Sand Specimens Research Articles

Metal corrosion in partially saturated sands: Pore fluid conductivity and water saturation

Sediments can facilitate the electrochemical processes that drive the corrosion of buried metallic components. Common analyses and guidelines emphasize the effect of pore fluid conductivity on soil corrosivity and overlook the effect of partial saturation; yet, most buried metals are situated within the vadose zone. The detailed experimental study reported herein used mass loss measurements from passive corrosion tests, X-ray microtomography, and image analyses to examine the evolution of corrosion in C-steel coupons embedded in sand specimens mixed with de-ionized water and brine at various degrees of saturation. Experimental observations show that corroding cells preferentially form at contacting grains, and that the evolution of corrosion is biased by the variability in packing density and saturation, while fluid conductivity plays a lesser role. Above all, results highlight the critical importance of percolating gas and water phases, and show that water-grain-metal interfaces restrict the actively corroding area to a fraction of the entire metal surface. A complementary macroscale analysis anticipates asymptotic conditions based on mass and charge conservation, and the transport of corroding agents and residuals. Together, the measurements and model results highlight the significant impact of the degree of saturation on corrosion rates and mass loss.

Electrodeposition-based self-healing technique for structures with loosely compacted sand

The natural erosion of sand along coastlines and in landfills is a complex phenomenon influenced by interactions among currents, waves, tides, and wind. Countermeasures against internal erosion in landfills often involve installing geotextile sheets and/or filters between seawalls and landfills. However, the mere installation of such structures proves insufficient for comprehensively monitoring and mitigating soil erosion, and ensuring adequate ground stability and safety is challenging. This study focuses on the application of electrodeposition for mitigating soil erosion and potentially repairing these structures. By applying a weak electric current to severely deteriorated objects, carbonate minerals, called electrodeposits, are deposited on the cathode side and can repair vulnerable areas through self-organized solidification. Experiments were conducted using various silica sand specimens to assess the applicability of electrodeposition to discrete sand. The results revealed that, in specimens with relatively large sand particles, such as those in silica sand No. 3, the sand adhered to the cathode, forming a solidified area approximately 15–17 mm high. A microstructural analysis indicated the presence of crystallized minerals resembling calcium carbonate bonding within the interstitial spaces between the sand particles. These experimental findings suggest that electrodeposition can be applied to enhance the stability and safety of sandy soil-based structures.

Laboratory evaluation of calcareous sand specimens with inclined sedimentary surfaces

Sedimentary processes often produce natural and blown calcareous sands that are deposited in inclined and layered formations. These calcareous sands frequently exist in a complex stress state with rotating principal stress axes that result in intricate mechanical properties. To investigate the mechanical behaviors of calcareous sands with inclined sedimentary surfaces, we developed a device to prepare hollow cylindrical specimens from artificially crushed calcareous sands. By combining this device with a hollow cylindrical torsional shear apparatus, undrained monotonic loading and pure principal stress rotation tests were conducted to investigate the static and dynamic properties of the inherently anisotropic calcareous sands. The results indicate that the shear dilatancy property is related to the principal stress direction; the shear dilatancy of calcareous sand decreases as the direction of the principal stress increases, and the peak stress ratio decreases with increasing principal stress direction and increases with increasing deposition direction. In the precyclic loading period, increases in the deposition direction led to increases in the stabilities of the specimens and decreases in excess pore pressure accumulation, which further affect the dynamic shear modulus and damping ratio of the calcareous sand. In the late stage of cyclic loading, the inherent anisotropies of the specimens are destroyed, so that the excess pressure and hysteresis loop characteristics start to converge.

Performance Evaluation of Sieve and Curtain Pluviators for Reconstituted Sand Specimen in Model Box

Performance Evaluation of Sieve and Curtain Pluviators for Reconstituted Sand Specimen in Model Box

Compressive behavior of manufactured sand recycled coarse aggregate concrete-filled steel tubular short columns

