scholarly journals Genuine and false pre-consolidation and yield pressures

2019 ◽  
Vol 92 ◽  
pp. 05001 ◽  
Author(s):  
Laurence D Wesley
Keyword(s):  
Measured Data ◽  
Soil Types ◽  
Log P ◽  
Test Results ◽  
Linear Scale ◽  
Consolidation Pressure ◽  
Oedometer Test ◽  
The Way

“It remains a mystery why the international profession still uses the awkward e-log p plots, and the incomplete and useless coefficient Cc which is not even determined from the measured data, but from a constructed line outside the measurements”. These are the words of Nilmar Janbu (1998). This paper does not solve the mystery; what it does is highlight the issue behind the mystery in the hope that the profession will face up to the defects of the log scale. An examination is made of oedometer test results when plotted to both scales. Examples are given for sedimentary and residual clays, and sands. It is shown that the e-logp plot routinely produces graphs from which pre-consolidation pressures or yield pressures can be determined. However, when plotted using an arithmetic (linear) scale, this apparent pre-consolidation or yield pressure is found, in most cases, to disappear. It is a false value created by the way the data are plotted. The paper does not deny that pre-consolidation or yield pressures exist in many soils; it gives examples for each of the soil types listed above. It is recommended that the term “yield pressure” be used in preference to “pre-consolidation pressure”, and that only the use of a linear scale will reveal whether such a pressure exists.

scholarly journals Consolidation Behavior and Compression Prediction Model of Coastal Cement Soil Modified by Nanoclay

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Wenjie Yu ◽  
Na Li ◽  
Mengdan Dai ◽  
Dongliang An ◽  
Biao Qian ◽  
...  
Keyword(s):  
Prediction Model ◽  
Cement Content ◽  
Exponential Model ◽  
Measured Data ◽  
Test Results ◽  
Consolidation Pressure ◽  
Improvement Effect ◽  
Linear Interval ◽  
Nanoclay Content ◽  
Cement Soil

Coastal cement soil modified by nanoclay (NCS) has particular research significance as a modification approach to improve the high compressibility of coastal cement soil (CCS). At curing ages of 7 days and 28 days, consolidation and SEM tests were performed on 6 groups of NCS samples with a nanoclay content between 0% and 10% and 6 groups of CCS samples with a cement content between 10 and 20%, and a compression prediction model was established based on the test results. Test results show that (1) there is a linear interval for the improvement effect of the increment of cement content on the compression of CCS samples. In this test, the cement content in this interval is between 12% and 18%. CCS with a cement content of 18% is preferred. (2) The improvement effect on the compression of the sample is better with a nanoclay content of 4% and 8%, but poor with a content of 2%. At a consolidation pressure between 100 kPa and 800 kPa, NCS with a nanoclay content of 4% is preferred. (3) Adhesion is better with a nanoclay content of 4%, and the filling effect is better with a content of 8%. (4) The cosine-power function-exponential model is established, and the measured data are fitted, and a prediction model for the compression amount of CCS and NCS is established.

ETUDE DU POUVOIR NUTRITIF EN PHOSPHORE DE CERTAINS SOLS DU QUEBEC A L'AIDE DU 32P

1976 ◽  
Vol 56 (3) ◽  
pp. 285-291
Author(s):  
B. TOUATI ◽  
C. PLENCHETTE ◽  
M. TABI
Keyword(s):  
Soil Phosphorus ◽  
Phosphate Fertilizer ◽  
Soil Types ◽  
K Value ◽  
Type Experiment ◽  
A Value ◽  
The Difference ◽  
The Way

In a pot-type experiment with ryegrass, 32P was used to label isotopically exchangeable soil phosphorus as well as a phosphate fertilizer. The tagging of both forms of phosphorus enable us to determine the pool (L) for soil reserves and the A value which is the availability of these reserves in the presence of fertilizer. The authors establish correlations between the ratio K = L/A and the assimilable phosphorus as determined by the Bray II method, and also between K and the "extra" phosphorus. The authors state that the latter was the difference between the plant phosphorus with and without fertilizer. From this study it is concluded: (1) that the K value seems to be a better criterion than the amount of assimilable phosphorus to estimate the phosphorus fertility of a soil; (2) that the study of the variation of the K value according to the soil types informs us about the reserves behavior and about the way of nutrition for the plant. The calculation of the K value is aimed toward a more adequate fertilization for given types of soil.

scholarly journals Experimental Research on Creep Characteristics of Nansha Soft Soil

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qingzi Luo ◽  
Xiaoping Chen
Keyword(s):  
Pearl River Delta ◽  
Soft Soil ◽  
Creep Damage ◽  
Pearl River ◽  
Test Results ◽  
Creep Failure ◽  
Consolidation Pressure ◽  
Creep Characteristics ◽  
Triaxial Creep ◽  
Shear Box

