Sand Columns Research Articles

SPH implementation of a critical state-based hypoplastic model for granular materials in large-deformation problems

In this work, an advanced hypoplastic model incorporating the critical state is integrated into smoothed particle hydrodynamics (SPH) for numerical investigation of problems with large deformation. This numerical method performs well in cases of element tests such as oedometer test, simple shear test and plain strain compression test, which usually own regular velocity fields. However, the standard SPH implementation will generate significant stress drift away from the failure surface in more complex geotechnical problems featured with dramatically-varying velocity field. This unrealistic stress state may deteriorate the stress state with a further step. As a result, a vicious circle takes place, which could give rise to a calculation failure. With this regard, a return mapping strategy is proposed to regulate the stress state locating beyond the failure surface. To this end, a closed-form solution to predicting the failure surface implicitly incorporated in the hypoplastic model is derived. Finally, the capability of the proposed numerical method is examined with two classical benchmark problems for granular materials, including the sand column collapse and rigid footing by comparing the numerical results with those from experiments and theoretical solutions.

Biomineralization Grouting for Beach Sand Cemented with MICP

Microbial-induced carbonate precipitation (MICP) is an environmentally friendly approach that relies on the production of calcium carbonate by microorganisms to construct or reinforce coastal structures. In order to address the disadvantages of current coastal countermeasures techniques, MICP is a cost-effective solution that can be used to repair and restore coastal habitats damaged by human activities. The resulting structures formed through MICP are strong and durable, providing long-term protection against erosion and flooding caused by storms or rising sea levels. Biominerals, including calcium carbonate or calcium phosphate, are used to create complex composites with organic molecules by combining the strength of inorganic materials with the versatility and biocompatibility of organic macromolecules. It is of the utmost importance to investigatethe functionality of MICP and scale up its deployment in various fields in order to thoroughly assess the instrument’s application. Coastal erosion has been a severe concern in archipelagic countries. Therefore, this study explored the Miyazaki coast in Japan and the Yogyakarta coastline in Indonesia to minimize coastal erosion using MICP. The bacteria found in Miyazaki (Sporosarcina species) and the Yogyakarta coast (Pseudoalteromonas tetradonis) were used in the experiment. As a result, the sample treated with a gradual injection of the cementation solution achieved about 6 MPa UCS after 21 days of treatment. The objective were investigated the potential biotreatment with original sand materials and to evaluate the long-term durability under saturated conditions. For these purposes, the MICP-treated sand columns were subjected to series of compression tests and wet-drying (WD) durability analysis.

Enrichment, characterization, and sand consolidation application of urease active calcite-producing bacteria.

Minerals such as calcium carbonate, which is prevalent in marble and limestone, are present naturally in rocks. Both physicochemical processes and microbial processes can result in the creation of calcium carbonate in nature, as is well documented. In this study, microbiologically induced calcite precipitation potential of three different Travertine-type water sources (Pamukkale Travertine Spring (PTS), Pamukkale Travertine Terraces (PTT), and Red Travertine of Karahayit (RTK)) using three different incubation media (NB, NB3, and ATCC1832) were investigated. After enrichment with ATCC1832 media, urease assays were positive for all of the microbial sources. The PTS and PTT were cultured with ATCC1832 medium for 48h, which showed the best results for urease activity and microbial growth among other samples. Metagenome analyses indicated that PTT enriched with ATCC1832 media contains > 99% Firmicutes, while PTS enriched with ATCC1832 contains > 99% Proteobacteria at the Phylum level. Results from SEM-EDX and XRD analysis revealed that calcite and/or vaterite were the minerals that emerged from the mineralization of the PTS and PTT during incubation. The type of calcium carbonate crystals tended to change from one form to another when the incubation period extends from 72 to 120h. Both the PTS and the PTT were able to precipitate calcite within the sand column. However, the bacteria from the PTT (26% CaCO3) outperformed those from the PTS (18% CaCO3) in terms of calcium carbonate deposition on the 21st day of incubation.

