A Simple and Practicable Approach on Implementing for the Reduced Triaxial Extension by the Conventional Triaxial Apparatus

2011 ◽  
Vol 250-253 ◽  
pp. 2089-2092
Author(s):  
Rong Jian Li ◽  
Xi An Li ◽  
Gao Feng Che ◽  
Wen Zheng ◽  
Wen Jun Chen
Keyword(s):  
Triaxial Compression ◽  
Stress Path ◽  
Test Results ◽  
Triaxial Apparatus ◽  
Eolian Sand ◽  
Conventional Triaxial Compression ◽  
The Difference ◽  
Shear Behaviors ◽  
The Impact ◽  
Triaxial Extension

Stress path is one of the very important factors of soil strength. It is significant to study the strength and reveal the importance of the impact of sand in different stress path conditions. Firstly, an ameliorating approach on implementing for the reduced triaxial extension by the conventional triaxial apparatus was discussed. Then, In order to study shear behaviors of the eolian sand under different stress path, two monotonic shearing tests with the conventional triaxial compression and the reduced triaxial extension stress path were performed and analyzed. The test results not only indicate that the amelioration on conventional triaxial apparatus is simple, practicable and inexpensive, but also reveal the difference of strength’s parameter between the reduced triaxial extension and conventional triaxial compression stress path. In sum, the stress path has important effect on the strength of the eolian sand.

Axial Unloading Test of Soil Based on the GDS Triaxial Apparatus

2014 ◽  
Vol 638-640 ◽  
pp. 407-411
Author(s):  
Shu Chao Zhang ◽  
Shao Hui He ◽  
Pei Wang ◽  
Lin Li
Keyword(s):  
Axial Load ◽  
Stress Path ◽  
Test Method ◽  
Radial Load ◽  
Test Results ◽  
Triaxial Apparatus

Normal triaxial apparatus is suited to the loading stress path test, some stress path triaxial apparatus can be used to unload radial load smaller than the axial load, but it is difficult to unload axial load smaller than the radial load or even unload the axial load to zero. Using the iso-diameter headgear, different axial-radial unload ratio tests were done on the GDS triaxial apparatus, and the axial load was unloaded smaller than the radial load. During the test, it was found there are some deficiencies in the GDSLAB system. The results conformed to the characteristics of unloading test, which well verified the correctness of the test method and test results.

Results of pig progeny testing in Great Britain

1965 ◽  
Vol 7 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Charles Smith
Keyword(s):  
Great Britain ◽  
Test Performance ◽  
Genetic Correlations ◽  
Performance Testing ◽  
Progeny Testing ◽  
Test Results ◽  
Genetic Changes ◽  
Mild Degree ◽  
The Difference ◽  
The Impact

SUMMARYFrom 1958 to 1962 over 800 boars and 3,000 sows were progeny tested at the national pig progeny testing stations in Great Britain. Their test results for four traits (daily gain, feed efficiency, average backfat and carcass length) have been used to study the amount and effectiveness of selection and to review the use of the test facilities and their effect on pig improvement.The amount of selection on test results was studied by measuring the difference in performance of animals with sons subsequently tested and all contemporary tested animals. The selection differentials found were from 0·05 to 0·30 standard deviation units for the four traits studied which represents a rather mild degree of selection. Thus selection could have had only a small effect in improving the testing population. In fact sons of tested animals showed little advantage over their contemporaries in test performance. Parent-offspring regressions were calculated and these, in agreement with theoretical estimates, indicated that selection would be effective and would lead to genetic changes in any of the four traits studied. Genetic correlations among the four traits were also calculated and indicated genetic compatability in improving the four traits concurrently.Two proposals intended to increase the impact of testing on pig improvement are put forward. These are (1) to restrict the testing facilities to a small nucleus set of breeders who could concentrate on testing and selection and (2) to replace the progeny testing by performance testing which would allow a more intense selection and a greater rate of improvement for the same testing facilities.

Experimental Study on Shear Strength of Intact Loess at Different Stress Paths

2011 ◽  
Vol 368-373 ◽  
pp. 2891-2894
Author(s):  
San Qing Su ◽  
Bo Tuan Deng ◽  
Jun Feng Hou ◽  
Zhen Lv
Keyword(s):  
Shear Strength ◽  
Triaxial Compression ◽  
Initial Moisture Content ◽  
Stress Path ◽  
Peak Strength ◽  
Deformation Capacity ◽  
Hardening Model ◽  
Conventional Triaxial Compression ◽  
Strength Behavior ◽  
Intact Loess

The conventional triaxial compression(CTC), triaxial compression(TC) and reduce triaxial compression(RTC) of ordinary loess in Xi，an Ba He was conducted with GDS stress path tests and the strength behavior and deformation capacity of loess was studied. The experimental results showed that the larger the initial moisture content, the smaller the shear strength. The strength characteristic of loess varied under different stress path. Relationships between σ and ε was strain hardening model. The peak strength of CTC is larger than that of TC and the peak strength of RTC was smaller.