A series of tests were performed to investigate the creep characteristics of soil in interactive marine and terrestrial deposit of Pearl River Delta. The secondary consolidation test results show that the influence of consolidation pressure on coefficient of secondary consolidation is conditional, which is decided by the consolidation state. The ratio of coefficient of secondary consolidation and coefficient of compressibilityCa/Ccis almost a constant, and the value is 0.03. In the shear-box test, the direct sheer creep failure of soil is mainly controlled by shear stress rather than the accumulation of shear strain. The triaxial creep features are closely associated with the drainage conditions, and consolidation can weaken the effect of creep. When the soft soil has triaxial creep damage, the strain rate will increase sharply.

scholarly journals Measuring the Lighting Quality in Academic Institutions: The UPM Faculty of Aerospace Engineering (Spain)

2020 ◽  
Vol 10 (23) ◽  
pp. 8345
Author(s):  
María Zamarreño-Suárez ◽  
Daniel Alcala-Gonzalez ◽  
Daniel Alfonso-Corcuera ◽  
Santiago Pindado
Keyword(s):  
Measured Data ◽  
Simulation Software ◽  
Aerospace Engineering ◽  
Fine Tuning ◽  
Current Status ◽  
Test Results ◽  
Wear And Tear ◽  
Lighting Simulation ◽  
Low Levels ◽  
Lighting Systems

This article analyzes the current status of the lighting quality at the Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio (ETSIAE), the aerospace engineering faculty at the Universidad Politécnica de Madrid (UPM), and evaluates possible improvement actions based on the use of DIALux® lighting simulation software together with measured data. The results show rather low levels of measured illuminance on classroom desks and blackboards in one of the buildings comprising the faculty. The improvements proposed (a new coat of paint on the walls and replacement of luminaires) were simulated in four individual classrooms representing all rooms in two of the ETSIAE buildings (where the lower illuminance levels were measured). In order to study these improvements, the current situation of the four selected classrooms was simulated using DIALux® and fine-tuning attenuation of the luminaires to take into account their wear and tear. The correlation between the DIALux® simulation and the test results was analyzed with quite good results. The results clearly reveal a need to fully replace the classroom lighting systems in ETSIAE building A (the oldest building, dating back to 1955). According to the results from the selected classrooms, the average lighting over the desks can be greatly improved by using LED technology in order to meet UNE 12464-1 standard (that is, 500 lx, from an initial situation with much lower illuminance values: 129 lx to 295 lx). This article represents an innovative way to perform lighting improvement projects as real measured lighting data is used as initial input for the lighting simulations.

Modified state parameter for characterizing static liquefaction of sand with fines

2009 ◽  
Vol 46 (3) ◽  
pp. 281-295 ◽  
Author(s):  
D. C. Bobei ◽  
S. R. Lo ◽  
D. Wanatowski ◽  
C. T. Gnanendran ◽  
M. M. Rahman
Keyword(s):  
Critical State ◽  
Volumetric Strain ◽  
State Parameter ◽  
Confining Pressure ◽  
Log P ◽  
Test Results ◽  
Static Liquefaction ◽  
Isotropic Consolidation ◽  
Failure Line ◽  
Soil Behaviour

An experimental study was carried out to investigate the static liquefaction behaviour of sand with a small amount of plastic and nonplastic fines. Five series of tests were conducted in drained and undrained conditions. The drained test results indicate not only that the failure line coincides with the critical state, but also that the development of volumetric strain during shearing was not sensitive to the initial confining pressure. In both isotropically and anisotropically consolidated undrained tests, a so-called “reverse behaviour” was consistently observed. The results were also interpreted in the critical state framework. The critical and steady state (CS/SS) data were found to trace along the same curve in e–log( p′) space, irrespective of the stress history and effective stress paths. A comparison between the isotropic consolidation line (ICL) and critical state (CS) curve showed that a small amount of fines can significantly change the shape and position of the ICL relative to the CS curve. Furthermore, the soil behaviour manifested in both drained and undrained shearing led to the development of a modified state parameter.

Mechanical Characteristics of Ningbo Marine Deposit Soft Clay under Different Stress Paths

2011 ◽  
Vol 250-253 ◽  
pp. 2093-2097
Author(s):  
Chen Bin ◽  
Jun Neng Ye ◽  
Gan Bin Liu
Keyword(s):  
Effective Stress ◽  
Mechanical Characteristics ◽  
Axial Strain ◽  
Soft Clay ◽  
Stress Path ◽  
Shear Mode ◽  
Test Results ◽  
Total Stress ◽  
Consolidation Pressure ◽  
Marine Deposit