Performance of acid- and base-modified biochars for the removal of antibiotics from water under dynamic conditions

The increased recycling of treated municipal wastewater (TMW) to agricultural land is potentially hampered by the presence of antibiotic compounds, which may lead to the spread of antibiotic resistance. Biochar-based adsorption has been widely assessed as a means of polishing TMW to remove antibiotics prior to use; however, relatively little is known about how acid and base modification of biochar impacts its antibiotic retention capabilities, especially under the dynamic (flow-through) conditions inherent in proposed polishing systems. Using small columns of sand mixed with dairy manure or rice husk biochars (initial pH = 8.48 and 8.91, respectively) modified with acid or base, the retention of trimethoprim (TMP), sulfamethoxazole (SMZ), and sulfapyridine (SPD) was assessed. For SMZ and SPD, retention by the columns was consistently markedly lower than that measured in batch studies, indicating that equilibrium data may overestimate the retention of more realistic (dynamic) systems. TMP was completely retained by all biochars under both conditions. In columns, SMZ retention was strongly controlled by its pH-dependent speciation (greater retention at low pH, i.e., in acid modified biochars). SPD retention was strongly controlled by biochar surface area, which was markedly increased in the acid-modified dairy manure biochar and base-modified rice husk biochar. The findings indicate that acid or base modification of certain biochars may improve retention of sulfonamide antibiotics (which are known to be particularly difficult to remove from TMW) even under dynamic conditions. Biochar-based polishing systems comprising such biochars may offer potential in mitigating the spread of antibiotics, and hence antibiotic resistance, in agricultural settings.

Bearing Capacity Characteristics Of Sand Columns Stabilized With Recycled bricks and Glass Material In Soft Soil

Bearing Capacity Characteristics Of Sand Columns Stabilized With Recycled bricks and Glass Material In Soft Soil

Mechanisms of increased small nanoplastic particle retention in water-saturated sand media with montmorillonite and diatomite: Particle sizes, water components, and modelling

The processes by which small nanoplastics (NPs) accumulate in soil are unclear. To clarify the different deposition processes that affect small NPs (< 30 nm) compared to larger NPs in the soil environment, due to their interaction with clays as major soil components, the transport behavior of two-sized NPs (20 and 80 nm) with two clays (diatomite (Diat) and montmorillonite (Mont)) in NaCl and CaCl2 solutions were investigated in water-saturated quartz sand columns. The experimental results showed that more 20 nm NPs could enter the lattice structure of Diat than Mont in NaCl solution. This contributed to the stronger deposition of 20 nm NPs by Diat on sand, which was associated with a lower k1d/k1 value (obtained from two-site kinetic attachment model). In contrast, 80 nm NPs had a stronger reversible retention than 20 nm NPs with Mont, even though both sizes of NPs-Mont displayed a similar transportability. In CaCl2 solution, the larger NPs-Mont hetero-aggregates formed with a stronger suppressed depth of φmax based on Derjaguin-Landau-Verwey-Overbeek theory. Thus, Mont had a stronger transport inhibition than Diat for both NPs sizes, with a lower k1d/k1. These findings could benefit in predicting the size-based deposition of NPs in a heterogenous soil environment.

Cotransport of Tl(I) and kaolinite colloids in water-saturated porous media: Two systems with different components

Media components and colloid particles may affect Tl(I) transport in water-saturated porous media. It is significant to study the cotransport of Tl(I) and kaolinite in two systems with different components under different ISs, pH and kaolinite concentrations. The results of experiments conducted in quartz sand columns indicated that Tl(I) transport was promoted under low pH and high IS, due to competition between Tl(I) and cations (Na+ and H+) for adsorption sites. The effect of kaolinite on Tl(I) transport changed from inhibition to promotion with increasing kaolinite concentration and decreasing pH, because colloidal particles and H+ occupy more adsorption sites and competed with Tl(I). In the mica-quartz sand column, Tl(I) transport was promoted at low pH, which was consistent with the results of the quartz sand column experiments. However, Tl(I) transport was inhibited under high IS, due to the adsorption of heavy metals caused by the unique structure of mica. Tl(I) transport was promoted when kaolinite was present, which occurred mainly because of the adsorption of Tl(I) by kaolinite colloids and competitive adsorption between Tl(I) and colloids. The transport curves were fitted by two-site nonequilibrium sorption model, two-site kinetic attachment/detachment model, and colloid-facilitated solute transport model, respectively. In this study, the transport process of Tl(I) and kaolinite in porous media with different components was explored in depth, and the role of media in Tl(I) transport was investigated using novel approaches. The results facilitate the predicting of Tl(I) transport in underground environments and support remediation efforts for Tl contaminated soil and groundwater.

Exploring the Impact of Surface Functionalization on the Reaction, Magnetophoretic, and Collective Transport Behavior of Nanoscale Zerovalent Iron.

