Study on the Characteristics of Elastic Wave Velocities of Rockmass under Different Test Methods

2012 ◽  
Vol 170-173 ◽  
pp. 449-452 ◽  
Author(s):  
Wu Xiu Ding ◽  
Hong Yi Wang ◽  
Bing Xie
Keyword(s):  
Elastic Wave ◽  
Influence Factors ◽  
Field Tests ◽  
Test Methods ◽  
Test Results ◽  
Penetration Test ◽  
Wave Velocities ◽  
Test Conditions ◽  
Study Results ◽  
Main Influence

There are many methods of testing elastic wave velocities of engineering rockmass such as the elastic wave penetration test between adits, elastic wave test on the adit wall and the borehole sonic method etc, but the test results vary with different test methods. It is important to understand and apply appropriately the test results. Based on the field tests, the characteristics of elastic wave velocities under different test methods are studied. The research indicates that the main influence factors of different test methods on wave velocities include the rockmass occurrence environments and the test conditions. For the elastic wave penetration test between adits, the rockmass occurrence environments are basically unchanged, and the influences of the test conditions are little, so the wave velocity obtained by this method is more scientific. The study results are important for the reasonable evaluation of engineering rockmass.

scholarly journals Evaluation of Bleeding Resistance in Chip Seal and Asphalt Emulsion Residue Rheology

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 670
Author(s):  
Preeda Chaturabong
Keyword(s):  
Influence Factors ◽  
Application Rate ◽  
Test Methods ◽  
Test Results ◽  
Asphalt Emulsion ◽  
Aggregate Gradation ◽  
Factors Affecting ◽  
Promising Tool ◽  
Chip Seal ◽  
Asphalt Emulsions

Chip seal bleeding is influenced by many factors, including design inputs, material properties, and project-specific conditions. It reduces the surface texture of the pavement and thus compromises the safety of the traveling public. Even though factors that bring about premature bleeding are known, currently, no laboratory test methods for evaluating bleeding in chip seals have been specified. The objective of this paper is to present the results of an investigation of the influence factors of asphalt emulsion residue properties measured by the ASTM D7405 multiple stress creep and recovery (MSCR) test, as well as other factors related to chip seal bleeding resistance as measured by the modified loaded wheel test (MLWT). In this study, the MSCR test was used as a tool for evaluating the performance of asphalt emulsions because it has been identified as a potential test related to bleeding in the field. In addition, MLWT was selected as a tool for evaluating chip seal bleeding performance in the laboratory. The results of the MLWT showed that the emulsion application rate (EAR), aggregate gradation, and emulsion properties were significant factors affecting bleeding. The MSCR test was found to be a promising tool for the performance evaluation of asphalt emulsion residue, as the test was able to differentiate between emulsion chemistries and modifications in terms of sensitivity to both temperature and stress. In relation to chip seal bleeding resistance, only the creep compliance (Jnr) obtained from the MSCR test results was identified as a significant property affecting potential for bleeding.

Ultimate Bearing Capacity of Headed Studs in Tensile Concrete Slab

2010 ◽  
Vol 163-167 ◽  
pp. 11-15
Author(s):  
Wen Qi Hou ◽  
Mei Xin Ye ◽  
Ye Zhi Zhang
Keyword(s):  
Bearing Capacity ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Influence Factors ◽  
Ultimate Bearing Capacity ◽  
Test Method ◽  
Test Results ◽  
Steel Girder ◽  
Push Out ◽  
Main Influence

Abstract. In the presented paper, reverse push-out test method was put forward and applied in the ultimate bearing capacity experiments of studs with concrete slab in tension. Ultimate bearing capacity experiments were carried out on 22 reverse push-out specimens composed of C50 or C40 concrete, 14MnNbq steel girder and Φ22studs. Results showed that ultimate bearing capacity of studs, pu, in tensile concrete slab is controlled by concrete failur, concrete strength, studs arragement and reinforcement ratio are the main influence factors of pu. Compared with that in compressive concrete, pu of Φ22 studs in tensile concrete is reduced about 30% averagely. According to the test results, a fitted load-slip relationship curve and a regression formula of pu for studs in tensile concrete were put forward, calculated results were in good agreement with the test results.