Uniaxial Stress-Strain Model for Concrete Confined by Rectangular Steel Tubes

2010 ◽  
Vol 163-167 ◽  
pp. 1005-1011
Author(s):  
Yue Ling Long ◽  
Jian Cai
Keyword(s):  
Triaxial Compression ◽  
Uniaxial Stress ◽  
Failure Criteria ◽  
Steel Tube ◽  
Test Results ◽  
Stress Strain ◽  
Steel Tubes ◽  
Concrete Core ◽  
Strain Behavior ◽  
The Difference

This paper presents a new model for uniaxial stress-strain relationship of concrete confined by rectangular steel tubes. The difference between concrete confinement effect provided by broad faces and that provided by narrow faces of steel tube is considered in the proposed model. The failure criteria for concrete subjected to triaxial compression is applied to estimate the ultimate strength of concrete core. The parameters of the model are determined based on the test results and the calculation of complete load-stress relationship curves is conducted for axially loaded rectangular CFT specimens using the model proposed in the paper. The concrete core strength and stress-strain behavior of rectangular CFT columns is found to exhibit good agreement with test results.

scholarly journals Study on the Permeability Evolution Model of Mining-Disturbed Coal

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hengyi Jia ◽  
Delong Zou
Keyword(s):  
Axial Stress ◽  
Triaxial Compression ◽  
Strain Curve ◽  
Stress Path ◽  
Coal Mass ◽  
Coal Bed ◽  
Permeability Evolution ◽  
Conventional Triaxial Compression ◽  
Deformation Stages ◽  
Triaxial Creep

Coal permeability plays an important role in the simultaneous exploitation of coal and coal-bed methane (CBM). The stress of mining-disturbed coal changes significantly during coal mining activities, causing damage and destruction of the coal mass, ultimately resulting in a sharp increase in permeability. Conventional triaxial compression and permeability tests were conducted on a triaxial creep-seepage-adsorption and desorption experimental device to investigate the permeability evolution of mining-disturbed coal. The permeability evolution models considering the influence of the stress state and stress path on the fracture propagation characteristics were established based on the permeability difference in the deformation stages of the coal mass. The stress-strain curve of the coal was divided into an elastic stage, yield stage, and plastic flow stage. As the axial stress increased, the permeability decreased and then increased, and the curve’s inflection point corresponded to the yield point. The permeability models exhibited a good agreement with the experimental data and accurately reflected the overall trends of the test results. The results of this study provide a theoretical basis for coal mine disaster prevention and the simultaneous exploitation of coal and CBM.

scholarly journals Simulation of Stress Paths Derived from FEM Analysis in Triaxial Tests

2013 ◽  
Vol 59 (1) ◽  
pp. 119-129
Author(s):  
M. Kowalska
Keyword(s):  
Laboratory Tests ◽  
Equivalent Stress ◽  
Fem Analysis ◽  
Stress Path ◽  
Triaxial Tests ◽  
Laboratory Equipment ◽  
Geotechnical Parameters ◽  
Triaxial Apparatus ◽  
Triaxial Extension

Abstract Reliable estimation of geotechnical parameters is often based on reconstruction of a complete loading process of subsoil on a specimen in laboratory tests. Unfortunately laboratory equipment available in many laboratories is sometimes limited to just a triaxial apparatus - the use of which generates difficulties whenever a non-axisymmetric problem is analysed.The author suggests two simple operations that may be done to improve the quality of simulation in triaxial tests. The first one is based on the use of triaxial extension along the segments of the stress path p’-q-θ for which the Lode’s angle values are positive. The second one consists in a modification of the equivalent stress value in such a way that the current stress level in the specimen complies with results of FEM analysis.

scholarly journals Study on Seismic Performance of Porcelain Pillar Electrical Equipment Based on Nonlinear Dynamic Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yaodong Xue ◽  
Yongfeng Cheng ◽  
Zhubing Zhu ◽  
Sheng Li ◽  
Zhenlin Liu ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Model ◽  
Electrical Equipment ◽  
Nonlinear Parameter ◽  
Seismic Excitation ◽  
Test Results ◽  
Nonlinear Seismic Response ◽  
Calculation Results ◽  
The Difference ◽  
The Impact

In order to consider the influence of nonlinear characteristics of porcelain pillar electrical equipment on the dynamic response under seismic excitation, a theoretical analysis method of nonlinear dynamics was raised to define the nonlinear parameter of the flange connection and establish a dynamic model of porcelain pillar electrical equipment. The theoretical analysis and the test results have a good degree of fitting, which verifies the correctness of the dynamic model and reveals the nonlinear seismic response law of the porcelain pillar equipment. According to the results, both the nonlinear calculation results of the displacement at the top end of the porcelain pillar and the stress at the bottom end of the porcelain pillar are smaller than the results in the linear calculation. The difference between them increases gradually with the increase of seismic excitation. The differences in displacement and stress at a seismic excitation of 0.5 g are 14.58% and 23.25%, respectively. When the nonlinear parameter increases to a certain value, the impact of maximum stress on the bottom of the porcelain pillar is very small and the change is not obvious. The research provides a theoretical reference for the seismic design of pillar electrical equipment.

