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Effect of drying-wetting cycles on pore characteristics and mechanical properties of enzyme-induced carbonate precipitation-reinforced sea sand

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 291-302页

作者： Ming Huang Kai xu Zijian Liu chaoshui xu Mingjuan Cui College of Civil Engineering Fuzhou UniversityFuzhou350108China Xiamen Rail Transit Construction and Development Group Co. Ltd.Xiamen361000China School of Civil Environment and Mining EngineeringThe University of AdelaideAdelaide5005Australia

Enzyme-induced carbonate precipitation(EICP)is an emanating,eco-friendly and potentially sound technique that has presented promise in various geotechnical applications.However,the durability and microscopic characteristics of EICP-treated specimens against the impact of drying-wetting(D-W)cycles is under-explored yet.This study investigates the evolution of mechanical behavior and pore charac-teristics of EICP-treated sea sand subjected to D-W cycles.The uniaxial compressive strength(UCS)tests,synchrotron radiation micro-computed tomography(micro-CT),and three-dimensional(3D)recon-struction of CT images were performed to study the multiscale evolution characteristics of EICP-reinforced sea sand under the effect of D-W cycles.The potential correlations between microstructure characteristics and macro-mechanical property deterioration were investigated using gray relational analysis(GRA).Results showed that the UCS of EICP-treated specimens decreases by 63.7% after 15 D-W cycles.The proportion of mesopores gradually decreases whereas the proportion of macropores in-creases due to the exfoliated calcium carbonate with increasing number of D-W cycles.The micro-structure in EICP-reinforced sea sand was gradually disintegrated,resulting in increasing pore size and development of pore shape from ellipsoidal to columnar and branched.The gray relational degree suggested that the weight loss rate and UCS deterioration were attributed to the development of branched pores with a size of 100-1000 m m under the action of D-W cycles.Overall,the results in this study provide a useful guidancee for the long-term stability and evolution characteristics of EICP-reinforced sea sand under D-W weathering conditions.

关键词： Enzyme-induced carbonate precipitation(EICP) Plant-based urease Drying-wetting(D-W)cycles Microstructure

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Experimental study of face passive failure features of a shallow shield tunnel in coastal backfill sand

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 252-271页

作者： Weifeng QIAN Ming HUANG Bingnan WANG chaoshui xu Yanfeng HU School of Civil Engineering Fuzhou UniversityFuzhou 350108China School of Civil Environment and Mining EngineeringUniversity of AdelaideAdelaide 5005Australia China First Highway Xiamen Engineering Co. Ltd.Xiamen 361000China

Face passive failure can severely damage existing structures and underground utilities during shallow shield tunneling,especially in coastal backfill sand.In this work,a series of laboratory model tests were developed and conducted to investigate such failure,for tunnels located at burial depth ratios for which C/D=0.5,0.8,1,and 1.3.Support pressures,the evolution of failure processes,the failure modes,and the distribution of velocity fields were examined through model tests and numerical analyses.The support pressure in the tests first rose rapidly to the elastic limit and then gradually increased to the maximum value in all cases.The maximum support pressure decreased slightly in cases where C/D=0.8,1,and 1.3,but the rebound was insignificant where C/D=0.5.In addition,the configuration of the failure mode with C/D=0.5 showed a wedge-shaped arch,which was determined by the outcropping shear failure.The configuration of failure modes was composed of an arch and the inverted trapezoid when C/D=0.8,1,and 1.3,in which the mode was divided into lower and upper failure zones.

关键词： tunnel face stability passive failure model test support pressure failure mode

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储层裂缝随机建模方法研究进展

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石油地球物理勘探 2018年第3期53卷 625-641页

作者：董少群曾联波 xu chaoshui 曹菡王圣娇吕文雅中国石油大学(北京)地球科学学院北京102249 油气资源与探测国家重点实验室北京102249 阿德莱德大学土木、环境和采矿工程学院澳大利亚阿德莱德5005 中国科学院对地观测与数字地球科学中心北京100094

作为研究裂缝空间展布的有效手段,储层裂缝建模可分为确定性建模与随机建模两大类,且随机建模方式应用广泛。储层裂缝随机建模包括基于空间剖分的裂缝建模、离散裂缝网络建模、基于变差函数的裂缝建模、基于多点地质统计学的裂缝建模和... 详细信息

