Biogeotechnics最新文献_第2页

Advanced bioinspired cellular confinement systems for improving the performance of reinforced soil beds 先进的生物激励细胞约束系统，用于改善加固土壤床的性能

Biogeotechnics

Pub Date : 2024-12-20 DOI: 10.1016/j.bgtech.2024.100160

Yang Zhao , Zheng Lu , Abdollah Tabaroei , Chuxuan Tang , Yinuo Feng , Hailin Yao

With the major developments that occurred during the past 40 years in the geotechnical engineering field, the usage of reinforcements in soils has been very common to improve the ultimate bearing capacity and reduce the footing settlements. These reinforcements consist of geogrids, geotextiles, geocells, etc., all of which are in the geosynthetic family. Among these geosynthetic families, geocell performs better in soil-reinforced beds. In this study, we proposed the nine types of bioinspired geocells to improve the soil beds. For this purpose, a total of twenty numerical models were calculated via FLAC^3D after validating the laboratory model tests in the literature. The numerical results demonstrated that, except for the circular type, the performance of other geocell forms regarding increased bearing capacity was nearly identical. Regarding diffusion angles, only the circular and honeycomb geocells exhibited larger diffusion angles. The opening pocket diameter more significantly influenced the stress and strain of geocells. Geocells with nearly circular shapes, such as circular, honeycomb, hexagonal, and square, typically demonstrated higher confining stresses within the geocell walls. Conversely, for shapes that deviate from the circular form, such as diamond, re-entrant, and double V-shaped designs, the irregularity of the pocket shape could cause an uneven distribution of confining stresses, potentially leading to higher normal deformations at some specific areas and stress concentration at the wall joints.

随着近40年来岩土工程领域的重大发展，在土体中使用加筋来提高极限承载力和减少地基沉降已经非常普遍。这些增强筋由土工格栅、土工织物、土工胞等组成，它们都属于土工合成材料家族。在这些土工合成材料家族中，土工格室在加筋土层中表现较好。在这项研究中，我们提出了九种类型的生物激励土工细胞来改善土壤床。为此，在验证了文献中的实验室模型试验后，通过FLAC3D计算了总共20个数值模型。数值计算结果表明，除圆形土工格室外，其他土工格室在增加承载力方面的性能几乎相同。在扩散角方面，只有圆形土工胞和蜂窝土工胞具有较大的扩散角。孔袋直径对土工格室的应力应变影响更为显著。近似圆形的土工单元，如圆形、蜂窝状、六角形和方形，通常在土工单元壁上表现出较高的围应力。相反，对于偏离圆形的形状，如菱形、重入形和双v形设计，袋形的不规则性可能导致围应力分布不均匀，可能导致某些特定区域的法向变形和壁面接缝处的应力集中。

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引用次数: 0

Bio-molding of lunar regolith with bio-carbonized magnesium oxide 生物碳化氧化镁在月球风化层中的生物成型

Biogeotechnics

Pub Date : 2024-12-20 DOI: 10.1016/j.bgtech.2024.100159

Jinquan Shi, Zihao Xiao, Yang Xiao, Hanlong Liu

As lunar exploration develops, lunar construction is increasingly prominent and the in-situ lunar regolith molding becomes a technical challenge. This study proposes a lunar regolith molding technology based on biocarbonated magnesium oxide (MgO) with urea pre-hydrolyzed, which has the potential to achieve an unconfined compressive strength (UCS) of approximately 10 MPa after 24 h of curing. The study investigates the physical and mechanical properties of biocarbonated lunar regolith samples with varying urea concentrations, bacterial concentrations, and MgO contents. Scanning electron microscopy (SEM) was employed to examine the microstructural properties of the samples. The results demonstrated that the maximum UCS and E₅₀ were achieved at a urea concentration of 1.0 mol/L, a bacterial concentration of 1.0, and a MgO content of 15%. However, the carbonate content test indicated that the highest urea efficiency was observed at 10% MgO. Microscopic images show that the produced hydromagnesite is the most structured at the urea concentrations of 1.0 mol/L and 2.0 mol/L, corresponding well with the strength performance of the specimens. The pre-hydrolysis method can promote the efficiency of biocarbonated magnesium oxide but it highly depends on the concentration of the produced carbonate. Conclusively, the findings of this study offer a promising avenue for lunar regolith molding.

