Effective stress vane shear strength correction factor correlations

1994 ◽  
Vol 31 (3) ◽  
pp. 335-342 ◽  
Author(s):  
Peter H. Morris ◽  
David J. Williams
Keyword(s):  
Shear Strength ◽  
Correction Factor ◽  
Effective Stress ◽  
Liquid Limit ◽  
Plasticity Index ◽  
Soil Parameters ◽  
In Situ Stresses ◽  
Rate Effects ◽  
Made In

A recent effective stress model of vane shear strength testing in soils can relate measured torques to vane shear strengths using theoretical analysis in terms of effective stress parameters. The strength estimates are based on known in situ stresses and soil parameters derived from laboratory testing. The model may be applied, for example, in obtaining theoretical estimates of conventional undrained vane shear strengths for comparison with field data and for use in stability analyses. However, the model incorporates a correction factor μv, analogous to Bjerrum's field vane shear strength correction factor μ, intended to compensate for pore-pressure and shearing-rate effects. This correction factor must be evaluated before reliable torque or shear strength estimates can be made in any given case. To facilitate this, the paper presents correlations of μv with both liquid limit and plasticity index, based on world-wide data from clays and silts. The correlations are compared with independent data from Norwegian clays. Key words : clay, correction factor, effective stress, liquid limit, plasticity index, silt, vane shear strength.

scholarly journals The New Empirical Equation Describing Damping Phenomenon in Dynamically Loaded Subgrade Cohesive Soils

2019 ◽  
Vol 9 (21) ◽  
pp. 4518 ◽  
Author(s):  
Soból ◽  
Głuchowski ◽  
Szymański ◽  
Sas
Keyword(s):  
Shear Strain ◽  
Effective Stress ◽  
Damping Ratio ◽  
Strain Range ◽  
Cohesive Soil ◽  
Plasticity Index ◽  
Dynamical Analysis ◽  
Soil Parameters ◽  
Cohesive Soils ◽  
Resonant Column Device

The damping ratio (D) is one of the key soil parameters in geotechnical issues where the soil is subjected to dynamic loads, like machines foundation, city tram and subway traffic, and driving of sheet pile or precast pile. Each of the abovementioned geotechnical problems is connected with significant damping, so its effect should be included in the dynamical analysis. Therefore, this article focuses on the damping phenomenon in cohesive soils from the capital of Poland, which is described by damping ratio (D). In this research, a set of the damping tests by free vibration method in resonant column device were conducted, and the influence of four selected factors, i.e., shear strain (γ), effective stress (p’), plasticity index (PI), and void ratio (e) on damping ratio in wide strain range was investigated and discussed. Based on the laboratory tests, the shear strain has the most impacts on the damping ratio characteristics; the plasticity index and the effective stress also have a significant influence. Based on the performed analysis, the authors propose the empirical equations with two sets of variables, the first for low and medium cohesive soil (PI < 20%) and the second for very cohesive soils (PI > 20%).

Halloysite behaving badly: geomechanics and slope behaviour of halloysite-rich soils

Clay Minerals ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 517-528 ◽  
Author(s):  
Vicki Moon
Keyword(s):  
Shear Strength ◽  
Bulk Density ◽  
High Mobility ◽  
Undrained Shear Strength ◽  
Field Conditions ◽  
High Peak ◽  
Plasticity Index ◽  
Undrained Shear

AbstractHalloysite-rich soils derived fromin situweathering of volcanic materials support steep stable slopes, but commonly fail under triggers of earthquakes or rainfall. Resulting landslides are slideflow processes, ranging from small translational slides to larger rotational failures with scarps characteristic of sensitive soils. Remoulding of failed materials results in high-mobility flows with apparent friction angles of 10–16°. The materials characteristically have high peak-friction angles (∼25– 37°), low cohesion (∼12–60 kN m−2) and plasticity ( plasticity index ∼10–48%), and low dry bulk density (∼480–1,080 kg m−3) with small pores due to the small size of the halloysite minerals. They remain saturated under most field conditions, with liquidity indexes frequently >1. Remoulded materials have limited cohesion (<5 kN m−2) and variable residual friction angles (15°–35°). Halloysite mineral morphology affects the rheology of remoulded suspensions: tubular minerals have greater viscosity and undrained shear strength than spherical morphologies.

A statistical evaluation of some engineering properties of eastern Canadian clays

1990 ◽  
Vol 27 (3) ◽  
pp. 373-386 ◽  
Author(s):  
Étienne J. Windisch ◽  
Raymond N. Yong
Keyword(s):  
Shear Strength ◽  
Statistical Evaluation ◽  
Undrained Shear Strength ◽  
Plasticity Index ◽  
Engineering Properties ◽  
Plastic Limit ◽  
Liquidity Index ◽  
Marine Clays ◽  
Undrained Shear

Statistics for data collected on eastern Canadian clays (Champlain, Goldthwait, Tyrrell, and Laflamme marine clays and Barlow–Ojibway lacustrine clays) are computed and analyzed. These clays are divided into three groups: eastern Canadian marine clays, Champlain clays (as an important part of the first group), and Barlow–Ojibway lacustrine clays. The analysis reveals significant differences between eastern Canadian clays and Scandinavian clays. Some relationships proposed in the literature and based on plasticity index, liquidity index, and plastic limit are found to be inapplicable to eastern Canadian clays. On the basis of a proposed method for estimating the undrained shear strength of normally consolidated eastern Canadian marine clays, the overconsolidation ratio is found to be equal to the ratio of the in situ undrained shear strength to the estimated normally consolidated undrained shear strength. Key words: undrained shear strength, plasticity index, liquidity index, plastic limit, statistical evaluation, over-consolidation ratio, lacustrian clays.

A reevaluation of using laboratory shear tests

1989 ◽  
Vol 26 (1) ◽  
pp. 162-164 ◽  
Author(s):  
G. Mesri
Keyword(s):  
Shear Strength ◽  
Correction Factor ◽  
Slip Surface ◽  
Undrained Shear Strength ◽  
Shear Tests ◽  
Text Data ◽  
Soft Clays ◽  
In Situ Data ◽  
Undrained Shear

The expression [Formula: see text] for the average undrained shear strength mobilized on a slip surface in the field resulted from in situ vane [Formula: see text] and oedometer [Formula: see text] data, combined with a correction factor μ obtained from the computed factor of safety of unstable embankments, footings, and excavations. It is shown here that the same expression for mobilized undrained strength of soft clays is also obtained from laboratory shear tests by taking into account anisotropy and time effects. This result is highly significant, since the laboratory undrained shear strength data, as well as the correction factor for the time effect, are completely unrelated to the in situ data that previously resulted in the expression for field mobilized undrained shear strength. Key words: mobilized undrained shear strength, in situ vane test, laboratory shear tests.

Sign in / Sign up

Export Citation Format

Share Document