Compaction Curve Research Articles

Visualization and quantification of soil laboratory impact compaction

As important methods to guide the field soil compaction, the standard and modified Proctor tests for laboratory compaction have remained unchanged for decades, which should be improved to better understand the compaction process and the properties of soils. In this study, an accelerometer was installed on a Marshall impact compactor to capture the dynamic response of three types of soils during compaction. The experimental test results indicated that the acceleration curve for each blow gradually evolved to a stable pattern following the progress of compaction, and the impact and gyratory locking points were linearly related with coefficient of determination R 2 equal to 0.59. The impact compaction curve could be further constructed by filtering the structural resonance, which can be used to quantify the compactability of soil materials. Although each type of soil had a unique set of compaction curves, the slope and value of compaction curve altered accordingly as the moisture content changed for the same soil. In addition, the average acceleration value at the final compaction stage could serve as the target value of soil stiffness. • A high-g accelerometer was utilized to capture the dynamic response of soil impact compaction. • The impact and gyratory locking points were related for soil compaction. • The soil impact compaction curve could be constructed by filtering the structural ringing.

Evaluation on effect of alkaline activator on compaction properties of red mud stabilised by ground granulated blast slag

<p class="Abstract">Any industrial waste has a potential to be used as a civil engineering material with an effective and appropriate waste management system. Like many industrial wastes, red mud (RM) and Ground granulated blast slag (GGBS) are some of the industrial wastes produced from aluminium and steel industries respectively. Utilization of only waste materials will not be effective without a suitable stabilizer, which forced to use an alkaline activator to satisfy the needs of a building materials. This paper evaluates measurements to assess the effect of alkaline activator on the compaction properties of GGBS stabilized RM. Different ratios of NaOH to Na<sub>2</sub>SiO<sub>3</sub> was used as an alkaline activator with 10, 20 and 30 percentage replacement of GGBS to RM and measured the compaction properties by using a mini compaction apparatus. Upon conducting standard and modified proctor compaction tests for various combinations of RM and GGBS, the compaction curves depicted that huge variation in maximum dry density and optimum moisture content with the change of GGBS percentage and different ratios of NaOH to Na<sub>2</sub>SiO<sub>3 </sub>are measured and analysed.Further the influence of compaction energy on the density characteristics of these trails were assessed for better understanding.</p>

Sediment deformation triggered by underlying magma intrusion

Magma intrusion often uplifts and deforms overlying strata to produce forced folds. How the amplitude changes of forced folds through time reflect the transverse thickness changes in the deformed sedimentary strata, and can thus shed light on the processes driving deformation. For example, we expect the original morphology of intrusion-induced forced folds to reflect the shape and emplacement history of the underlying magma body. However, in sedimentary basins, the geometry of forced fold above ancient, buried magma body is a function of intrusion-induced uplift and post-emplacement compaction. Few studies have attempted to separate such syn- and post-intrusion deformation, meaning we poorly understand how burial-related compaction can modify forced fold geometry. This paper deals with the forced folds which are presently buried to depths of 2350–2600 m and caused by underlying magma intrusions, using high-resolution 3D seismic data and well data from the Pearl River Mouth Basin, northern South China Sea. The contribution of differential compaction (compaction-related deformation) was estimated by calculating sediment compaction curve, which allows the reconstruction of original syn-emplacement fold amplitude. This study shows that during magma emplacement, overlying strata greatly thin due to shear compaction. Moreover, burial can increase the amplitude of forced fold, improving their potential for capturing and storing fluids, and making it attractive site for hydrocarbon accumulation or carbon sequestration.

