Soil Abrasion Research Articles

Comparative evaluation conducted on the selection of the type of roller shredder for the cultivation of plowed land

The results of experimental investigations into the features of the roller shredder that breaks down plowed land one by one are presented in this article. This allowed for the determination of the optimum roller parameter values and the examination of the shredder type selection. According to experimental research, selecting the right type of roller is primarily responsible for guaranteeing that the field surface is completely treated. Typically, these rollers are working parts with slats, gear-slats, or rods for installation on a reel that provide moisture feeding at the level necessary for germination in compliance with agrotechnical requirements. Slatted, toothed-slatted, and rod roller shredders with comparable diameters were designed and used in experimental investigations to confirm the results that we had acquired. In experimental studies, after using different constant diameter roller shredder, the influence of soil on the degree of abrasion, its density and drag resistance was studied. To reduce the influence of various variable factors on the results obtained, the experiments were carried out on a specially prepared agricultural background, which was first plowed and then leveled. In order to test the theoretically based parameters of the roller shredder selected for experimental research in the field, a fixed-diameter roller shredder base with a coverage width of 1.5 m and strips with gear strips and rod strips that can be installed on them were developed and prepared. Based on the results of experimental studies, the following can be noted: in order for the quality and density of soil abrasion to meet agrotechnical requirements, and the tensile resistance of the coil to be minimal, the roller shredder must be with a slatt.

Experimental study on the influences of cutter geometry and material on scraper wear during shield TBM tunnelling in abrasive sandy ground

When shield TBM tunnelling in abrasive sandy ground, the rational design of cutter parameters is critical to reduce tool wear and improve tunnelling efficiency. However, the influence mechanism of cutter parameters on scraper wear remains unclear due to the lack of a reliable test method. Geometry and material optimisation are often based on subjective experience, which is unfavourable for improving scraper geological adaptability. In the present study, the newly developed WHU-SAT soil abrasion test was used to evaluate the variation in scraper wear with cutter geometry, material and hardness. The influence mechanism of cutter parameters on scraper wear has been revealed according to the scratch characteristics of the scraper surface. Cutter geometry and material parameters have been optimised to reduce scraper wear. The results indicate that the variation in scraper wear with cutter geometry is related to the cutting resistance, frictional resistance and stress distribution. An appropriate increase in the front angle (or back angle) reduces the cutting resistance (or frictional resistance), while an excessive increase in the front angle (or back angle) reduces the edge angle and causes stress concentration. The optimal front angle, back angle and edge angle for quartz sand samples are α = 25°, β = 10° and γ = 55°, respectively. The wear resistance of the modelled scrapers made of different metal materials is related to the chemical elements and microstructure. The wear resistances of the modelled scrapers made of 45#, 06Cr19Ni10, 42CrMo4 and 40CrNiMoA are 0.569, 0.661, 0.691 and 0.728 times those made of WC-Co, respectively. When the alloy hardness is less than 47 HRC (or greater than 58 HRC), scraper wear decreases slowly with increasing alloy hardness as the scratch depth of the particle asperity on the metal surface stabilizes at a high (or low) level. However, when the alloy hardness is between 47 HRC and 58 HRC, scraper wear decreases rapidly with increasing alloy hardness as the scratch depth transitions from high to low levels. The sensitive hardness interval and recommended hardness interval for quartz sand are [47, 58] and [58, 62], respectively. The present study provides a reference for optimising scraper parameters and improving cutterhead adaptability in abrasive sandy ground tunnelling.

Evaluating the wear of cutting tools using a tunnel boring machine laboratory simulator