Based on a series of consolidated-undrained stress path tests, the mechanical characteristics of Ningbo marine deposit soft clay under K0 consolidation condition are systematically studied for different consolidation pressure, i.e.,60, 120 and 200kPa, in the GDS stress path triaxial system. Three kinds of stress path, i.e., DE (increase p), DG(constant p) and DF(reduce p), are carried out, and the characteristics of stress-axial strain relation, stress path and strength under different stress paths are compared. The test results show that the effective stress paths under consolidated-undrained shear are mainly related to initial consolidation, and the controlled shear mode has evident effect on the effective stress paths. In addition, the stress path has a certain influence on both the total stress and the effect stress strength.

scholarly journals The property changes of ammunition elements due to the exploitation time

2015 ◽  
Vol 36 (1) ◽  
pp. 91-104
Author(s):  
Dariusz Ampuła
Keyword(s):  
Gamma Distribution ◽  
Research Methodology ◽  
Probability Distributions ◽  
Test Results ◽  
Normal Distributions ◽  
Standard Normal ◽  
Evaluation Module ◽  
Property Changes ◽  
Two Parameters ◽  
The Way

Abstract The way carry out of analysis concerning correctness working of evaluation module proposed in functioning research methodology, chosen features elements of artillery fuses was presented in the article. Probability distributions of the aptitude time of tested ammunition elements were applied for verification of undertaken post diagnostic decisions. The analysis of test results chosen fuses elements, based on the standard normal distributions were executed, further the graphic interpretations of these distributions were made. A measurement of the strength of resistance decline of the side-bolt spring was chosen for the analysis, as a way of checking MG-37 and MG-57 fuse types features. Furthermore, the author presents an illustrative comparison of normal distributions, which confirms that post diagnostic decisions had been undertaken correctly. The graphic interpretations of analyzed test results of MG-37 fuse elements type were executed by means of two-parameters gamma distribution in the comparison. Concise conclusions confirming the correctness of functioning of evaluation module in the research methodology were introduced at the end of the article.

scholarly journals FREE TIME AND SOCIAL RELATIONSHIPS IN A GROUP OF STUDENTS FROM TWO HIGH SCHOOLS IN BOTOSANI COUNTY

2021 ◽  
Author(s):  
Adriana Albu ◽  
◽  
Mihaela Vlada ◽  
Adina Nechita ◽  
Florin Dima ◽  
...  
Keyword(s):  
High School ◽  
Social Relationships ◽  
Leisure Activities ◽  
Free Time ◽  
Test Results ◽  
Chi Squared ◽  
Watching Tv ◽  
The City ◽  
School Activity ◽  
The Way

Introduction: it is necessary to assess the way students spend their free time in the final years of high school due to the poor results that have appeared recently in the baccalaureate exams. Methods: the study was carried out using a group of 202 students from the 11th and 12th grades from a National College (117 pupils) and a High School (85 pupils) from the city of Dorohoi, Botosani County. The young people filled in a questionnaire with questions about leisure activities and social relationships. The results were processed using Pearson's chi-squared test. Results and discussions: The time allocated daily for physical activity is mostly 15-30 minutes (23.76%) with significant differences between the two schools (p˂0.05). The time spent watching TV is mostly 0.5-1 hours (35.64%) with insignificant differences between grades (p>0.05). Most students (44.05%) do not sit at the computer, the calculated differences being statistically insignificant (p>0.05). When looking at social relationships we take into account friends, where in the majority of cases (32.4%) students have „one” true friend. This is a usual result because in this period of the adolescent's life the role the group of friends plays decreases, with significant differences between school years (p˂0.05). In their free time, they go out into town, mostly 2-3 evenings per week (28.71%), but there are also 31.68% negative answers. Parents are less concerned about school activity (“never” answers – 34.15%) with significant differences between grades (p˂0.01). Parents are also less concerned with the way their children spend their free time (“never” answers – 34.65%) with significant differences between school years (p˂0.05). Conclusions: there is a series of situations that guide us towards a modest concern for the future, both from students and their parents.

On Using References as Evidence

2009 ◽  
Vol 48 (06) ◽  
pp. 503-507 ◽  
Author(s):  
J. Talmon ◽  
J. Brender
Keyword(s):  
Medical Informatics ◽  
Scientific Evidence ◽  
Evidence Base ◽  
Measured Data ◽  
The Way

Summary Background: One has to start to consider references as a kind of evidence similar to measured data and observations. Moreover, proper referencing adds to the credibility of a paper and gives appropriate credits to work of others. Experience of reviewers and editors indicate that there is room for improvement in the way that our scientific evidence base is referred to. Objective: To provide guidelines for referencing in medical informatics publications. Method: The authors have collected examples of poor as well as good referencing as encountered in manuscripts submitted for review as well as in published literature. Results and Conclusion: A set of 12 rules for proper referencing was derived. The rationale for each rule is provided and examples of rule violations and proper use of the rule are pre sented.

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