Coarse Granular Materials Research Articles

Experimental Investigation on Shear Strength at the Permeable Concrete–Fine-Grained Soil Interface for Slope Stabilization Using Deep Socket Counterfort Drains

In slopes where high pore water pressure exists, deep counterfort drains (also called drainage trenches or trench drains) represent one of the most effective methods for improving stability or mitigating landslide risks. In the cases of deep or very deep slip surfaces, this method represents the only possible intervention. Trench drains can be realized by using panels or secant piles filled with coarse granular material or permeable concrete. If the trenches are adequately “socket” into the stable ground (for example sufficiently below the sliding surface of a landslide or below the critical slip surface of marginally stable slopes) and the filling material has sufficient shear strength and stiffness, like porous concrete, there is a further increase in shear strength due to the “shear keys” effect. The increase in shear strength is due both to the intrinsic resistance of the concrete on the sliding surface and the resistance at the concrete–soil interface (on the lateral surface of the trench). The latter can be very significant in relation to the thickness of the sliding mass, the “socket depth”, and the spacing between the trenches. The increase in shear strength linked to the “shear keys effect” depends on the state of the porous concrete–soil interface. For silty–clayey base soils, it is very significant and is of the same order of magnitude as the increase in shear resistance linked to the permanent reduction on the slip surface in pore water pressure (draining effect). This paper presents the results of an experimental investigation on the shear strength at the porous interface of concrete and fine-grained soils and demonstrates the high significance and effectiveness of the “shear keys” effect.

A continuous-discontinuous deformation analysis method for research on the mechanical properties of coarse granular materials

The mechanical properties of coarse granular materials play a crucial role in the safety of rockfill dams. From a mesoscopic viewpoint, the macroscopic mechanical properties of these materials are a result of the interactions between particles and the progression of particle breakage. Traditional continuum-based numerical methods struggle to accurately analyze the mechanical properties of coarse granular materials. Discontinuous deformation analysis (DDA) is a more suitable algorithm for studying these properties due to its significant benefits in block displacement mode and open-close iteration for contact handling. In this paper, a continuous-discontinuous deformation analysis method (CDDA) based on the conventional DDA is developed for the numerical investigation of coarse granular materials' mechanical properties. This method incorporates critical kinetic damping, multi-stageloading, stricter displacement convergence criteria and particle breakage simulation. It can provide a comprehensive representation of deformation, particle breakage, force chain, shear zone, and stress–strain curve evolutions. The CDDA results are found to be consistent with indoor test results and can more effectively disclose the deformation and failure mechanism of coarse granular materials. Furthermore, CDDA is employed to examine the impacts of particle size and end friction, leading to valuable insights regarding these effects.

A Unified General Resistance Formula for Uniform Coarse Porous Media

Many authors studied the nonlinear relationship between seepage velocity and hydraulic gradient in coarse granular materials. They managed different approaches and variables to define the resistance formula applicable to that type of granular media. Based on the analysis of the different approaches and experimental data obtained by the corresponding authors, we propose a unified general seepage equation applicable to large-sized granular materials. Such an equation gives unity to the main nonlinear resistance formulas developed to date. Particularly relevant are the conclusions regarding the relationship of the linear (α*) and quadratic (β*) dimensionless coefficients of the resistance formula with the representative size of the particle and the geometrical features of the porous materials.

Investigation on the triaxial creep characteristic of coarse granular materials with different initial void ratios

The creep deformation of coarse granular materials is closely related to the state of creep stress and the degree of compaction. A serious of triaxial creep tests using the single-line method were carried out to investigate the influence of initial void ratio and triaxial stress state on the creep deformation and creep strain direction of coarse granular materials. The test results primarily indicate that the creep strain increases with an increase in initial void ratio under identical stress conditions, and the volumetric creep strain decreases with an increase in stress ratio under high confining pressure conditions. Furthermore, the variation in the initial void ratio has little influence on the direction of creep strain under the same creep stress state. The effect of generalized stress on the final creep strain and creep dilation ratio were further discussed. It was observed that the final deviatoric creep strain exhibits a stronger correlation with the deviatoric stress q compared to the mean normal stress p. Additionally, the creep dilatancy decreases with an increase in stress magnitude under identical stress ratio conditions. Based on the test results, a computation model for the final deviatoric creep strain with the consideration of initial void ratio and creep stress was proposed by modifying a basic power function with deviatoric stress q as the variable. After that, a modified stress-dilatancy equation for coarse granular materials was used to predict the direction of strain during creep process. Finally, the final volumetric creep strain was indirectly calculated by integrated the computation model for the final deviatoric creep strain and the creep stress-dilatancy equation. The reasonable of the proposed model was verified through a comparison of computation results and test results.