Improving Mudstone Materials in Badland in Southwestern Taiwan by Increasing Density and Low-Cement Amount

The southwestern foothills in Taiwan contain abundant mudstone, which softens or slakes easily when contacting water. Thereafter, this condition causes high rates of erosion during heavy rain, eventually leading to the formation of badlands. To increase land use value in Taiwan, this study aimed to offer a new solution with the use of compaction techniques and also adding a small amount of cement as soil amendment. We examined the feasibility of this concept by performing a series of tests, including the basic physical property test, compaction test, unconfined compression test, static triaxial CU and UU tests, consolidation test, California bearing ratio (CBR) test, and triaxial permeability test. The specimens were created based on the controlled moisture at the wet side along the compaction curve. Three clods, three preparation methods, and two types of cement content were used for specimen preparation. The test results revealed that clod will affect the results of unconfined compression strength and soil permeability. For mudstone with added cement, its unconfined compression strength increased 7- to 10-fold and its shear strength increased 2- to 3-fold. The results of consolidation and the CBR test showed that improvement is possible by using low amounts of cement. Overall, the present method not only adheres to low-carbon and environmental protection requirements, but also verifies the feasibility of using compacted mudstone as an engineering material.

Geo-environmental and geotechnical characterization of municipal solid waste from the selective collection in São Paulo city, Brazil

This paper presents the characterization of municipal solid waste (MSW) randomly collected from two material recovery facilities in São Paulo city, before (input — recyclables) and after (output — rejects) the sorting processes. Geo-environmental and geotechnical tests were performed on shredded samples and a digestion method was applied to detect the metals As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn concentrations using an ICP OES. The objective was to assist future activities of integrated solid waste management and soil pollution. Results showed different particle sizes comparing the input (44.6%) and the output MSW (75.1%) passing through the 100-mm sieve. Organic matter and ash contents indicated the influence of inorganic carbon due to the plastics’ presence, with values varying between 6 and 13%. The pH values obtained were neutral and the electrical conductivity of the MSW rejects suggested a higher amount of ions, with values above 1000 µS/cm. Metals analyses show that Cd, Cu, Ni, Pb, and Zn are present in high concentrations, depending on the types of the materials. Standard Proctor compaction curves yielded maximum dry unit weight varying from 6.6 to 10.0 kN/m3 and optimum moisture contents from 20 to 42%. Cohesion ranged from 1.3 to 31.3 kPa and friction angle from 3.2 to 42.9°. The results are comparable with those obtained for other countries using different MSW treatments and contribute to the data basis for MSW from the selective collection, aiming the integrated solid waste management, serving for other countries that adopt MSW sorting and recycling.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-18281-w.

Simulation of ductile grain deformation and the porosity loss predicted model of sandstone during compaction based on grain packing texture

The content of ductile grains and grain packing texture have great influence on the quality of sandstone, especially tight sandstone. A new simulation method for ductile grain deformation during compaction in sandstone under triaxial stress servo based on the discrete element method (DEM) was established. The micro-mechanical parameters for the simulation were obtained using physical experimental data in the literature. The numerical simulation results of single ductile grains and sandstone with ductile grains confirmed the reliability of the simulation method, where the effect of grain crushing, cementation and dissolution on porosity evolution were not considered. The simulation and physical experiment results show the porosity of sandstone decreases linearly with the increase of ductile grain content. The relationship between porosity and effective stress can be predicted using exponential model, when the grain packing texture was one-component nature packing texture dominated and ductile grain content was less than 50%. When the grain packing texture changes to binary packing and the content of ductile grains was less than 50%, the porosity evolution curve show some fluctuations, and the monitoring compaction curve showed that the relationship between effective stress and porosity can not be represented by exponential model. The void ratio changes of sandstone with binary packing texture during compaction can be predicted based on grain packing texture, and the correlation coefficient between the predicted and simulated void ratio changes (△e) were high, the average errors accounts less than 6% of the average of void ratio changes (△e) when the content of ductile grains were less than 25%. The errors between predicted and simulated void ratio changes (△e) based on packing texture increases with the increase of ductile grain content. When the content of ductile grains exceeded 50%, the exponential model was no longer applicable for sandstone, while the logarithmic model is better. In addition, the proposed simulation method is significant for the study of porosity evolution process and the quantitative evaluation of the relative importance of its diagenesis in sandstone having ductile grains.

