Clean Quartz Sand Research Articles

Stress-dilatancy behavior of marine coral sand incorporating non-plastic fines

The existed understanding of stress-dilatancy behavior is predominantly based on experiments conducted with clean quartz sand, with limited research focusing on coral sand. Particularly, impacts of fines and density state on stress-dilatancy response of marine coral sand is of significant concern. This work presents a systematic investigation into these issues through meticulously controlled geotechnical tests, coupled with corresponding discussion and interpretation. Results show that at a high stress level, both pure coral sand and its mixtures consistently undergo shear contraction regardless of fines proportion and density state. However, mixtures with minimal fines experience shear contraction initially, followed by dilatancy under a medium-low stress level. Friction angle at peak state (φps) and critical state (φcs), excess friction angle (φex), and maximum dilatancy angle (ψmax) decrease powerfully as increasing fines content. Besides, the lower and upper limits of variation for φps, φcs, φex concerning ψmax were presented. Correlation between φex and ψmax highlights that Bolton's stress-dilatancy equation, developed for pure sand, remains applicable provided that fines content remains below the threshold value. Additionally, gray correlation result suggests that fines post the dominant influence on above behaviors, followed by density state and stress level. Finally, potential mechanism behinds the influences of fines and density state was explored from the view of particle column buckling.

Measurements of Geologic Characteristics and Geophysical Properties of Sediments From the New England Mud Patch

The characterization of physical, geological, and geophysical properties of sediments within the New England Mud Patch (NEMP) was undertaken to provide a physical basis for acoustic inversions associated with the SeaBed Characterization EXperiment 2017 (SBCEX17). Using a suite of 89 sediment cores (piston/trigger, gravity [acoustic], and vibracore), a comprehensive database of laboratory-based sediment analyses, geophysical core logs, and the results of seismic reflection profiling, we formulate a three-layer lithostratigraphic model of the area within and immediately adjacent to the SBCEX17 focus area, referred to as the seabed experiment area (SEA). The uppermost lithostratigraphic unit, Unit 1, is relatively homogenous clayey- to sandy silt, with consistent downcore textural, mineralogical, and physical property attributes. Unit 2 is a variable-thickness transitional layer between Unit 1 and Unit 3, whose properties reflect a decrease in proximal erosion and transition to a lower energy depositional environment. Unit 3 is clean quartz sand containing abundant shells and shell fragments that was regionally deposited during Holocene sea-level rise. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">210</sup> Pb and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> C radiocarbon geochronologies spanning the past 13 000 years are used to facilitate intercore comparison across the SEA. Analytical results and laboratory methods used in the derivation of those results are described in detail, serving as a reference for ongoing and future investigation of the SEA and entire NEMP. Although the derived lithostratigraphic model of the SEA is in good agreement with past evaluations of the regional sedimentology, comparisons of the lithostratigraphic and seismostratigraphic models highlight several significant incompatibilities that remain to be satisfactorily explained.

The study of the effect of clay type in the reservoir composition on the oil replacement coefficient and change of physical-chemi- cal properties of water in the treatment by electrical field

The paper considers the impact of direct electrical current and clay type in the reservoir composition on the replacement coefficient of oil with water, on the changing of boundary tension and the hydrogen value of oil replacing water. The formation models were developed from clean quartz sand with separate addition of 10–20 % monmorillonitic or kaolinite type of clay. Alkali produced water was used as an electrolyte, by means of which Girmaki oil was replaced. It was defined that significant impact of electric current field on the parameters of oil replacement with water occurs in the presence of the montmorillonitic clay in the composition of formation model. In the presence of the kaolinite less than 10 % oil was recovered compared to the initial oil saturation. Thermal energy appearing in the impact with electric current has a specific effect on the changing of parameters of coefficient of oil replacement with water. It was revealed that the field of direct electric current contributes to the interrelation between water electrolytes and oxygen compounds of oil, intensifies ion exchange processes between the alkali water replacing the oil and clay particles of the skeleton of porous medium.