Study of non-linear flow in coarse granular material through converging boundaries

Over the past century, there has been a continuously growing research interest in fluid seepage through coarse porous material. Experimental data on nonlinear flow behaviour in several coarse granular materials are provided in the current work. The aim of the present work is to investigate, theoretically and experimentally, the seepage patterns arising from non– Darcy fluid flows through coarse granular materials, with a particular reference to the effect of convergence. Along with the above, the effect of variation in size and shape of the media on the seepage patterns is also analyzed. Experiments have been conducted on flow through porous material with converging permeameter and equations relating the different parameters affecting the seepage flow are established. A thorough review of different regimes of seepage flow has been carried out. In order to meet the prime objective, i.e., to propose governing equations for different regimes of radial seepage flow, experiments are conducted in a converging permeameter with crushed rock and small glass balls as solid material and water as fluid media. The analysis of the experimental data is carried out in two phases. In first phase, coefficient of resistance and Reynolds number is computed using ‘volume diameter’ as ‘characteristic length’. Then expressions relating these two parameters are proposed for different regimes of flow. In second phase, hydraulic radius is used as characteristic length while defining the coefficient of resistance and Reynolds number. Then analysis is repeated as done in first phase and the corresponding equations have been proposed relating the coefficient of resistance and Reynolds number.

S2933 BRIC Type 3? A Case of Benign Recurrent Intrahepatic Cholestasis Unlinked to ATP8B1 and ABCB11

Introduction: Benign Recurrent Intrahepatic Cholestasis (BRIC) is a genetic disorder with two common subtypes: BRIC I (mutated ATP8B1 gene), and BRIC II (mutated ABCB11 gene). Diagnosis requires high degree of suspicion and is confirmed by genetic testing. There are rare cases where patients lack both of the typical mutations. We present a patient with clinical, lab and histological evidence of BRIC without the usual mutations. Case Description/Methods: A 17-year-old male with no medical history presented with yellow eyes, pruritus, and acholic stools for six weeks, without triggering illness or stress. He denied fatigue, fevers, rash, dizziness, nausea, vomiting, diarrhea, constipation, arthralgias, melena, hematochezia, or hematemesis. He had no tattoos, blood transfusions, or allergies. He denied medications, alcohol, smoking, and drug use. On exam, he was icteric, with normal abdominal exam, and Alkaline Phosphatase 370 U/L, ALT 96 U/L, AST 66 U/L, and conjugated bilirubin of 6.7 mg/dL. Serological tests were normal, including antibodies for hepatitis A/B/C, CMV, EBV, HIV; alpha-1 antitrypsin; ceruloplasmin; iron, transferrin, C28Y/H63D mutations; TSH; antinuclear, anti-smooth muscle, anti-liver kidney microsomal, anti-mitochondrial antibodies; serum tissue transglutaminase; urine chlamydia and gonorrhea. Liver ultrasound had no biliary dilation. Genetic testing revealed negative ATP8B1 and ABCB11. Nonfocal liver biopsy showed bland cholestasis with coarse granular material in dilated bile canaliculi, compatible with a disorder of intrahepatic cholestasis, with morphologically similarities to biopsies seen in BRIC. He received ursodiol and symptoms improved. He stopped ursodiol after discharge and presented six months later with similar lab abnormalities. Repeat serological workup was normal. He received ursodiol and symptoms resolved again (Figure). Discussion: Diagnostic criteria for BRIC include episodes of jaundice separated by a symptom-free interval of at least six months, lab and histological evidence of non-inflammatory cholestasis, non-dilated biliary ducts, and no other explanatory causes. Our patient satisfied these diagnostic criteria. Some evidence indicates the presence of additional disease loci for low γ-GT BRIC, explaining why some patients diagnosed with BRIC on clinical and histopathologic evidence lack usual mutations in ATP8B1 or ABCB11. This disorder is informally termed “BRIC 3”; it is unclear which genes are implicated in this form and further research is needed.Figure 1.: Histopathologic appearance of the liver biopsy. Bland centrilobular cholestasis with coarse granular biliary material within dilated bile canaliculi, without any significant inflammation, bile duct damage, or ductular reaction.

