Vibratory Roller Research Articles

TO SPECIFICATION OF THE FORCE OF A VIBRATORY ROLLER ON THE SOIL

As a result of the analysis of tillage rollers, it was revealed that the main design feature is to ensure the required specific pressure on the soil, consequently, it is necessary to increase the roller mass per 1 m of the working width, whereas it leads to metal consumption increase of the tool. Based on the obtained data, we developed a fundamentally new design of the vibratory roller, its application will ensure the fulfillment of agrotechnical requirements for soil density with a minimum metal consumption of 70 kg/m. High-quality tillage with a vibratory roller is ensured by a passive drive of unbalancers installed on the axis of a hollow cylinder. To determine the center of mass of the unbalancers, the KOMPAS 3D v 20 program was used, which allows to obtain the desired result with an accuracy of 0.000001 mm. It was revealed in the course of the theoretical study that the unbalancers create vibrations with an amplitude of 0.00008 ... 0.0011 m at a rotation frequency of 800 min-1 due to their displacement in relation to the axis of the vibratory roller. Also, it was revealed that when the unbalancers are displaced in relation to the roller axis, the position of their center of gravity changes by approximately the same value. Concurrently, the specific pressure of the vibratory roller on the soil changes from 732.81 N/m to 1275.28 N/m, increasing by 74% in case of displacement of the unbalancers in relation to the axis of the vibratory roller up to the maximum value of a = 20 mm. Field studies of the proposed roller showed that the quality of soil compaction by the proposed vibratory roller with improved parameters and modes of operation is better than that of the most common rollers, namely, ZKVG-1.4 and ZKKSH-6.

Analysis of the Effect of Three Different Dynamic Models Embedded into the Seat Suspension System on the Ride Performance of a Vibratory Roller

Analysis of the Effect of Three Different Dynamic Models Embedded into the Seat Suspension System on the Ride Performance of a Vibratory Roller

New fractional-order proportional integral derivative semi-active control composite magnetorheological damping system

In this paper, semi-active control analysis and research on the vibration reduction system of vibratory roller with nonlinear stiffness and fractional damping are carried out. A two-degree-of-freedom semi-vehicle mathematical model with nonlinear stiffness and fractional damping is established, and the fractional calculus operator in the model is approximated by using the Oustaloup filter algorithm. The vibration characteristics of passive control, proportional integral derivative control, and fractional-order [Formula: see text] control on the vibration reduction system of the vibratory roller are simulated and analyzed. Results show that the vibration reduction effect of the first-stage vibration reduction device of the vibratory roller is evidently improved by using fractional-order [Formula: see text] controller. Compared with traditional passive control, the parameters are increased by about 40%, and the vibration intensity evaluation grade of the vibratory roller can be improved by about one level, which provides a new idea for the research of the vibration reduction system of the vibratory roller.

Analysis of the structural composition of the soil during field studies of a soil-cultivating vibratory roller

The article presents the results of experimental studies of a soil-cultivating vibratory roller, as a result of which adequate mathematical models were obtained from the standpoint of compliance with the reference values of the structural composition of the soil. According to the results of the research, it was revealed that the quality of rolling by the developed vibratory roller is 23.9% better than that of the serially produced roller KKZ-6. The optimal speed of movement of the unit and the frequency of rotation of unbalancers are also determined.

Studies of the vibratory roller from the standpoint of compliance with the agrotechnical requirements of soil density and structure

The article presents a completely new design of a vibrating roller that has no analogues. To identify the main design and regime parameters that allow to ensure high-quality operation of the vibratory roller from the standpoint of compliance with the agrotechnical requirements for soil density and structure, we conducted field experiments, the results of which revealed that the maximum value of the optimization criterion k cэ = 0.81 is achieved at the unit speed ν = 11 km/h and rotational speed of unbalancers n = 800 min-1.