To study the mechanical properties of manufactured sand recycled aggregate concrete-filled steel tubular (RACFST) columns, a total of 81 square short RACFST column specimens with different types of manufactured sand and natural sand were created and subjected to axial compression tests. The variables included sand type, core concrete strength, slenderness ratio, and steel tube thickness. The failure mode, axial load-displacement curve, axial compressive capacity, and deformation capacity of the specimens were analyzed in detail. The results indicate that the failure mode of the specimen is generally waist drum-type failure and shear-type failure, and both of them are local buckling. The load-displacement curve of the manufactured sand specimen is similar to that of the natural sand specimen, but the steel tube of the manufactured sand specimen yields later than that of the natural sand specimen. Generally, the limestone manufactured sand specimen has the highest axial compressive capacity and the best ductility ratio, while the pebble manufactured sand specimen has an axial compressive capacity similar to the natural sand specimen but a lower ductility ratio. The effects of concrete compressive strength, slenderness ratio, and steel tube thickness on specimens with manufactured sand are similar to those with natural sand. Based on the results of this experimental study, a formula for calculating the axial compressive capacity of square RACFST columns is provided.

Experimental investigation of the influence of drainage condition on change in saturation of sheared sand

This paper investigates the validity of the interpretation of results from testing saturated axisymmetric triaxial compression (ATC) sand specimens utilizing 3D synchrotron micro-computed tomography (SMT) to probe localized events that are completely missed or misinterpreted when analyzing ATC measurements based on global standard measurements. Drained and undrained experiments were conducted at low and high back pressures (BPs) coupled with multiple in situ 3D-SMT to acquire high-resolution scans of the specimens at different axial strains. Specimens tested under low BP exhibited a large pore air volume change, which was not detected by the pump system that represents standard volume measurement. The increase in air volume caused a significant reduction in the degree of saturation leading to a possible transition from saturated to partially saturated constitutive behavior. Undrained experiments exhibited a significant volume change contrary to the assumption of negligible volumetric strain for saturated undrained experiments. Air bubbles within the shear band for drained and undrained low BP specimens showed opposite capillary pressure responses, increased for drained and decreased for undrained cases, due to the variation in the mechanism by which each of the two experiments predominantly counters the volume expansion within the shear band.

Liquefaction and reliquefaction mitigation of sand specimen treated with prefabricated vertical drains: An experimental investigation

This study examines the performance of prefabricated vertical drains (PVD) against liquefaction and reliquefaction. A series of 102 shakings were performed using 1g shaking table apparatus on untreated and treated sand specimens prepared with 25% relative density. Sinusoidal waveform experimented with three different repeated shaking patterns and independent events for two different frequencies (2 Hz and 3.5 Hz) with 1-min duration. Two different installation methods; drainage alone method (PVD-D) and drainage along with densification (PVD-DD) were experimented. Durability of PVD were examined from geotextile tensile testing apparatus and digital image correlation. These experiments demonstrated excellent durability characteristics of PVD filter even after exposed to repeated shakings. Treated specimens improved the resistance to reliquefaction due to radial drainage offered by PVD which has retarded the excess pore pressure (EPP) generation. In addition, densification induced during the installation of PVD also contributed for restricting EPP, however, the induced sand densification achieved during repeated shaking events were not responsible for increased resistance against liquefaction/reliquefaction. Results indicate that the maximum pore pressure ratio in treated specimens were restricted within threshold design limit (≤0.60) for most of the events, even when the untreated specimens completely liquefied or generated a maximum value near unity.

Shearing Behavior at the Interface of Sand-Structured Surfaces Subjected to Monotonic Axial Loading

Enhancing the interface shear strength is crucial in the capacity and design of several geotechnical structures when subjected to static loading. The efficiency of these structures can be enhanced by utilizing innovative designs that allow the mobilization of higher interface shear resistance with bio-inspired-engineered or structured (rough) surfaces when compared to conventional smooth or random rough surfaces of the same geometry (i.e., soil-foundation contact area). Bio-inspired-engineered surfaces used in this study are developed after surfaces with snakeskin-inspired and engineered rough designs that maximize the interface shear resistance in cohesionless and cohesive soils. The frictional behavior and resistance of the bio-inspired-engineered surfaces were experimentally evaluated utilizing a modified interface direct shear apparatus on three locally available sand specimens. Results from tests on smooth surfaces against three different sands mobilized almost the same resistance and soil contraction. The results indicate a behavior significantly influenced by the shape and arrangement of the surface features, accompanied by larger resistance and volume dilation. A parametric study on the characteristics of the structured elements on three sands revealed the isolated impact of elements arrangement, shape, and roughness on the maximum attainable interface strength. The surface element characteristic ratio is found to control the load-transfer mechanism between sand and bio-inspired-engineered structured surfaces. Doi: 10.28991/CEJ-2024-010-10-06 Full Text: PDF