Numerical investigation of the performance of engineered barriers in controlling stormwater runoff

In this paper, 2-dimensional, hydro-mechanically coupled finite element analyses are conducted to assess the performance of an engineered barrier, constructed from natural geomaterials, aimed at reducing flood risk in urban environments. The barrier consists of an unsaturated compacted soil layer with water holding properties and a drainage layer of a coarse granular material, that acts as a capillary break, and is constructed on top of the natural soil, in this case London clay. The barrier is vegetated so that its water storage capacity is renewed after each rainfall event. Sophisticated boundary conditions are used to simulate the effect of precipitation and evapotranspiration. The evolution of the rainfall infiltration and runoff rate is simulated both for a treated soil column with an engineered barrier and an untreated one consisting solely of in-situ London Clay. The percolation rate of rainfall water from the bottom of the barrier is also estimated. This comparison highlights the effectiveness of the engineered barrier in reducing the risk of fast flooding, in preventing excessive deformations and in protecting underground infrastructure during wetting and drying cycles. The effect of the hydraulic properties and geometry of the barrier is investigated by means of an extensive parametric analysis. Finally, recommendations for the design of barrier systems are made.

Packing, compressibility, and crushability of rockfill materials with polydisperse particle size distributions and implications for dam engineering

In rockfill dam engineering, particle breakage of rockfill materials is one of the major factors resulting in dam settlement. In this study, one-dimensional compression tests on a series of coarse granular materials with artificially-graded particle size distributions (PSDs) were carried out. The tests focused on understanding the role of initial PSDs in the dense packing density, compressibility and crushability of coarse granular materials. The effects of fractal dimension (D) and size polydispersity (θ) of PSDs were quantitatively analyzed. Two different loading stages were identified from the logarithms of the stress–strain relationships, with the turning point marked as the yield stress. A similar effect of initial PSDs was observed on the packing density and low-pressure modulus of coarse granular materials. The packing density and low-pressure modulus increased monotonically with θ, and their peak values were attained at a D value of approximately 2.2. However, there was no unique correspondence between the dense packing density and low-pressure modulus. The particle breakage was influenced differently by the initial PSDs, and it decreased with the values of D and θ. The emergence of the unique ultimate state was also identified from both the compression curves and PSDs of the samples after the tests. The potential implications of the test results in the design of both low and high rockfill dams were also demonstrated.

A Novel Procedure to Measure Membrane Penetration of Coarse Granular Materials

The membrane penetration effect will significantly influence the measurement of specimen volume deformation in the triaxial test. This paper presents a novel procedure for measuring and correcting the membrane penetration of rubber by using a newly developed multiscale triaxial apparatus. A series of triaxial tests on coarse granular materials was conducted with different specimen diameters, and it is found that the proportion of volume change due to membrane penetration decreases linearly with increasing specimen diameter. To reduce the margin of error induced by membrane penetration in the triaxial test, it is recommended to use specimens of larger size. Such a method can facilitate the correction and estimation of the membrane penetration effect of coarse granular materials.

Bayesian Approach To Improve The Confidence Of The Estimation Of The Shear Strength Of Coarse Mine Waste Using Barton’s Empirical Criterion

The evaluation of the shear strength of waste rock is required for the verification of the stability of high waste dumps, especially those that reach hundreds of meters in height. Mine waste rock material in open pit mining contains particles of metric scale which precludes the utilisation of commercial laboratory testing equipment. To overcome testing limitations, the shear strength of waste rock is frequently estimated using the empirical criterion of Barton-Kjærnsli. This criterion takes into consideration the nonlinearity of the shear strength envelope, characterising the behaviour of very coarse granular materials submitted to high loads. In the criterion, a stress-dependent structural component of the shear strength is parametrised with the equivalent roughness (R) and equivalent strength (S) and the structural component is added to the basic friction angle (φb) of the parental rock to determine the shear strength of the waste rock material. This paper demonstrates the use of Bayesian inference to determine the best set of parameters φb, R and S that satisfied both: large-scale laboratory testing results characterising a waste rock material, and reconciliation data from observations of stability of the waste dumps. The methodology allows the estimation of project-specific model parameters that honour both, laboratory data and site performance information. This objective is achieved through the estimation of correction factors to downgrade the strength from laboratory to field scale.