Time-Dependent Compression Behavior of Sands under Oedometric Conditions

A set of experimental data on the time-dependent oedometric compression behavior of sands is presented. The investigation focuses on the behavior of a clean quartz sand with respect to creep, strain-rate response, stress relaxation, and strain and strain rate history. The influence of different fine contents up to 25% by weight on creep, strain rate response, and stress relaxation are studied. The tests were conducted under vertical effective stress levels up to 7,500 kPa with specimens of medium dense and very dense relative density. The tests show a stress and density dependent creep behavior regardless of the fine content. Creep of sands with more than 14% by weight fine content can be described by a constant Cα/Cc ratio, whereas clean sand shows varying ratios. The response of the soils upon sudden changes in loading strain rate changes from clean sand, which exhibits only a temporary response of the stress-strain behavior, to the sands with more than 14% by weight fine content, which have a permanent response of the stress-strain behavior with continued straining. Stress relaxation tests show decreasing normalized stress relaxation σ/σ0 with increasing vertical effective stress. The behavior is independent of the density. It is described by the oedometric swelling index κ0. The tests on the influence of strain rate history show that the creep behavior of the sands is not dependent on it in the time scales studied.

Cone penetration tests in dry and saturated Ticino sand

It is commonly assumed that dry and saturated sands exhibit similar cone resistance–relative density relationships. Some studies pointed out that partial saturation and calcareous sands with considerable fines content are potential factors affecting these relationships. However, there is experimental evidence in Shaqour Bull Eng Geol Environ 66:59-70, (2006) that clean uncemented quartz sand may exhibit lower cone resistance in saturated conditions. The present study aims on contributing towards better understanding the effect of water saturation on cone resistance in sand. For this purpose, Ticino sand samples were prepared dry and saturated in a calibration chamber and cone penetration tests were performed over a wide range of relative densities and at two consolidation stresses. Overall, it was observed that dry and saturated samples exhibited similar cone resistances. Only slightly higher cone resistances were observed for dry samples at the lower consolidation stress. Two anomalous samples, which were tested dry at medium relative density, were found to exhibit way higher cone resistances than expected from published cone resistance–relative density relationships. The Young's modulus was observed to be proportional to cone resistance and independent of whether a sample was tested dry or saturated, being therefore considered as more robust soil property for cone resistance relationships.

Assessing the Adsorption of Bipyridinium Herbicides on Model Soil Granular Media

In this research work, the adsorption of two bipyridinium herbicides (i. e., Diquat and Paraquat) on natural soil and on model soil surfaces has been studied at different water chemistries commonly found in the environment (e.g., pH, supporting electrolyte, and presence of humic or fulvic acids). The experimental work was carried out in the laboratory, using experimental batches of clean quartz sand, silanized quartz sand and sandy soil as a model of agricultural topsoil where herbicides are commonly used and can be adsorbed. The concentrations reached at the equilibrium were analyzed by UV-Visible Spectroscopy for the supernatant fraction of the samples. The concentrations were fitted using adsorption isotherms to determine the adsorption mechanisms (i.e., chemisorption or physisorption) at the interface. In general terms, we have encountered that the nature of the soil matrix plays an important role on the study of pollutant adsorption. In experiments carried out on silica sand, the most abundant component of the natural soil matrix, no significant sorption was observed (&amp;lt;1.5 mg/g) for any of the herbicides. Yet, in experiments carried out on the presence of clay and natural organic matter (i.e., fulvic and humic acids), the adsorption of both herbicides is much higher, likely due to the chemical structure of the molecules that might facilitate the complexation with both herbicides. This investigation improves our understanding of the role that soil granular components play on the absorption of two commonly used herbicides and adequately predict their fate in natural aquatic environments.

Laboratory investigation into the monotonic and cyclic behaviour of a clean sand stabilised with colloidal silica

This paper presents a laboratory investigation into passive stabilisation of liquefiable sands by means of colloidal silica (CS). In order to examine the improvement of the mechanical behaviour of liquefiable sands stabilised with CS, an extensive laboratory testing programme comprising unconfined compressive strength and Brazilian tensile strength tests, as well as undrained monotonic and cyclic triaxial tests, was performed on a clean quartz sand treated with CS. The test results are compared to the corresponding results for the untreated sand. The effects of CS concentration, curing time, density and confining stress on the monotonic and cyclic response of the treated sand are examined, among others. It is shown that stabilisation of the tested sand with CS significantly improves both the undrained monotonic and cyclic strength. The influence of CS concentration on the monotonic response is reduced with increasing mean effective stress. Cyclic resistance, however, is shown to be practically unaffected by CS concentration. Furthermore, cyclic straining at 5 to 10% of double-amplitude axial strain does not influence the undrained shear strength of the stabilised sand.