This study provides a systematic analysis of the transport and magnetophoretic behavior of nanoscale zerovalent iron (nZVI) particles, both bare and surface functionalized by poly(ethylene glycol) (PEG) and carboxymethyl cellulose (CMC), after undergoing a chemical reaction. Here, a simple and well-investigated chemical reaction of methyl orange (MO) degradation by nZVI was used as a model reaction system, and the sand column transport and low-gradient magnetophoretic profiles of the nanoparticles were measured before and after the reaction. The results were compared over time and analyzed in the context of extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to understand the particle interactions involved. The colloidal stability of both bare and functionalized nZVI particles was enhanced after the reaction due to the consumption of metallic Fe content, resulting in a significant drop in their magnetic properties. As a result, they exhibited improved mobility across the sand column and a slower magnetophoretic collection rate compared to the unreacted particles. Here, the colloidal filtration theory (CFT) was employed to analyze the transport behavior of nZVI particles across the packed sand column. It has been observed that the surface properties of the reacted functionalized particles changed, possibly due to the entrapment of degraded products within the polymer adlayer. Moreover, quartz crystal microbalance with dissipation (QCM-D) measurements were performed to reveal the viscoelastic contribution of the adlayer formed by both bare and functionalized nZVI particles after the reaction on influencing their transport behavior across the sand column. Finally, we proposed the implementation of a high-gradient magnetic trap (HGMT) to reduce the transport distance of the colloidally stable CMC-nZVI, both before and after the reaction. This study sheds light on the behavioral changes of iron nanoparticles after the reaction and highlights environmental concerns regarding the presence of reacted nanoparticles.

A model to quantify permeability in solute mixing precipitation porous media

The effects of the concentration and flow velocity of the solution on calcite precipitation process in porous media and its permeability were investigated with a combined experimental and modeling approach. In the column precipitation experiments, calcite precipitation was mainly distributed at the inlet of experimental column and quickly decreases along the flow direction, and precipitates completely wrapped the quartz sands at the inlet, and the gaps between the quartz sands were filled. The permeability coefficient of experimental column decreases quickly in the early stage and then decreases slowly. The calcite precipitates in the experimental column increased with the saturation index and gradually stretched along the flow direction with the flow velocity increase. The precipitates were distributed within 1.0 cm of the experimental column inlet. In the model, based on the classical Kozeny-Carman equation and the principle of series superposition, a coupled model of mineral precipitation and permeability coefficient in porous media was developed, the model was verified, and the parameter sensitivity was analyzed. It revealed that the mineral precipitation at the inlet interface of experimental column was the dominant factor determining the permeability coefficient of porous media. When considering solution conditions, the saturation indices SI and flow velocity V were the main factors affecting calcite precipitation and permeability coefficient in porous media. When the solution conditions were not considered, the quartz sand diameter ds, the length of quartz sand column L and porosityφ aiming at mineral precipitation had higher sensitivity, and the porosity ϕ aiming at permeability coefficient had higher sensitivity.

A method for imaging water transport in soil–snow systems with neutron radiography

Abstract Liquid water at the ground–snow interface is thought to play a crucial role in the release of glide-snow avalanches, which can be massive and threaten infrastructure in alpine regions. Several mechanisms have been postulated to explain the formation of this interfacial water. However, these mechanisms remain poorly understood, in part because suitable measurement techniques are lacking. Here, we demonstrate the use of neutron radiography for imaging water transport in soil–snow systems. Columns of sand, gravel and snow were used to simulate the capillary forces of the soil–vegetation–snow layering found in nature. The columns were connected to a water reservoir to maintain a constant-pressure boundary condition and placed in a climatic chamber within the neutron beam. We show that neutron radiography is capable of measuring changes in the optical density distribution (related to liquid water content) within all three layers of the model system. Results suggest that a porous interface between the sand and snow may induce the formation of a water layer in the basal snowpack. Improved understanding of the water transport in soil–snow systems should lead to better prediction of glide-snow avalanche release and could also benefit other fields such as snow hydrology.

