Dynamic Compaction Research Articles

A Case Study on the use of Dynamic Compaction for Densifying Silty Sand Strata

A Case Study on the use of Dynamic Compaction for Densifying Silty Sand Strata

Aggregate migration and self-organisation properties of asphalt mixtures during compaction process

The objective of this investigation is to analyze the migration behaviours and self-organisation properties of aggregate-asphalt particle system. The three-dimensional discrete element dynamic compaction model was established, and the accuracy and reliability were validated by self-developed particle migration tracking test. The evaluation indices of aggregate particles was measured to investigate the migration behaviours of aggregates and its evolution law. The self-organisation behaviours of aggregate-asphalt particle system were explored combined with the contact behaviours. The results indicate that the migration process of aggregate particles can be delimited into three stages of compaction degree lower than 50%, from 50% to 70%, and above 70%. The larger the aggregate size, the more significant the rotation migration. Under the combined effect of migration and contact, the coarse aggregates migrate to find stable contact points to self-organize the skeleton structure. Asphalt mortar fills the voids eliminated to self-organize the dense structure.

Correction to: Effectiveness of high-energy dynamic compaction on Layered soil-rock mixture geomaterials based on field test

Correction to: Effectiveness of high-energy dynamic compaction on Layered soil-rock mixture geomaterials based on field test

Effectiveness of high-energy dynamic compaction on Layered soil-rock mixture geomaterials based on field test

Effectiveness of high-energy dynamic compaction on Layered soil-rock mixture geomaterials based on field test

Dynamic Compaction of High Groundwater Level Subgrade of Buildings: A Model Test-Based Analysis of Stress Distribution and Reinforcement Mechanisms

Dynamic Compaction of High Groundwater Level Subgrade of Buildings: A Model Test-Based Analysis of Stress Distribution and Reinforcement Mechanisms

Static Compaction for Sustainable Geotechnical Solutions: A Comprehensive Study

The objective of this research is to develop an improved uniaxial static compaction method to address the limitations of the traditional Proctor's dynamic approach for soil compaction. This new approach offers reduced labor, enhanced soil density, and increased compactness. The study compares of static soil compaction characteristics with various soil parameters and explores the concept of Equivalent Static Compaction Energy (ESCE). A diverse range of fine-grained soils with varying range of plasticity was investigated, and a significant correlation of compaction parameters attained by static compaction was observed with the corresponding value of static compaction energy, degree of saturation, void ratio, and plastic limit of soil. The research resulted in the creation of constant-energy curves for static compaction, which were compared to dynamic compaction curves from four compaction attempts. From the study, the ESCE corresponding to standard Proctor, reduced standard Proctor, and reduced modified Proctor tests were found to be within the range of 180-340, 155-308, and 532-664 KJ/ m3, respectively. It was also observed for the static compaction method that after reaching the maximum level of compaction, the dry unit weight of the soil specimen remains constant with further increases in compaction energy.

Investigation of dynamic effect of rapid impact compaction

Dynamic compaction is a soil improvement technique which involves the repeated application of an impact load to a contact area of the soil surface induced by heavy weights. Experimental measurements were prepared for evaluation of the ground wave propagation induced by the rapid impact compaction. Influence of increase of subsoil stiffness during compaction and terrain configuration were investigated. When the shear strength of soil is exceeded during the penetration of the compaction footing, increase of peak particle velocities is slower but still clearly visible along the measurement line. The peak particle velocity is damped by the subsoil below 5 mm s−1 within 40–50 m from the source of excitation. Attenuation radius is affected by the terrain configuration, when terrain elevations cause the increase of acceleration amplitudes. Rigid bodies in the ground, such as foundation structures, could have similar influence. Dominant frequencies are in the interval from 20 to 40 Hz regardless the distance from the source of excitation or the density of the treated subsoil. Obtained results are preferably related to the given boundary conditions. However, wave propagation pattern and change of its characteristics during densification of the subsoil are applicable at another construction sites considering their particularities.

Response of a Coral Reef Sand Foundation Densified through the Dynamic Compaction Method

Dynamic compaction is a method of ground reinforcement that uses the huge impact energy of a free-falling hammer to compact the soil. This study presents a DC method for strengthening coral reef foundations in the reclamation area of remote sea islands. Pilot tests were performed to obtain the design parameters before official DC operation. The standard penetration test (SPT), shallow plate-load test (PLT), and deformation investigation were conducted in two improvement regions (A1 and A2) with varying tamping energies. During the deformation test, the depth of the tamping crater for the first two points’ tamping and the third full tamping was observed at two distinct sites. The allowable ground bearing capacity at two disparate field sites was at least 360 kPa. The reinforcement depths were 3.5 and 3.2 m in the A1 and A2 zones, respectively. The DC process was numerically analyzed by the two-dimensional particle flow code, PFC2D. It indicated that the reinforcement effect and effective reinforcement depth were consistent with the field data. The coral sand particles at the bottom of the crater were primarily broken down in the initial stage, and the particle-crushing zone gradually developed toward both sides of the crater. The force chain developed similarly at the three tamping energies (800, 1500, and 2000 kJ), and the impact stress wave propagated along the sand particles primarily in the vertical direction.

