scholarly journals Empirical Estimation of Uniaxial Compressive Strength of Rock: Database of Simple, Multiple, and Artificial Intelligence-Based Regressions

2021 ◽  
Author(s):  
Adeyemi Emman Aladejare ◽  
Emmanuel Damola Alofe ◽  
Moshood Onifade ◽  
Abiodun Ismail Lawal ◽  
Toochukwu Malachi Ozoji ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Rock Properties ◽  
Regression Equations ◽  
Compression Tests ◽  
Empirical Estimation ◽  
Empirical Relationships ◽  
Laboratory Procedure ◽  
Engineering Projects

AbstractEmpirical relationships for estimating Uniaxial Compressive Strength (UCS) of rock from other rock properties are numerous in literature. This is because the laboratory procedure for determination of UCS from compression tests is cumbersome, time consuming, and often considered expensive, especially for small to medium-sized mining engineering projects. However, these empirical models are scattered in literature, making it difficult to access a considerable number of them when there is need to select empirical model for estimation of UCS. This often leads to bias in estimated UCS data as there may be underestimation or overestimation of UCS, because of the site-specific nature of rock properties. Therefore, this study develops large database of empirical relationships between UCS and other rock properties that are reported in literatures. Statistical analysis was performed on the regression equations in the database developed. The typical ranges and mean of data used in developing the regressions, and the range and mean of their R2 values were evaluated and summarised. Most of the regression equations were found to be developed from reasonable quantity of data with moderate to high R2 values. The database can be easily assessed to select appropriate regression equation when there is need to estimate UCS for a specific site.

Empirical estimation of uniaxial compressive strength of shale formations

Geophysics ◽  
2014 ◽  
Vol 79 (4) ◽  
pp. D227-D233 ◽  
Author(s):  
Mohsen Farrokhrouz ◽  
Mohammad Reza Asef ◽  
Riyaz Kharrat
Keyword(s):  
Compressive Strength ◽  
Young’S Modulus ◽  
Uniaxial Compressive Strength ◽  
Young's Modulus ◽  
Primary Objective ◽  
Alternative Methods ◽  
Rock Properties ◽  
Empirical Estimation ◽  
Shale Formations ◽  
Core Samples

The uniaxial compressive strength of rock ([Formula: see text]) is an important parameter for petroleum engineers, drilling operations, and all related activities from exploration through to production and abandonment. A thorough understanding of the parameters affecting [Formula: see text] is a basic prerequisite for accurate geomechanical modeling of the reservoir and overburden properties. Uniaxial compressive strength plays a significant role in mud weight determination while drilling, especially for a troublesome lithology such as shale. However, standard geomechanical practice requires well-preserved core samples for measurement of [Formula: see text] in the lab. Because core samples are not often available, there is a need for alternative methods to obtain fit-for-purpose values of [Formula: see text], based on other related rock parameters. Our primary objective was to identify a minimum set of related rock properties that could be used to predict [Formula: see text]. From a review of existing data in the literature, supplemented by laboratory measurements on Iranian samples, we established a database and accomplished extensive statistic analysis. Also, a normality test was executed to make sure a statistically acceptable set of data was collected. We suggested that two parameters of Young’s modulus ([Formula: see text]) and porosity ([Formula: see text]), which might be estimated from geophysical log data, were sufficient for a reliable prediction of [Formula: see text] in shale formations, and the overall contribution of [Formula: see text] was more than [Formula: see text]. We obtained a prediction equation with improved accuracy compared to previous investigations. Furthermore, we determined that the relative sensitivity of shale strength to porosity and Young’s modulus very much depended on the range of porosity.

scholarly journals Plane-Strain Compressive Strength of Columnar-Grained and Granular-Snow Ice

1977 ◽  
Vol 18 (80) ◽  
pp. 505-516 ◽  
Author(s):  
R. Frederking
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Plane Strain ◽  
Uniaxial Compressive Strength ◽  
Ice Cover ◽  
Anisotropic Structure ◽  
Compression Tests ◽  
Isotropic Structure ◽  
Plane Strain Case

Abstract An ice cover impinging on a long straight structure is assumed to be under a condition of plane strain. A technique is described for performing plane-strain compression tests, and results are presented for the strain-rate dependence of strength. The plane-strain compressive strength of ice having anisotropic structure (columnar-grained ice) is at least two and a half times the uniaxial compressive strength, whereas the plane-strain compressive strength of ice having an isotropic structure (granular-snow ice) is at most 25% greater than the uniaxial case. The greater plane-strain compressive strength of columnar grained ice when the loading and confining directions are in the plane of the ice cover, can be attributed to its anisotropic structure, which leads to a different failure mechanism for the plane-strain case.

EFFECT OF PETROLOGICAL FEATURES ON MECHANICAL PROPERTIES OF ROCK SALT FROM THE LGOM (LEGNICA–GŁOGÓW COPPER DISTRICT)

2016 ◽  
pp. 51-64 ◽  
Author(s):  
Katarzyna CYRAN ◽  
Tomasz TOBOŁA ◽  
Paweł KAMIŃSKI
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Rock Salt ◽  
Fluid Inclusions ◽  
Mechanical Parameters ◽  
Research Results ◽  
Strength Tests ◽  
Crystal Boundaries

The paper presents the attempt to find a correlation between the content of impurities and mechanical parameters of rock salt from the LGOM. Research was carried out in three steps: uniaxial compressive strength tests, determination of the content of insoluble minerals (impurities), and observations under the microscope and Raman microspectroscopy. The research results reveal that the rock salt which is characterized by low content of insoluble minerals (0.13–2.11% wt.) shows no correlation between the mechanical properties and the content of impurities. However, it was found that mechanical properties depend on both the distribution of impurities in halite crystals and the presence of fluid inclusions and hydrocarbons along the crystal boundaries. Moreover, the distribution of anhydrite at the edges of halite crystals may influence an increase of rock salt strength. On the contrary, the presence of fluid inclusions and hydrocarbons along the halite crystal boundaries may reduce the rock salt strength.