随着月球探测的深入，月球建设日益突出，月球风化层的原位成型成为一项技术挑战。本研究提出了一种基于尿素预水解的生物碳化氧化镁（MgO）的月球风化层成型技术，该技术在固化24 h后有可能实现约10 MPa的无侧限抗压强度（UCS）。该研究考察了不同尿素浓度、细菌浓度和MgO含量的生物碳化月球风化层样品的物理力学特性。采用扫描电子显微镜（SEM）对样品的显微组织性能进行了研究。结果表明，尿素浓度为1.0 mol/L、细菌浓度为1.0、MgO含量为15%时，UCS和E50最大。碳酸盐含量测试结果表明，MgO浓度为10%时尿素效率最高。显微图像表明，尿素浓度为1.0 mol/L和2.0 mol/L时制备的氢菱镁矿结构最优，与试样的强度性能吻合较好。预水解法可以提高生物碳化氧化镁的效率，但对所得碳酸盐的浓度依赖性较大。最后，这项研究的发现为月球风化层成型提供了一条有希望的途径。

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引用次数: 0

Microbially induced carbonate precipitation for soil improvement: Insights from a meter-scale radial grouting trial 微生物诱导碳酸盐沉淀改善土壤：来自米尺度径向灌浆试验的见解

Biogeotechnics

Pub Date : 2024-12-09 DOI: 10.1016/j.bgtech.2024.100157

Guijie Sang , Rebecca J. Lunn , James M. Minto , Grainne El Mountassir

Despite the growing interest in microbially induced carbonate precipitation (MICP) for geotechnical applications, reports on meter-scale MICP trials for soil improvement remain limited, and controlling and predicting cementation efficiency on a large-scale is even more scarce. This study presented a meter-scale improvement of a poorly-graded sand (initial dry density: 1581 kg/m³, porosity: 40 %) through MICP in a cylindrical cell (diameter: 1 m; thickness: 15 cm) using a radial flow injection strategy, which involves injecting fluids radially from a single well located at the center while maintaining a constant hydraulic head at the outer boundary. Nine cycles of a two-phase MICP treatment were applied: Phase 1- injection of 0.7 pore volumes (PVs) of bacterial solution and 1-L water pulse; Phase 2- injection of 1.4 PVs of 0.5 mol/L cementing solution in two stages (i) 0.7 PV injection two hours after the bacteria were injected, and (ii) a further 0.7 PV injection the following morning after an overnight static reaction period. We observed non-uniform CaCO₃ precipitations along the distance from the central well and over the depth, which was induced by the decreasing flux towards the outer boundary under the radial flow pattern, along with influences from layered soil packing and hydraulically induced flow channels. CaCO₃ precipitation with distance from the central well follows a symmetric Gaussian-type distribution, with sufficient cementation to retrieve full-length cores occurring near the midpoint between the central well and the outer boundary. The unconfined compressive strengths of the full-length cores were in the range of 1.2–6.8 MPa with CaCO₃ contents of 0.08–0.17. Our study suggests that cementation level under radial flow conditions is controllable on a large scale and highly dependent on the injection volume of both bacteria and rinsing water pulse. The study provides a solid baseline for predicting and controlling CaCO₃ distribution in large-scale MICP soil improvement using a two-phase radial injection approach.

