Biogeotechnics最新文献

{"title":"Cementor: A toolbox to generate bio-cemented soils with specific microstructures","authors":"Aoxi Zhang ,&nbsp;Anne-Catherine Dieudonné","doi":"10.1016/j.bgtech.2024.100081","DOIUrl":"10.1016/j.bgtech.2024.100081","url":null,"abstract":"<div><p>Bio-cemented soils can exhibit various types of microstructure depending on the relative position of the carbonate crystals with respect to the host granular skeleton. Different microstructures can have different effects on the mechanical and hydraulic responses of the material, hence it is important to develop the capacity to model these microstructures. The discrete element method (DEM) is a powerful numerical method for studying the mechanical behaviour of granular materials considering grain-scale features. This paper presents a toolbox that can be used to generate 3D DEM samples of bio-cemented soils with specific microstructures. It provides the flexibility of modelling bio-cemented soils with precipitates in the form of contact cementing, grain bridging and coating, and combinations of these distribution patterns. The algorithm is described in detail in this paper, and the impact of the precipitated carbonates on the soil microstructure is evaluated. The results indicate that carbonates precipitated in different distribution patterns affect the soil microstructure differently, suggesting the importance of modelling the microstructure of bio-cemented soils.</p></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 3","pages":"Article 100081"},"PeriodicalIF":0.0,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929124000135/pdfft?md5=3037c7005fb9a8bc0f03a908de111987&pid=1-s2.0-S2949929124000135-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140085672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of plant growth and spacing effects on bioengineered slopes subjected to rainfall","authors":"Farshad Yazdani ,&nbsp;Hamed Sadeghi ,&nbsp;Pouya AliPanahi ,&nbsp;Mostafa Gholami ,&nbsp;Anthony Kwan Leung","doi":"10.1016/j.bgtech.2024.100080","DOIUrl":"10.1016/j.bgtech.2024.100080","url":null,"abstract":"<div><p>Shallow landslides can be mitigated through the hydro-mechanical reinforcement provided by vegetation. Several critical parameters, such as plant spacing and plant age, play a significant role in influencing bioengineered slope stability facilitated by vegetation. However, the coupling of these effects on the stability of vegetated slope has been ignored. The objective of this study is to investigate the hydro-mechanical impact of vegetation growth and spacing on the stability of bioengineered slopes based on the predictions of a calibrated numerical model against field measurements. The impact of vegetation is investigated, with specific attention given to different plant spacing and growth stages, utilizing <em>Schefflera arboricola</em>. In the context of rainfall, it was observed that younger vegetation demonstrated more effective matric suction retention and recovery up to 25 kPa compared to the aged vegetation. Vegetation was revealed to substantially enhance the factor of safety up to 0.3 compared to the bare slope. Plant growth and reducing plant spacing increased the impact of root systems on both hydraulic and mechanical stability, primarily attributable to the influence of root cohesion rather than transpiration rates. The results revealed that the mechanical contribution to the factor of safety enhancement was raised from one-third to two-thirds because of the vegetation-induced cohesion within the growing rooted zone.</p></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 2","pages":"Article 100080"},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929124000123/pdfft?md5=1433735d4e0d0634c3f9a335edfac71d&pid=1-s2.0-S2949929124000123-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139966200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on time effect and prediction model of shear strength of root-soil complex under dry-wet cycle","authors":"Zhengjun Mao ,&nbsp;Xu Ma ,&nbsp;Yuncen Liu ,&nbsp;Mimi Geng ,&nbsp;Yanshan Tian ,&nbsp;Jiewen Sun ,&nbsp;Zhijie Yang","doi":"10.1016/j.bgtech.2024.100079","DOIUrl":"10.1016/j.bgtech.2024.100079","url":null,"abstract":"<div><p>Triaxial compression tests were conducted on the alfalfa root-loess complex at different growthperiods obtained through artificial planting. The research focused on analyzing the time variation law of the shear strength index and deformation index of the alfalfa root-loess complex under dry-wet cycles. Additionally, the time effect of the shear strength index of the alfalfa root-loess complex under dry-wet cycles was analyzed and its prediction model was proposed. The results show that the PG-DWC (dry-wet cycle caused by plant water management during plant growth period) causes the peak strength of plain soil to change in a \"V\" shape with the increase of growth period, and the peak strength of alfalfa root-loess complex is higher than that of plain soil at the same growth period. The deterioration of the peak strength of alfalfa root-loess complex in the same growth period is aggravated with the increase of drying and wetting cycles. Compared with the 0 days growth period, the effective cohesion of alfalfa root-loess complex under different dry-wet cycles maximum increase rate is at the 180 days, which are 33.88%, 46.05%, 30.12% and 216.02%, respectively. When the number of dry-wet cycles is constant, the effective cohesion