A data-driven method for real-time compaction quality evaluation of a cement-stabilized base layer

Adequate and uniform compaction is essential for the safety and durability of a pavement structure. The current compaction quality control, which relies on limited spot tests data, cannot provide timely feedback about compaction quality. The main objective of this paper is to develop a novel data-driven method for compaction quality assessment of cement-stabilized base in a real-time manner. The basic idea is to consider the drum of the vibratory roller together with the underlying cement-stabilized base layer as a spring-mass-dashpot system. The compaction level of the base is connected to the stiffness of the system and to the corresponding natural frequencies. In this study, the vibration of the drum was monitored during operation. The fundamental mode natural frequency of the system at different compaction levels of the base was identified by the fast Bayesian fast Fourier transform method. The results indicate that the natural frequency of the vibratory system has a positive correlation with the degree of compaction (DOC) of the underlying cement-stabilized base layer. Therefore, a novel and practical method for on-site compaction quality assessment utilizing measured natural frequency is proposed in this paper. A data-driven classification method based on support vector machine (SVM) was developed to realize the compaction quality evaluation. The classification results show that the proposed method can recognize signal patterns corresponding to different DOCs. The proposed method combines vibration theory and machine learning to provide a technical reference for the research of continuous compaction control with vibratory rollers.

Development of a Fatigue Damage Model for Roller Compacted Concrete Pavement Based on In Situ Saw-Cut Beams and Accelerated Pavement Performance

As a durable, economical, and low-maintenance concrete material, roller compacted concrete (RCC) is steadily becoming the preferred choice for many pavement applications. However, the fatigue models in current pavement thickness design procedures have generally been found to over-predict the RCC pavement fatigue damage under in situ heavy truck loading. In this study, a comprehensive beam fatigue test experiment was performed using field saw-cut RCC slab samples from two full-scale accelerated pavement testing (APT) sections to investigate the fatigue behavior of in situ RCC pavements. This is the first research study to investigate the fatigue behavior of field RCC beam samples prepared and constructed with a high-density asphalt-type paver and a vibratory roller. The results indicate that a well-compacted RCC pavement can achieve higher flexural strength and exhibit better fatigue life than conventional concrete pavement. Based on the beam fatigue test results and in situ fatigue performance of APT test sections, an RCC fatigue-life model was developed, providing a more accurate solution for estimating the allowable number of load repetitions of RCC pavements subjected to vehicular fatigue loading. This model could be used in RCC thickness design procedures to determine the optimum RCC design thickness and long-term fatigue performance of RCC pavements for roadway application.

METHOD FOR DETERMINING PROPERTIES OF ASPHALT CONCRETE MIXTURE COMPACTED BY VIBRATORY ROLLER

The paper investigates the process of force interaction of a vibrating roller with a layer of asphalt concrete mixture. To describe the stress-strain state of the compacted layer during the interaction of the latter with a vibration roller, the Kelvin body was used. On the basis of the law of behavior of the Kelvin body, a simulation model has been developed, the result of which is a phase trajectory in the coordinates “force–displacement” for the system “drum–asphalt concrete mixture”. An analytical study of the characteristic points of the phase trajectory was carried out, as a result of which the relationship between the properties of the asphalt concrete mixture and the force effect in the area of contact of the roller with the compacted layer was established. In addition, a condition was obtained for continuous rolling of the asphalt-concrete layer with a vibrating roller, the observance of which makes it possible to increase the resource of the roller by reducing the wear of the latter. The results obtined can be used to establish the relationship between the operating modes of the vibratory roller and the properties of the compacted layer of the asphalt concrete mixture.

Improving the vibratory roller's ride comfort under off-road soil grounds by applying the seat's negative-stiffness elements

This study proposes the cab's hydraulic mount (HM) and seat's negative-stiffness elements (NSE) to reduce the cab shaking and improve the ride comfort of the vibratory rollers. A vehicle dynamic model is built to assess the vehicle's ride comfort under deformable soil grounds. The indexes of the root-mean-square (r•m•s) seat displacement (Zw1), r•m•s seat acceleration (aw1), and r•m•s cab pitching acceleration (awϕ2) are selected to assess the ride comfort. The study results indicate that the seat's ride comfort and cab's pitch angle are greatly improved by using the NSE and HM under various working conditions. Especially, the Zw1, aw1, and awϕ2 are remarkably reduced by 36.4%, 82.4%, and 50.9% in comparison without the NSE and HM when the vehicle is travelling on deformable soil grounds, respectively. Consequently, the application of the NSE on the seat's suspension of vibratory rollers or other vehicles can further enhance the driver's ride comfort and health.