Development and testing of environment friendly nanohybrid coatings for sustainable agriculture technologies

Less than 50% of the applied urea fertilizer is taken up by plants due to poor nitrogen (N) use efficiency which affects overall agricultural productivity and leads to serious environmental and economic problems. Additionally, soils with high salinity might limit zinc (Zn) availability. Low Zn use efficiency (<30%) when applied as synthetic salts, e.g., zinc sulfate has therefore minimized their applicability. Within the past two decades, nanotechnology has gained a lot of interest in the development of effective nano fertilizers with high nutrient use efficiency (NUE). In this perspective, the approach of coating conventional fertilizers with nano materials especially, the ones which are essential nutrients has researched because of their high use efficiency and reduced losses. In this work, a novel and innovative formulation of hybrid nano fertilizer has been prepared for the sustainable release of nutrients. Zinc oxide nanoparticles (ZnO-NPs <50 nm) were incorporated into the biodegradable polymer (gelatin) and coated on urea using a fluidized bed coater. Among all the formulations, GZnSNPs (1.5% gelatin+0.5% elemental Zn as ZnO-NPs) showed a significant delay in urea release (<80 %) after 120 min). The sand column experiment showed sustainable Zn release for GZnSNPs i.e., 2.7 ppm vs. 3.5 ppm (GZnS) after the 6th day. Moreover, a substantial increase in wheat grain yield (6500 kg/ha), N uptake (46.5 kg/ha) and Zn uptake (21.64 g/ha) were observed for fields amended with GZnSNPs. The composition of GZnSNPs was valuable since this attracted the highest return relative to the other treatments. Gelatin supplied small N-containing molecules, resulting in extra value addition with ZnO-NPs thus increasing yield and fertilizer properties more relative to the same amount of elemental Zn given via bulk salt. Therefore, the findings of the current study recommend the use of ZnO-NPs in the agricultural sector without any negative effects on yield and NUE.

One-phase MICP and two-phase MISP composite cementation

Microbial-induced carbonate precipitation (MICP) cementation of sand results in the generation of waste liquid containing ammonium ions, posing environmental pollution concerns that necessitate appropriate treatment prior to discharge. To address this issue, the addition of hydrogen phosphate (HPO42−) and magnesium (Mg2+) ions to the biocementation waste solution (BWS) enables the efficient conversion of ammonium (NH4+) ions into environmentally friendly bio-struvite (Cell-MgNH4PO4(H2O)6, MgNH4PO4·6H2O or NH4MgPO4·6H2O) through microbial-induced struvite precipitation (MISP), thereby mitigating environmental pollution risks. X-ray diffraction (XRD) patterns confirm the presence of struvite minerals, while field emission scanning electron microscopy (FESEM) images reveal the blocky or irregular blocky structure of bio-struvite, with sizes ranging from 10 to 25 μm. The bio-struvite effectively fills the pores between sand particles, resulting in reduced permeability. Following 4 cementation levels, the permeability coefficient of the bio-struvite cemented sand column measures 5.04 × 10−3 cm/s, with a bio-struvite content of 5.12 % within the sand column. The principal chemical components of the cementitious materials in MICP and MISP composite cementation sand consist of struvite (MgNH4PO4(H2O)6, MgNH4PO4·6H2O or NH4MgPO4·6H2O) and calcium carbonate (CaCO3), forming spherical or massive aggregates smaller than 10 μm. The most effective composite cementation sands exhibit an average permeability coefficient of 4.85 × 10−4 cm/s and an unconfined compressive strength (UCS) of 197.96 kPa. Consequently, MICP and MISP composite cementation sand significantly diminishes permeability and offers a viable solution for desert dust control.

Enhancing persulfate activation by carbon − based Mn − Fe nanoparticles for groundwater ISCO treatment: Efficiency, stability and mechanism

Persulfate − based in situ chemical oxidation (ISCO) is a promising approach for groundwater treatment due to its potential. However, the development of catalysts with sufficient activity and stability in persulfate oxidation remains a long − term goal. In this study, we aimed to address this challenge by preparing bimetallic nanoparticles coated with porous nitrogen − doped graphene shells, known as MnFe − NC, to activate peroxydisulfate (PDS). The unique structural feature of MnFe − NC, with metallic crystal nanoparticles encapsulated in carbon shells, ensured excellent persulfate activation performance of MnFe − NC, even during repeated cycles and extended periods of storage. To evaluate the practical application of MnFe − NC, MnFe − NC/PDS was installed in sand columns for the ISCO of sulpiride (SPR), achieving removal efficiencies of approximately 100 % during a continuous 7 − day reaction process. MnFe − NC/PDS exhibited remarkable tolerance to pH changes and environmental interference commonly encountered in groundwater treatment scenarios. Combined with density functional theory calculations, Mn5C2 and Fe2N were identified as the key active site for MnFe − NC activation of PDS. The decomposition mechanism of SPR in the system was further analyzed, including the cleavage of C–N/C–C, denitration reaction, and substitution reaction. These findings provide important insights into the intricate processes involved in the degradation of refractory organic pollutants. The developed MnFe − NC catalyst for PDS − based ISCO exhibits great potential in the remediation of refractory organic pollutant − contaminated groundwater.