作为研究裂缝空间展布的有效手段,储层裂缝建模可分为确定性建模与随机建模两大类,且随机建模方式应用广泛。储层裂缝随机建模包括基于空间剖分的裂缝建模、离散裂缝网络建模、基于变差函数的裂缝建模、基于多点地质统计学的裂缝建模和基于分形特征迭代的裂缝建模等五类。本文结合实例详细介绍了五类随机建模方法的原理、特点及其适用性。第一类方法适用于简单裂缝系统建模,第二、三、四类方法适用于大部分裂缝系统建模,第五类方法适用于分形特征明显的裂缝系统(如压裂诱导缝)建模。同时本文系统分析了各类方法的优缺点,并展望了储层裂缝随机建模方法的发展趋势。

关键词：裂缝随机建模空间剖分离散裂缝网络变差函数多点地质统计学分形

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Field implementation of enzyme-induced carbonate precipitation technology for reinforcing a bedding layer beneath an underground cable duct

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第4期15卷 1011-1022页

作者： Kai xu Ming Huang Jiajie Zhen chaoshui xu Mingjuan Cui College of Civil Engineering Fuzhou UniversityFuzhou350108China School of Civil Environment and Mining EngineeringUniversity of AdelaideAdelaide5005Australia

A suitable bearing capacity of foundation is critical for the safety of civil structures.Sometimes foundation reinforcement is necessary and an effective and environmentally friendly method would be the preferred choice.In this study,the potential application of enzyme-induced carbonate precipitation(EICP)was investigated for reinforcing a 0.6 m bedding layer on top of clay to improve the bearing capacity of the foundation underneath an underground cable duct.Laboratory experiments were conducted to determine the optimal operational parameters for the extraction of crude urease liquid and optimal grain size range of sea sands to be used to construct the bedding layer.Field tests were planned based on orthogonal experimental design to study the factors that would significantly affect the biocementation effect on site.The dynamic deformation modulus,calcium carbonate content and longterm ground stress variations were used to evaluate the bio-cementation effect and the long-term performance of the EICP-treated bedding layer.The laboratory test results showed that the optimal duration for the extraction of crude urease liquid is 1 h and the optimal usage of soybean husk powder in urease extraction solution is 100 g/L.The calcium carbonate production rate decreases significantly when the concentration of cementation solution exceeds 0.5 mol/L.The results of site trial showed that the number of EICP treatments has the most significant impact on the effectiveness of EICP treatment and the highest dynamic deformation modulus(Evd)of EICP-treated bedding layer reached 50.55 MPa.The area with better bio-cementation effect was found to take higher ground stress which validates that the EICP treatment could improve the bearing capacity of foundation by reinforcing the bedding layer.The field trial described and the analysis introduced in this paper can provide a practical basis for applying EICP technology to the reinforcement of bedding layer in poor ground conditions.

关键词： Enzyme-induced carbonate precipitation (EICP) Plant-based urease Underground cable duct Foundation reinforcement

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裂缝密度约束的离散裂缝网络建模方法与实现

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地质论评 2018年第5期64卷 1302-1313页

作者：董少群曾联波曹菡 xu chaoshui 王圣娇油气资源与探测国家重点实验室中国北京102249 中国石油大学(北京)地球科学学院中国北京102249 中国科学院遥感与数字地球研究所中国北京100094 阿德莱德大学土木、环境和采矿工程学院澳大利亚阿德莱德5005

如何高效地用多种类型资料(如地震、测井、岩芯等)所得到的裂缝信息对离散裂缝网络建模至关重要。为此本文提出一种裂缝密度约束的离散裂缝网络建模方法,将多种裂缝先验信息转换为裂缝密度,通过密度约束裂缝网络模型。方法对裂缝位置的... 详细信息

如何高效地用多种类型资料(如地震、测井、岩芯等)所得到的裂缝信息对离散裂缝网络建模至关重要。为此本文提出一种裂缝密度约束的离散裂缝网络建模方法,将多种裂缝先验信息转换为裂缝密度,通过密度约束裂缝网络模型。方法对裂缝位置的确定方法进行改进,从编程的角度对二维和三维实现进行了分析,同时讨论了方法的适用性及参数设定。为验证方法效果,实例分析部分选用鄂尔多斯盆地延河剖面附近的一井区数据进行裂缝建模,并与实际生产资料进行比对,结果表明该方法所建立的裂缝模型与实际生产数据吻合。