The operation of radial lip seals in contaminated environments and the significance of the test rig design

2000 ◽  
Vol 214 (2) ◽  
pp. 167-178 ◽  
Author(s):  
K. W. Shore ◽  
F. R. Hall ◽  
J. M. Hampshire ◽  
G. D. Carnell
Keyword(s):  
Experimental Tests ◽  
Test Methods ◽  
Ball Bearings ◽  
Bearing Failure ◽  
Test Results ◽  
Data Logging ◽  
Test Rig ◽  
Lip Seal ◽  
Test Conditions ◽  
Lip Seals

The performance and basic rating life of rotating contact ball bearings have increased substantially over recent years, but the performance of radial lip seals, designed to protect these bearings against the ingress of contaminants, has not. In particular, the failure of the lip seals used to protect self-lubricating ball bearings has been identified as a major cause of bearing failure. To understand in detail the mechanisms of failure, these bearings and seals have to be assessed by performing carefully controlled experimental tests. As elastomeric lip seals are intrinsically sensitive to test conditions, their performance is often subject to statistical scatter. Therefore, the design of test rigs to carry out this research is vital so as to eliminate as many unwanted variables as possible. Typical test rigs and the usual tests previously carried out by the major bearing manufacturers are detailed, and the performance of both the test rigs and the seals are discussed. A new radial lip seal test rig, designed specifically for assessing seal performance is shown, and improved test methods and data logging are detailed. Typical lip seal test results are presented and analysed. The aim of this work is to characterize empirically lip seal behaviour under both contaminated and uncontaminated conditions, enabling a deeper understanding of lip seal performance to aid future improved lip seal designs to be formulated.

The Research of Negative Ion Test Method for Fabric

2013 ◽  
Vol 756-759 ◽  
pp. 138-140 ◽  
Author(s):  
Yun Sen Sun ◽  
Bo Qiu ◽  
Qing Shan Li
Keyword(s):  
Influence Factors ◽  
Test Methods ◽  
Test Method ◽  
Ion Concentration ◽  
Negative Ion ◽  
Testing Device ◽  
Test Results ◽  
Influence Of Temperature ◽  
Functional Textiles ◽  
Temperature And Humidity

We developed a device for automatic closed friction and analyzed its test results in this paper, which showed the influence factors in the test methods of textile negative ion occurrence amounts. The textile negative ion occurrence amounts in different time stages were tested in this process; the analysis of its influence of temperature and humidity has certain reference significance for improving testing device for testing textile negative ion concentration, on the basis, functional textiles were also studied. Finally, we put forward the influence factors in the test methods of textile negative ion occurrence amounts.

scholarly journals Evaluation of Compressive Strength and Stiffness of Grouted Soils by Using Elastic Waves

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
In-Mo Lee ◽  
Jong-Sun Kim ◽  
Hyung-Koo Yoon ◽  
Jong-Sub Lee
Keyword(s):  
Elastic Wave ◽  
Elastic Waves ◽  
Large Strain ◽  
Small Strain ◽  
Test Results ◽  
Wave Velocities ◽  
Strength Tests ◽  
Soil Media ◽  
Strength And Stiffness ◽  
Particulate Soil

Cement grouted soils, which consist of particulate soil media and cementation agents, have been widely used for the improvement of the strength and stiffness of weak ground and for the prevention of the leakage of ground water. The strength, elastic modulus, and Poisson’s ratio of grouted soils have been determined by classical destructive methods. However, the performance of grouted soils depends on several parameters such as the distribution of particle size of the particulate soil media, grouting pressure, curing time, curing method, and ground water flow. In this study, elastic wave velocities are used to estimate the strength and elastic modulus, which are generally obtained by classical strength tests. Nondestructive tests by using elastic waves at small strain are conducted before and during classical strength tests at large strain. The test results are compared to identify correlations between the elastic wave velocity measured at small strain and strength and stiffness measured at large strain. The test results show that the strength and stiffness have exponential relationship with elastic wave velocities. This study demonstrates that nondestructive methods by using elastic waves may significantly improve the strength and stiffness evaluation processes of grouted soils.

Study on Mathematical Simulation of Nitrogen Oxides (NOx) Formation of Coal-Fired Boiler

2011 ◽  
Vol 354-355 ◽  
pp. 319-324
Author(s):  
Li Jun Heng ◽  
Kun Jie Duan ◽  
Chang Zheng He
Keyword(s):  
Nitrogen Oxides ◽  
Mathematical Models ◽  
Mathematical Simulation ◽  
Field Test ◽  
Theoretical Basis ◽  
Influence Factors ◽  
Field Tests ◽  
Test Conditions ◽  
Fluent Software ◽  
Simulation Results

There exist certain limitations to research the law and influence factors of the nitrogen oxides formation only with the help of field tests, because the nitrogen oxides formation of the boiler is influenced by various factors. The flow, combustion mathematical models interrelated and so on are established taking the 410t/h boiler fired tangentially as a prototype by the use of the fluent software. All the mathematical models are verified and modified with the aid of routine field test data, and the accuracy and reliability of the mathematical models are improved. Then NOx formation performance is stimulated in allusion to the influence factors without field test conditions. The mathematical simulation results show that mathematical models can provide a sufficient theoretical basis to analyze accurately combustion and NOx formation law in furnace, and the deficiencies of field tests have been made up.