Characteristics of particle breakage and constitutive model of coarse granular material incorporating gradation evolution

Single particle crushing tests were carried out to research the breakage characteristics of natural rockfill particle. The results showed that the size distribution of broken particles can be described by the normal distribution, and the size distributions of all size fractions converge to a uniform normal distribution after being normalised by the size of the parent particle. Based on the breakage characteristics of rockfill particles, a gradation evolution model was proposed to predict the evolution of the gradation curve of triaxial specimen. This model adopts the loading manner of incremental stress. The correlation among the relative breakage indexes was analysed in terms of the ratio of areas enclosed by the gradation curves and it was found that there is a linear relationship between different indexes. This indicates that there is no essential difference among these indexes from the mathematical point of view. Finally, an elastoplastic constitutive model incorporating the gradation evolution model was developed. This model can predict the stress–strain behaviour and gradation evolution of triaxial specimens of limestone rockfill under the conditions of consolidation, drained and quasi-static shear loading.

Experimental Study on the Reliability of Scaling Down Techniques Used in Direct Shear Tests to Determine the Shear Strength of Rockfill and Waste Rocks

The determination of shear strength parameters for coarse granular materials such as rockfill and waste rocks is challenging due to their oversized particles and the minimum required ratio of 10 between the specimen width (W) and the maximum particle size (dmax) of tested samples for direct shear tests. To overcome this problem, a common practice is to prepare test samples by excluding the oversized particles. This method is called the scalping scaling down technique. Making further modifications on scalped samples to achieve a specific particle size distribution curve (PSDC) leads to other scaling down techniques. Until now, the parallel scaling down technique has been the most popular and most commonly applied, generally because it produces a PSDC parallel and similar to that of field material. Recently, a critical literature review performed by the authors revealed that the methodology used by previous researchers to validate or invalidate the scaling down techniques in estimating the shear strength of field materials is inappropriate. The validity of scaling down techniques remains unknown. In addition, the minimum required W/dmax ratio of 10, stipulated in ASTM D3080/D3080M-11 for direct shear tests, is not large enough to eliminate the specimen size effect (SSE). The authors’ recent experimental study showed that a minimum W/dmax ratio of 60 is necessary to avoid any SSE in direct shear tests. In this study, a series of direct shear tests were performed on samples with different dmax values, prepared by applying scalping and parallel scaling down techniques. All tested specimens had a W/dmax ratio equal to or larger than 60. The test results of the scaled down samples with dmax values smaller than those of field samples were used to establish a predictive equation between the effective internal friction angle (hereafter named “friction angle”) and dmax, which was then used to predict the friction angles of the field samples. Comparisons between the measured and predicted friction angles of field samples demonstrated that the equations based on scalping scaling down technique correctly predicted the friction angles of field samples, whereas the equations based on parallel scaling down technique failed to correctly predict the friction angles of field samples. The scalping down technique has been validated, whereas the parallel scaling down technique has been invalidated by the experimental results presented in this study.

Comparative Analysis of Selected Concrete Mix Design Methods Based on Cost‐Effectiveness

Concrete is an amalgamated material that is composed of coarse granular materials embedded in a hard matrix of material that fills the void among the aggregate particles and binds them together. Concrete ingredients have to be properly classified and proportioned to build a mix that will be economical as well as meet the minimum requirements of functionality, safety, and economics. For this, there should be appropriate proportioning or mixing methods to arrive at the right combination of ingredients for making concrete according to the given specifications. Due to this, this study was intended to conduct a comparative analysis among selected concrete mix design methods, American Concrete Institute (ACI), British Department of Energy (DOE), Ethiopian Building Code of Standards (EBCS), and Indian standards (IS), by using experimental investigation for normal concrete production, focusing on cost‐effectiveness. The concrete ingredients’ physical properties were compared as a requirement, and concrete mechanical properties were examined as per the method of concrete mix design on the 7th, 14th, and 28th days of curing. The experimental result of compressive strength for those selected concrete mix design methods with the 7th, 14th, and 28th ages has fulfilled the desire for concrete strength. However, on the 28th day of curing, compressive strength results of ACI, DOE, EBCS, and IS methods were achieved at 133.68%, 121.04%, 124.56%, and 121.04%, respectively. On the one hand, regarding the material of concrete consumption, the EBCS, DOE, and ACI methods were cast‐off in an excess amount (52.2 kg/m3, 40 kg/m3, and 20 kg/m3) of cement, respectively, concerning the IS method. But the IS method was consuming 300 kg of cement per m3 of concrete. Finally, it is concluded that the result of the compressive strength test after 28 days showed that the specimens prepared using the mixing proportions obtained from the ACI standard met the extreme compressive strength requirement more than the other methods. On the other hand, the ACI, DOE, and EBCS methods are the most expensive to absorb an excessive quantity of cement when compared to the IS method. However, the overall result showed that the concrete designed as per the IS method is relatively easy to work with and cost‐effective for developing countries such as Ethiopia for the production of normal grade concerts.