Improving the vibratory roller's ride comfort under off-road soil grounds by applying the seat's negative-stiffness-elements

Improving the vibratory roller's ride comfort under off-road soil grounds by applying the seat's negative-stiffness-elements

Compaction quality evaluation of subgrade based on soil characteristics assessment using machine learning

The reliable correlation model for intelligent compaction (IC) is to be developed by integrating characteristics of the filling material and control parameters of the vibratory roller. Key characteristics of the backfill soil from the construction site of Rongwu Highway are tested through the modified Proctor test and the direct shear test. A well-documented dataset is built by summarizing 4000 shear strengths from open literature and 246 data from laboratory tests in this study. The PSO-BP-NN model is developed based on this dataset to predict the shear strength and compactness of the subgrade soil in the scope of mechanical properties and compaction powers. The importance analysis of the input variables is performed with the Random Forest algorithm. The influence mechanism is analyzed in sequence. The plain soil and the lime soil demonstrate typical compaction curves, and the lime soil is less sensitive to the influence factors. An optimal compaction power exists for determining the optimal moisture content utilizing the shear strength, tending to be less conservative. The moisture content is the most important factor for the compactness, followed by the compaction power; the particle size is suggested to be considered for real-time evaluations. The compaction mechanism is mainly attributed to the water film theory and the electrochemical property of the filling soil. This study aims to provide a reliable model to estimate the compactness in the aspect of material properties so as to enhance the accuracy of the IC model.

Investigation of a Vibrational Tillage Roller on Soybean Crops

Currently, one of the main tasks facing agricultural production is to provide the country’s population with high-quality food with a maximum reduction in the share of imports. To get stable and high yields, it is necessary to use modern equipment. Recently, the main emphasis has been on equipping machines with electronics, while less and less attention is paid to the design of agricultural machines. Despite the large number of mechanization means of soil rolling, they often do not ensure the fulfillment of agrotechnical requirements for soil rolling. (Research purpose) The research purpose is to test the effectiveness of using the developed vibrating roller in the field on soybean crops. (Materials and methods) The article presents the fundamentally new vibration roller, the distinctive feature of which is the presence of a passive drive of disbalancers mounted on the rotating axis of a hollow cylinder. In the field conditions, the quality of work of the developed vibrating roller and mass-produced rollers was compared using the coefficient of compliance with the standard. (Results and discussion) The use of a vibrating roller give a higher quality of soil rolling, a 42 percent better value of the optimization criterion compared to the KKZ-6 roller. The soybean seedlings are more harmonious compared to rolling in other rollers. (Conclusions) The rolling of soybean crops with the proposed vibrating roller allowed to increase its yield to 33.5 quintals per hectare (by 27.4 percent) compared to 26.3 quintals per hectare after rolling the crops with the KKZ-6 rollers mass- produced by the industry. The innovative features of the proposed vibrating roller make it possible, when implementing the traditional rolling technology, to obtain a large yield practically without increasing capital investments, thereby increasing the profitability of legume production.

Acute Effect of Vibration Roller With and Without Rolling on Various Parts of the Plantar Flexor Muscle.

A single use of a vibration foam roller likely increases the range of motion (ROM) without decreasing muscle strength and athletic performance. However, to date, no study compared the effects of a vibration roller with and without rolling on various parts of the plantar flexor muscle. Therefore, this study aimed to compare the effects of the vibration foam roller with rolling or without rolling at the muscle-tendon junction (MTJ) or the muscle belly on dorsiflexion (DF) ROM, passive torque at DF ROM, shear elastic modulus, muscle strength, and jump performance. Fifteen healthy young males performed the following three conditions: (1) vibration rolling over the whole muscle-tendon unit, (2) static vibration on muscle belly, and (3) static vibration on MTJ for three-set 60-s vibration in random order. In this study, DF ROM, passive torque, shear elastic modulus, muscle strength, and single-leg drop jump were measured before and immediately after the interventions. The DF ROM and passive torque at DF ROM were increased after all three conditions, whereas the shear elastic modulus was decreased after vibration rolling and static vibration on the muscle belly, but not following static vibration of the MTJ. In addition, there were no significant changes in muscle strength and jump performance in any group. Our results showed that vibration with rolling or static vibration on muscle belly could be effective to improve ROM and muscle stiffness without adverse effects of muscle strength and athletic performance.