Undrained Monotonic and Cyclic Response of Weakly Cemented Sand

This paper presents a laboratory investigation into the monotonic and cyclic responses of weakly cemented sand. An extensive laboratory testing program comprising unconfined compressive strength and tensile strength tests, as well as undrained monotonic and cyclic triaxial tests, was performed on clean quartz sand, with cement contents (CCs) varying from 1% to 8%. The effect of various parameters, among which are the cementation content, density, effective stress and curing time is examined. Even at the smallest CC of 1%, a distinctive enhanced behavior of the cemented sand over that of the uncemented was observed. At a given density and effective confining stress, increasing cementation results in the decrease of contractiveness of sand under monotonic shearing and in the transition of cyclic behavior from flow-type liquefaction to cyclic mobility type.

Influence of size disparity on small-strain shear modulus of sand-fines mixtures

Characterizing the small-strain shear modulus (G0) of sand with fines is of importance in geotechnical applications since natural sand is usually not clean but contains a certain amount of fines. This paper presents an experimental study to investigate G0 values of several sand-fines mixtures, formed by mixing clean quartz sands of different sizes with crushed silica fines of varying quantity. Focus of the study is on the possible interplay between the influence of particle size disparity and the influence of fines contents for which current understanding is not adequate. By defining the particle size disparity as D50/d50, where D50 is the mean size of base sand and d50 is the mean size of fines, a critical range of size disparity is found to be approximately between 4 and 7. When the size disparity is smaller than 4, the role of fines is manifested mainly by fines content; when the size disparity is beyond 7, the contribution of fines to the load transfer gradually becomes negligible because in this case fine grains tend to roll into the voids. A new concept, referred to as combined size disparity, is proposed to capture the influence of fines content and the influence of size disparity in a collective manner. By adopting this concept, an empirical relationship is proposed for estimating G0 values of sand-fines mixtures. The predictive performance of the relationship is then examined using literature data and a reasonably good agreement between prediction and measurement is obtained.

Shear wave velocity and stiffness of sand: the role of non-plastic fines

Current knowledge on the shear wave velocity (Vs) and associated stiffness (G0) of sand is built mainly on the results of extensive laboratory studies on clean quartz sands. Often natural sands are not clean, but contain a certain amount of fines. The role of fines in altering the stiffness of sands is a matter of great concern, yet remains poorly understood. This paper presents an investigation into the problem through well-controlled laboratory experiments in conjunction with analysis and interpretation at the macro and micro scale. The laboratory experiments were conducted for a sequence of mixtures of clean quartz sand and crushed silica fines under saturated conditions, by the simultaneous use of the resonant column (RC) and bender element (BE) techniques. A broad range of states in terms of void ratio, confining stress and fines content was covered so as to obtain a comprehensive view on the effect of fines and the possible interplay with other factors. Both the RC and BE tests showed that G0tends to decrease continuously as the quantity of fines is increased and the reduction rates are similar; a similar stress dependence is also obtained for G0from both types of testing. Nevertheless, G0values obtained from BE tests are notably greater than those obtained from RC tests, and this effect of testing method is shown to be coupled with the sample reconstitution method. A new approach that allows unified characterisation of G0values for both clean sand and sand–fines mixtures is developed in a sound theoretical framework, thereby providing important insights into the various empirical correlations that involve G0(or Vs) in geotechnical engineering practice. A new micro-scale mechanism is also suggested for the observed effect of fines, which attributes the reduction of G0caused by fines to the decrease in the coordination number at an approximately constant void ratio.

Toward a Cost-Efficient Method for Monitoring of Traffic-Derived Pollutants with Quartz Sand Boxes