Application of Cross model for granular flow and impact analysis using three-dimensional B-spline material point method

Granular flow and impact, such as landslides and debris flows, are typical problems involving large deformations of non-Newtonian free surfaces, which are of great interest in geological engineering and also pose challenges for traditional mesh-based numerical methods. As an enhancement of the traditional Material Point Method (MPM), the B-Spline Material Point Method (BSMPM) can not only effectively reduce mesh-crossing and quadrature errors, but also facilitate the tracking and capturing of free surfaces and contact interfaces. In this paper, the non-Newtonian general Cross model, the rheological parameters of which are determined by the Bingham model and the Mohr-Coulomb yield criterion, is introduced into the three-dimensional BSMPM (3D BSMPM) for simulating granular flow and impact problems. Interparticle effects of granular materials are represented by artificial damping forces. Dynamic simulations are carried out on the collapse of sand column and glass beads, the flow of bentonite suspensions, and the impact between granular mass and elastic obstacles. The overall evolution of granular flow and impact behavior are presented and compared with existing experimental and/or original MPM results. It is found that the proposed method well reproduces the overall process of granular flow and impact behavior, including its various stages of formation, acceleration, deceleration, and deposition, as well as the impact pressure. The results show that the granular flow and impact behavior can be well represented by the proposed 3D BSMPM with the Cross rheological model, demonstrating the effectiveness of the proposed method in simulating complicated environmental fluid dynamics.

Soil colloids can significantly enhance spreading of polybromodiphenyl ethers in groundwater by serving as an effective carrier

Polybromodiphenyl ethers (PBDEs), the widely used flame retardants, are common contaminants in surface soils at e-waste recycling sites. The association of PBDEs with soil colloids has been observed, indicating the potential risk to groundwater due to colloid-facilitated transport. However, the extent to which soil colloids may enhance the spreading of PBDEs in groundwater is largely unknown. Herein, we report the co-transport of decabromodiphenyl ester (BDE-209) and soil colloids in saturated porous media. The colloids released from a soil sample collected at an e-waste recycling site in Tianjin, China, contain high concentration of PBDEs, with BDE-209 being the most abundant conger (320 ± 30 mg/kg). The colloids exhibit relatively high mobility in saturated sand columns, under conditions commonly observed in groundwater environments. Notably, under all the tested conditions (i.e., varying flow velocity, pH, ionic species and ionic strength), the mass of eluted BDE-209 correlates linearly with that of eluted soil colloids, even though the mobility of the colloids varies markedly depending on the specific hydrodynamic and solution chemistry conditions involved. Additionally, the mass of BDE-209 retained in the columns also correlates strongly with the mass of retained colloids. Apparently, the PBDEs remain bound to soil colloids during transport in porous media. Findings in this study indicate that soil colloids may significantly promote the transport of PBDEs in groundwater by serving as an effective carrier. This might be the reason why the highly insoluble and adsorptive PBDEs are found in groundwater at some PBDE-contaminated sites.

Increased Microbially Induced Calcium Carbonate Precipitation (MICP) Efficiency in Multiple Treatment Sand Biocementation Processes by Augmentation of Cementation Medium with Ammonium Chloride

The cementation medium for ureolytic microbially induced calcium carbonate precipitation (MICP) typically consists of urea and a calcium source. While some studies have augmented this basic medium, the effects of adding substrates such as ammonium chloride are unclear. The studies detailed in this paper sought to quantify the effect of the ammonium chloride augmentation of cementation medium (CM) on the process of MICP. An aqueous MICP study was initially carried out to study the effects of adding ammonium chloride to the urea–calcium cementation medium. This batch test also explored the effect of varying the concentration of calcium chloride dihydrate (calcium source) in the CM. A subsequent sand column study was undertaken, whereby multiple treatments of CM were injected over several days to produce a biocement. Six columns were prepared using F65 sand bioaugmented with Sporosarcina pasteurii, half of which were injected with the basic medium only and half with the augmented medium for treatment two onwards. Effluent displaced from columns was tested using ion chromatography and Nesslerisation to determine the calcium and ammonium ion concentrations, respectively, and hence the treatment efficiency. Conductivity and pH testing of effluent gave insights into the bacterial urease activity. The addition of 0.187 M ammonium chloride to the CM resulted in approximately 100% chemical conversion efficiency within columns, based on calcium ion measurements, compared to only 57% and 33% efficiency for treatments three and four, respectively, when using the urea–calcium medium. Columns treated with the CM containing ammonium chloride had unconfined compressive strengths which were 1.8 times higher on average than columns treated with the urea–calcium medium only.