Experimental study on the influence of particle morphology on compression characteristics of coral sand in South China Sea

Particle morphology is an important physical parameter that influences the engineering properties of coral sand, especially its compressibility. According to the quantitative analysis of particle morphology via the dynamic image analysis technology, a series of one-dimensional compression tests on coral sand and quartz sand with different particle morphology and densities were performed to reveal the effect of particle morphology on the compressibility of coral sand. The results demonstrated that the morphology of particles can be quantified using the shape-angularity group indicator (SAGI), whereas the SAGI of coral sand was greater than that of quartz sand. Coral sand exhibited a yield stress ranging from 1 to 2.5 MPa, and compressive deformations in both coral sand and quartz sand were dominated by irreversible plastic deformation. As the SAGI and densification increased, the number of particle coordination increased while the contact stress between grains decreased, which caused the yield stress of coral sand specimens to increase as well as the compression index and particle crushing rate to decrease. The SAGI of quartz sand particles remained relatively unchanged while that of coral sand particles gradually decreased after crushing, i.e., the coral sand particles developed a more regular shape after crushing.

Accelerated carbonation of non-plastic soils mixed with hydrated lime: index properties influencing binder formation rate and mechanical improvement

Chemical stabilization—the mixing of additives like cement, lime, or fly-ash with soil to improve its mechanical properties—conventionally relies on hydration reactions to generate a binder. Accelerated soil carbonation is a nascent alternative method, whereby carbon dioxide is intentionally introduced in soil mixed with alkali additives to generate a carbonate binder and sequester carbon dioxide. Non-plastic sand and silt specimens mixed with hydrated lime were carbonated for varying amounts of time at different water contents and densities to evaluate the index properties influencing the rate of carbonation and degree of mechanical improvement. It was demonstrated that volumetric air and water contents primarily govern the rate of binder formation and that mechanical properties are influenced by the carbonate binder content and density. Under optimum conditions, soil specimens could be fully carbonated within 3 to 24 hours and unconfined compressive strengths as great as 3 to 4 MPa were achieved. The degree of strength improvement is comparable to cement-stabilized materials with similar dependence on soil type, density, and binder content. If techniques are developed that enable carbonation at scale, the sequestration of carbon dioxide would offset emissions associated with production of chemical additives used for chemical stabilization.

Threshold strain for the accumulation of excess pore-water pressure in saturated coral sands under complex cyclic loading patterns

The liquefaction of coral sands caused by the accumulation of excess pore-water pressure is a major factor contributing to catastrophic events on coral reefs, and accurately estimating this excess pore-water pressure accumulation holds significant importance. High-quality laboratory test results are essential for analytical or numerical calculations. In this study, a new test method is employed to conduct a series of undrained, multi-staged, stress-controlled multidirectional hollow cylinder tests on saturated coral sand under complex loading conditions. The concept of threshold strain (γt) and the method for determining γt of saturated coral sand specimens under complex loading conditions are proposed. The test results demonstrate that γt of saturated coral sand remains insensitive to cyclic loading conditions (including frequency, stress path, and mode) but increases with increasing relative density. The range of volumetric threshold strain, degradation threshold strain, and flow threshold for saturated coral sand under different initial states and cyclic loading conditions are 0.0183%–0.0341%, 0.0242%–0.0454%, and 1.006%–1.614%, respectively. This research provides a novel approach for accurately determining input parameters required for resolving and implementing coupled models in numerical modeling.

Experimental study on the workability of sands conditioned with bentonite-silty clay modified slurry