尽管人们对微生物诱导碳酸盐沉淀（MICP）在岩土工程中的应用越来越感兴趣，但关于微米尺度MICP土壤改良试验的报道仍然有限，而大规模控制和预测胶结效率的报道更是稀缺。该研究采用径向流注入策略，通过MICP对一种差级配砂（初始干密度为1581 kg/m3，孔隙度为40 %）进行了米级改造（直径为1 m，厚度为15 cm），该策略包括从位于中心的单井径向注入流体，同时在外部边界保持恒定的水力水头)。采用两相MICP处理9个循环：第1期-注射0.7孔体积（pv）的细菌溶液和1 l水脉冲；第2阶段-分两阶段注射1.4 PV的0.5 mol/L固井溶液(i)在注射细菌后2小时注射0.7 PV, （ii）在静反应过夜后第二天早上再注射0.7 PV。我们观察到CaCO3在距离中心井的距离和深度上的不均匀降水，这是由于径向流模式下向外边界的通量减少，以及分层土壤堆积和水力诱导流道的影响。CaCO3随距离中心井的远近而沉淀遵循对称的高斯型分布，在中心井和外边界之间的中点附近有足够的胶结，可以回收全长岩心。全长岩心无侧限抗压强度范围为1.2 ~ 6.8 MPa， CaCO3含量为0.08 ~ 0.17。我们的研究表明，径向流动条件下的胶结水平在很大程度上是可控的，并且高度依赖于细菌的注入量和冲洗水脉冲。该研究为利用两相径向注入方法预测和控制大规模MICP土壤改良中CaCO3的分布提供了坚实的基础。

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引用次数: 0

Kitchen waste bone-driven enzyme-induced calcium phosphate precipitation under microgravity for space biocementation 微重力下厨房垃圾骨驱动酶诱导磷酸钙沉淀用于空间生物胶结

Biogeotechnics

Pub Date : 2024-12-08 DOI: 10.1016/j.bgtech.2024.100156

Zhen Yan , Kazunori Nakashima , Chikara Takano , Satoru Kawasaki

This study validates the feasibility of extracting calcium and phosphorus from kitchen waste bones for crude enzyme-induced calcium phosphate precipitation (EICPP) under both normal and microgravity conditions. The experimental results demonstrate no significant differences in the degree of reaction and characteristics of precipitation between these environments. By leveraging local resources, reducing material transport costs, and addressing waste management challenges, this research underscores the potential for extraterrestrial construction, thereby enhancing sustainability in space environments. These findings offer promising insights for the application of space biocementation, particularly during the expansion phase of human settlements.

本研究验证了在正常和微重力条件下从厨余骨中提取钙和磷用于粗酶诱导磷酸钙沉淀（EICPP）的可行性。实验结果表明，不同环境间的反应程度和降水特征无显著差异。通过利用当地资源、降低材料运输成本和解决废物管理挑战，本研究强调了地外建筑的潜力，从而提高了空间环境的可持续性。这些发现为空间生物胶结的应用提供了有希望的见解，特别是在人类住区的扩展阶段。

引用次数: 0

High-temporal-resolution ERT characterization for vegetation effects on soil hydrological response under wet-dry cycles 干湿循环下植被对土壤水文响应影响的高时间分辨率ERT表征

Biogeotechnics

Pub Date : 2024-12-02 DOI: 10.1016/j.bgtech.2024.100155

Wei Yan , Weiming Xu , Taosheng Huang , Ping Shen , Wan-Huan Zhou

Characterization of vegetation effect on soil response is essential for comprehending site-specific hydrological processes. Traditional research often relies on sensors or remote sensing data to examine the hydrological properties of vegetation zones, yet these methods are limited by either measurement sparsity or spatial inaccuracy. Therefore, this paper is the first to propose a data-driven approach that incorporates high-temporal-resolution electrical resistivity tomography (ERT) to quantify soil hydrological response. Time-lapse ERT is deployed on a vegetated slope site in Foshan, China, during a discontinuous rainfall induced by Typhoon Haikui. A total of 97 ERT measurements were collected with an average time interval of 2.7 hours. The Gaussian Mixture Model (GMM) is applied to quantify the level of response and objectively classify impact zones based on features extracted directly from the ERT data. The resistivity-moisture content correlation is established based on on-site sensor data to characterize infiltration and evapotranspiration across wet-dry conditions. The findings are compared with the Normalized Difference Vegetation Index (NDVI), a common indicator for vegetation quantification, to reveal potential spatial errors in remote sensing data. In addition, this study provides discussions on the potential applications and future directions. This paper showcases significant spatio-temporal advantages over existing studies, providing a more detailed and accurate characterization of superficial soil hydrological response.