Experiment Study on the Durability of Geotechnical Prestressed Anchorage Structure under Cyclic Loading

2011 ◽  
Vol 90-93 ◽  
pp. 201-207 ◽  
Author(s):  
Si Feng Zhang ◽  
Xiu Guang Song ◽  
Yan Mei Li
Keyword(s):  
Cyclic Loading ◽  
Fatigue Failure ◽  
Influence Factors ◽  
Test Methods ◽  
Test Results ◽  
Practical Engineering ◽  
Repetitive Loading ◽  
Failure Regularities ◽  
Loading Scheme

Based on the analysis of the pretension force influence factors for geotechnical prestressed anchorage cables that are used in a practical engineering, the cyclic loading characteristics of prestressed force long-term variation is revealed, and the conception of large and small cycles of prestressed force variety are also put forward. Based on these analysis, a device for the fatigue failure test and the corresponding test methods are manufactured and developed to analyze the durability problem of the inner bond section of prestressed anchorage structure under repetitive loading and cyclic loading. In the experiment, the means of indoor similar model test is adopted, in which the different loading scheme and loading amplitude were taken into account. According to the test results, the fatigue failure regularities of inner bond section for geotechnical prestressed anchorage structure are revealed.

Galling 50 , a Stochastic Measure of Galling Resistance

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Scott R. Hummel ◽  
Jeffrey Helm
Keyword(s):  
Stainless Steels ◽  
Test Methods ◽  
Reduction Technique ◽  
Test Results ◽  
Sigmoidal Function ◽  
Test Conditions ◽  
Stochastic Measure ◽  
Overall Performance ◽  
Data Reduction Technique ◽  
Applied Stresses

A new parameter called the Galling50 value is proposed to provide a statistically relevant measure of galling resistance. The Galling50 value represents the stress value where galling is expected to occur in 50% of the specimens tested. Galling50 is determined from the analysis of a series of tests that measure the probability of galling at different applied stresses. A method for graphically representing experimental galling data is presented. A sigmoidal function is used to mathematically represent the overall performance of the galling results. Similar to previous test methods, the proposed method provides a single parameter for reporting galling resistance results, making it suitable for comparison between different materials and test conditions. Test results for type 303, 304, and 316 stainless steels are given as an example of the testing and data reduction technique.

Study on the Dynamics Characteristics of Elastic Wave of Weathered Zone in Longmen Grottoes

2011 ◽  
Vol 105-107 ◽  
pp. 1509-1512
Author(s):  
Wu Xiu Ding ◽  
Hong Yi Wang
Keyword(s):  
Elastic Wave ◽  
Attenuation Coefficient ◽  
Wave Velocity ◽  
P Wave ◽  
Test Results ◽  
S Wave ◽  
Wave Velocities ◽  
Weathered Zone

Based on the test results, the wave velocity and the attenuation rule of elastic wave of weathered zone in Longmen Grottoes are studied. The wave velocity decreases with the increasing of the attenuation coefficient in a certain range. When wave velocity decreases to a certain value, there is not a relationship between wave velocity and attenuation coefficient. The attenuation coefficient thresholds of P-wave 0.01and S-wave 0.1 separate good rockmass quality from poor rockmass quality. The test results show that the elastic wave velocities of the surrounding rocks are generally high, which indicates that the rockmass skeleton is solid. But the rockmass anisotropy is obvious, which indicates that the structure planes are more developed. The results of the study are important for the protection of historical relics.

Analisa Pengujian Repeatability Timbangan Elektronik dengan Metode Syarat Teknis Timbangan Non Otomatis dan Metode NMI Australia

2019 ◽  
Vol 4 (2) ◽  
pp. 176-183
Author(s):  
Ponco Wali
Keyword(s):  
Research Method ◽  
Test Methods ◽  
Test Results ◽  
Repeat Testing ◽  
Testing Method ◽  
Technical Requirements

Testing repeat electronic scales with non-automatic scales technical requirements so far is fairly long if not using a calculator or computer. The aim of this research is to compare the repeatability testing method of electronic scales using methods according to the technical requirements of non-automatic scales and the Australian NMI method, both of which refer to OIML R76 in determining the validity or cancellation of electronic scales repeatability testing. This research method is done through repeat testing on 3 samples of electronic scales, then on each electronic scale 2 test methods are performed. The conclusion is that the electronic scales repeatability testing uses the non-automatic scales technical requirements method and the Australian NMI method has some differences although both refer to OIML R76. These differences include several points, namely the charge used, the method of adding additions, the formula for determining electronic scales, and different test results. The Australian NMI method is deemed to make it easier and more time efficient compared to the non-automatic weighing technical requirements method.

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