关键词：离散裂缝网络裂缝密度裂缝建模测井参数设定

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Carbon sequestration potential of the Habanero reservoir when carbon dioxide is used as the heat exchange fluid

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Journal of Rock Mechanics and Geotechnical Engineering 2016年第1期8卷 50-59页

作者： chaoshui xu Peter Dowd Qi Li School of Civil Environmental and Mining Engineering & South Australia Centre for Geothermal Energy Research University of Adelaide State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences

The use of sequestered carbon dioxide(CO) as the heat exchange fluid in enhanced geothermal system(EGS) has significant potential to increase their productivity, contribute further to reducing carbon emissions and increase the economic viability of geothermal power generation. Coupled COsequestration and geothermal energy production from hot dry rock(HDR) EGS were first proposed 15 years ago but have yet to be practically implemented. This paper reviews some of the issues in assessing these systems with particular focus on the power generation and COsequestration capacity. The Habanero geothermal field in the Cooper Basin of South Australia is assessed for its potential COstorage capacity if supercritical COis used as the working fluid for heat extraction. The analysis suggests that the major COsequestration mechanisms are the storage in the fracture-stimulation damaged zone followed by diffusion into the pores within the rock matrix. The assessment indicates that 5% of working fluid loss commonly suggested as the storage capacity might be an over-estimate of the long-term COsequestration capacity of EGS in which supercritical COis used as the circulation fluid.

关键词： Carbon sequestration Carbon dioxide(CO_2) geological storage capacity Enhanced geothermal system(EGS) CO_2-EGS Habanero project

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Riverine sulfate sources and behaviors in arid environment,Northwest China:Constraints from sulfur and oxygen isotopes

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Journal of Environmental Sciences 2024年第3期137卷 716-731页

作者： Yifu xu Wenjing Liu Bing xu Zhifang xu Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The fate of riverine sulfate ion (SO_(4)^(2-)) and its environmental effects in arid environment are difficult to evaluate due to its complicated sources and strongly coupled behaviors with water cycle which is significantly modified by humans.To understand the sulfur cycle in aquatic systems in arid environment,the chemical and sulfur and oxygen isotopic compositions (δ^(34)S_(SO4)and δ^(18)O_(SO4)) of major rivers around the Badain Jaran Desert,northwestern China,were investigated.These rivers had averaged SO_(4)^(2-)content at 1336μmol/L,over 10times higher than the global average.The δ^(34)S_(SO4)and δ^(18)O_(SO4)values ranged from-5.3‰to+11.8‰and+1.6‰to+12.8‰,respectively.The end-member analysis and the inverse model showed that riverine sulfate was mainly derived from evaporites dissolution (0-87%),sulfide oxidation (13%-100%) and precipitation (0-33%),indicating heterogeneity in sulfur sources and behaviors along the river drainage with the lithology variations and climate gradients.Multiple isotopic tools combining with hydro-chemistry compositions could be applied to reveal sulfur cycle in arid environment.Based on the calculation,sulfide oxidation plays the primary role in the headwater and upstream in the Qilian-Mountains area,where sulfide is widely exposed.While the proportion of evaporites dissolution contributing to riverine sulfate is much higher in downstream in a drier environment.Besides,less precipitation and higher temperature can lead to more intensive evaporation,affecting the process of sulfide oxidation and enhancing the rates of evaporites dissolution and sulfate precipitation in the basin.

关键词： Sulfur and oxygen isotopes Source apportionment Inverse model Arid environment Inland rivers Northwestern China

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Biohythane production from two-stage anaerobic digestion of food waste:A review

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Journal of Environmental Sciences 2024年第5期139卷 334-349页

作者： Xiaona An Ying xu Xiaohu Dai State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

The biotransformation of food waste(FW)to bioenergy has attracted considerable research attention as a means to address the energy crisis and waste disposal problems.To this end,a promising technique is two-stage anaerobic digestion(TSAD),in which the FW is transformed to biohythane,a gaseous mixture of biomethane and biohydrogen.This review summarises the main characteristics of FW and describes the basic principle of TSAD.Moreover,the factors influencing the TSAD performance are identified,and an overview of the research status;economic aspects;and strategies such as pre-treatment,co-digestion,and regulation of microbial consortia to increase the biohythane yield from TSAD is provided.Additionally,the challenges and future considerations associated with the treatment of FW by TSAD are highlighted.This paper can provide valuable reference for the improvement and widespread implementation of TSAD-based FW treatment.