Purpose. One of the most common problems in mechanized excavation is the cutting tool wear, which has a great impact on the final cost of the project and its duration. Also, one of the most important factors affecting the wear of cutting tools is the operating parameters of the tunnel boring machine (TBM). Within the framework of this research, a tunnel boring machine laboratory simulator was designed and constructed to investigate the tunnel excavation process in the laboratory. Methods. A few of the features of this device are that it operates horizontally, has a low rotation speed, keeps the pins in contact with fresh soil throughout the test, and has the possibility of measuring the torque of the device during the test. A study of the cutting tool wear was conducted using granulation prepared from Tabriz metro line 2, as well as using operating parameters of mechanized excavation machines, such as penetration rate and cutter head rotation speed. Findings. The research results showed that by reducing the rotation speed of the cutter head from 35 to 10 rpm, the average wear of cutting tools is reduced by 63%. Also, by reducing the excavation time from 80 to 10 minutes, the cutting tool wear is reduced by 58%. The wear of cutting tool increases with increasing moisture content from 0 to 10%, and then decreases with increasing moisture content from 10 to 25%. Originality. During this research, a new device was designed and built to simulate tunnel excavation mechanisms. This laboratory simulator measures wear percentage, penetration rate and torque. Practical implications. There has been significant progress in predicting soil abrasion rates, but there are few accepted models for predicting cutting tool wear and soil abrasion rates. During the design and construction of the tunnel boring machine laboratory simulator, the effect of operating parameters on wear of cutting tool was examined.

New soil abrasion testing method for evaluating the influence of geological parameters of abrasive sandy ground on scraper wear in TBM tunneling

When shield TBM tunneling in abrasive sandy ground, scrapers are loaded with heavy forces resulting from the extrusion and friction processes of sand particles. Scraper wear reflected as displacement or desquamation is related to soil parameters. Due to the lack of reliable test methods, experimental studies on the influence of soil parameters on scraper wear are limited. In the present study, existing soil abrasion testers have been reviewed to discuss the advantages and deficiencies. An improved WHU-SAT soil abrasion tester has been developed to study the influence mechanism of soil parameters on scraper wear. Experimental studies have been conducted to evaluate the variation of scraper wear with quartz content, particle size, particle shape and water content. Two soil abrasion tests have been performed for each case. Scraper wear has been considered to be the average value. The results indicate that scraper wear increases with the increase of quartz content and the growth rate increases. It is related to the particle crushing and adhesion effect of limestone sand. As the average particle size increases, the extrusion and friction between the modeled scraper and the sand particles increases first and then decreases. Thus, scraper wear increases first and then decreases with the increase of average particle size. The trend is generally comparable to the corresponding changes in scraper wear with water content. As quartz balls collide with sand particles and destroy the microscopic friction system composed of scrapers and asperities, scraper wear decreases as the increase of roundness and the falling rate decreases. Optimized solutions such as soil abrasivity evaluation, tunnel alignment optimization and soil discharge improvement have been proposed to alleviate the influence of soil parameters on scraper wear. The present study promotes the rational estimation of sand abrasivity and scraper consumption during the feasibility study of abrasive sandy gournd tunneling using shield TBM.

Risk-based methodology to optimize geotechnical site investigations in tunnel projects

The scope of geotechnical investigations in tunnel projects is generally driven by the allocated resources rather than the expected variability in the ground conditions. Uncertainties in ground conditions may lead to poor decisions in project planning and active risk management. This paper presents a systematic and rational methodology to identify priority locations of additional geotechnical investigations for soft ground tunneling applications based on tunnel risks, site conditions, and project-related constraints. The methodology is applied to the cutter tool wear risk and quantifies the uncertainty in soil abrasivity index (SAI), the relevant geotechnical parameter. Preliminary geotechnical investigation data and site conditions from an actual tunnel project in an urban environment are used to illustrate the proposed methodology and demonstrate its effectiveness. Pluri-Gaussian simulation and sequential Gaussian simulation are used to characterize the 3D spatial variability in soil units and soil abrasivity, respectively, along the tunnel alignment. The study integrates geospatial assessments of SAI uncertainty and consequences of tool wear to develop an R index map that delineates the impact of uncertainty in tool wear rate. Project constraints of drilling accessibility and budget are incorporated in the R index map to find locations of additional geotechnical investigations. The study simulates a virtual sampling of additional boreholes and quantifies the reduction in uncertainty in tool wear rate and tunnel boring machine (TBM) intervention locations. Additional investigation at priority locations is found to reduce cutterhead intervention location uncertainty by approximately 90 rings (160 m). Further, integrating the uncertainty in tool travel distance is found to influence the cutterhead intervention location uncertainty by approximately 40 rings.

Microstructure and Soil Wear Resistance of D517 Coating Deposited by Electric Spark Deposition.