DEM modelling of particle fragmentation during compaction of particles

This work presented a numerical study based on the discrete element method (DEM) to understand the effect of particle fragmentation on compaction dynamics and the properties of formed compacts. An improved fragmentation model based on the force criterion and the Apollonian fragments replacement was implemented to the model to mimic particle breakage. Through growth and relaxation of progeny particles, the fragmentation model was able to significantly reduce mass loss during particle fragmentation while maintain the mechanical response of the parent particles. The model was validated by comparing with literature data in terms of compaction curve and the evolution of particle size distribution (PSD). Three stages were identified in the Hecker plot highlighting the strong effect of particle fragmentation. The effect of compact height was investigated, showing particle fragmentation decreased with increasing compact height at the early stage of compaction due to the larger degree of particle rearrangement, but the final PSD was similar for all the compacts. Analysis indicated particle fragmentation energy accounted for 2% of the total input energy while more than 50% of input energy was to overcome the friction between particles.

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.

Mechanical Behaviour of Completely Decomposed Granite Soil with Tire Rubber Granules and Fibres.

Mixing soil with waste tire rubber granules or fibres is a practical and promising solution to the problem of global scrap tire pollution. Before successful applications, the mechanical behaviour of the soil–rubber mixture must be thoroughly investigated. Comprehensive laboratory studies (compaction, permeability, oedometer and triaxial tests) were conducted on the completely decomposed granite (CDG)–rubber mixtures, considering the effects of rubber type (rubber granules GR1 and rubber fibre FR2) and rubber content (0–30%). Results show that, for the CDG–rubber mixture, as the rubber content increases, the compaction curves become more rubber-like with less obvious optimum moisture content. The effect on permeability becomes clearer only when the rubber content is greater than 30%. The shape effect of rubber particles in compression is minimal. In triaxial shearing, the inclusion of rubber particles tends to reduce the stiffness of the mixtures. After adding GR1, the peak stress decreases with the increasing rubber content due to the participation of soft rubber particles in the force transmission, while the FR2 results in higher peak stress especially at higher rubber contents because of the reinforcement effect. For the CDG–GR1 mixture, the friction angle at the critical state (φ’cs) decreases with the increasing rubber content, mainly due to the lower inter-particle friction of the CDG–rubber interface compared to the pure CDG interface, while for the CDG–FR2 mixture, the φ’cs increases with the increasing rubber content, again mainly due to the reinforcement effect.

Influence of Rock Block Content on Compaction Characteristics of Graded Coarse-Grained Fillers

The bearing capacity, stability, and durability of subgrade are affected by the compaction quality of fillers to a large extent. In this study, samples of graded coarse-grained fillers with different rock block contents were designed and prepared with the aid of an improved continuous gradation equation for coarse-grained soils. Then standard compaction tests of these samples with different water content conditions were conducted to understand the influence of rock block content on the compaction characteristics of graded coarse-grained fillers. Results show that the compaction curve peaks of graded coarse-grained fillers always increase with the rock block content. The maximum dry density of graded coarse-grained fillers increases linearly with the rock block content in approximation, while the optimal water content is the opposite. The optimal water content of graded coarse-grained fillers decreases in nonlinearity with characteristics of rapidly first and then slowly. Two empirical formulas about the rock block content were summarized for predicting the maximum dry density and optimal water content of graded coarse-grained fillers. The results of this study can provide a reference for the engineering application of graded coarse-grained fillers.

Estimation of aquitard hydraulic conductivity and skeletal specific storage considering non-Darcy flow

Darcy's law has been widely used to study the groundwater drainage process within an aquitard. However, non-Darcy flow is frequently encountered in laboratory and in situ investigations. With consideration of a sudden drop in boundary hydraulic heads, aquitard compaction characteristics and their sensitivities to the non-Darcy flow control variables were analyzed. The non-Darcy flow was found to retard groundwater drainage, and the retardation effects were much more significant at early-to-intermediate time points. Under this specific boundary condition, the time–compaction curve in a log–log graph at early time points was found to be close to a straight line, whose slope can be used to indirectly evaluate the extent of the non-Darcy effect. A non-Darcy flow-based type curve method was developed for estimating aquitard hydraulic conductivity (K) and skeletal specific storage (Ss), and this method was used to interpret the time–compaction data recorded in a laboratory experiment. The tested aquitard was determined to be associated with non-Darcy flow due to the fact that the time–compaction curve deviated from the Darcy's law-based theoretical curve. Darcy's law resulted in an underestimated K. In contrast, the estimated Ss was almost unaffected by the flow state, if the observation lasted long enough to reach final steady compaction.