of the alfalfa root-loess complex overall increases with the growth period. However, it gradually decreases comparedwith the previous growth period, and the minimum increase rate are all at the 180 days. For the same growth period, the effective cohesion of the alfalfa root-loess complex decreases with the increase of the number of dry-wet cycles. This indicates that EC-DWC (the dry-wet cycles caused by extreme natural conditions such as continuous rain) have a detrimental effect on the time effect of the shear strength of the alfalfa root-loess complex. Finally, based on the formula of total deterioration, a prediction model for the shear strength of the alfalfa root-loess complex under dry-wet cycles was proposed, which exhibits high prediction accuracy. The research results provide useful guidance for the understanding of mechanical behavior and structural damage evolution of root-soil composite.</p></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 2","pages":"Article 100079"},"PeriodicalIF":0.0,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929124000111/pdfft?md5=f303312d05fa5279822810e797b36183&pid=1-s2.0-S2949929124000111-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139891229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Announcement: Winner of the Inaugural Biogeotechnics Lecture Award","authors":"","doi":"10.1016/j.bgtech.2024.100078","DOIUrl":"https://doi.org/10.1016/j.bgtech.2024.100078","url":null,"abstract":"","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 2","pages":"Article 100078"},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S294992912400010X/pdfft?md5=9801fbbcfa3456c84f018fe8c3b46e14&pid=1-s2.0-S294992912400010X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140813584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on time effect and prediction model of shear strength of root-soil complex under dry-wet cycle","authors":"Zhengjun Mao, Xu Ma, Yuncen Liu, Mimi Geng, Yanshan Tian, Jiewen Sun, Zhijie Yang","doi":"10.1016/j.bgtech.2024.100079","DOIUrl":"https://doi.org/10.1016/j.bgtech.2024.100079","url":null,"abstract":"","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"812 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139831363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triaxial compression test of MICP sand column and simulation of failure process","authors":"Siriguleng Bai ,&nbsp;Kai Li ,&nbsp;Tala Bao ,&nbsp;Chi Li","doi":"10.1016/j.bgtech.2024.100071","DOIUrl":"10.1016/j.bgtech.2024.100071","url":null,"abstract":"<div><div>Microbially induced calcium carbonate precipitation (MICP) technology can induce calcium carbonate crystals with cementation and stable performance in the process of microbial metabolism or enzymization through the regulation of environmental factors MICP can be used as a cementing agent to cement cohesionless sand particles to form the materials with the characteristics of higher strength, better durability and environmental friendliness, as well as a good engineering application prospect. In this paper, the shear strength of sand column was tested by triaxial compression tests, and the strength index was obtained. In order to further study the micro-strength mechanism and the failure process, based on the discrete element method, a numerical model of MICP cemented sand column was established considering the factors of matrix soil particle gradation, particle morphology, content ratio of induced calcium carbonate, pore distribution characteristics, inter-particle cementation and so on. The failure process of MICP cemented sand column under load was analysed by numerical simulation, and the reliability of the numerical model was tested by combining with the stress intensity curve of samples under test conditions. The results indicate that compared with the actual triaxial tests of MICP cemented sand column, although there are deviations in stress and strain, cohesion and internal friction angle, the numerical simulation shows similar development law and intensity amplitude, and the same failure trend. The work in this paper verifies the reliability of the numerical model and provides a theoretical basis for the subsequent analysis of the factors influencing the geotechnical mechanical properties of biomineralized materials.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 3","pages":"Article 100071"},"PeriodicalIF":0.0,"publicationDate":"2024-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139632237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydraulic characteristics and vegetation performance of the Yellow River sediment modified by biochar","authors":"Baoyong Liu ,&nbsp;Mingji Liao ,&nbsp;Yong Wan ,&nbsp;Xingxing He ,&nbsp;Dongli Wang","doi":"10.1016/j.bgtech.2024.100070","DOIUrl":"10.1016/j.bgtech.2024.100070","url":null,"abstract":"<div><p>The Yellow River sediment (YRS) is an important potential soil resource for the mine land reclamation and ecological restoration in the arid regions of northern China. However, it has the shortcomings of poor water-holding capacity and needs to be modified urgently. Therefore, two types of biochar, namely rice husk biochar (RHB) and coconut shell biochar (CSB), were utilized in this study to modify the YRS and compared with rice husk ash (RHA). Some engineering properties of the modified YRS (MYRS), including pore structure, water retention, permeability, and vegetation performance, were investigated by considering the effects of