Field Observation and Settlement Prediction Study of a Soft Soil Embankment under Rolling Dynamic Compaction

Rolling dynamic compaction (RDC) has been found to be useful for compaction soils and is now widely used globally. Because RDC is not often used in soft soils with poor engineering properties, field monitoring was used to study the soft clay embankment responses under RDC conditions in this study. Analysis of the monitoring data revealed that the response of the soil occurred mainly in the first 20 passes. Field monitoring revealed a strong correlation between settlement, horizontal displacement, and pore water pressure. The depth of impact of RDC on the soft soil embankment was between 3 and 3.5 m. Although settlement prediction is an important issue for construction, there is a lack of prediction methods for RDC-induced soil settlement. In this study, we used three different machine learning algorithms: random forest regression (RFR), multilayer perceptron (MLP), and extreme gradient boosting (XGBoost) to predict the total settlement and uneven settlement induced by RDC on the soft soil embankment. The three prediction models were compared, and the predictive accuracy of these models was assessed. This study analyzes and summarizes the effect of RDC application on a soft clay embankment and explores the machine learning method used for settlement prediction based on monitoring data, which provides some methods and ideas for research on the application of RDC on soft soil foundations.

Influence of particle breakage on bulk density of dynamically compacted coarse aggregates

The article presents the first discrete element method (DEM) simulations of dynamic compaction in the Proctor test. The aim of the simulations was to analyze the influence of particle breakage on the density of intensely compacted granular assembly. Results from simulations and laboratory tests were compared. Simulations with non-breakable aggregates enabled separation of the influence of change in particle size distribution and particle rearrangement. Both factors play an essential role in increasing the bulk density of the sample in the case of the tested (gap-graded) aggregate. Simulations with breakable particles reproduce the laboratory tests results better, both qualitatively and quantitatively. The conclusions provide a better understanding of the aggregate compaction process, which is crucial for developing novel compaction strategies and minimizing the environmental impact of the construction process.

A theoretical model and verification of soil column deformation under impact load based on the Duncan-Chang model

The dynamic compaction method has been widely adopted in foundation treatment to densify the soil fillers. However, for the complexity of the impact behavior and soil mechanical properties, the theoretical research of dynamic compaction lags behind its practice for complex soil properties and stress paths. This paper presents a theoretical model applied to describe soil column plastic deformation under impact load. The relationship among stress increment, strain increment, and plastic wave velocity was derived from the aspect of propagation characteristics of stress waves in soil first. Combined with the Duncan-Chang Model, a one-dimensional theoretical model was established then. A numerical model was developed further to check the performance of the model. It showed that the deformation at the end of the soil column was mushroom-shaped. Both the axial and lateral deformation increased with the impact velocity. While some particles located at the side of the soil column end may splash under repeated impact. The theoretical deformations of the soil column were consistent with the experimental results both in the direction of axial and lateral.

Study on Elevation Effect of Vibration Velocity by Dynamic Compaction on Loess High Slope Based on Dimensional Analysis Method

Study on Elevation Effect of Vibration Velocity by Dynamic Compaction on Loess High Slope Based on Dimensional Analysis Method

Impact of initial conditions on the effectiveness of rolling dynamic compaction of granular soils

A finite element model (FEM) of rolling dynamic compaction (RDC) technology of a BH 1300 4 sided 8 tonne impact roller, developed previously by the authors, has shown to have reasonable agreement with that observed in the field. The use of this FEM is likely to provide high fidelity insights into the capability of the BH 1300 4 sided 8 tonne impact roller, namely in predicting the settlement and densification of an underlying granular material. A parametric study utilising this FEM with respect to initial density and shear strength parameters is undertaken to explore the relationship these properties have to the settlement and densification of a soil subject to RDC with a BH 1300 4 sided 8 tonne impact roller. The empirical relationships constructed within this study are validated against field trials from the literature of the roller improving sandy gravel fill at typical operating speeds of 10 km/h.

