scholarly journals SOIL STRENGTH CRITERION WITH ACCOUNT FOR SHEAR RESISTANCE CAUSED BY PARTICLE ENGAGEMENT

2019 ◽  
Vol 14 (1) ◽  
pp. 36-42
Author(s):  
A. Yu. MIRNYY
Keyword(s):  
Yield Criterion ◽  
Strength Criterion ◽  
Shear Resistance ◽  
Soil Test ◽  
Cohesive Soils ◽  
Fine Grained ◽  
Precise Calculation ◽  
Common Criteria ◽  
Geotechnical Design ◽  
New Criterion

Shear resistance of soil becomes vital in geotechnical design of dams and embankments, and also landslides stabilization. Historically, the Mohr-Coulomb yield criterion was used for such problems solving — it appears to be suitable for the most of fine-grained soils. But in case of gravel soils, it was noticed that they possess so-called "cohesion" although there is no physical mechanism of such behavior. This extra shear resistance of non-friction nature is caused by the particle engagement. The engagement phenomenon was usually studied by hydro engineers, but since deep excavations and heavy structures are becoming common in civil engineering, more precise calculation becomes critical. This issue is dealing with the new yield criterion for gravel soils development. The most common criteria for non-cohesive soils and the parameters they are based on are analyzed. The proposed yield criterion is based on invariant stress parameters and concerns friction, cohesion and engagement between particles. It also takes into account second principal stress by using a non-fixed sliding plane. The parameters of this criterion are physically justified and can be determined by a standard soil test. Although it still needs experimental validation, this new criterion appears to be prospective for the usage in numerical modeling, as it is universal and versatile.

scholarly journals The Role of Frost Processes in the Retreat of River Banks

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1812
Author(s):  
Karol Augustowski ◽  
Józef Kukulak
Keyword(s):  
Relative Role ◽  
Freezing And Thawing ◽  
Fine Grained ◽  
Fluvial Processes ◽  
Precise Calculation ◽  
Erosion Pins ◽  
Summer Half ◽  
Lateral Erosion ◽  
Summer Flood

The rate of bank retreat was measured using erosion pins on the alluvial banks of the rivers in the Podhale region (the boundary zone between Central and Outer Carpathians) during the hydrological year 2013/2014. During the winter half-year (November–April), the bank retreat was mainly caused by processes related to the freezing and thawing of the ground (swelling, creep, downfall). During the summer half-year (May–October), fluvial processes and mass movements such as lateral erosion, washing out, and sliding predominated. The share of fluvial processes in the total annual amount of bank retreat (71 cm on average) was 4 times greater than that of the frost phenomena. Erosion on bank surfaces by frost phenomena during the cold half-year was greatest (up to 38 cm) on the upper parts of banks composed of fine-grained alluvium, while fluvial erosion during the summer half-year (exceeding 80 cm) mostly affected the lower parts of the banks, composed of gravel. The precise calculation of the relative role of frost phenomena in the annual balance of bank erosion was precluded at some stations by the loss of erosion pins in the summer flood.

scholarly journals A New Shear Strength Criterion for Rock Masses with Non-Persistent Discontinuities Considering the Nonlinear Progressive Failure Process

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4694
Author(s):  
Bowen Zheng ◽  
Shengwen Qi ◽  
Songfeng Guo ◽  
Xiaolin Huang ◽  
Ning Liang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Friction Coefficient ◽  
Progressive Failure ◽  
Strength Criterion ◽  
Rock Masses ◽  
Basic Form ◽  
Shear Strength Criterion ◽  
Nonlinear Shear ◽  
New Criterion ◽  
Internal Friction Coefficient

The shear strength characteristics of rock masses containing non-persistent discontinuities are strongly affected by discontinuities and rock bridges. The linear Jennings criterion cannot reflect the nonlinear mechanical behavior during progressive failure of rock masses with non-persistent discontinuities. In this study, a new nonlinear shear strength criterion was developed. First of all, a series of shear test data about artificial rock mass samples were collected on the basis of the published literatures, and five types of samples were differentiated according to the positions of discontinuities. After that, a new nonlinear shear strength criterion was proposed by introducing two correction coefficients A and B into the basic form of the Jennings criterion, which could correct the weight of the cohesion and the internal friction coefficient of rock bridges respectively. Then, the new criterion was determined by fitting the basic form of the Jennings criterion with the laboratory data. It was found that the parameters A and B had a nonlinear exponential and negative exponential relation with the connectivity rate respectively. It indicated that both the cohesion and the internal friction coefficient estimated by the new criterion were superior to those estimated by the Jennings criterion. Compared with the linear Jennings criterion, the new nonlinear shear strength criterion had a better applicability.

Effect of Inherent Anisotropy on the Behavior of Fine-Grained Cohesive Soils

2018 ◽  
Vol 17 (6) ◽  
pp. 687-697 ◽  
Author(s):  
Chia Zarei ◽  
Hossein Soltani-Jigheh ◽  
Kazem Badv
Keyword(s):  
Cohesive Soils ◽  
Inherent Anisotropy ◽  
Fine Grained

Scour by jets in cohesionless and cohesive soils

2007 ◽  
Vol 34 (6) ◽  
pp. 744-751 ◽  
Author(s):  
Kerry A Mazurek ◽  
Tanvir Hossain
Keyword(s):  
Impinging Jets ◽  
Coarse Grained ◽  
Cohesive Soils ◽  
Wall Jets ◽  
Fine Grained ◽  
Water Jets ◽  
Turbulent Wall Jets ◽  
Turbulent Wall ◽  
Turbulent Water ◽  
Unified Method

A technique is developed in this paper to unify the methods of analyzing scour by turbulent water jets in cohesionless and cohesive soils. Data from previous studies using circular turbulent impinging jets and circular turbulent wall jets are used to compare the scour in low void ratio cohesive soils to that in uniform sands and gravels. Scour by these jets is related to the dimensionless excess stress on the soil bed. It is seen that this parameter will likely work well for developing a method to predict scour for circular wall jets that is applicable to both materials. However, a circular impinging jet appears to vary appreciably in its interaction with the bed between the two types of soil, which makes developing a unified method to predict scour by impinging jets more difficult. Key words: erosion, scour, water jets, cohesionless sediments, cohesive sediments, fine-grained soils, coarse-grained soils.

