Influence Analysis and Stepwise Regression of Coal Mechanical Parameters on Uniaxial Compressive Strength Based on Orthogonal Testing Method

Abstract

Uniaxial compressive strength (UCS) and peak strain (PS) are essential indices for studying the mechanical properties of coal and rock masses, and they are closely related to mechanical parameters such as the elastic modulus (E), Poisson’s ratio (υ), cohesion (C) and internal friction angle (Φ) of coal and rock masses. This study took the No. 2-1 coal seam of Zhaogu No. 2 Mine, in Henan Province, China, as the research object. An RMT-150B servo testing machine was used to test all mechanical parameters, including the E, υ, C and Φ of coal and rock masses. Based on the principle of orthogonal testing, Three Dimensions Fast Lagrangian Analysis of Continua (FLAC3D) was used to select E, υ, C, Φ, tensile strength (Rm) and dilation angle (Ψ) as initial participation factors. Using these six parameters and a five-level combination scheme (L25 (56)), the influence of coal mechanical parameters on UCS and PS was investigated, using the software SPSS for stepwise regression analysis, and a uniaxial pressure-resistant regression prediction equation was established. The research showed that, under uniaxial compression conditions, the main parameters controlling UCS of coal masses are C and Φ; conversely, the main parameters controlling PS are E and C. UCS and PS exhibit significant linear relationships with these main controlling parameters. Here, a stepwise regression prediction equation was established through reliability verification analysis using the main controlling parameters. This prediction method produces very small errors and a good degree of fit, thus allowing the rapid prediction of UCS. The precision of the stepwise regression model depends on the number of test samples, which can be increased in the later stages of a design project to further improve the precision of the projection model.

Preparation and Biocompatibility of Poly Methyl Methacrylate (PMMA)-Mesoporous Bioactive Glass (MBG) Composite Scaffolds

“…The rebound number can be converted to uniaxial compressive strength (UCS-MPa) that, according to Wang R. and Yuan Z. [ 43 ] can be correlated to a qualitative evaluation of sample hardness.…”

Evolution of Peak Shear Strength of Rock Fractures Under Conditions of Repetitive Dry and Wet Cycling

“…The orthogonal experimental design method is based on mathematical statistics and the orthogonality principle. This method involves selecting representative points from a large number of experimental data, and arranging and analyzing these in multifactor experiments using an orthogonal table (e.g., Li and Hao, 2018;Yang et al, 2020;Zhang et al, 2020). The influencing factors include the normal stress, pH value of the soaking solution, and dry-wet cycle number.…”

Bench Testing and Modeling Analysis of Optimum Shifting Point of HMCVT

“…Regression Analysis. In order to compare and verify the accuracy of mathematical model based on response surface methodology, the test data obtained by the RSM was used to establish mathematical model in stepwise regression analysis [26][27][28][29]. e basic theory of stepwise regression modeling is to conduct F-test for each stepwise introduced independent variable and then conduct the t-test with the selected variable if the variable is selected.…”