With the widespread application of Earth Pressure Balance (EPB) shield technology, the generation of shield muck has been increasing yearly. This paper aims to investigate the effectiveness of bentonite-silty clay modified slurry (BSC) as a soil conditioner for enhancing the workability of sands during EPB shield tunneling, thus enabling the recycling and reuse of the discarded muck (waste silty clay). Standard slump tests were conducted on three typical sand specimens from Shenyang Metro Line 6. The influence of the types of conditioners and slurry injection ratio (SIR) on slump values were examined to determine an optimal conditioning scheme tailored to the specific formation conditions. Furthermore, the study explored the combined use of BSC and foam to improve workability, employing a three-factor four-level orthogonal experiment. Finally, the rheological parameters (yield stress) derived from the slump tests provide valuable insights for assessing material flow within the tunneling system. The results show that comparative analyses with pure bentonite slurries reveal that BSC is a suitable, economical, and effective alternative for soil conditioning. The particle size distribution of sand specimens significantly influences the conditioning process, necessitating adjustments to SIR and slurry viscosity for optimal results. When the slump value of slurry-conditioned soil falls within the range of 150–250 mm, the slump test can be effectively used to estimate its yield stress under atmospheric conditions. This study contributes to the development of sustainable and economical solutions for soil conditioning in urban tunnel projects, particularly by utilizing excavated materials effectively.

Effects of enzyme-induced carbonate precipitation technique on multiple heavy metals immobilization and unconfined compressive strength improvement of contaminated sand

Enzyme-induced carbonate precipitation (EICP) has been studied in remediation of heavy metal contaminated water or soil in recent years. This paper aims to investigate the immobilization mechanism of Zn2+, Ni2+, and Cr(VI) in contaminated sand, as well as strength enhancement of sand specimens by using EICP method with crude sword bean urease extracts. A series of liquid batch tests and artificially contaminated sand remediation experiments were conducted to explore the heavy metal immobilization efficacy and mechanisms. Results showed that the urea hydrolysis completion efficiency decreased as the Ca2+ concentration increased and the heavy metal immobilization percentage increased with the concentration of Ca2+ and treatment cycles in contaminated sand. After four treatment cycles with 0.5 mol/L Ca2+ added, the immobilization percentage of Zn2+, Ni2+, and Cr(VI) were 99.99 %, 86.38 %, and 75.18 %, respectively. The microscale analysis results presented that carbonate precipitates and metallic oxide such as CaCO3, ZnCO3, NiCO3, Zn(OH)2, and CrO(OH) were generated in liquid batch tests and sand remediation experiments. The SEM-EDS and FTIR results also showed that organic molecules and CaCO3 may adsorb or complex heavy metal ions. Thus, the immobilization mechanism of EICP method with crude sword bean urease can be considered as biomineralization, as well as adsorption and complexation by organic matter and calcium carbonate. The unconfined compressive strength of EICP-treated contaminated sand specimens demonstrated a positive correlation with the increased generation of carbonate precipitates, being up to 306 kPa after four treatment cycles with shear failure mode. Crude sword bean urease with 0.5 mol/L Ca2+ added is recommended to immobilize multiple heavy metal ions and enhance soil strength.

Comparative study on the effect of SRB and Sporosarcina pasteurii on the MICP cementation and solidification of lead–zinc tailings

The production of tailings sand due to mining and smelting activities is one of the reasons for the accelerated environmental pollution caused by heavy metals, drawing social attention to the management of tailings sand. Microbially induced carbonate precipitation (MICP) is an environmentally friendly soil remediation technique that is gradually becoming the preferred method for soil stabilisation and heavy metal pollution control. To address the issues of heavy metal pollution release and the loose particle structure of lead–zinc tailings sand (LZTS), this study employs a layered MICP approach. The solidification effects of two typical mineralising bacteria, sulfate-reducing bacteria (SRB) and Sporosarcina pasteurii, on LZTS, were compared for the first time. The results show that the maximum unconfined compressive strength (UCS) of SRB cemented solidified lead–zinc tailings sand (SRB-CS-LZTS) specimens is 0.22 MPa, while that of S. pasteurii cemented solidified lead–zinc tailings sand (SP-CS-LZTS) specimens is 0.95 MPa. Compared with the UCS of SRB-CS-LZTS, the UCS of SP-CS-LZTS increased by 3.32 times. The effect of S. pasteurii on the improvement of UCS and immobilisation of heavy metal ions was greater than that of SRB. The immobilisation effect of SRB on SO42- in the LZTS was better than that of S. pasteurii. Compared with SRB, the biological CaCO3 formed by S. pasteurii exhibited stronger adhesion and was more suitable for the cementation and solidification of LZTS. This study uses MICP technology to treat LZTS, aligning with the green environmental concept and providing a reference for the bioremediation of multiple heavy metals in tailing areas.

