scholarly journals Experimental Investigations on Creep Behavior of Coal under Combined Compression and Shear Loading

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Rongbin Hou ◽  
Leige Xu ◽  
Duoxin Zhang ◽  
Yanke Shi ◽  
Luyang Shi
Keyword(s):  
Inclination Angle ◽  
Creep Test ◽  
Creep Behavior ◽  
Shear Loading ◽  
Peak Strength ◽  
Term Strength ◽  
Creep Tests ◽  
Inclination Angles ◽  
Pure Compression

The creep behavior of rock has received much attention for analyzing the long-term response and stability of underground rock engineering structures. Numerous studies have been carried out on the creep properties of various rocks under pure compression conditions. However, little attention has been paid to the creep behavior of rocks in a combined compression-shear loading state. In this work, a novel combined compression and shear test (C-CAST) system was used to carry out inclined uniaxial compression tests and creep tests for various inclination angles (0°, 5°, 10°, and 15°). The results revealed that the peak strength of the coal decreased with the inclination angle of the specimen, which could provide the basis for setting up a creep test scheme. Multistage compression-shear creep tests were carried out on specimens with different inclination angles. Based on the analysis of the creep test data, the creep behavior of the coal in a combined compression-shear state was studied. It was found that the specimen inclination affected the time-dependent deformation, long-term strength (LTS), and time to failure. Compared with the specimen under pure compression, the inclination specimens tend to produce large shear strain with time, while they were more prone to shear failure. The reduction of the long-term strength was closely associated with the increase of the specimen inclination angle when the angle was more than 5°. Moreover, the ratio of the peak strength to the LTS was not affected by the specimen inclination, which is considered an inherent characteristic. We anticipate that the results obtained will assist in pillar design and long-term stability analysis.

An Experimental Study on the Creep of FRC Sub-Base for Pavement Using a New Testing Device

2013 ◽  
Vol 639-640 ◽  
pp. 493-497
Author(s):  
Woo Tai Jung ◽  
Sung Yong Choi ◽  
Young Hwan Park
Keyword(s):  
Creep Test ◽  
Strain Curve ◽  
Hydraulic Pressure ◽  
Slight Variation ◽  
Test Results ◽  
Creep Tests ◽  
Loading Device ◽  
Permanent Load ◽  
Term Creep

The hydraulic loading device commonly used for creep test necessitates continuous recharge of the hydraulic pressure with time and is accompanied by slight variation of the permanent load at each recharge. Therefore, accurate test results cannot be obtained for long-term creep tests requiring time-dependent behavioral analysis during more than 6 months. This study conducts creep test as part of the analysis of the long-term characteristics of fiber-reinforced lean concrete sub-base of pavement. The creep test is executed using the new load-amplifier device not a conventional loading device. Since the results of the preliminary verification test on the new creep test device show that constant permanent load is applied without significant variation, it can be expected that more accurate measurement of the creep will be possible in a long-term compared to the conventional hydraulic device. In addition, the creep test results of sub-base specimens reveal the occurrence of large instantaneous elastic strain, differently from the strain curve observed in ordinary concrete, as well as the occurrence of small creep strain leading to low creep coefficient.

scholarly journals Effect of Moisture Content On The Time-Dependent Mechanical Characteristics of Loess

2021 ◽  
Author(s):  
Lijie Chen ◽  
Jianbing Peng ◽  
Fei Xie ◽  
Yanqiu Leng ◽  
Penghui Ma ◽  
...  
Keyword(s):  
Moisture Content ◽  
Failure Mode ◽  
Shear Failure ◽  
Time Dependent ◽  
Shanxi Province ◽  
Peak Strain ◽  
Term Strength ◽  
Creep Tests ◽  
Effect Of Moisture

Abstract It is of great significance to study the time-dependent mechanical properties of loess, as loess landslides are closely related to them. The purpose of this study is to investigate the effect of moisture content on instantaneous and time-dependent deformation, strength and failure behaviors of undisturbed loess specimens from Nangou in Yan'an City, Shanxi Province, China, via triaxial shearing tests and multi-loading triaxial creep tests under moisture contents of 5%, 10%, 17% and 22%. The results show that the time-dependent deformation of loess increase with the moisture content, while the time-dependent deformation rate decreases slowly. The soil deformation is divided into four stages based on the peak strain rate. Furthermore, the instantaneous and long-term strength of loess decrease with increasing moisture content, and the instantaneous strength decreases more than the long-term strength. The failure mode of undisturbed loess changes from shear failure to homogeneous failure with increasing moisture content; when the failure mode is shear failure, the thickness of the shear band that forms at the specimen surface over time is smaller than the corresponding thickness that forms instantaneously. Finally, the macroscopic morphology and microstructure of loess specimens were considered together to analyze the effect of moisture content on the instantaneous and long-term mechanical behavior of loess and to discuss the process of loess deformation to failure.

scholarly journals Flexural creep behavior of structural insulated timber panels

2021 ◽  
Author(s):  
Mohammad Hossein Zarghooni
Keyword(s):  
Creep Test ◽  
Creep Behavior ◽  
Experimental Testing ◽  
Test Methods ◽  
Load Test ◽  
Test Results ◽  
Financing Costs ◽  
Wood Frame ◽  
Term Creep

A Structural Insulated Panel (SIP) is a panel composed of insulation core laminated between two oriented-strand boards (OSB). SIPs deliver building efficiencies by replacing several components of traditional residental and commercial construction, including: (i) studs; (ii) insulation; (iii) vapour barrier; and (iv) air barrier. A SIP-based structure offers superior insulation, exceptional strength, and fast installation. Besides those benefits, the total construction costs are less with SIPs compared to wood-framed homes, expecially when considering speed of construction, less expensive HVAC equipment required, reduced site waste, reduction construction financing costs, more favourable energy-efficient mortages available, and lower cost of owning a home built with SIPS. This thesis presents the experimental testing on selected SIP sizes to investigate their short- and long-term creep behavior under sustained loading. The experiment study performed in a manner to comply with applicable test methods and, Canadian Codes. Short-term creep test results showed the structural adequacy of the tested panels, while the long-term creep test results established the increase in panel total deflection with time. The ultimate load test results showed that the structural qualification of SIPs is "as good as" the structural capacity of the conventional wood-frame buildings.

