nicolas Argibay
Keyword(s):  
Shear Strength ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Low Friction ◽  
Friction Behavior ◽  
Important Conclusion ◽  
Fundamental Properties ◽  
Wide Range ◽  
Boundary Sliding ◽  
Metal Interfaces

AbstractThe friction behavior of metals is directly linked to the mechanisms that accommodate deformation. We examine the links between mechanisms of strengthening, deformation, and the wide range of friction behaviors that are exhibited by shearing metal interfaces. Specifically, the focus is on understanding the shear strength of nanocrystalline and nanostructured metals, and conditions that lead to low friction coefficients. Grain boundary sliding and the breakdown of Hall–Petch strengthening at the shearing interface are found to generally and predictably explain the low friction of these materials. While the following is meant to serve as a general discussion of the strength of metals in the context of tribological applications, one important conclusion is that tribological research methods also provide opportunities for probing the fundamental properties and deformation mechanisms of metals.

Shear-friction behavior of concrete-to-concrete interface under direct shear load

2021 ◽  
Vol 238 ◽  
pp. 112211
Author(s):  
Jin Xia ◽  
Kuang-yi Shan ◽  
Xiao-hui Wu ◽  
Run-li Gan ◽  
Wei-liang Jin
Keyword(s):  
Shear Load ◽  
Direct Shear ◽  
Friction Behavior ◽  
Shear Friction ◽  
Concrete Interface

Parametric study of multi-story, perforated, partially grouted masonry walls subjected to in-plane cyclic actions

2020 ◽  
Author(s):  
Klaus Medeiros ◽  
Kyle Chavez ◽  
Fernando S. Fonseca ◽  
Guilherme Parsekian ◽  
Nigel G. Shrive
Keyword(s):  
Experimental Data ◽  
Shear Strength ◽  
Aspect Ratio ◽  
Load Capacity ◽  
Axial Stress ◽  
Reinforcement Ratio ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Initial Stiffness ◽  
Vertical Reinforcement

Finite element models were developed to assess the influence of several parameters on the load capacity, deflection, and initial stiffness of multi-story, partially grouted masonry walls with openings. The base model was validated with experimental data from three walls. The analyses indicated that the load capacity of masonry walls was considerably sensitive to the ungrouted and grouted masonry strengths and mortar shear strength; moderately sensitive to the vertical reinforcement ratio and aspect ratio; slightly sensitive to the axial stress; and almost insensitive to the opening size, reinforcement spacing, and horizontal reinforcement ratio. The deflection of the walls had well-defined correlations with the masonry strength, vertical reinforcement, axial stress and aspect ratio. The initial stiffness was especially sensitive to the axial stress and the aspect ratio, but weakly correlated with the opening size, and the spacing and size of the reinforcement.

Sign in / Sign up

Export Citation Format

Share Document