scholarly journals NUMERICAL AND EXPERIMENTAL RESEARCH OF ROCK FAILURE MECHANISM AND ITS DEPENDENCE ON mi HOEK-BROWN FAILURE CRITERION

2021 ◽  
Vol 36 (3) ◽  
pp. 157-165
Author(s):  
Sina Salajegheh ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari

Rock failure mechanism is one of the most important issues in rock mechanics engineering which plays a key role in the stability analysis of various structures. Therefore, different failure criteria have been proposed to understand the failure mechanism of rocks. One of the most commonly used rock failure criteria is the Hoek-Brown criterion, in which there is a parameter called mi, which is very important to the response provided by this criterion. Due to the importance of conducting extensive studies on this parameter, in this current research, by performing a series of experimental triaxial compressive strength test and numerical simulating in PFC-2D code, the effect of the Hoek-Brown constant mi on the failure mechanism and crack growth of different rocks has been studied. Based on the results of this study, it was found that the effect of parameter mi on the failure mechanism of different rocks varied according to the type of rocks, and the greatest effect of this parameter was on the peak strength of rocks. In addition, it was found that under higher lateral pressures, there are less destructive cracks in rocks, and as a result, they show more ductile behaviour.

2019 ◽  
Vol 248 ◽  
pp. 256-266 ◽  
Author(s):  
Mahdi Ashtari ◽  
Seyedeh Elham Mousavi ◽  
Akbar Cheshomi ◽  
Mashallah Khamechian

2018 ◽  
Vol 203 ◽  
pp. 06022
Author(s):  
Salmia Beddu ◽  
Daud Mohamad ◽  
Fadzli Mohamed Nazri ◽  
Siti Nabihah Sadon ◽  
Mohamed Galal Elshawesh

This study investigates the self-curing concrete using baby polymer diapers as substitute method of curing process in order to improve mechanical and physical properties of concrete. Three different proportion of baby polymer diapers which are 1%, 3% and 5% were mix with concrete. Slump, compressive strength and drying shrinkage test were performed in order to study the workability, strength and durability of the concrete. All concrete were tested for 1, 3, 7, 14, and 28 days for drying shrinkage test. Meanwhile, all concrete were test at 3, 7 and 28 days for compressive strength test. Compressive strength of concrete containing 5% baby polymer diapers show the highest strength at 28 days compared to others percentage. Thus, it indicates that application of baby polymer diaper as self-cure agent can improve the concrete performances.


2014 ◽  
Vol 2 (1) ◽  
pp. 75-82
Author(s):  
Elivs M. Mbadike ◽  
N.N Osadebe

In this research work, the effect of mound soil on concrete produced with river sand was investigated. A mixed proportion of 1.1.8:3.7 with water cement ratio of 0.47 were used. The percentage replacement of river sand with mound soil is 0%, 5%, 10%, 20%, 30% and 40%. Concrete cubes of 150mm x 150mm x150mm of river sand/mound soil were cast and cured at 3, 7, 28, 60 and 90 days respectively. At the end of each hydration period, the three cubes for each hydration period were crushed and their average compressive strength recorded. A total of ninety (90) concrete cubes were cast. The result of the compressive strength test for 5- 40% replacement of river sand with mound soil ranges from 24.00 -42.58N/mm2 a against 23.29-36.08N/mm2 for the control test (0% replacement).The workability of concrete produced with 5- 40% replacement of river sand with mound soil ranges from 47- 62mm as against 70mm for the control test.


Author(s):  
Edward Dinoy ◽  
Yohanes Gilbert Tampaty ◽  
Imelda Srilestari Mabuat ◽  
Joseph Alexon Sutiray Dwene

The compressive strength test is one of the technical properties or compressive strength tests that are commonly used in rock mechanics to determine the collapse point or the elasticity of rock against maximum pressure. The rock collapse point is a measure of the strength of the rock itself when the rock is no longer able to maintain its elastic properties. The purpose of this test is to find out how long the rock maintains its strength or elasticity properties when pressure is applied, and to find out the difference between the strength of compact rock and rock that has fractures when pressure is applied. Rocks that have fractures will break more easily or quickly when pressure is applied compared to compact rocks. This analysis is carried out by comparing the rock strength of each sample, both those that have fractures and compact rocks. To find out these differences, laboratory testing was carried out. The test results show the value (compressive strength test 57.76 MPa), (elastic modulus 5250.000MPa), (Poisson ratio 0.05) and the average value of rock mechanical properties test (axial 0.91), (lateral-0.279), and (volumetric 0.252) . Based on the test results above, it shows that rocks that have fractures will break more easily when pressure is applied, compared to compact rocks that have a long time in the uniaxial compressive strength test.


2020 ◽  
Vol 323 ◽  
pp. 01018
Author(s):  
Wei-Ting Lin ◽  
Lukáš Fiala ◽  
An Cheng ◽  
Michaela Petříková

In this study, the different proportions of co-fired fly ash and ground granulated blast-furnace slag were used to fully replace the cement as non-cement blended materials in a fixed water-cement ratio. The recycled fine aggregates were replaced with natural fine aggregates as 10%, 20%, 30%, 40% and 50%. The flowability, compressive strength, water absorption and scanning electron microscope observations were used as the engineered indices by adding different proportions of recycled fine aggregates. The test results indicated that the fluidity cannot be measured normally due to the increase in the proportion of recycled fine aggregates due to its higher absorbability. In the compressive strength test, the compressive strength decreased accordingly as the recycled fine aggregates increased due to the interface structure and the performance of recycled aggregates. The fine aggregates and other blended materials had poor cementation properties, resulting in a tendency for their compressive strength to decrease. However, the compressive strength can be controlled above 35 MPa of the green non-cement blended materials containing 20% recycled aggregates.


2019 ◽  
Vol 3 (2) ◽  
pp. 81-89
Author(s):  
Angga Pirman Firdaus ◽  
Jonbi

Indonesia ranks second in the world's largest plastic waste producer after China. Each year, Indonesia can contributeup to 187.2 million tons of plastic waste, while China reaches 262.9 million tons of plastic waste. Based on the data, one way to utilize plastic waste by using plastic waste as a mixture of concrete, where the plastic used is polypropylene (PP) plastic with different percentage of concrete mixture, the test includes compressive strength test and tensile concrete. The results of concrete compressive strength testing with polypropylene (PP) plastic waste mixture of 5%, 10% and 15% at age 28 in aggregate aggregate mixture decreased by 5.15%, 6.89% and 13.53%. As for the result of concrete tensile strength test with polypropylene (PP) plastic waste mixture of 5%, 10% and 15% at age 28 in crude aggregate mixture decreased 17,61%, 24,13% dan 23,24%.


Author(s):  
Muhammad Arslan ◽  
Muhammad Asif Saleem ◽  
Maria Yaqub ◽  
Muhammad Saleem Khan

The focus of this research work was to analyse the effect of different types of curing oncompressive strength of concrete structures. For this purpose, 54 test specimens of cylindrical shape wereprepared. These specimens were cured with different methods and were tested on different age days toanalyse the effect of curing on compressive strength. Test specimens cured with conventional water curingmethod gives the highest results as compared to the other adopted methods.


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