Application of FEM tools in efficient field implementation of dynamic replacement of soft soils

ABSTRACT A dynamic finite element methodology (FEM) was developed to simulate an entire dynamic replacement (DR) program of clay with sand involving multiple poundings. The main objective of this research was to employ FEM and geotechnical test data such as cone penetration test (CPT) data at the site to predict the maximum achievable sand column (SC) depth and the corresponding optimum levels of attributing parameters such as number and height of pounder drops. Another goal was to predict the pore pressure generated in clay due to pounding. A full-scale ground improvement project was used to guide the analytical process. Comparison of FEM predictions and field measurements showed the potential of using FEM to achieve the above objectives in advance of the field work. Finally, a step – by-step procedure for using a FEM procedure to predict the optimum field setup and hence improve the efficacy of DR field implementation is illustrated.

Thermal conductivity of dried biocemented sand at higher calcification

Thermal conductivity of dried biocemented sand at higher calcification

Natural organic matter and ionic strength (CaCl2) affect transport, retention and remobilization of silica encapsulated DNA colloids (DNAcol) in saturated sand columns

In the terrestrial environment, interactions between natural organic matter (NOM) and colloids can lead to the formation of an environmental corona around colloids, influencing their transport behaviour and, ultimately, their ecotoxicity. We used a synthetically designed colloid tagged with DNA (DNAcol) as a surrogate for natural colloids and investigated its transport in saturated sand columns. We varied the concentrations of NOM and ionic strength (CaCl2), to better understand the transport and release of DNAcol in porous media under both steady and transient porewater chemistry conditions. In addition, we aimed to understand the main factors that control deposition and release of DNAcol under tested conditions. To induce transient chemistry, we replaced the injection solution containing NOM and/or CaCl2 with Milli-Q water. The results showed that the deposition rate of DNAcol was inversely proportional to the concentration of NOM. The deposition rate increased significantly even under low ionic strength (CaCl2) conditions of tested conditions. Notably, the influence of NOM on the transport of DNAcol was most pronounced at the lowest range of [Ca2+]/DOC ratios, and the attachment of DNAcol to the sand grains was negligible. Moreover, the results showed while the DLVO theory captured the general trend of experimental results, it significantly underestimated the deposition of DNAcol in the presence of CaCl2. Under transient porewater chemistry conditions, colloid remobilization was observed upon flushing the column with Milli-Q water, leading to a secondary peak in the breakthrough curves. We observed that under transient porewater chemistry conditions, when the ionic strength of the solution was 10 mM, the magnitude of the remobilization peak was more significant compared to conditions with 1 mM ionic strength. Our work emphasized the complex interplay between water quality on the one hand and deposition and release of colloidal matter in saturated porous media on the other hand.

Experimental Study on Bio-Reinforcement of Calcareous Sand through Hydrochloric Acid Solution Precipitation into Cementing Solution.

Microbially induced carbonate precipitation (MICP) technology holds great potential in enhancing soil properties. MICP can be employed to enhance the stability and strength of diverse sandy soil, but it has the shortcoming of low curing efficiency. In response to the identified problem, this study aims to investigate an optimized treatment protocol that involves formulating a cementing solution in a hydrochloric acid (HCl) solution to enhance the solidification rate in the MICP reaction and evaluate its effectiveness. The results indicate that when preparing a 1 M cementing solution in a 0.2 M HCl solution, it promotes the rapid bonding of calcareous sand particles, resulting in an unconfined compressive strength (UCS) of 1312.6 kPa in the sand column after five treatments. Compared to the conventional test group, the experimental group containing HCl exhibited an approximately 1357% increase in UCS. The analysis unveiled the pivotal role of metal ions dissolved from calcareous sand by HCl in enhancing the UCS of MICP-treated calcareous sand. The proposed experimental methodology serves as a valuable tool for designing treatment strategies for MICP-cemented calcareous sand in practical engineering applications.