The abrasion failure is the key factor for prolonging the service life and energy saving of furrow openers. The hardness enhancement was reported to be an effective strategy to increase the wear resistance against the soil abrasion. D517 coatings were deposited on Q235 steel by electric spark to improve the wear-resistant property with an affordable cost for farmers. The wear behavior of the coatings was characterized in a pin on disk friction equipment and a homemade soil abrasion simulation system. The soil adhesion, which is highly related to energy consumption, was also evaluated. Results showed that D517 coatings revealed dendrite structure with some randomly distributed carbides. The electric current exerted a great influence on the microstructure, hardness, friction coefficient, and soil wear rate. The wear rate of samples deposited with 80 A and 90 A reduced to 79% and 84%, respectively, as compared with the normalized heat-treated 65 Mn steel after 6 h in soil. This work provides a promising solution to increase the wear resistance of furrow openers. It needs to be noted that the coating would increase the soil adhesion of the opener, which needs to be further explored to decrease the energy consumption.

Effects of Soil Conditioning on Tool Wear for Earth Pressure Balance Shield Tunneling in Sandy Gravel Based on Laboratory Test

Abstract Soil conditioning plays an important role in reducing soil abrasivity and wear of cutting tools in earth pressure balance shield tunneling, leading to service life extension of cutting tools. In this article, an experimental study to assess the abrasivity of conditioned soil with different conditioners, namely foam and slurry, was carried out using a soil abrasion tester. The abrasive characteristics of the tested soil samples were quantitatively assessed through the measurement of weight loss of the steel cubes fixed on the propeller. Preliminary test results indicate that both foam and slurry can modify the sandy gravel to a suitable state according to slump test and decrease soil abrasivity significantly. The torque, which reflects the interaction between the propeller and tested materials, is used to provide insights into the soil-tool contact. Potential relationships between tool wear and tool position are also investigated.

Spatial distribution of mangrove using a geographic information system in Aceh Besar

The mangrove forest ecosystem is unique, both because of the subtract of siltation which results in less soil abrasion, high soil salinity, and experiencing a cycle of inundation by tides. Only a few plant species survive in such a place, and most of these species are unique to mangroves because they have undergone a process of adaptation and evolution. It is not widely known how far the mangrove areas are spread in Aceh. Therefore, research needs to be carried out with the aim of knowing the extent of the sustainability of mangrove management in terms of sediment characteristics. Information about the distribution, area and change of mangrove land cover can be determined by spatial analysis using a Geographical Information System (GIS) using ArcGIS. The method used in this research is the transect method and analysed based on the identification of mangrove species. Based on the analysis of the results of the study, it was identified that the mangrove species found in the research location of Peukan Bada sub-district (West Aceh Besar) consit of Rhizopora mucronata and Sonneratia alba, while the mangrove species found in Baitussalam (north Aceh Besar) were Rhizopora mucronata and Sonneratia alba. Meanwhile, based on observations with satellite imagery and location surveys, it was found that the mangroves in Baitussalam sub-district were denser and spread evenly than in the Peukan Bada area.

Assessment of Durability and Service Life of Two-Layer Hardened Earth Cutters in Various Soil Conditions

Introduction. The earth cutter resource depends on the characteristics of the materials they are made from. In particular, the important parameters that directly affect the tillage tool parts efficiency and durability are the values and ratios of the coefficients of relative wear resistance of the two-layer parts materials, as a rule of the hardened deposited layer and the base material (steel). It is established that the characteristics of the relative wear resistance of the materials for earth cutter parts vary depending on the treated soil properties. The objectives of the study are to consider the influence of soil conditions on the values of the relative wear resistance coefficients of two-layer earth cutter part materials and to carry out a comparative assessment of their resource and use efficiency. Materials and Methods. The authors gave a generalized dependence of the wear proportionality to the existing specific pressures values. The characteristics of soil abrasion were given. The scientific substantiation of the changes in the characteristics of the materials wear resistance at various values of specific pressures was given. Results. The results of the operational resource tests and the studies of two-layer and monometallic earth cutters are presented. The influences of the values of the operating specific pressures on the coefficients of the relative wear resistance of the materials for the tillage machine parts are determined. Discussion and Conclusion. The authors have found out that the coefficients of relative wear resistance of materials are not constant, but vary depending on the current surface specific pressures. The correlation of the specific pressure values with the parameters of the tillage operation, in particular with the furrow slice hardness was established. It has been found that while increasing the cultivated soil hardness, the coefficients of various materials relative wear resistance get closer to each other. The difference varies from 1.80 to1.85 times.