Effect of Rock Properties on Excavation-Loading Operation in Selected Quarries

2013 ◽  
Vol 824 ◽  
pp. 86-90 ◽  
Author(s):  
B. Adebayo ◽  
A.E. Aladejare
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Strong Relationship ◽  
Strength Properties ◽  
Biotite Granite ◽  
Point Load ◽  
Rock Properties ◽  
Filling Rate ◽  
Strength Parameters ◽  
Point Load Strength

The effect of rock properties on excavation-loading operation in quarries was investigated by conducting test on the mechanical properties of selected rocks. These rock samples were tested in the laboratory for specific gravity, point load strength, uniaxial compressive strength and mineral composition using weigh balance, point load tester, 1100kN compression machine and petrological microscope respectively. The filling rates of the front end loaders bucket were determined. The result obtained show that value of uniaxial compressive strength varied from 29.22 MPa-30.87 MPa. The bucket filling rate varied from 0.180-0.250 m3/s and 0.145-0.170 m3/s for porphyritic biotite granite and coarse biotite granite respectively. There is strong relationship between bucket filling rate and strength properties with values of R2 ranging from 0.9737 to 0.9981.Therefore strength parameters of the rock have effect on excavation loading operation in quarries.

Study on Damage of Rock Samples with Single-Hole under Uniaxial Compression Condition

2012 ◽  
Vol 446-449 ◽  
pp. 3810-3813
Author(s):  
Bing Xie ◽  
Huai Feng Tong ◽  
Xiang Xia
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compression ◽  
Uniaxial Compressive Strength ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Compression Tests ◽  
Rock Samples ◽  
Single Hole ◽  
Compression Condition

Numerical specimens with single-hole is established by particle flow code PFC2D and uniaxial compression tests are conducted. Studies have shown that uniaxial compressive strength of specimen with single hole is less than complete specimens. As the holes move to the end of specimen, the uniaxial compressive strength first increases and then tends to decrease.

scholarly journals Plane-Strain Compressive Strength of Columnar-Grained and Granular-Snow Ice

1977 ◽  
Vol 18 (80) ◽  
pp. 505-516 ◽  
Author(s):  
R. Frederking
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Failure Mechanism ◽  
Plane Strain ◽  
Uniaxial Compressive Strength ◽  
Ice Cover ◽  
Anisotropic Structure ◽  
Compression Tests ◽  
Isotropic Structure ◽  
Plane Strain Case

AbstractAn ice cover impinging on a long straight structure is assumed to be under a condition of plane strain. A technique is described for performing plane-strain compression tests, and results are presented for the strain-rate dependence of strength. The plane-strain compressive strength of ice having anisotropic structure (columnar-grained ice) is at least two and a half times the uniaxial compressive strength, whereas the plane-strain compressive strength of ice having an isotropic structure (granular-snow ice) is at most 25% greater than the uniaxial case. The greater plane-strain compressive strength of columnar grained ice when the loading and confining directions are in the plane of the ice cover, can be attributed to its anisotropic structure, which leads to a different failure mechanism for the plane-strain case.

scholarly journals Modelling Hydration Swelling and Weakening of Montmorillonite Particles in Mudstone

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 428 ◽  
Author(s):  
Changlun Sun ◽  
Guichen Li ◽  
Yuantian Sun ◽  
Jintao He ◽  
Haoyu Rong
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Uniaxial Compressive Strength ◽  
Underground Water ◽  
Experimental Results ◽  
Microscopic Structure ◽  
Compression Tests ◽  
Stress Changes ◽  
Mineral Components ◽  
Compaction Stress

It is of paramount importance to understand the hydration swelling and weakening properties of clay minerals, such as montmorillonite, to determine their mechanical responses during deep underground argillaceous engineering. In this study, the mineral components and microscopic structure of mudstone were characterised using X-ray powder diffraction and field-emission scanning electron microscopy. Experimental schemes were devised to determine the properties of mudstone under the influence of underground water and stress; these involved compacting montmorillonite particles with various water contents and conducting uniaxial compression tests. Experimental results demonstrated that compaction stress changes the microscopic structure of the montmorillonite matrix and affects its properties, and stress independency was found at particular water and stress conditions. Two equations were then obtained to describe the swelling and weakening properties of the montmorillonite matrix based on the discrete element method; further, the hydration swelling equation represents the linear decrease in the density of the montmorillonite matrix with an increase in the water content. It was also determined that the water dependency of uniaxial compressive strength can be described by negative quartic equations, and the uniaxial compressive strength of the montmorillonite matrix is just 0.04 MPa with a water content of 0.6. The experimental results are in good agreement with the calculated solutions and provide an important experimental basis to the understanding of the mechanical properties of montmorillonite-rich mudstones under the influence of underground water and stress.

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