研究植被对土壤响应的影响是理解特定地点水文过程的基础。传统研究通常依赖于传感器或遥感数据来检测植被带的水文特性，但这些方法受到测量稀疏性或空间不准确性的限制。因此，本文首次提出了一种数据驱动的方法，该方法结合了高时间分辨率电阻率层析成像（ERT）来量化土壤水文响应。在台风“海葵”引起的不连续降雨期间，在中国佛山一个植被覆盖的斜坡上部署了延时ERT。共收集了97次ERT测量，平均时间间隔为2.7 小时。基于直接从ERT数据中提取的特征，应用高斯混合模型（Gaussian Mixture Model， GMM）量化响应水平，对影响区域进行客观分类。基于现场传感器数据，建立了电阻率-水分含量相关性，以表征干湿条件下的入渗和蒸散发。研究结果与植被量化常用指标归一化植被指数（NDVI）进行了比较，揭示了遥感数据中潜在的空间误差。此外，本研究还对其潜在应用前景和未来发展方向进行了讨论。与现有研究相比，本文展示了显著的时空优势，提供了更详细和准确的浅层土壤水文响应表征。

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引用次数: 0

Impact behavior and strain rate effects of artificial limestone by MICP 人工石灰石的冲击行为及应变速率效应

Biogeotechnics

Pub Date : 2024-11-22 DOI: 10.1016/j.bgtech.2024.100154

Yaru Lv , Lin Wu , Zhigang Duan , Yuchen Su , Dongdong Zhang

Natural cemented calcareous sand and limestone are highly complex and not well understood in terms of the mechanical behavior due to the difficulty of obtaining undisturbed samples from far sea. This paper proposes an artificial method in a laboratory setting using microbial-induced carbonate precipitation (MICP) to simulate the natural process of cementation of limestone. The artificially cemented sand has a high degree of similarity with the natural weakly limestone in three aspects: (1) the mineral composition of the cemented material is also granular calcite and acicular aragonite; (2) the microstructure in interconnected open pore network can be gradually closed and contracted with cementation. The porosity reaches to approximately 9.2%; (3) both the stress-strain relationship and the unconfined strength closely resemble that of natural weakly limestone. Furthermore, both static and dynamic behaviors of artificial limestone were studied by quasi-static compression tests and Split Hopkinson Pressure Bar (SHPB) tests, finding that the unconfined strength of weakly artifical limestone exponentially increases with increasing strain rate. A rate-dependent bond strength was proposed and implemented in software to reveal the mechanism of strain rate effects. It is found that the loading velocity is too high to keep in sync with the initiation and propagation of cracks under impact loading. This delay-induced viscosity may restrict the movement of the surrounding balls, thus increasing resistance.

天然胶结钙质砂和石灰石非常复杂，由于难以从远海获得未受干扰的样品，因此在力学行为方面尚未得到很好的理解。本文提出了一种在实验室环境下利用微生物诱导碳酸盐沉淀（MICP）模拟石灰石胶结自然过程的人工方法。人工胶结砂与天然弱灰岩在三个方面具有高度的相似性：(1)胶结材料的矿物组成同样为粒状方解石和针状文石；(2)随着胶结作用，相互连通的开孔网络中的微观结构会逐渐闭合和收缩。孔隙度达到约9.2%；(3)应力应变关系和无侧限强度与天然弱灰岩基本相似。通过准静态压缩试验和劈裂霍普金森压杆（SHPB）试验研究了人工灰岩的静态和动态特性，发现弱人工灰岩的无侧限强度随着应变速率的增加呈指数增长。为了揭示应变速率效应的机理，提出并在软件中实现了速率相关的粘结强度模型。研究发现，在冲击载荷作用下，加载速度过大，无法与裂纹的萌生和扩展同步。这种延迟引起的粘性可能会限制周围球的运动，从而增加阻力。