This study aims at understanding characteristics of current traffic pollution at roadsides and to assess the use of magnetic parameters for a cost-efficient monitoring concept. We conducted a systematic monitoring study of roadside pollution at three sites in southern Germany and one site at Lanzhou/China. For this purpose, we installed ground-based monitoring boxes filled with clean quartz sand at different distances (1, 2, and 4 m) from the road. Mass-specific magnetic susceptibility (χ), heavy metal (HM) contents, and polycyclic aromatic hydrocarbon (PAH) concentrations all showed decreasing values with distance to the roadside. The temporal variations over 2 years of monitoring reveal an overall increasing trend but differences in depth migration due to seasonal effects (i.e., precipitation). A magnetite-like phase turned out to be responsible for the enhancement of χ. Significant positive correlations between χ and total PAHs as well as HMs for the German sites suggest that χ—which can be measured fast and convenient—can be used as a proxy for traffic-derived PAH and HM pollution. However, in the much drier region of Lanzhou, the relationship of χ with HMs is much weaker, which might be caused by specific materials used in road construction and heavy vehicles. From the obtained results, we conclude that an appropriate roadside monitoring procedure based on magnetic signatures should best use a single thin (1–2 cm) layer of clean quartz sand protected against lateral material translocation.

Small-strain shear modulus of volcanic granular soil: An experimental investigation

While volcanic soils exist in many places around the world, their mechanical behavior is however less extensively studied as compared to the conventional soil type such as quartz sand and clay. This paper presents an experimental study investigating the small-strain shear modulus (G0) and associated shear wave velocity (Vs) of a volcanic granular soil collected from the northeast of Japan that was affected by the devastating 2011 Tohoku earthquake. Reconstituted soil specimens were tested at different packing densities and confining stress levels by using the resonant column technique, and the pressure and density dependence of shear modulus was established for the soil. The study showed that under otherwise similar conditions, the G0 value of the volcanic soil was markedly lower than that of clean quartz sands, but it tended to increase significantly when the fine particles in the soil were removed. This finding suggests that the presence of fines plays an important role in the mechanical behavior of volcanic soils. A practical model accounting for the influence of fines and the pressure and density dependence is proposed and it is shown to provide reasonable estimates of G0 for both volcanic soils and clean quartz sands studied.

Monitoring-based discrimination of pathways of traffic-derived pollutants

We conducted a systematic monitoring study of roadside pollution based on surface-based samplers (U-channels) and samplers at different heights (poles). The study aim was to discriminate pathways of traffic-derived pollutants by surface runoff, splash water and airborne transport, and to assess the use of magnetic parameters for efficient monitoring concepts. At two high traffic density roads in southern Germany, we installed vertical poles at 0.5-m and 1.5-m distances from the roadside with samplers at various heights (surface, 0.5 m and 2 m), along with 4-m long U-channels (at the surface and 2.5 cm above it) perpendicular to the road. Clean quartz sand was used as collector material. Mass-specific magnetic susceptibility (χ), heavy metal (HM) and polycyclic aromatic hydrocarbon (PAH) concentrations all showed a significant increase over one year in pole and U-channel collectors. Systematic differences of χ, PAH and HM concentrations in samples at various heights and distances from the road indicate a common pathway of magnetic particles and pollutants and a dominance of splash-water transport. A magnetite-like phase turned out to be responsible for the enhancement of χ. Significant positive correlations between χ and total PAHs as well as HMs suggest that χ can be used as a proxy for traffic-derived PAH and HM pollution. The results of our monitoring studies could be used to provide basic knowledge to support the development of new monitoring approaches for traffic-derived pollution along roadsides.

Inspection of a high-cycle accumulation model for large numbers of cycles (N=2 million)

The high-cycle accumulation (HCA) model for sand proposed by Niemunis et al. (2005) [16] has been developed based on numerous drained cyclic triaxial tests with 100,000 cycles. In the present paper the validity of the HCA model, in particular its function fN and flow rule m, for larger numbers of cycles is inspected. For that purpose, drained long-term cyclic triaxial tests with 2 million cycles have been performed on 13 clean quartz sands with different grain size distribution curves. For all tested sands, the function fN, describing the shape of the strain accumulation curves εacc(N), has been found suitable up to 2 million cycles. The same applies to the cyclic flow rule m, determining the ratio of the volumetric and deviatoric strain accumulation rates. Based on the data from the long-term tests, correlations between the HCA material parameters entering fN and characteristics of the grain size distribution curve (d50 and Cu) have been improved for the application to 2 million cycles. These correlations are suitable for a simplified calibration of the HCA model and were validated up to 100,000 cycles only so far.

