scholarly journals Substantiation of determination of strength performance of coarse-grained media by the oblique shear method

2021 ◽  
Vol 315 ◽  
pp. 01005
Author(s):  
Sergey Shabaev ◽  
Sergey Ivanov
Keyword(s):  
Particle Size ◽  
Granular Media ◽  
Design Method ◽  
Construction Materials ◽  
Road Construction ◽  
Coarse Grained ◽  
Open Pit ◽  
Strength Performance ◽  
Maximum Particle

The constantly increasing loads of vehicles predetermine the search for ways to improve both design methods, technological processes and the search for ways to improve the quality of road construction materials. The increasing volumes of open-pit coal mining require finding ways to improve the haul roads of open-pit coal mines. Thus, a qualitatively new approach is needed to determine the strength performance of coarse-grained media. In this work, it is proposed to determine the strength performance of granular media by the oblique shear method, since today there is no design method to determine the strength performance of coarse-grained media. The proposed design of the advanced oblique shear apparatus makes it possible to determine the strength performance of pre-compacted coarse-grained media with a particle size of up to 20-30 mm. To avoid the effect of keyways and chaotic results, the optimum clearance between the upper and the lower holders should be 0.3 times the maximum particle size.

scholarly journals Oblique shear method for determining strength performance of pre-compacted very coarse soils

2020 ◽  
Vol 59 (3) ◽  
pp. 115-122
Author(s):  
Sergey Nikolaevich SHABAEV ◽  
◽  
Natal’ya Vasil’evna KRUPINA ◽  
Viktor Aleksandrovich SHALAMANOV ◽  
Nikita Aleksandrovich MARTEL’ ◽  
...  
Keyword(s):  
Particle Size ◽  
Weighted Average ◽  
Breaking Load ◽  
Crushed Stone ◽  
Open Pit ◽  
Crushed Rock ◽  
Strength Performance ◽  
Average Value ◽  
Maximum Particle Size ◽  
Maximum Particle

The relevance of the work. Crushed stone, crushed rock and very coarse (mostly crushed plant) soils are the most widely used in the construction of open pit haul roads. However, the strength performance of these media has been studied insufficiently, due, inter alia, to the fact that there are no reliable methods for their determination. The purpose of the work is to develop a reliable method for determining the strength performance of pre-compacted crushed stone, crushed rock and very coarse soils. Research methods. To achieve the purpose, an analysis of the design features of the existing oblique shear apparatus was carried out, elements and nodes were identified that needed refinement to ensure test media pre-compaction, a statistical analysis of the data obtained on the improved oblique shear apparatus, as well as their comparison with the results obtained by testing according to standard methods, were performed. Research results. A design of an improved oblique shear apparatus has been developed, which allows determining the strength performance of statically and dynamically pre-compacted crushed stone, crushed rock and very coarse soils. The required geometric parameters of its individual elements are determined depending on the maximum particle size of the test media, and the order of preparation for the experiment and its conduct is given. Conclusions. The proposed design of an improved oblique shear apparatus allows determining the strength performance of pre-compacted crushed stone, crushed rock and very coarse soils with a particle size of up to 20–30 mm. In order to avoid the occurrence of a keyway effect and to obtain chaotic results, the optimal clearance between the upper and lower holders should be 0.3 of the maximum particle size. To obtain the confidence interval of the measured breaking load value ±10% of the weighted average value with a confidence level of 90% when implementing the oblique shear method, taking into account possible misses, it is necessary to repeat the experiment with the same factors at least 5 times.

scholarly journals Improving the method for determining the granular media strength performance by oblique shear test

2020 ◽  
Vol 174 ◽  
pp. 01064
Author(s):  
Sergey Shabaev ◽  
Nikita Martel ◽  
Artemy Shtark ◽  
Elmira Rysbekova
Keyword(s):  
Granular Media ◽  
Shear Resistance ◽  
Coarse Grained ◽  
Open Pit ◽  
Shear Stresses ◽  
Density Structure ◽  
Strength Performance ◽  
Improved Design ◽  
Under Construction ◽  
Shear Area

To ensure the strength performance of the pavement of open pit truck roads, it is necessary that it conforms not only to the designed required deformation (elasticity) modulus, but also to the condition for ensuring the shear resistance of structural layers made from non-cohesive and lowly cohesive granular media. However, today there are no reliable methods for determining the strength performance of coarse-grained materials, therefore, for them there are no designstrength values, and therefore their shear resistance is not evaluated, which is a serious omission. It is proposed to evaluate the strength performance of granular media by the oblique sheartest, for which an improved design of oblique shear apparatus was developed, which made it possible to adjust the granular medium density (structure) to the corresponding density (structure) under construction conditions. An analysis was also made of the influence of the angle of inclination of the shear area on the predicted values of normal and shear stresses arising in the cross section, which made it possible to establish the recommended values of this indicator depending on the prevailing particle size of the test medium.