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引用次数: 0

Polymer-assisted soybean crude urease carbonate precipitation technique for soil improvement 聚合物辅助大豆粗脲酶碳酸酯沉淀改良土壤技术

Biogeotechnics

Pub Date : 2024-11-17 DOI: 10.1016/j.bgtech.2024.100147

Zalfa Maulida Ihsani , Naoki Kinoshita , Hideaki Yasuhara , Heriansyah Putra

This study presents a sustainable approach to soil improvement by integrating polyvinyl alcohol (PVA) into the Soybean Crude Urease Carbonate Precipitation (SCU-CP) technique. The research aims to enhance SCU-CP, which utilizes soybean-derived urease to precipitate calcium carbonate, bonding soil particles and increasing strength. Challenges such as low solution viscosity and inconsistent carbonate precipitation are addressed by incorporating PVA, a biodegradable polymer that improves viscosity and retention. Comprehensive evaluations reveal significant findings: increasing PVA concentration enhances solution viscosity and results in higher calcium carbonate precipitation. Water retention assessments show that the PCP-1% treatment increases saturation water content (w_s) to 0.263 compared to 0.217 for untreated soil, while also reduces the air-entry value (α). Unconfined Compressive Strength (UCS) tests indicate substantial improvement for PCP-1%, achieving approximately 140 kPa, with values reaching 179 kPa after 28 days. Calcium carbonate content measurements reveal that SCU-CP exhibits a variable distribution (standard deviation of 1.13), while PCP-1% demonstrates a more uniform distribution (standard deviation of 0.60), indicating improved effectiveness. Durability assessments through wet-dry cycling show that SCU-CP experiences a mass loss of 36.5%, while PCP-1% retains only 5% mass loss and maintains a UCS values. SEM images indicate that SCU-CP forms spherical structures, whereas PCP-1% produces a more diverse and crystalline morphology, suggesting better nucleation and distribution. Overall, the polymer-assisted SCU-CP technique (PCP) demonstrates significant potential for effective soil improvement.

本研究提出了一种将聚乙烯醇（PVA）融入大豆粗脲酶碳酸酯沉淀（SCU-CP）技术的可持续土壤改良方法。利用大豆脲酶沉淀碳酸钙，结合土壤颗粒，提高强度的SCU-CP是此次研究的目标。PVA是一种可生物降解的聚合物，可以提高粘度和保持性，解决了溶液粘度低和碳酸盐沉淀不一致等问题。综合评价显示了显著的发现：增加PVA浓度会提高溶液粘度，导致碳酸钙析出量增加。保水性评价表明，与未处理土壤的0.217相比，PCP-1%处理土壤的饱和含水量（ws）增加到0.263，同时空气进入值（α）也降低。无侧限抗压强度（UCS）测试表明，PCP-1%有了显著改善，达到约140 kPa， 28天后达到179 kPa。碳酸钙含量测量结果表明，SCU-CP呈可变分布（标准差为1.13），而PCP-1%的分布更为均匀（标准差为0.60），表明其有效性有所提高。通过干湿循环进行的耐久性评估表明，SCU-CP经历了36.5%的质量损失，而PCP-1%只保留了5%的质量损失，并保持了UCS值。SEM图像显示SCU-CP形成球形结构，而PCP-1%的形貌更加多样化和结晶化，表明SCU-CP的成核和分布更好。总体而言，聚合物辅助SCU-CP技术（PCP）显示出有效改良土壤的巨大潜力。

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引用次数: 0

Influence of environmental conditions on the growth of Pleurotus ostreatus in sand 沙地环境条件对平菇生长的影响

Biogeotechnics

Pub Date : 2024-11-03 DOI: 10.1016/j.bgtech.2024.100137

Emmanuel Salifu , Giuseppe Di Rauso Simeone , Giacomo Russo , Maria A. Rao , Gianfranco Urciuoli , Grainne El Mountassir