Porosity and Compaction State at the Active Pāpaku Thrust Fault in the Frontal Accretionary Wedge of the North Hikurangi Margin

AbstractCharacterization of the porosity evolution across the sedimentary section entering subduction zones and accreted sediments provide valuable information for understanding the deformation history at accretionary margins and the physico‐chemical processes in and around fault zones. International Ocean Discovery Program Expeditions 372 and 375 drilled, logged, and cored the reference section on the incoming plate (Site U1520) and across the active Pāpaku thrust (Site U1518), which is a <30° westward‐dipping splay fault in the frontal accretionary wedge at the north Hikurangi margin in a region where tsunami earthquakes and recurrent slow slip events are documented. We observe strong variations of physical properties across the thrust fault. In particular, interstitial porosity increases by ∼10% through the fault zone while it exponentially decreases with depth, showing lower values in the hanging‐wall (HW; on average, ∼36%) than in the footwall (∼42%). Based on comparisons of porosity with the compaction curve at Site U1518 with that of reference Site U1520, we infer an overcompaction in the HW and a nearly normal compaction in the footwall of the Pāpaku thrust. We suggest that the porosity pattern across the thrust infers differences in the maximum burial depth of sediments, characterized by an overcompacted HW that has been uplifted, thrusted, and concomitantly tectonically eroded above the footwall. Porosity data indicate hydrostatic conditions around the thrust fault contrasting with commonly assumed excess pore pressure at the plate interface.

Evaluation of Soil Compaction Characteristics at a Construction Site in Al-Khalis City, Northeast of Iraq

Soil compaction characteristics namely optimum moisture content and maximum dry density are frequently used as criteria to control field compaction specifications. This study aims to evaluate the compaction characteristics of soil at a construction site located in AL-Khalis City, northeast of Iraq. Ten soil samples were collected from the study area; five samples were augured to perform the Standard Proctor compaction tests to investigate the relationship between the moisture content and the dry density of the soil. A core cutter method was implemented to collect additional five samples used to determine the field dry density of soil and to calculate compaction ratio. The results showed that optimum moisture content values were ranged from 15.4 to 22.5% while maximum dry density values were ranged from 1.63 to 1.83 g/cm3. The effect of the compaction effort on the compaction curves was investigated. Increasing the compaction effort increases the maximum dry density and decreases the optimum moisture content of the soil. In addition, a linear relationship between the maximum dry density and optimum moisture content (correlation coefficient R2=0.937) is noticed. This relationship is compared with similar relationships from the literature. Finally, compaction ratio, commonly used to evaluate compaction specifications, was calculated. Compaction ratio values indicate that the soil was compacted at the site to satisfactory ranges suitable for engineering construction work.

О некоторых закономерностях изменения плотности в литосфере Северной Евразии

A method is proposed for calculating the normal compaction curve of rocks for the deep parts of the lithosphere. It is based on the analysis of petrophysical characteristics and interpretation of gravitational anomalies. The main regularities of density changes in the lithosphere of Northern Eurasia are investigated. It has been shown that the density section of the region’s lithosphere is characterized by alternation of paragenetically connected decompacted-compacted (relative to normal compaction) rock complexes at all levels of the lithosphere from the surface layers of bottom sediments to the mantle. These zones of decompacted-compacted rocks complexes have a global distribution.