Discrete Element Modeling of Vibration Compaction Effect of the Vibratory Roller in Roundtrips on Gravels

Abstract This paper aims to study the vibration compaction mechanism of the vibratory roller on gravels using a two-dimensional discrete element method. The roadbed model was established by gravel particles with irregular shapes, which was closer to reality. The performance parameters of the vibratory roller, such as operating frequency and rolling velocity, were investigated to explore their influences on the operating efficiency of the vibratory roller in roundtrips. The frequencies of 15 Hz and 17 Hz were proved to be the optimal frequency and resonance frequency in the current simulations, respectively. The vibratory roller could achieve a better vibration compaction effect with less power consumption at the optimal frequency. In addition, the number of roundtrips and power consumption should be considered in the selection of the optimal rolling velocity. The movement direction and the contact force distribution of gravels were illustrated by the displacement field, velocity field, as well as the contact force chains. Our results provide a better understanding of the mechanical behavior of gravel particles and their interactions with the vibratory roller.

Engineering characteristics of coral reef and site assessment of hydraulic reclamation in the South China Sea

Calcareous soil is a peculiar geotechnical medium which is utilized as land filler for engineering activities, such as the Maldives, Middle East, and South China Sea (SCS). Since the hydraulic dredged calcareous soil has a wide grain size distribution, irregular particle shape, crushable particles, high porosity, and poor uniformity, ground-improvement was conducted to improve the bearing capacity and reduce foundation settlement. In this paper, the geological conditions, material characteristics, and mechanical behavior of dredger fill site on a coral reef in the SCS were studied. The densification of soil using deep vibro-compaction combined with impact rolling was investigated. An innovative method of sprinkling water during impact rolling was put forward to improve rolling efficiency and soil compactness. A set of modified in-situ measurement and calculation methods suitable for the compactness of calcareous soil were put forward. Based on in-situ test results, the relationship between the soil bearing capacity and blow count of dynamic penetration test was established. It was suggested that the two-point parallel and arranged in equilateral triangles vibro-flotation method is effective for the reinforcement of hydraulic dredged calcareous soil, and after vibro-flotation, the loose soil on the ground surface should be compacted with a 25 kJ three-side impact roller for 20 passes and then compacted with 25 t smooth vibratory roller until there are no visible wheel tracks. In addition, the methods of ground improvement, in-situ test, and foundation evaluation were proposed to contribute to coral reef engineering designers. This paper also provides new insights for coral reef foundation filling and improvement around the world.

A roller for soil cultivation and its optimal operating parameters in vibration mode

The optimal parameters and operating modes of vibratory roller for soil compaction after sowing winter wheat were substantiated. For objective function - the optimum coefficient of variation of density of soil during operation of vibratory roller for compacting winter wheat regression equation was obtained in the planning according to the BK plan of the experiment. The adequacy of model according to Fisher criterion, the significance and reliability of coefficients of regression equation was established. The response surface obtained by the shape of hyperboloid rotation was studied, two-dimensional sections of three factors were constructed on optimization criterion. With its minimum value, the optimal parameters of vibratory roller were established: the mass of roller is 293 kg, the spring stiffness is 11.95 kN/m, the working speed of roller is 9.6 km/h. The minimum value of optimization criterion is 10.43%.

Discussion for transitional material’s compaction construction technique of faced rockfill dam of one hydro-junction project

The transitional material zone was between the cushion material zone and the sandy gravel zone in the Faced Rockfill Dam of one Hydro-junction Project, which was from the C3 material yard with the diameter of less than 150.00 mm. By the in situ compaction tests of transitional material, its construction technique and parameters were obtained. Study showed that: its relative density was satisfied with the designed requirement (no less than 0.90) when it was compacted 8 times by the 26.0t self-propelled vibration roller at the speed of 2.0km/h on the conditions including the 20.0cm layout layer and the 5.0% water sprinkled content. Then there were series of compaction tests under the low temperature in winter. The study results was guided for the compaction construction of transitional material in the dam and was as the reference as the similar engineering.