Comparison between Soil Abrasion Test (SAT) and Soil Abrasion Index (SAI)

Abstract The performance of soft-ground tunnel boring machines can be significantly impacted by soil abrasivity. During the last decade, several soil abrasion testing systems have been developed to characterize abrasivity of various soil mixes in different conditions. This article discusses the comparison between the results of a Soil Abrasion Test (SAT) developed by Stiftelsen for Industriell og Teknisk Forskning (SINTEF)/Norwegian University of Science and Technology (NTNU) and the Soil Abrasion Index (SAI) testing system developed by the authors. The reason for this comparison is the availability of SAT results for a few tunneling projects that were constructed in recent years. Obtaining any relationship or correlation between the SAI and SAT will allow the use of some of the machine field performance data to evaluate the ability of SAI in predicting the wear on these machines. The study of SAT has been conducted on the testing device designed and fabricated based on the original specifications of NTNU. The study was designed to evaluate the sensitivity of the SAT testing system to some of the controlling parameters and testing procedures as compared to the SAI test. This article summarizes the result of a series of specially designed tests to evaluate the impact of various testing parameters on SAT results as well as a comparison of the results between the two tests.

Influence of propeller material hardness, testing time, rock properties, and conditioning on LCPC rock abrasiveness test

LCPC rock abrasiveness test is gaining popularity for quick estimation of rock and soil abrasiveness in the preliminary site exploration stage of tunneling projects. However, there are parameters such as test propeller hardness and testing time, which may affect the test results thereby influencing the tool wear rate estimates of the tunneling machines employed in those projects. This study evaluates LCPC rock abrasiveness test by using both the standard (grade XC 12; 60-75 HRB) steel and hard cold work tool (54-56 HRC) steel propellers. It is found that the wear in the case of hard steel propellers, ABRh (g/t), is almost 70% less than that in the ABRs (g/t) of standard/soft steel propellers. It is established that 40–60% of the propeller wear occurs during the first 2 min of testing. Moreover, bentonite slurry as a conditioning agent produced promising results in the reduction of ABRh (g/t) values in contrast to the unconditioned test results. The correlation of LCPC test parameters ABRh (g/t) and BRh (%) with the geomechanical rock properties and rock wear indices especially Schimazek’s F value and rock abrasiveness index (RAI) show similar trends to the ones obtained using soft steel propellers in the previous studies. However, breakability BR (%) is found to have no appreciable difference once measured using both the soft and hard steel propellers.

Laboratory Test Methods for Assessing the Abrasivity of Rocks and Soils in Geotechnology and Mining Applications

Abstract In geotechnology and mining, tools and equipment interact with aggressive geological material, causing the wear of these components. For this reason, it is important to determine the rate of abrasivity of individual geological materials, depending on the type of interaction with the tool. Various abrasivity tests have been developed in laboratories. Some of them are general, while others are special. What they all have in common is that they attempt to determine the abrasivity of rocks or soils in relation to the wear of the test specimens. This article gives an overview of the laboratory test methods for assessing the abrasivity of geological materials, which are useful in the field of geotechnology and mining engineering. General and special abrasivity tests are presented in detail. The aim of the article is to present existing laboratory tests to assess the abrasivity of rocks and soils, based on which further investigations of wear can be considered as part of a comprehensive approach to this tribological problem. Understanding of the wear mechanisms is the basis for the development of wear-resistant tools and models for predicting the tool life.

The effect of the particle size distribution curve on the abrasivity of non-cohesive soils in LCPC test

Despite the widespread use of soil excavating tools, including soft ground shield TBMs, there is not any universally accepted method for soil abrasivity assessments. However, different experimental models have recently developed to study the abrasivity of soil materials. LCPC test, developed in Laboratoire Central des Ponts et Chaussées, is one of the most common, simplest, and most available approaches, which has wide use in the prognosis of wear on soil and hard rock cutting tools. In the present study, the effect of the distribution curve of soil particle size on its abrasive behavior was investigated. Synthetic abrasive samples were made with mixing crushed silica grains and fine silica particles in different ratios. LCPC tests were performed on the samples under different water contents and stress levels. The obtained LCPC abrasive coefficient values revealed the effect of the distribution curve of soil particle size on its abrasive behavior. Based on the results, fine particles alone do not result in high wear rates. However, their presence, especially in wet conditions, has a considerable effect on the recorded wear amounts. Moreover, increasing the share of fine particles in the composition of the abrasive sample decreases the effect of applied stress levels on wear rates.