Facilitated transport of titanium dioxide nanoparticles by humic substances in saturated porous media under acidic conditions

The transport behavior of titanium dioxide nanoparticles (TiO2 NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO2 NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L−1. Facilitated transport of TiO2 NPs was likely attributable to the increased stability of TiO2 NPs and repulsive interaction between TiO2 NPs and quartz sands due to the adsorbed HS. The mobility of TiO2 NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO2 NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl2. In addition, calculated Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO2 NPs, while the secondary energy minimum could play an important role in the retention of TiO2 NPs at 100 mmol L−1 NaCl. Straining and gravitational settlement of larger TiO2 NPs aggregates at 1 mg L−1 HS, pH 5.0, and 2 mmol L−1 CaCl2 could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO2 NPs and TiO2 NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L−1 CaCl2. Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO2 NPs over the range of solution chemistry examined in this study.

Improved simplified calibration procedure for a high-cycle accumulation model

The high-cycle accumulation (HCA) model proposed by Niemunis et al. [16] predicts permanent deformations due to a drained cyclic loading with many small cycles (i.e. N≥103 cycles with strain amplitudes εampl≤10−3). The strain amplitude is the most important influencing parameter of the rate of strain accumulation ε̇acc. Based on tests on a medium coarse sand, a square relationship ε̇acc~(εampl)2 has been used in the HCA model so far. The new test results presented in this paper indicate, however, that the exponent of the amplitude-dependence may vary between 1.3 and 2.4, depending on the tested material. This comes out of 150 drained cyclic triaxial tests with 105 load cycles performed on 14 clean quartz sands with specially mixed grain size distribution curves. Consequently, an additional material constant Campl has been introduced into the HCA model describing the amplitude dependence according to ε̇acc~(εampl)Campl. The additional parameter requires a revision of the simplified calibration procedure proposed by Wichtmann et al. [24] which uses correlations between the HCA model parameters and granulometric (d50, Cu) or index properties (emin). Furthermore, the new cyclic test data reveal that the existing correlations are inappropriate for well-graded granular materials (Cu≥5). Enhanced correlations suitable also for more well-graded sands are proposed in the paper. The possible error of a HCA model prediction with parameters fully or partly determined from the correlations is discussed.

Carbon mineralization following additions of fresh and aged biochar to an infertile soil

Biochar (BC) aging that has not undergone soil processing before adding to soils may have a different effect on soil carbon (C) mineralization in the short term. This article focuses on studying short-term effects of fresh and aged biochars (without soil processing) on C mineralization in a typical infertile soil in the hilly red soil region of southern China. Tree bark charcoals with known ages of 10years (BC10years) and 4months (BC4months) were collected and fresh biochar (BCfresh) was produced in the laboratory using the same feedstock under similar conditions. A 42day incubation experiment was conducted with treatments consisting of soil +2% BC10years (SB10-2), soil +2% BC4months (SB4-2), soil +2% BCfresh (SBf-2), soil +5% BCfresh (SBf-5) and soil only (CK). Treatments with clean quartz sand (with a similar volume) instead of the soil were also conducted. During the incubation, enhanced C released as CO2 (CO2-C) was observed in SB4-2, SBf-2 and SBf-5; but not in SB10-2, and no CO2-C was detected in the quartz sand treatments. Biochar additions increased the C amount in the treated soil. After incubation, minor changes of dissolved organic C were detected after biochar additions. The highest values of dissolved organic nitrogen and ammonium nitrogen were detected in SB10-2. Biochar additions increased microbial biomass C, and pH levels with the highest values recorded in SBf-5 (14.71mgkg−1 and pH5.30). The results suggest that soil C mineralization can be enhanced by the addition of fresh (BCfresh) or relatively young biochar (BC4months), but is not evident when aged biochar (BC10years) is added. The biochar, whether newly produced or aged for several months without soil processing, can promote C mineralization of infertile soils in a relatively short time, but this does not appear to be the case for biochar aged for 10years without soil processing.