关键词： Two-stage anaerobic digestion(TSAD) Food waste(FW) Methane production Hydrogen production

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Identification of high oxygen-consuming substances in stormwater drainage systems illicitly connected with sewage system

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Journal of Environmental Sciences 2024年第4期138卷 132-140页

作者： Chen xu Zuxin xu Wenhai Chu Shanshan Wu Rong Xiao Lei Su State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Ministry of Education Key Laboratory of Yangtze River Water Environment Tongji UniversityShanghai 200092China Guangzhou Resource Environmental Protection Technology Co. Ltd.Guangzhou 510030China

The dissolved oxygen content in water is an important indicator for assessing the quality of the water environment,and maintaining a certain amount of dissolved oxygen is essential for the healthy development of the ecological environment.When a water body is anoxic,the activity of anaerobic microorganisms increases and organic matter is decomposed to produce a large number of blackening and odorizing substances,resulting in black and odorous water bodies,which is a very common and typical phenomenon in China.Presently,there is still a relatively universal occurrence of illicitly connected stormwater and sewage pipes in the urban drainage pipe network in China,which makes oxygen-consuming substances be directly discharged into rivers through stormwater pipes and consume the dissolved oxygen in the water bodies,resulting in an oxygen deficiency of the water.This induces seasonal or year-round black and stink phenomena in urban rivers.Hence,identifying high oxygen-consuming substances,which lays the foundation for the subsequent removal of oxygen-consuming substances,is essential.Through a series of comparisons of water quality indicators and analysis of organic characteristics,it was found that the oxygen consumption capacity of domestic sewage was higher than that of industrial wastewater in the selected area of this study,and the oxygen-consuming substances of domestic sewage were small molecular amino acids.By comparing 20 conventional free amino acids,it was found that seven of them consumed oxygen easily,and compared with chemical oxygen consumption,biological oxygen consumption was in a leading position.

关键词： Urban drainage system Oxygen-consuming substances Domestic sewage Amino acid

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Aldehyde oxidase mediated enantioselective metabolic health risk of dinotefuran

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Science China Chemistry 2024年第6期67卷 2079-2091页

作者： Liwei xu Xinxin xu Hua Kuang Chuanlai xu Xiaoling Wu State Key Laboratory of Food Science and Resources Jiangnan UniversityWuxi214122China International Joint Research Laboratory for Biointerface and Biodetection and School of Food Science and Technology Jiangnan UniversityWuxi214122China Collaborative Innovation center of Food Safety and Quality Control in Jiangsu Province Jiangnan UniversityWuxi214122China

Chiral pollutants often pose significant differential environmental health risks.In this study,the biotransformation of chiral dinotefuran(DIN)and its enantioselective metabolic toxicity mechanisms have been systemically investigated.Firstly,reversedphase chromatography-high resolution mass spectrometry was developed to quantify the content of DIN R/S chiral enantiomer with pg level sensitivity,revealing a lower elimination rate constant(K_(e))of S-DIN(0.730 h^(-1))than R-DIN(0.746 h^(-1)).Secondly,the interaction mechanism between DIN metabolism and important endogenous bioactive molecules,such as aldehyde oxidase(AOX)and neurotransmitters,was revealed.The DIN nitro-group was converted into a guanidine group by the reducing site of nearby flavin adenine dinucleotide(FAD)in AOX with the preferred higher affinity of S-configuration.Meanwhile,the endogenous tryptophan(Trp)aldehyde metabolic intermediate,5-hydroxyindoleacetaldehyde(5-HIAL),provides a persistent electron donor for DIN reduction via the oxidation-catalyzed site in AOX,resulting in remarkable up-regulation of monoamine neurotransmitters such as serotonin and dopamine.Thirdly,the higher level of neurotransmitters further mediated dysregulation of oxylipin homeostasis via the serotonergic pathway,where S-DIN exhibited more pronounced liver lipid damage and environmental health risk with the accumulated lipid biomarkers,oxidized triglyceride(OxTG)and oxidized sphingomyelin(OxSM).This study elucidates the AOX-mediated enantioselectivity metabolic pathway of DIN,providing a new analytical method for chiral pollutants and paves the way for their health risk assessments.

关键词： neonicotinoid dinotefuran enantiomer aldehyde oxidase metabolomics health risk

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