Intelligent vulnerability prediction of soil erosion hazard in semi-arid and humid region

Soil erosion by water and other anthropogenic activities in the semi-arid and humid region is noticed as a major issue in the reduction in natural land by the loss of soil nutrients. The seven standard parameters were suggested in the literature for the assessment of soil erosion hazard, viz. soil loss, sediment yield, run-off potential, land capability class, drainage density, sediment transport index, and slope. In the present study, the combination of intelligent vulnerability prediction, multi-criteria decision-making, and geographic information system techniques provides an effective approach to identify the soil erosion hazard in the semi-arid and humid region. It makes this process more effective and efficient as the vulnerability of soil erosion hazard can be predicted by the proposed trained models for any locations that have the streamlined values of above seven parameters as suggested in this paper. The standard machine learning classifiers such as k-nearest neighbour, decision tree, random forest (RF), multinomial naive bays, adaptive boosting, and gradient adaptive boosting (GAB) have been applied on the spatial data set of “Pairi” river watershed found in “Chhattisgarh”, India. There are five categories of soil abrasion, viz. “very low”, “low”, “medium”, “high”, and “very high”, in this data set that represents an index of soil erosion hazard. The experimental results have given 91.5140% and 90.5525% accuracy using RF and GAB, respectively, whereas a much better log-loss measure, i.e. 0.27, is obtained by the GAB in comparison of 0.93 with RF. The results have been verified by visiting the ground truth locations.

Reduction of abrasive wear via hardfacing of mouldboard ploughshare

The phenomenon of soil abrasion occurs when machines interact with soil. Ploughshare wear due to abrasion by hard soil particles is a major problem related to the use of tillage and it seriously affects the agricultural production economy. The objective of current study is to increase the wear resistance of ploughshare by hardfacing. The ploughshare produced from EN42 high carbon steel were hardfaced with different types of hardfacing electrodes. These hardfacing electrodes, designated as HF-5M (Chromium-carbide based), HF-3 (Iron-carbide based) and HF-7 (Manganese-carbide based) and Terrahard-85 were used for hardfacing deposits and applied through shield metal arc welding (SMAW) method. Wear tests on the regular and hardfaced shares were conducted in the actual field environment. The changes in dimension and weight loss were lower for the hardfaced ploughshares and shown better wear resistance in comparison to regular ploughshares. It was observed that chemical composition and the microstructure of material played an important role in wear resistance along with hardness.

Assessing Effectiveness of Various Wear-Resistant Materials Used as Hard Facings in Mining Applications

Characterizing the abrasiveness of soil/rock and the allowable wear of hard-facing products in various conditions is a critical factor in selection of the best material for certain applications related to drilling and excavation in mining and construction industries. The Soil Abrasion Index test machine at Colorado School of Mines (CSM) is one of the recently developed unique systems capable of testing soil/crushed rock abrasion under various conditions, such as dry, wet, and saturated settings. It is also capable of testing the performance of various types of hard-facing materials in a given geo-material. This paper studies the wear properties of different hard-facing materials in various crushed rocks from a surface mining operation in the iron range region of the USA. The hard-facing materials include regular and hardened steels and six different specialized hard facings, based on chromium carbide. The soil/rock include a standard sand and two rock samples from the surface mine. Fourteen abrasion tests were conducted, where the weight loss of each hard-facing material was measured over timespans up to 1 h of testing. The results show the distinct performance differences between the steels with 17 HRC and 43 HRC hardness and the hard-facing products for this application. The results show the possibility to evaluate the abrasiveness of different rocks at a mine or construction site and the performance of various hard facings in similar working conditions. This is a practical solution for selection of the cutting tool or reinforcement of bucket lips and truck beds for comparison of relative wear life between different wear-resistant materials.