Pleurotus ostreatus, a saprotrophic fungus, has been proposed for the remediation of organic contaminants in soils and more recently for modifying the hydraulic and mechanical behaviour of granular soils. The in situ performance of fungal-based biotechnologies will be controlled by the fungal growth and associated biochemical activity that can be achieved in soil. In this study, the influence of environmental conditions (temperature, degree of saturation), substrate type (lignocellulose and spent coffee grounds) and concentration on the mycelium growth of P. ostreatus in sand are investigated. Furthermore, the evolution of growth/survival indicators (respiration, ergosterol concentration) and enzymatic activity (laccase, manganese peroxidase) are investigated. Temperature was shown to have a strong influence on the growth of P.ostreatus in sand: growth was observed to be delayed at low temperatures (e.g. 5 °C), whereas growth was prevented at high temperatures (e.g. 35 °C). No growth was observed at very low degrees of saturation (S_r=0% and 1.2%), indicating there is a critical water content required to support P.ostreatus growth. Within the mid-range of water contents tested radially, growth of P.ostreatus was similar. However, growth under saturated soil conditions was restricted to the air-water atmosphere due to the requirement for oxygen availability. Low substrate concentrations (1%–5%) resulted in high radial growth of P.ostreatus, whereas increasing substrate content further acted to reduce radial growth, but visual observations indicated that fungal biomass density increased. These results are important for understanding the feasibility of P.ostreatus growth under specific site conditions and for the design of successful treatment strategies.

平菇（Pleurotus ostreatus）是一种腐养真菌，已被提出用于修复土壤中的有机污染物，最近还被用于改变颗粒土壤的水力和力学行为。真菌生物技术的原位性能将受到真菌生长和相关生物化学活性的控制，这些活性可以在土壤中实现。本研究考察了环境条件（温度、饱和度）、底物类型（木质纤维素和废咖啡渣）和浓度对沙中P. ostreatus菌丝生长的影响。此外，还研究了生长/生存指标（呼吸、麦角甾醇浓度）和酶活性（漆酶、锰过氧化物酶）的演变。温度对沙中postreatus的生长有很强的影响：观察到在低温（例如5°C）下生长迟缓，而在高温（例如35°C）下生长受阻。在非常低的饱和度（Sr=0%和1.2%）下，没有观察到生长，这表明存在支持postreatus生长所需的临界含水量。在径向测定含水量的中程范围内，青霉的生长情况相似。然而，由于对氧气有效性的要求，饱和土壤条件下的生长仅限于空气-水气氛。低底物浓度（1% ~ 5%）下，绿僵菌的径向生长较高，而增加底物含量会进一步抑制径向生长，但肉眼观察表明真菌生物量密度增加。这些结果对于了解青霉在特定场地条件下生长的可行性和设计成功的处理策略具有重要意义。

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引用次数: 0

Soil-water retention capacity of expansive soil improved through enzyme induced carbonate precipitation-eggshell powder 酶促碳酸盐沉淀-蛋壳粉提高膨胀土的保水性

Biogeotechnics

Pub Date : 2024-10-25 DOI: 10.1016/j.bgtech.2024.100146

Yunlong Liu , Yanyan Xia , Mudassir Mehmood , Lei Wang , Wen Nie , Yingao Zhao , Zhencai Luo

Enzyme Induced Carbonate Precipitation (EICP) has been extensively investigated as a promising approach to improve engineering properties of soil, while Eggshell Powder (ESP) is an agricultural waste that effectively fills soil pores. The ESP provides abundant nucleation at sites for the EICP process, further promoting the effective precipitation of calcium carbonate. The research presented in this paper investigated the Soil Water Characteristic Curves (SWCC), permeability coefficient, and microstructure of expansive soil before and after EICP and EICP+ESP modification. A series of laboratory experiments were conducted, including soil water characteristic tests, permeability tests and Scanning Electron Microscopy (SEM). The results proved that the addition of EICP and EICP+ESP into natural expansive soil resulted in a gradual decline in air entry value, residual water content, and permeability coefficient, indicating an increase in water retention capacity and a decrease in permeability. Furthermore, with the intrusion of EICP and EICP+ESP, the contact between particles becomes smoother, and the soil pores become more equally distributed. Ultimately, there was an enhancement in water retention capacity of the natural expansive soil. This study emphasizes the synergistic potential of combining EICP and EICP+ESP as stabilizing additives to enhance the water retention capacity of expansive soil. Moreover, the reuse of ESP provides a sustainable solution for the resource utilization of agricultural waste and the improvement of expansive soil using bio-inspired methods.