Determination of maximum particle size in magnetic fluids

2016 ◽  
Vol 78 (2) ◽  
pp. 269-272 ◽  
Author(s):  
I. M. Aref’ev ◽  
A. V. Lebedev
Keyword(s):  
Particle Size ◽  
Magnetic Fluids ◽  
Maximum Particle Size ◽  
Maximum Particle

scholarly journals Experimental Studies of Scale Effect on the Shear Strength of Coarse-Grained Soil

2022 ◽  
Vol 12 (1) ◽  
pp. 447
Author(s):  
Shuya Li ◽  
Tiancheng Wang ◽  
Hao Wang ◽  
Mingjie Jiang ◽  
Jungao Zhu
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Scale Effect ◽  
Friction Angle ◽  
Coarse Grained ◽  
Test Results ◽  
Maximum Particle Size ◽  
Maximum Particle ◽  
Coarse Grained Soil

Shear strength is an essential index for the evaluation of soil stability. Test results of the shear strength of scaled coarse-grained soil (CGS for short) are usually not able to accurately reflect the actual properties and behaviors of in situ CGS due to the scale effect. Therefore, this study focuses on the influence of the scale effect on the shear strength of scaled CGS, which has an important theoretical significance and application for the strength estimation of CGS in high earth-rock dam engineering. According to previous studies, the main cause of the scale effect for scaled CGS is the variation of the gradation structure as well as the maximum particle size (dmax), in which the gradation structure as a characteristic parameter can be expressed by the gradation area (S). A total of 24 groups of test soil samples with different gradations were designed by changing the maximum particle size dmax and gradation area S. Direct shear tests were conducted in this study to quantitatively explore the effect of the gradation structure and the maximum particle size on the shear strength of CGS. Test results suggest that the shear strength indexes (i.e., the cohesion and internal friction angle) of CGS present an increasing trend with the improvement of the maximum particle size dmax, and thus a logarithmic function relationship among c, φ, and dmax is presented. Both cohesion (c) and internal friction angle (φ) are negatively related to the gradation area (S) in most cases. As a result, an empirical relationship between c, φ, and S is established based on the test results. Furthermore, a new prediction model of shear strength of CGS considering the scale effect is proposed, and the accuracy of this model is verified through the test results provided by relevant literature. Finally, the applicability of this model to different types of CGS is discussed.

Alternative method of determining resilient modulus of subbase soils using a static triaxial test

2001 ◽  
Vol 38 (1) ◽  
pp. 117-124
Author(s):  
Dong-Soo Kim ◽  
Gi-Chul Kweon ◽  
Suckkeun Rhee
Keyword(s):  
Particle Size ◽  
Resilient Modulus ◽  
Triaxial Compression ◽  
Testing Procedure ◽  
Loading Frequency ◽  
Bulk Stress ◽  
Maximum Particle ◽  
Effect Of Particle Size ◽  
Static Triaxial Test

The cyclic test for the determination of resilient modulus (MR) is often too complex and time-consuming to be applicable on a production basis. Therefore, the development of a simple and reliable alternative MR testing technique is essential for the application in the mechanistic design of a flexible pavement system. Seven disturbed subbase soils were collected from the actual pavement projects for testing. To evaluate the effect of particle size on MR, standard MR tests with various maximum particle sizes and specimen diameters were performed using three subbase soils. The resilient moduli determined from various specimen sizes with the same particle-size distribution were almost identical. However, the value of the slope parameter k2 in the bulk stress model was constant, but the value of k1 increased with a decrease in maximum particle size. The effects of mean effective stress, loading frequency, and number of loading cycles on modulus were evaluated from torsional shear (TS), triaxial (TX), and MR tests. The alternative MR testing procedure using the static TX test was proposed considering deformational characteristics of subbase soils. The predicted MR values from the proposed method matched well with those determined by the standard MR test, showing the capability of the proposed method for determining MR.Key words: resilient modulus (MR), alternative MR test, subbase soils, triaxial compression test, deformational characteristics, particle size.

CREDO RADON UA – INFORMATION MODEL FOR CALCULATION OF ROAD CONSTRACTION

2019 ◽  
pp. 34-42
Author(s):  
Volodymyr Karedin ◽  
Nadiya Pavlenko
Keyword(s):  
Design Process ◽  
Static Loading ◽  
Computer Aided Design ◽  
Experimental Studies ◽  
Construction Materials ◽  
Residual Deformation ◽  
Road Construction ◽  
Information Support ◽  
Existing Structures ◽  
Road Pavement

CREDO RADON UA software provides an automated calculation of the strength of the pavement structures of non-rigid and rigid types, as well as the calculation of the strengthening of existing structures. In the article, one can see the main features and functionality of the CREDO RADON UA software, the main points in the calculations according to the new regulations. Information support of the design process includes necessary databases, informational and helping materials that make up the full support of the pavement design process. The concept of CREDO RADON UA 1.0 software is made on the use of elasticity theory methods in calculations of initial information models of pavements. Performing optimization calculations, the roadwear in CREDO RADON UA is designed in such a way that no unacceptable residual deformation occurs under the influence of short-term dynamic or static loading in the working layer of the earth bed and in the structural layers during the lifetime of the structure. The calculation algorithms were made in accordance with the current regulatory documents of Ukraine. CREDO RADON UA software allows user to create information bases on road construction materials and vehicles as part of the traffic flow for calculations. The presented system of automated modeling makes it easier for the customer to control the quality of design solutions, to reasonably assign designs to layers of reinforcement, to quickly make comparisons of calculations of different designs for the optimal use of allocated funds. Prospects for further improvement of the program should be the results of theoretical and experimental studies on filling the databases, which are used as information support for automated design of road structures. Keywords: CREDO RADON UA, road, computer-aided design, repair project, road pavement, strengthening, construction, rigid pavement, elasticity module, a transport stream, calculation method, information support, dynamic or static loading.

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