Research on the resistance of cement-based materials to sulfate attack based on MICP technology

To evaluate the effect of Microbial Induced Calcium Carbonate Precipitation (MICP) on the enhancement of early resistance to sulfate attack of cementitious materials. In this paper, firstly, the effect of Bacillus subtilis (BM) on the carbonation depth as well as the carbonation rate of standard as well as carbonation-conditioned cementitious sand specimens was investigated. Secondly, the compressive strength and volumetric deformation of the specimens at different ages of immersion in sulfate solution were investigated. Finally, the changes of hydration products before and after the addition of BM were analyzed by X-ray diffraction analysis (XRD), and the microscopic pore structure of the specimens after erosion was analyzed by low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscope (SEM), which revealed the mechanism of the improvement of BM on the resistance to sulfate erosion of the cementitious materials. The results showed that the initial compressive strength of BM carbonised curing specimens, ordinary carbonised curing specimens and BM standard curing specimens were increased by 42.0%, 34.0% and 4.0%, respectively, compared with the ordinary standard curing specimens, respectively, compared with the control group, and the loss of the final compressive strength was reduced by 37.4%, 25.4%, and 14.5%, and the expansion rate was reduced by 31.3%, 22.0%, after sulfate erosion for 6 months, 5.2%, and porosity decreased by 24.2%, 13.6%, and 9.9%. Microbial mineralization accelerated the reaction between Ca2+ in the pore solution and atmospheric CO2, and the calcite formed filled the pores to make the structure denser, increasing the initial compressive strength of the specimens and reducing the loss of properties when exposed to sulfate solution. Therefore, the application of MICP technology in cementitious materials provides a new direction for the development of durable and sustainable cementitious materials.

A Simplified Model to Predict the Repeated Shear Strain during the Cyclic Triaxial Test by Using an Elastic Coefficient-Damping Ratio System

Some researchers in past years have tried to develop a simplified method for analyzing soil liquefaction. However, the correctness of the pore water pressure in the model will affect the results. In addition, the formulas derived are not easy, and the exact parameters of the model are difficult to obtain. This study used a mass-spring-damping system to simulate the repeated strain of liquefaction cyclic triaxial tests. Because the model is simple and the parameters are easy to understand and obtain, it also shows the extensibility of this model. During the parameter study, damping coefficient c and spring coefficient k parameters decreased with the increasing cyclic number. Preliminary results of the research show that this model can further simulate the repeated strain obtained by cyclic triaxial tests without considering the variation of effective stress during cyclic loading. Four samples were used to verify the model’s correctness, and their boring sites were found in Yunlin areas, Taiwan. Simulation results show that the spring-damping system is feasible for simulated cyclic triaxial tests because the simulated results correlate to the testing results in trend. Generally, the first cycle number simulation will be less accurate because the pore water pressure of the specimen changes rapidly when the performance has just started. In contrast, the increase in subsequent cycles may be biased due to cyclic stress variation and soil plasticity during simulation. In the future, pure sand specimens created in the laboratory will be suggested for simulation.

Measurements of Shear Wave Velocity for Collapsible Soil

This paper examines the effects of collapsible soil structure on shear wave velocity. The study attempts to simulate hydraulic fill sand deposits, which represent a natural soil deposition process that can result in a collapsible soil structure. A series of resonant column tests and bender element tests on Ottawa sand was conducted on sand specimens and prepared by dry pluviation and simulated hydraulic fill methods subjected to various confining pressures. Shear wave velocities measured from both methods of deposition are compared and discussed. Results from this study show that for soil specimens with the same void ratio, samples prepared by simulated hydraulic fill have a lower shear modulus and shear wave velocity than the specimens prepared by dry pluviation, and the differences are more pronounced at higher confining pressures. The resonant column test results performed in this study were consistent with results from the discrete element analysis, full-scale testing, and centrifuge testing. The discrete element analysis suggests that soil fabric and number of particle contacts are the key factors affecting the shear wave velocity. These factors are dependent on the methods of deposition. Results from this study examining hydraulic fill collapsible structure shear wave velocity provide a step forward toward a better correlation between soil dynamic properties measured in field and laboratory tests.