Experimental Study on Direct Shear Creep Characteristics and Long-Term Strength of Red Layer Sliding Zone Soil in Southern Hunan

2013 ◽  
Vol 842 ◽  
pp. 782-787 ◽  
Author(s):  
Feng Zhu ◽  
Zhong Yuan Duan ◽  
Zhen Yu Wu ◽  
Yu Qi Wu ◽  
Tian Long Li ◽  
...  
Keyword(s):  
Shear Stress ◽  
Term Strength ◽  
Direct Shear ◽  
Creep Tests ◽  
Shear Creep ◽  
Creep Characteristics ◽  
Southern Hunan ◽  
Sliding Soil ◽  
Sliding Zone

The creep characteristics of red layer sliding soil under the condition of different vertical loads and water contents were studied through a series of direct shear creep tests. Tests results showed that the water infiltrated to the sliding zone along the fissure of red layer sliding belt due to the crush of red layer sliding rock, leading to softening of sliding zone and acceleration of shear creep. When the shear stress reached the limit of long-term shear strength, sliding soil was broken suddenly with small vertical loads (50 kPa and 100kPa), while the sliding soil presented as a constant acceleration creep with enough vertical loads (200 kPa and 300 kPa). The inflection point in shear stress-shear displacement isochronous curve corresponded to the long-term strength of the soil.

Predicting the Long-term Creep Behavior of Plastics Using the Short-term Creep Test

2004 ◽  
Vol 19 (3) ◽  
pp. 313-319 ◽  
Author(s):  
S. D. Lim ◽  
J. M. Rhee ◽  
C. Nah ◽  
S.-H. Lee ◽  
M.-Y. Lyu
Keyword(s):  
Creep Test ◽  
Creep Behavior ◽  
Short Term ◽  
Term Creep ◽  
Short Term Creep

scholarly journals Experimental Researches on Long-Term Strength of Granite Gneiss

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Lin Liu ◽  
Weiya Xu
Keyword(s):  
Quantitative Methods ◽  
Strain Curve ◽  
Granite Gneiss ◽  
Term Strength ◽  
Creep Tests ◽  
New Methods ◽  
Tangent Method ◽  
Triaxial Creep ◽  
Triaxial Creep Tests

It is important to confirm the long-term strength of rock materials for the purpose of evaluating the long-term stability of rock engineering. In this study, a series of triaxial creep tests were conducted on granite gneiss under different pore pressures. Based on the test data, we proposed two new quantitative methods, tangent method and intersection method, to confirm the long-term strength of rock. Meanwhile, the isochronous stress-strain curve method was adopted to make sure of the accuracy and operability of the two new methods. It is concluded that the new methods are suitable for the study of the long-term strength of rock. The effect of pore pressure on the long-term strength of rock in triaxial creep tests is also discussed.

Creep Behavior of Building Silicone Sealant under Long-Term External Loading and its Time-Stress Equivalence

2014 ◽  
Vol 633 ◽  
pp. 451-454
Author(s):  
Xiao Gen Liu ◽  
Yi Wang Bao ◽  
Xiu Fang Wang
Keyword(s):  
Creep Curve ◽  
Creep Behavior ◽  
External Loading ◽  
Nonlinear Creep ◽  
Creep Tests ◽  
Time Stress ◽  
Silicone Sealant ◽  
Term Creep ◽  
Term Performance

The main mechanics behavior character of building silicone sealant is its time dependence£¬which lies in the existence of the interior timepiece or the characteristic time. The creep behaviors were fundamental to evaluating the long-term performance of the building silicone sealant under long-term external loading. A series of creep tests of building silicone sealant were conducted in the laboratory under different combinations of external loads, the characteristics of the creep curve were obtained. In this work, the creep behaviors of building silicone sealant were also investigated under various temperatures at invariable stress. The test measurements show that the creep behavior of building silicone sealant are nonlinear, Nonlinear creep behavior is analyzed by means of the equivalence principle of time-stress, the main creep curve under reference stress was obtained by fitting with the viscoelastic rheological model. So the long-term creep behavior of the building silicone sealant under lower stress can be predicted by short-term creep behavior under higher stress.

scholarly journals Creep Resistance of VM12 Steel

2016 ◽  
Vol 61 (3) ◽  
pp. 1635-1640 ◽  
Author(s):  
A. Zieliński ◽  
G. Golański ◽  
J. Dobrzański ◽  
M. Sroka
Keyword(s):  
Functional Properties ◽  
Creep Test ◽  
Creep Resistance ◽  
Practical Aspect ◽  
Test Results ◽  
Creep Tests ◽  
Steam Parameters ◽  
Term Creep ◽  
Long Term Impact

Abstract This article presents selected material characteristics of VM12 steel used for elements of boilers with super- and ultra-critical steam parameters. In particular, abridged and long-term creep tests with and without elongation measurement during testing and investigations of microstructural changes due to long-term impact of temperature and stress were carried out. The practical aspect of the use of creep test results in forecasting the durability of materials operating under creep conditions was presented. The characteristics of steels with regard to creep tests developed in this paper are used in assessment of changes in functional properties of the material of elements operating under creep conditions.

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