scholarly journals Effect of Stress Path on the Failure Envelope of Intact Crystalline Rock at Low Confining Stress

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1119
Author(s):  
Shantanu Patel ◽  
C. Derek Martin
Keyword(s):  
Numerical Modelling ◽  
Uniaxial Tension ◽  
Laboratory Tests ◽  
Triaxial Compression ◽  
Stress Path ◽  
Crystalline Rock ◽  
Intact Rock ◽  
Particle Model ◽  
Underground Excavations ◽  
The Impact

Numerical modelling is playing an increasing role in the interpretation of geological observations. A similar phenomenon is occurring with respect to the interpretation of the stress–strain response of intact rock measured in laboratory tests. In this research, the three-dimensional (3D) bonded particle model (BPM) with flat-jointed (FJ) contact was used to investigate the impact of stress paths on rock failure. The modified FJ contact model used for these studies numerically captured most of the intact rock behavior of Lac du Bonnet granite observed in the laboratory. A numerical simulation was used to track the behavior of this rock for different stress paths, starting with uniaxial tension and compression loading conditions. The migration from uniaxial tension to triaxial compression is challenging to simulate in physical laboratory tests but commonly observed around underground excavations. The numerical modelling methodology developed for this research tracks this stress path and the impact of the intermediate stress on peak strength at low confinements, commonly found around underground excavations.

scholarly journals Comparative Analysis of Increasing Online Purchase Decisions during the Covid-19 Pandemic Period among Tangerang area and South Tangerang

2021 ◽  
Vol 19 (1) ◽  
pp. 48
Author(s):  
Diana Silaswara ◽  
Andy Andy ◽  
Tjong Se Fung
Keyword(s):  
Comparative Analysis ◽  
Regression Equations ◽  
Purchase Decisions ◽  
Test Results ◽  
Purchasing Decisions ◽  
Online Purchase ◽  
Two Factors ◽  
The Difference ◽  
The Impact ◽  
The Relationship

The basis of research aims to determine the impact of the Covid-19 pandemic, especially on the factors that trigger online purchase decisions made. This study is a comparative study because it compares the effect of Online Promotion (X1) and Lifestyle (X2) Online Purchasing Decisions (Y) between the areas of Tangerang City and South Tangerang. The research questionnaire was distributed within 11 days and obtained 165 valid respondents. The questionnaire was processed using the SPSS 20 program, and from the validity test results it turns out that only 38 statements are valid. From other test results, it was found that the statement was constant, normally distributed and did not occure heteroscedastidity and multicollinearity in the two regression equations formed in each region. The relationship between variables in each region is not very strong. The results obtained are that all hypotheses are proven, namely: Online Promotion and Lifestyle Influence on Purchasing Decisions, as well as proven that there are differences in influencing factors in the two regions. The difference that occurs is in Tangerang City the dominant purchasing decision is influenced by the Online Promotion offered, while in South Tangerang the two factors affect equally.

scholarly journals Pengaruh VariasiArus dan Posisi Pengelasan SMAW terhadap Sifat Mekanik Baja ST 37

2021 ◽  
Vol 14 (2) ◽  
pp. 134-139
Author(s):  
Iwan Nugraha Gusniar ◽  
Ahmad Juhri ◽  
Viktor Noubnome
Keyword(s):  
Tensile Strength ◽  
Weld Metal ◽  
Impact Test ◽  
Current Strength ◽  
Steel Plates ◽  
Test Results ◽  
Strong Current ◽  
The Difference ◽  
The Impact ◽  
Welding Position

The purpose of this study was to determine the difference in the value of tensile strength, impact and microstructure test results on ST 37 steel plates due to variations in current strength of 80 A, 85 A and 90 A and 1G, 2G and 3G welding positions. The results of this study show the value of Max.load, current strength of 80 A 3G welding position gets the highest value of 5650 kgf, value of Tinsile strength, current strength of 80 A 3G welding position gets the highest value of 44.78 (kgf/mm2), then the strain value, the current strength of 80 A for the 3G welding position gets the highest value of 0.9% and the value of the modulus of elasticity, the current strength of 80 A for the 3G welding position gets the highest value of 97.94 (GPa,KN/mm2), In the value of the impact test results, the current strength of 80 A is the 1G welding position that gets the highest value, which is 116 Joules. In the observation of microstructure testing, 3 points were carried out, Weld metal, HAZ and Base metal at each strong current

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