Behavior of Sand Specimens Subjected to Cyclic Loads under Drained and Undrained Conditions in Variable Loading Amplitudes

Dynamic loads with different magnitudes cause shear stress and strain in the soil and increase the pore water pressure, reducing soil strength and leading to structural failure. This article presents the behavior of natural river-sand specimens subjected to cyclic loads under both drained and undrained conditions, as observed in cyclic triaxial tests conducted in the laboratory. The experiments were performed on sand specimens with a relative compaction of 0.95 when changing the loading amplitude with three different levels of 30 kPa, 50 kPa and 60 kPa. Experimental results show that, under the condition of drained cycle load, the pore water pressure does not form; only accumulated strain and dynamic parameters are almost unchanged. Meanwhile, with the condition of undrained cyclic load, the pore water pressure increases and causes liquefaction of the specimen, then the axial strain increases dramatically and is not capable of recovery. When varying the loading amplitude under drained condition, the initial-strength values increase as the amplitude of the load increases. This trend has the opposite direction when testing under undrained condition, which means that when increasing the loading amplitude, the initial-strength values decrease and the liquefaction potential of the specimens is faster. Further, under the undrained condition, the loading amplitude of 30 kPa effect is almost negligible on the liquefaction ability of the specimen. Keywords: Sand, Drained condition, Undrained condition, Loading amplitude, Cyclic triaxial tests

Multi-objective optimization of sustainable cement-zeolite improved sand based on life cycle assessment and artificial intelligence

Background Cement-zeolite improved sand can be used in diverse civil engineering applications. However, earlier research has not duly optimized its production process to attain best mechanical strength, lowest cost, and least environmental impact. This study proposes a multi-objective optimization approach using back-propagation neural network (BPNN) to predict the mechanical strength, along with an adaptive geometry estimation-based multi-objective evolutionary algorithm (AGE-MOEA) to identify the best parameters for cement-zeolite-improved sand, filling a long-lasting research gap. Methods A collection of unconfined compression tests was used to evaluate cemented sand specimens treated with stabilizers including portland cement (at dosages of 2, 4, 6, 8, and 10%) and six dosages of natural zeolite as partial replacement for cement (0, 10, 30, 50, 70, and 90%) at different curing times of 7, 28, and 90 days. The study further conducts a detailed analysis of life cycle assessment (LCA) to show how partial zeolite replacement for cement impacts the environment. Through a tuning process, the BPNN model found the optimal architecture and accurately predicted the unconfined compressive strength of cement-zeolite improved sand systems. This allowed the AGE-MOEA to optimize zeolite and cement dosages, density, curing time, and environmental impact. Results The results of this study reveal that the optimal range of zeolite was between 30-45%, which not only increased cemented sand strength, but also reduced the cost and environmental impact. It is also shown that increasing the zeolite replacement to 25-30% can increase the ultimate strength of cemented sand, yet exceeding this limit can cause the strength to decrease. Conclusions Zeolite has the potential to serve as an alternative for cement in applications that involve cemented sand, while still achieving mechanical strength performance, which is comparable or even superior. From an LCA standpoint, using zeolite as partial cement replacement in soil improvement projects is a promising alternative.

Experimental study on the effects of water content on the compression characteristics and particle breakage of calcareous sand

The particle breakage effect and compression characteristics of calcareous sand are related to the water content in the sand material. However, the effects of water content on the particle breakage and compression characteristics of calcareous sand have rarely been investigated. In this work, 50 sets of confined compression tests were conducted on calcareous sand specimens, and the compression characteristics and particle breakage effects of two single-particle-size groups (particle size ranges of 1–0.5 mm and 0.5–0.25 mm) of calcareous sand were investigated under five different water contents. The test results showed that with the increase in the water content, the final compression deformation of calcareous sand was positively correlated with the water content. The final compression deformation decreased when the water content reached a certain value. The water content corresponding to the peak final compression deformation was related to the gradation of the calcareous sand; the specific values were 10% and 15% for particle size ranges of 1–0.5 mm and 0.5–0.25 mm, respectively. With the increase in the water content, the slope of the loading curve of calcareous sand appeared to increase and then decrease, reaching maximum when the water content was 10%. Moreover, the slope of the loading curve was close to twice that of the loading curve of dry sand, whereas the slope of the unloading curve changed little. Under the same water content, the initial gradation had no effect on the compression and unloading characteristics of the specimens beyond a vertical pressure of 1 MPa. The effects of the variation in the water content on the particle breakage of calcareous sand were mainly reflected in the softening effect of water on the specimen particles, which reduced the Mohr strength of the particles.