Introduction to Rock and Soil Abrasivity Index (RSAI)

Characterizing the abrasiveness of rock and soil and developing predictive models for wear of various tools that interact with such geo-materials is critical in selection of best tool materials for applications in earthmoving, drilling, mining, construction, tunneling, and agricultural industries. This paper introduces a Rock and Soil Abrasivity Index (RSAI), utilizes the abrasive wear theory for defining the parameters and examines a testing method for quantitative assessment of the index. The test method measures the wear mass of a target tool material (i.e. steel or hard facing) while it is pressed against the crushed rock or soil medium in a relative motion under high contact stresses based on a defined test protocol for reliability and repeatability. The RSAI is defined as the product of wear volume and hardness of tool divided by the work or energy deployed to overcome frictional forces, as measured by the torque in the device. The RSAI is expected to vary in the 0–100 range for the softest to the hardest possible rock and soil samples and conditions. The RSAI for various soil and crushed rock samples were experimentally determined and presented. Also, the correlation between the RSAI, Cerchar Abrasion Index (CAI) and Soil Abrasion Test (SAT) value, as the most common forms of abrasion testing of soil and rock is discussed.

Water content, effective stress, and rotation speed impact on the abrasivity of granular soils in LCPC test results

The development of mechanized tunneling technology and the extent of its application in the soft grounds have revealed the importance of soil abrasivity studies more. As one of the first methods of soil abrasivity assessment, LCPC test is widely used in predicting the wear of cutting tools in soft grounds. In this study, the effect of water content, rotation speed, and applied stress on the abrasivity of crushed silica particles are investigated with the LCPC tests. The results showed that water content has a considerable effect on the abrasive behavior of silica particles. The occurrence of drainage during the tests considerably changed the dominant conditions of moisture and affected the observed wear rates. The obtained correlation between the effective stress levels and recorded wears showed that the theory of granular soils compaction can be used to describe the variations of soil abrasivity with water content changes. Moreover, the results showed a direct linear correlation between the rotation speed of steel propellers and measured wears. The same correlation was also found between effective stress levels and wear amounts. However, in the samples with higher water content than 10 percent, the effect of stress on the wear rates increases with the increase of propeller rotation speed.

The negative impact of illegal gold mining on the environmental sector in Batang Asai, Jambi

The negative impact of Illegal Gold Mining / IGM on the environmental sector in Batang Asai District, Sarolangun Regency, Jambi was investigated through a descriptive qualitative method. The purpose of this study was to determine the negative impact of IGM activities to several ecosystems, the effect of IGM on community activities, and some efforts to reduce IGM. The instruments of data collection included observation, interviews, and documentation. Data were analysed through data reduction, data presentation, and conclusion withdrawal. The results showed that IGM activity had a negative impact on the environment namely noise pollution, dust, degradation on the quality of Batang Asai River, forest conversion, river siltation, the emergence of large holes, overburden, soil abrasion, the disappearance of Meranti plants (Shorea sp. ) and Damar (Agathis Damara). Besides that, other impacts were the declining population of Semah Fish (Tor sp.) which had become the special characteristic of fish in the area. Some efforts were made by the government to overcome and foster IGM activities, e.g. by providing counselling and sanctions in a judicial and non-judicial manner that was carried out continuously.

Effects of gravel content and particle size on abrasivity of sandy gravel mixtures

During soft ground tunnel construction, the presence of sandy gravel stratum often causes serious wear and tear of cutting tools. In this paper, an experimental study to assess abrasivity of sand-gravel materials with different gravel content (GC) and gravel size (GS) was carried out with a horizontally oriented mechanical mixing device. The abrasive characteristics of testing materials were quantitatively assessed through the measurement of weight loss on the testing steel cube, with a focus on the influence of GC and GS of the mixtures. Experimental testing results indicate that GC and GS have significant impact on soil abrasion and tool wear, through affecting the packing density of the sand-gravel mixtures, breakage resistance of particles, and the soil-tool wear mechanisms. The torque required to drive the propeller in the sand-gravel mixtures during the abrasivity test was measured and provided more insights into the abrasivity of mixtures and the associated soil-tool wear mechanisms. In addition, potential relationships between coefficient of uniformity (Cu) and coefficient of curvature (Cc) of the sand-gravel mixtures and the tool wear were sought.