酶诱导碳酸盐沉淀（EICP）作为改善土壤工程性质的一种有前景的方法得到了广泛的研究，而蛋壳粉（ESP）是一种有效填充土壤孔隙的农业废弃物。ESP为EICP过程提供了丰富的成核，进一步促进了碳酸钙的有效沉淀。本文研究了EICP和EICP+ESP改造前后膨胀土的土壤水分特征曲线（SWCC）、渗透系数和微观结构。进行了一系列室内试验，包括土壤水分特性试验、渗透性试验和扫描电镜（SEM）。结果表明，在天然膨胀土中添加EICP和EICP+ESP，使膨胀土的进气量、残余含水量和渗透系数逐渐下降，表明膨胀土的保水性增加，渗透性降低。此外，随着EICP和EICP+ESP的侵入，颗粒之间的接触变得更加平滑，土壤孔隙分布更加均匀。最终，天然膨胀土的保水能力得到增强。本研究强调了EICP和EICP+ESP作为稳定添加剂对膨胀土保水性的协同增效作用。此外，ESP的再利用为农业废弃物资源化利用和生物改良膨胀土提供了可持续的解决方案。

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引用次数: 0

Physical property of MICP-treated calcareous sand under seawater conditions by CPTU 用 CPTU 分析海水条件下经 MICP 处理的钙质砂的物理性质

Biogeotechnics

Pub Date : 2024-10-22 DOI: 10.1016/j.bgtech.2024.100131

Kemeng Yu, Yuling Ran, Jie Shi, Menglan Duan, Zhongkun Ouyang

MICP (Microbially induced calcite precipitation), an environmentally friendly soil improvement technique, has great potential in ocean engineering due to its ability to promote the precipitation of calcium carbonate through microbial activity to enhance the engineering properties of geomaterials. In this study, piezocone penetration test (CPTU) is used to evaluate the effectiveness of MICP treatment in calcareous sand. The change of physical properties (relative density D_r and total unit weight γ_t) of MICP treated calcareous sand is investigated by conducting CPTU on the geomaterials prepared in a series of mini calibration chambers (25 cm × 50 cm). Results indicate that CPTU (tip stress, sleeve friction, and porewater pressure) measurements can be used to interpret the physical characteristics of calcareous sand treated with MICP under seawater conditions. Additionally, a relationship between CPTU measurements, physical parameters (relative density D_r and total unit weight γ_t) of MICP treated calcareous sand is proposed and calibrated. The findings of the research extend the implementation of in-situ testing techniques such as CPTU towards physical property evaluation of bio-treated geomaterials in ocean environment, and demonstrate the potential of scaling up MICP techniques for broader engineering application.

微生物诱导方解石沉淀（MICP）是一种环境友好型土壤改良技术，由于其能够通过微生物活动促进碳酸钙沉淀，从而提高土工材料的工程特性，因此在海洋工程中具有巨大潜力。在本研究中，采用压陷渗透试验（CPTU）来评估 MICP 处理钙质砂的效果。通过对在一系列微型校准室（25 厘米 × 50 厘米）中制备的土工材料进行 CPTU，研究了经 MICP 处理的钙质砂的物理性质（相对密度 Dr 和总单位重量 γt）的变化。结果表明，CPTU（尖端应力、套筒摩擦力和孔隙水压力）测量值可用于解释经 MICP 处理的钙质砂在海水条件下的物理特性。此外，还提出并校准了经 MICP 处理的钙质砂的 CPTU 测量值与物理参数（相对密度 Dr 和总单位重量 γt）之间的关系。研究结果将 CPTU 等原位测试技术的应用范围扩大到海洋环境中生物处理过的土工材料的物理性质评估，并证明了 MICP 技术在更广泛的工程应用中的扩展潜力。

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引用次数: 0