New mixture design approach to paper sludge ash-based stabilizers for treatment of potential irrigation earth dam materials with high water contents

In those cases where construction-generated soils with high water contents are used as filling or embankment materials, it is sometimes difficult to satisfy the specified compaction degrees. Recently, soil stabilization using a paper sludge ash-based stabilizer (PSAS) has been developed. Paper sludge (PS) ash is waste generated by the incineration of PS discharged from paper mills. It has been found that PS ash can absorb and retain excess water; and therefore, PS ash can simultaneously improve the stability of muds when it is mixed with them. However, the current mixture design approach for PSAS-treated soils is only applicable to muds with water contents exceeding the liquid limits and cannot be applied to construction-generated soils in which the coarse fraction is dominant. Therefore, this study evaluated the effects of a PSAS on the compaction and mechanical characteristics of coarse-grained soils to use them as materials for irrigation earth dams. A series of compaction tests were conducted on two types of soil samples treated with a PSAS to investigate its effects on the compaction characteristics. The compaction characteristics obtained from the tests were assessed considering the water absorption and retention performance of the PSAS. It was found that the modified optimum water content w*opt of the treated samples, which was evaluated using the amount of water unabsorbed and unretained by the PSAS, was almost equal to the wopt of the untreated samples. Consequently, a new mixture design approach was proposed based on the compaction characteristics. The calculated results successfully demonstrated that, if the compaction curve of an untreated sample and the water absorption and retention ratio, Wab, of the PSAS corresponding to a certain curing period are obtained, the range in the PSAS addition amount, APS1m3, required to attain the targeted compaction degree, (Dc)target, for the curing period can be estimated without conducting compaction tests on the treated samples. Finally, the strength characteristics of the treated samples prescribed by the proposed mixture design method were investigated by conducting CBR tests and CU¯TC tests. Based on the test results, discussions were made on the contribution of the proposed mixture design to the strength development of the treated samples and on the development mechanism.

Improvement of the Shear Strength Parameters of a Granular Volcanic Soil Using Type I Portland Cement

The purpose of this research is to improve the parameters of shear strength in granular volcanic soil, by adding a percentage of Portland type I cement. The first step for this research was to classify the soil through a Granulometry test, according to the Unified Soil Classification System (USCS), the result was considered as a poorly graded sand with gravel also considered by The American Association of State Highway and Transportation Officials (AASHTO) as “A-1-b”. In addition, the compaction curve of the volcanic soil has a Maximum Dry Density (MDD) of 1.21 kg/cm2 and an optimum moisture content of 17.8%. Also, the friction angle of 33.5° and a cohesion of 0 kg/cm2, and the results of the Direct Shear Test indicate the Residual Stresses of 0.63, 1.34 and 2.65 kg/cm2 according to the Normal Stresses 1, 2 and 4 kg/cm2, respectively. The second step was to apply a Modified Proctor Test as following: one sample for natural soil and four samples adding 3%, 5%, 7% and 9% of cement. Finally, applied the Direct Shear Test: one sample for natural soil and three samples adding 3%, 5%, and 7% of cement after 7 days of curing, then three more samples are taken adding 3, 5% and 7% of cement at 14 days of curing. The results of the Modified Proctor Test of the volcanic soil with the addition of 5% cement has a maximum peak of a Maximum Dry Density of 1.33 kg/cm2 and with an Optimal Moisture Content of 22.7%, improved the MDD by 10% in regard to the natural soil. And the results of the Direct Shear Test shown in each sample an increase from 14.6% to 79.1% in the friction angle in comparison with the natural soil from 25.8% to 161.5% in shear strength. Likewise, the behavior of the volumetric deformation is shown, presenting a greater contraction when a normal stress of 1 kg/cm2 is applied and a greater expansion when a normal stress of 4 kg/cm2 is applied. Also, the volcanic soil at 7 days of curing with 7% cement addition increases its resistance by 67.34% and the volumetric variation decreases by 50% and the volcanic soil at 14 days of curing with 5% addition of cement increases its resistance by 103.40% and the volumetric variation decreases by 25%.