A Unified Characteristic Theory for Plastic Plane Stress and Strain Problems

2003 ◽  
Vol 70 (5) ◽  
pp. 649-654 ◽  
Author(s):  
Y.-Q. Zhang ◽  
H. Hao ◽  
M.-H. Yu
Keyword(s):  
Plane Stress ◽  
Yield Criterion ◽  
Strength Criterion ◽  
Rigid Plastic ◽  
Strength Criteria ◽  
Special Cases ◽  
Characteristic Theory ◽  
Characteristic Methods ◽  
Von Mises ◽  
Suitable Characteristic

Based on the unified strength criterion, a characteristic theory for solving the plastic plane stress and plane strain problems of an ideal rigid-plastic body is established in this paper, which can be adapted for a wide variety of materials. Through this new theory, a suitable characteristic method for material of interest can be obtained and the relations among different sorts of characteristic methods can be revealed. Those characteristic methods on the basis of different strength criteria, such as Tresca, von Mises, Mohr-Coulomb, twin shear (TS) and generalized twin shear (GTS), are the special cases (Tresca, Mohr-Coulomb, TS, and GTS) or linear approximation (von Mises) of the proposed theory. Moreover, a series of new characteristic methods can be easily derived from it. Using the proposed theory, the influence of yield criterion on the limit analysis is analyzed. Two examples are given to illustrate the application of this theory.

scholarly journals Seamens’ Sign: A Novel Electrocardiogram Prediction Tool for Left Ventricular Hypertrophy

2021 ◽  
Author(s):  
Philip Walker ◽  
Cathy Jenkins ◽  
Jeremy Hatcher ◽  
Clifford Freeman ◽  
Nickolas Sr ◽  
...  
Keyword(s):  
Left Ventricular Hypertrophy ◽  
Ventricular Hypertrophy ◽  
Retrospective Chart Review ◽  
Left Ventricular ◽  
Ease Of Use ◽  
Rater Agreement ◽  
Study Objective ◽  
Test Characteristics ◽  
Common Criteria ◽  
New Criterion

Abstract Study Objective: We developed a novel, quick, easy to use electrocardiogram (ECG) screening criterion (Seamens’ Sign) for left ventricular hypertrophy (LVH). This new criterion was defined as the presence of QRS complexes touching or overlapping in two contiguous precordial leads. Methods: This study was a retrospective chart review of 2184 patient records. The primary outcome was whether Seamens’ Sign was noninferior in confirming LVH compared to other common criteria. Test characteristics were calculated for each of the LVH criteria. Inter-rater agreement was assessed on a random sample using Cohen’s Kappa. Results: Median age was 63, 52% of patients were male and there was a 35% prevalence of LVH by transthoracic echocardiogram (TTE). Nine percent were positive for LVH on ECG based on Seamens’ Sign. Seamens’ Sign had a specificity of 0.92. Tests assessing noninferiority indicated Seamens’ Sign was non-inferior to all criteria (p < 0.001) except for Cornell criterion for women (p = 0.98). Seamens’ Sign had 90% (0.81-1.00) inter-rater agreement, the highest of all criteria in this study. Conclusion: When compared to both the Sokolow-Lyon criteria and the Cornell criterion for men, Seamens’ Sign is noninferior in ruling in LVH on ECG. Additionally, Seamens’ Sign has higher inter-rater agreement compared to both Sokolow-Lyon criteria as well as the Cornell criteria for men and women, perhaps related to its ease of use.

Evaluation of a Modified Soluble Sulfate Determination Method for Fine-Grained Cohesive Soils

2002 ◽  
Vol 25 (1) ◽  
pp. 85 ◽  
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
AJ Puppala ◽  
C Viyanant ◽  
AP Kruzic ◽  
...  
Keyword(s):  
Cohesive Soils ◽  
Determination Method ◽  
Fine Grained ◽  
Soluble Sulfate ◽  
Sulfate Determination

Field Testing: The Standard Penetration Test

1986 ◽  
Vol 2 (1) ◽  
pp. 21-26 ◽  
Author(s):  
S. Thorburn
Keyword(s):  
Field Testing ◽  
Standard Penetration Test ◽  
Cohesive Soils ◽  
Test Results ◽  
Penetration Test ◽  
Test Procedures ◽  
Weak Rocks ◽  
Fine Grained ◽  
Introductory Lecture ◽  
Strength And Stiffness

AbstractThis introductory lecture discusses the international use of the standard penetration test (SPT) and presents the proposals for International Reference Test Procedures. The application of the SPT as a means of assessing the strength and stiffness of weak rocks is mentioned together with the reliance upon the test at the present time for estimating the liquefaction potential of saturated fine grained non-cohesive soils. The various aspects of the execution of the SPT are discussed which can provide variable and unrepresentative values of resistance (N values).The principle of measuring energy losses and making adjustments to the N values is introduced as a basis for ensuring comparability of test results.Reference is made to the general descriptions of the SPT given in BS 5930:1981 and to the lack of clear guidance in this British Standard.

Sign in / Sign up

Export Citation Format

Share Document