Characteristics of current roadside pollution using test-monitoring plots

The aim of the study was the qualitative recognition of the existing roadside pollutants deposited in topsoils located close to roads with high traffic volume. So far, the studies have helped to determine the content of pollutants that accumulated over a long period of time. Traditionally, it has been difficult to distinguish between roadside pollution and pollution from other industrial sources. In order to avoid such problems and to accurately recognize present threats originating from road traffic, test-monitoring plots were installed in Poland (Gliwice and Opole), Germany (Tübingen, Ulm and Böblingen), Finland (Helsinki), Tajikistan (Dushanbe) and China (Lanzhou). To install the monitoring plots, the upper 7cm of topsoil was removed and replaced with boxes filled with clean quartz sand. The sand, with a known chemical composition and neutral magnetic (diamagnetic) properties, was considered as a neutral matrix for the accumulation of traffic pollutants. Within 24months of exposure, both the magnetic susceptibility values and heavy metal content increased, but with highly diverse differences. The highest values were observed in Germany, Tajikistan and China. Correlation coefficients between the magnetic susceptibility values and investigated elements, as well as PAHs indicate that magnetic susceptibility is a geophysical parameter that can be used, under defined conditions, as an indicator of soil pollution caused by traffic emissions.

Biogeochemical Interface Formation: Wettability Affected by Organic Matter Sorption and Microbial Activity

Batch incubation and column percolation experiments with dissolved organic matter solution at different pH values were performed to investigate the effect of organic matter sorption and microbial activity on the wettability of clean quartz sand particles. Sodium azide was used as a biocide to control microbial activity. Changes in wettability were evaluated by contact angle measurements. Wettability of the quartz sand was found to significantly decrease after sorption of organic matter. An adsorbed C content of &lt;0.1 g C kg−1 turned out to be effective in increasing the contact angle from initially 30 to &gt;70°. Results of the percolation experiments revealed that the change in contact angle was depth dependent, with the greatest increase in the upper part of the columns. The low C/N ratio (&lt;10) of the organic matter adsorbed in the upper part of the sand columns percolated without biocide addition suggested that the depth dependency was caused not only by sorption of organic matter but also was affected by microbial activity. This finding was supported by an increasing contact angle for sand columns percolated with a solution close to neutral pH (6.7), where more favorable living conditions for bacteria could be assumed. We also observed a trend of a linear inverse relationship between C/N ratio and contact angle, i.e., increasing contact angle with decreasing C/N ratio. Overall, the results indicated that the formation of biogeochemical interfaces can strongly change the original wetting properties of mineral particle surfaces.

Flow rule in a high-cycle accumulation model backed by cyclic test data of 22 sands

The flow rule used in the high-cycle accumulation (HCA) model proposed by Niemunis et al. (Comput Geotech 32: 245, 2005) is examined on the basis of the data from approximately 350 drained long-term cyclic triaxial tests (N = 105 cycles) performed on 22 different grain-size distribution curves of a clean quartz sand. In accordance with (Wichtmann et al. in Acta Geotechnica 1: 59, 2006), for all tested materials, the “high-cyclic flow rule (HCFR)”, i.e., the ratio of the volumetric and deviatoric strain accumulation rates \(\dot{\varepsilon}_{\rm{v}}^{{\rm acc}}/\dot{\varepsilon}_{\rm{q}}^{{\rm acc}}\), was found dependent primarily on the average stress ratio ηav = qav/pav and independent of amplitude, soil density and average mean pressure. The experimental HCFR can be fairly well approximated by the flow rule of the modified Cam-clay (MCC) model. Instead of the critical friction angle \(\varphi_{\rm{c}}\) which enters the flow rule for monotonic loading, the HCA model uses the MCC flow rule expression with a slightly different parameter \(\varphi_{\rm{cc}}\). It should be determined from cyclic tests. \(\varphi_{\rm{cc}}\) and \(\varphi_{\rm{c}}\) are of similar magnitude but not always identical, because they are calibrated from different types of tests. For a simplified calibration in the absence of cyclic test data, \(\varphi_{\rm{cc}}\) may be estimated from the angle of repose \(\varphi_{\rm{r}}\) determined from a pluviated cone of sand (Wichtmann et al. in Acta Geotechnica 1: 59, 2006). However, the paper demonstrates that the MCC flow rule with \(\varphi_{\rm{r}}\) does not fit well the experimentally observed HCFR in the case of coarse or well-graded sands. For an improved simplified calibration procedure, correlations between \(\varphi_{\rm{cc}}\) and parameters of the grain-size distribution curve (d50, Cu) have been developed on the basis of the present data set. The approximation of the experimental HCFR by the generalized flow rule equations proposed in (Wichtmann et al. in J Geotech Geoenviron Eng ASCE 136: 728, 2010), considering anisotropy, is also discussed in the paper.