A method for generating a block system of coarse granular materials that strictly meet gradation requirements

The discontinuous deformation analysis (DDA) method provides unique advantages in simulating the mechanical properties of coarse granular materials. However, the DDA method cannot automatically generate numerical samples of coarse granular materials that can strictly meet the gradation requirements. Therefore, to solve this problem, a new generation method is proposed for generating a block system of coarse granular materials. First, a particle is randomly selected from the basic morphology database and randomly scaled and rotated to match the particle size requirements of the current gradation, based on the relevant requirements for laboratory tests of coarse granular materials. The accumulated particle area will enter the next gradation when it meets the area proportion requirements of the gradation, and this step is repeated gradually from the large particle size group to the small particle size group. Second, the random drop area, which has the same diameter as the coarse granular sample but a height several times that of the sample, is defined. The particles are randomly placed in this area in order of large to small particle size groups, and the requirements of nonoverlapping and noncrossing between particles or between particles and boundaries must be met. When the efficiency of random dropping is very low or even fails, it is important to keep increasing the sample height multiplier. Third, a DDA-based compaction operation is performed to obtain a stable block system with close particle contact. Fourth, a coarse granular material sample that fully meets the gradation requirements is obtained by gradually adjusting the height of the prepared sample. Finally, an example is used to demonstrate the feasibility of the proposed algorithm.

Study on the influence of different discrete forms of DDA block on mechanical properties of coarse granular material

In the triaxial compression test of soil engineering, particle breakage may occur under the double action of axial and lateral loads. So, for the DDA simulation, the internal discretization of DDA block should be carried out at first. However, different discretization may affect the final simulation results. To solve this problem, the DDA numerical models based on triangular discretization, Voronoi discretization and no discretization are established to carry out the triaxial test simulation of coarse granular material, and the influence of different discretization of DDA block on mechanical properties of coarse granular materials was compared. An improved DDA was used to simulate the triaxial tests under different confining pressures, The numerical results show that the deviatoric stress-strain curves of the three discrete forms become steeper and the peak strength also increases with the increase of confining pressure. Under the same confining pressure, the deviatoric stress-strain curve with no discretization is the steepest and the peak strength is also the largest. Although deviatoric stress-strain curve of the triangular discretization is gentler, its peak strength is closer to that with no discretization compared with the Voronoi discretization. The triangular discretization model gradually changes from contraction to dilation in the loading process, and the higher the confining pressure is, the more obvious the contraction is. At the same time, the direction of contact force gradually changes from the initial minor principal stress direction to the major principal stress direction, forming an obvious force chain, and the final particle breakage mostly occurs in an ‘X’ shaped region. The developed DDA method can accurately reflect the evolution of mechanical properties of coarse granular materials under various working conditions, and the research results can provide reference for the discrete form of blocks in similar simulation.

Rheological investigation of effect of high temperature on geothermal drilling fluids additives and lost circulation materials

High temperatures (HT) and the corrosive environment make the design of a geothermal drilling fluid a highly complex task. The presence of HT exacerbates the problems due to thermal degradation. Geothermal aquifers usually combine high-temperature and complex chemistry, making them highly corrosive. Although geothermal drilling fluids are exposed to thermal degradation, research of the effect on mud rheological properties in temperatures near or above 149°C (300°F) is limited.In this study, a High Pressure-High Temperature (HPHT) rheology setup was used to measure drilling fluids' properties up to 204.4°C (400°F). Rheological behavior of viscosity, density, lost circulation, and alkalinity control additives were analyzed at HT. It was found experimentally that Bentonite alone is thermally stable at HT. In contrast, Caustic Soda showed a tendency to gelate at temperatures above 93.3°C (200°F), adversely affecting mud rheology. Alkalinity control materials to replace Caustic Soda were evaluated. Among them, Lime presented the best thermal stability at 204.4°C with a range of variation of 0.0024 Pa.s (2.4 cP) on apparent viscosity after three consecutive tests. Besides, it was tested 11 different lost circulation materials (LCM) for understanding their rheological behavior at HT. It was found that HT has less impact on fine granular materials rheological behavior with an average increase of 17.7% compared with the baseline. In contrast, flaky, fibrous, and coarse granular materials presented a more apparent impact in WBM rheology with a deviation of 166% compared with the baseline.