Experimental and analytical study on the reinforcement mechanism of in-pipe deep dynamic compaction in loose sandy soil

Experimental and analytical study on the reinforcement mechanism of in-pipe deep dynamic compaction in loose sandy soil

Impact of diffraction on screening of dynamic compaction waves with barriers

Impact of diffraction on screening of dynamic compaction waves with barriers

Compaction characteristics and mechanism of the ADC12 alloy powder by laser impact compaction

This paper focuses on the dynamic compaction experimental investigation of ADC12 alloy powder using laser impact, leveraging the high strain rate and controllable precision of pulsed lasers. The effects of varying laser energy (Em) and impactor thickness on the relative density, microstructure, and microhardness of the ADC12 alloy powder billets were examined. Utilizing 2D multi-particle finite element simulation (2D MPFEM), the densification mechanism of these billets was analysed with the help of coordination numbers. The simulation also provided insights into the particle velocity, equivalent plastic strain, and adiabatic temperature increase during compaction. Key findings include that a relative densification of up to 97.27% in the billets is achievable when the laser energy reaches 6J. Notably, a decrease in impactor thickness at constant laser energy leads to a more uniform microstructure and microhardness in the billet. Simulations with the 2D MPFEM demonstrate that thinner impactors allow billets to absorb more energy, thereby increasing particle velocity and plastic strain. This enhances both the relative density and mechanical properties of the billets. The simulation explores the stress distribution during compaction and captures the adiabatic temperature rise on the surface of the pressed billet that occurs in the transient, which is consistent with experimental revelations that heat softens or even locally melts the particles to produce sintering. This study offers new insights into the formation process of these billets from a microstructural standpoint, elucidating the relationship between processing conditions and the resulting material properties.

A new method for rapid preparing high-strength saturated clay samples in large-scale model tests

The preparation of high-strength saturated clay samples for large-scale model tests presents a significant challenge in geotechnical engineering. The slurry consolidation method has been conventionally employed to prepare saturated clay, despite its time-consuming and labor-intensive nature. Therefore, this study proposes a rapid preparation technique for clayey soils utilizing the dynamic compaction method, enabling the facile preparation of saturated clay samples by compacting the soils from an unsaturated state. During compaction, the void ratio decreases, thereby increasing the degree of saturation and enhancing the soil strength. Critical to this method are two variables: the moisture water content and the soil density, which are determined through bench-scale compaction tests using the Proctor compaction test apparatus. These tests establish the relationships between moisture content and density, degree of saturation, and soil strength. The moisture content aligning with the target soil strength is selected as the target moisture content for model-scale soil preparation, whereas the moisture content-density relationship sets the target density value. The laboratory tests validate that the soil strength of the saturated model-size clay samples prepared using the proposed method fulfills the requisite criteria, indicating its effectiveness for rapid preparation of high-strength saturated clay samples in large-scale model tests.

Dynamic compaction of nickel nanopowders: Experiment and MD simulation using the laser shock method

In this paper, a method of dynamic compaction of nanopowders by laser shock is proposed, which is suitable for the compaction of micro-parts with the advantage of high strain rate and controllability. The effect of pre-pressure and laser energy on the mechanical properties and microstructural characteristics of nickel compacts were analysed experimentally. The results indicate a progressive improvement in the mechanical properties of nickel billets with increasing prepressure and laser energy. Notably, under the prepressure of 3 GPa and laser energy of 1.8 J, dense nickel compacts were achieved with the relative density of 94.45% and the microhardness of 170–240 Hv. Molecular dynamics simulation reveals that at a certain pressure threshold, plastic deformation, lattice modification, and dislocation slip occur among nanoparticles, causing strain hardening and a gradual increase in relative density. Furthermore, nanoparticle size inversely correlates with the compaction pressure. The main bonding mechanism of particles is cold welding.

Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers

Correlation Between Dynamic CBR and Compaction and Bearing Capacity of Pavement Foundation Layers

Quantification and Optimization of Compaction Energy Used in Earth Construction: Case of Static and Dynamic Compaction

Earth construction is a sustainable and environmentally friendly approach to building. In addition to their good thermal performance, earth materials are abundant, inexpensive, and readily available, reducing the need for resource-intensive materials like concrete and steel. Regarding the construction process of earth structures, which is based on compaction, there is often a difference between the laboratory compaction process and the onsite one. The energy consumed onsite to produce earth structures is still approximative and uncontrolled, which affects considerably the mechanical performances of earth walls. Then, the investigation of the optimal compaction energy is necessary. To optimize the on-site compaction energy used in rammed earth (RE), an experimental study is carried out to compare the dynamic compaction usually applied to produce RE walls to the static compaction using a mechanical press. By considering increasing dynamic and static energies, the physical and mechanical properties are analyzed for each case. The obtained results show that RE walls can be replaced by prefabricated pressed earth blocks where the compaction energy is reduced by 60% and the compressive strength is enhanced by 70% using static compaction, thus achieving 4 MPa without stabilization. This solution allows to reduce the execution time and to control the quality of earth buildings.