Quantification of impact compaction locking point for asphalt mixture

The volumetric properties of asphalt mixture are main elements of the interaction of asphalt and aggregate. To ensure a stable structure of compacted asphalt mixture, the concept of locking point was developed to characterize the amount of compaction efforts which are needed to achieve a stable compaction state. The traditional way of defining locking point was based on the change of volume of mixtures during compaction. In this study, the locking point was defined based upon compaction curves from impact compaction. The locking point for two types of dense-graded asphalt mixtures (AC-20C and AC-13C)and one type of open graded asphalt mixture (SMA13) was evaluated by both impact compaction and gyratory compaction. The influence of compaction temperature and asphalt content on locking points was also investigated. Results showed that it was feasible to identify the locking points for impact compaction. The locking point of impact compaction could be analogically determined according to the locking point of the gyratory compaction. The size of Marshall mold may influence impact compaction curves.

Improving asphalt pavement intelligent compaction based on differentiated compaction curves

Although the Intelligent Compaction (IC) technology has been widely used on the asphalt pavement compaction nowadays, the potential of compaction curve and the target IC measurement value (ICMV) has still not been well clarified, and the actual practices using IC rollers mainly focus on the roller passes and asphalt temperature. The present study investigated the interrelations among asphalt temperature, compactibility, dynamic modulus, and ICMV through resurfacing projects in Tennessee. It was found that the original IC compaction curve could only offer limited information, and the target ICMV value was strongly affected by the asphalt temperature. A further investigation using asphalt vibratory compactor, gyratory compactor, and Witczak model indicated that the effect of temperature on the asphalt modulus and its compactibility varies. To explore the potential of IC technology, the original IC compaction curves were further divided according to the initial compaction temperature, and the practical “cessation temperature” for the breakdown roller could be identified. Based on the findings, the criteria to improve the IC resurfacing compaction were suggested, and it was well in accordance with the test results of core samples. As a result, the asphalt temperature and roller passes are still suggested for the IC asphalt compaction. However, it is based on a better understanding of IC by the differentiated compaction curves.

Soil stiffness as a function of dry density and the degree of saturation for compaction control

A data set of the coefficient of vertical subgrade reaction for a plate diameter of 30 cm, KP.FWD, measured by Portable Falling Weight Deflectometer tests in full-scale compaction tests on sandy soil using various types of compaction machines was analysed. Based on this analysis and the previous analysis of a CBR data set from another full-scale compaction test series, a set of conclusions could be drawn. The soil stiffness indexes (SSIs), CBR and KP.FWD, can be expressed by, respectively, an empirical equation multiplying a function of ρd and another of Sr, where CBR and KP.FWD decrease significantly as Sr increases. As such, ρd values cannot be estimated from SSI alone. By fixing the field ρd – w compaction curve by keeping the soil type and the field compaction energy level, CELf, to those in the field compaction tests in which the SSI – ρd – Sr correlation has been calibrated, field compacted ρd &w states can be estimated by measuring the SSI values. Then, by the upper-bound and lower-bound control of SSI, the field compacted states approach the specified target, where, typically, ρd = the maximum dry density for CELf and Sr = the optimum degree of saturation, (Sr)opt. A method to incorporate this indirect but fast SSI-based compaction control into the conventional ρd &w-based compaction control is proposed.

Numerical analyses on compaction behavior of nonwoven glass fiber fabric

In this study, thickness of single- and multi-layer nonwoven glass fiber fabric in dry and wet state was monitored during compaction and relaxation periods under a pressure range of 2 to 200 kPa. The results were numerically analyzed via power-law model and strain energy calculation. The compaction behavior of three-layer dry fabric stack showed the highest fitness to the power-law modeling. The findings of the power-law model revealed the lack of nesting between adjacent layers and showed that the repeated compaction/relaxation practice and the presence of resin significantly increased the fiber content. The outcomes of the model also indicated: (1) multi-layer fabrics tend to be compressed more easily than single-layer fabric (2) wet fabrics and relaxation periods display higher stiffening index than dry fabrics and compression periods, respectively. The compaction and relaxation curves tracing different paths pointed that some of the compaction energy was absorbed by the fabric. Thanks to the friction mechanism between layers, multi-layer fabrics absorbed more compaction energy (i.e. relaxed better) than single-layer fabric. However, the presence of the resin reduced the relaxation (i.e. the amount of absorbed compaction energy).