Mechanical properties of a mortar with melted plastic waste as the only binder: Influence of material composition and curing regime, and application in Bamako

In recent years, serious environmental problems induced by plastic wastes have drawn considerable attention across the world and new initiatives have been adopted to recycle plastic wastes into construction materials. One of the promising initiatives is the use of plastic waste as the only binding phase to make concrete/mortar-like construction materials. However, how key engineering properties of concrete/mortar-like materials with melted plastic as the only binder change with material composition and curing conditions are not well known. This paper aims to investigate the effect of curing conditions and granular material size on the mechanical properties (compressive and splitting tensile strengths) of a mortar with melted plastic waste (high density polyethylene (HDPE) and low density polyethylene (LDPE)) as the only binder (MPB: mortar with melted plastic waste binder). Moreover, it presents a study conducted in the city of Bamako (Mali) to evaluate the use of MPB to make interlocking paving blocks for use on non-traffic areas in residential or municipal construction projects. Two curing conditions, namely, air dry at ambient temperature and water curing were used for this research. Moreover, the size of the granular materials (sand and gravel) was varied in order to assess its impact on the properties of the corresponding MPB sample formulations with given plastic content and HDPE/LDPE (H/L) ratio. Granular material size and curing conditions were found to have significant impact on the mechanical strengths of the MPB materials. Regardless of age and H/L ratio, the MPB samples cured in water showed lower strength (compressive and tensile) than the specimens cured at ambient temperature under controlled laboratory conditions, while adding coarse granular materials helped to improve these strength properties. Furthermore, the mechanical performance of the proposed MPB-interlocking paver is superior to that of the interlocking Portland cement-based pavers that are commercially available on the Bamako’s market. Moreover, the cost of the Portland cement-less MPB-paver will be substantially lower than that of the Bamako’s commercial Portland cement-paver. The obtained results place this MPB material as a promising candidate for making interlocking pavers or other products, while reducing the amount of plastic waste to be managed and the cost of interlocking pavers.

A Unified View of Nonlinear Resistance Formulas for Seepage Flow in Coarse Granular Media

There are many studies on the nonlinear relationship between seepage velocity and hydraulic gradient in coarse granular materials, using different approaches and variables to define the resistance formula applicable to that type of granular media. On the basis of an analysis of the existing formulations developed in different studies, we propose an approach for comparing the results obtained by some of the most important studies on state-of-the-art seepage flow in coarse granular media.

Review on the correlation between mixing, microstructure and strength of cementitious products with nanoparticles

Concrete is manmade multiphase composite where coarse granular materials are embedded in a hard matrix of binder, filling the space between the aggregate particles and gluing them all together that strengthens with time on hydration. Addition of nanoparticles further enhances the properties of the concrete such as early strength, refined micro structure and enhanced durability. Nanoparticles are added to cementitious composites by dry mixing with cement or dispersion in water. The challenge associated with it is the uniform dispersion of the nanoparticles in the matrix of the composite. The type of mixer and the mixing pattern affect the fresh and hardened properties of the concrete. This article reviews the effect of dispersion of nano particles, type of mixer and mixing pattern on the properties of cementitious composites.

The Behavior of a Coarse Granular Material under Complex Stress Conditions

In recent years, dozens of high rockfill dams are under construction or planning for hydropower exploration in western China. In dam construction, the mechanical behavior of coarse granular material greatly affects the compatible deformation of dam body. In this article, an indirect in situ density prediction approach for coarse granular material is firstly proposed to solve the technical obstacle on prediction of the material density in thick overburden layer of a dam site in southwest China. Adopting a self-developed large-scale true triaxial apparatus with a special friction-reduction technique, four series of true triaxial tests were then performed to investigate the behavior of a coarse granular material with a maximum particle diameter of 60 mm. Test results show that the peak strength of the material increases together with the increasing confining stress and the increasing intermediate principal stress ratio. The material dilatancy is restricted by both the confining stress and the intermediate principal stress ratio. With the increase in intermediate principal stress ratio, the internal friction angle increases firstly and then decreases slightly, but the slope of stress path reduces gradually. The tested peak states were compared with several well-known strength criteria under the framework of generalized stress, showing a good fitness with the Lade–Duncan criterion and underestimation by the Mohr–Coulomb criterion and the Matsuoka–Nakai criterion. The strength envelope in the π plane shrinks with the increasing confining stress.