Influence of Laboratory Compaction Method on Compaction and Strength Characteristics of Unbound and Cement-Bound Mixtures

During road construction, granular materials for the unbound base course (UBC) and cement-bound base course (CBC) are mostly compacted by vibratory rollers. A widespread laboratory test for determining the optimal moisture content (OMC) and maximum dry density (MDD) of the mixture for installation in UBC and CBC is the Proctor test. Considering that the Proctor test does not produce any vibrations during compaction, this paper compares the Proctor test and the vibrating hammer test. The examination was conducted on UBC and CBC with varying cement content and aggregate types. All mixtures were compacted by both methods with the aim of determining the compaction and strength characteristics. The results indicated the high comparability of the two test methods for mixtures with natural aggregate in terms of MDD, OMC, density and strength characteristics (California bearing ratio (CBR) for UBC and 28-day compressive strength for CBC). For mixtures with higher cement content, the OMC difference depending on the laboratory compaction method used can be significant, so the laboratory compaction method should be chosen carefully, particularly for moisture-susceptible materials. This paper also reveals that by increasing the proportion of rubber in the mixture, the compaction and strength characteristics differ significantly due to the compaction method. Therefore, when using alternative and insufficiently researched materials, the compaction method should also be chosen carefully.

Meso-Scale Kinematic Responses of Asphalt Mixture in Both Field and Laboratory Compaction

Compaction is one of the most critical steps in asphalt pavement construction. Traditional compaction relies heavily on engineering experience and post-construction quality control and can lead to under/over compaction problems. The emerging intelligent compaction technology has improved compaction quality but is still not successful in obtaining mixture properties of a single pavement layer. Besides, very few studies have discussed the internal material responses during field and laboratory compaction to explain the meso-scale (i.e., particle scale) compaction mechanism. Knowledge in those areas may greatly promote the development of smart compaction. Therefore, this study aims to investigate the kinematic behavior of the asphalt mixture particles (translation and rotation) under six types of field and laboratory compaction methods and establish the relationship between the field and the laboratory compaction by using a real-time particle motion sensor, SmartRock. It was found that particle movement pattern was mainly affected by the compaction mode. At the meso-scale where particle behavior is the focus, the kneading effects of a pneumatic-tire roller can be simulated by laboratory gyratory and rolling wheel compaction, and the vibrating effects of a vibratory roller can be simulated by Marshall compaction. However, none of those laboratory compaction methods can completely simulate the field compaction. Under vibratory rolling, particle acceleration decreased fast in the breakdown rolling stage. Under pneumatic-tire rolling, particle angular position change was related to aggregate skeleton, and particle relative rotation showed a decreasing trend that was consistent with the laboratory gyratory compaction results. Those kinematic responses can potentially be used to monitor density change in field compaction.

A new evaluation of the fatigue design criteria of roller compacted concrete (RCC) pavements

Although mechanical fatigue loading can generally cause critical stresses in pavement systems, there have been few studies that specifically investigate fatigue behavior of roller-compacted concrete (RCC). Possible reasons for this lack include the complexity and time-consuming nature of fatigue tests as well as difficulties in producing RCC prismatic specimens because of stiff consistency in their fresh state. In this experimental study, to simulate actual field-compaction procedures, three RCC mixes of different performance categories were compacted in a plate mold by first applying a vibratory plate compactor, followed by a small-scale vibratory hand roller. Fatigue behavior of RCC mixtures was investigated by applying fatigue loads at five different stress ratios on beam specimens taken from the compacted plates. The average fatigue strength of RCC corresponding to 2 million loading cycles was found to be about 62.5% of the ultimate static strength, showing that RCC performs better than conventional concrete under fatigue. Using a Weibull distribution, the failure probabilities of these mixtures were also determined and expressed as an S-N-P curve. The relationships between RCC fatigue life and mixture design parameters showed that the degree of compaction of a specimen significantly affects the fatigue performance of RCC. A fatigue-life model considering the mixture parameters was also developed, providing a more realistic and novel solution than other RCC fatigue life-estimation models found in the literature that consider only stress ratios. This model is less conservative than those currently used in pavement design.