biochar types and dosages. Results showed that the addition of the three materials decreased the bulk density of the YRS and increased the volume of extremely micro pore (<em>d</em>&lt;0.3 µm), as well as the effective porosity and capillary porosity, thus contributed to an increase in the water-holding capacity of the sediment. Among the three conditioners, RHB is optimal choice for improving the water-holding capacity of YRS. Furthermore, the effect becomes more pronounced with increasing application rates. With the addition of the three materials, the permeability coefficients of MYRS gradually decreased, while the water retention rate during evaporation significantly increased. The pot experiment showed that the three conditioners all had significant promoting effect on the growth of oats. In particular, compared to plain soil, the total biomass of oats grown for 21 days increased by 17.46%, 32.14%, and 49.60% after adding 2%, 4%, and 8% RHB, respectively. This study introduces a new approach for using YRS as planting soil in arid and semi-arid areas of China to facilitate mine ecological restoration.</p></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 2","pages":"Article 100070"},"PeriodicalIF":0.0,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929124000020/pdfft?md5=bb18831666c933e2e92601c7b5f400e9&pid=1-s2.0-S2949929124000020-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139633442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory testing on cracking characteristics and improvement mechanism of coral mud","authors":"Huaqiang Fang,&nbsp;Xuanming Ding,&nbsp;Yifu Li,&nbsp;Hong Wang,&nbsp;Junyu Ren","doi":"10.1016/j.bgtech.2024.100069","DOIUrl":"10.1016/j.bgtech.2024.100069","url":null,"abstract":"<div><p>In recent years, the development and construction of island reefs have been flourishing. Due to the remoteness of island reefs from the mainland, the scarcity of building materials, and the high transportation costs, it is imperative to use local marine resources, and the potential value and status of coral mud on island reefs, which is formed by the remains of corals and other biological entities, is becoming increasingly prominent. Utilization and optimization of natural resources on island reefs have become a brand-new research direction and challenge. This article mainly focuses on the development of a new type of green engineering material, coral mud, for use in building surface layers. Thickness effects, PVA fiber (vinylon staple fiber) modification, and HPMC (Hydroxypropyl Methyl Cellulose) adhesive modification are taken into consideration. Through laboratory tests and image processing technology, fractal theory, and electron microscopy experiments, the macro-meso-microscopic multi-scale cracking rules of the coral mud surface layer and the optimization modification rules of PVA fibers and HPMC adhesives are revealed. The results demonstrate that the performance of the coral mud surface layer is superior to that of the kaolin surface layer, and the 10 mm thickness performs better than the 5 mm and 20 mm thicknesses. As the thickness of the coral mud surface layer increases, the contact between coral mud particles becomes denser, the scale of surface micro-cracks decreases, and the number of micro-pores decreases. PVA fibers can effectively inhibit the further development of macro and micro cracks and play a good bridging role. There is a bonding and adhesion relationship between coral mud and PVA fibers, and they have a good synergistic effect in inhibiting macro and mesoscopic cracks. With the increase in HPMC adhesive content, the number of micro-cracks and the scale of micro-cracks decrease accordingly, and the structure and performance of the coral mud surface layer are further improved. Overall, PVA fibers are more effective than HPMC adhesives in inhibiting the cracking of the coral mud surface layer. This provides valuable guidance for the development and application of coral mud in wall surface materials.</p></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 2","pages":"Article 100069"},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929124000019/pdfft?md5=fec38b338711bc7ea091b8ebaf46e6b0&pid=1-s2.0-S2949929124000019-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139453784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of layer thickness on desiccation cracking behaviour of a vegetated soil","authors":"Congying Li ,&nbsp;Qing Cheng ,&nbsp;Chaosheng Tang ,&nbsp;Yingdong Gu ,&nbsp;Lingxin Cui ,&nbsp;Haowen Guo","doi":"10.1016/j.bgtech.2023.100068","DOIUrl":"10.1016/j.bgtech.2023.100068","url":null,"abstract":"<div><p>The objective of this study is to explore how different layer thicknesses affect the desiccation cracking behaviour of vegetated soil. During the experiment, an electronic balance was employed to quantify water evaporation, while a digital camera was utilized to capture the initiation and progression of soil surface cracking. Results indicate that in the early drying process, the rate of evapotranspiration in vegetated soil correlates positively with leaf biomass. For soil samples with the same layer thickness, the constant rate stage duration is consistently shorter in vegetated soil samples than in their bare soil counterparts. As the layer thickness increases, both vegetated and bare soil samples crack at higher water content. However, vegetated soil samples crack at lower water content than their bare soil counterparts. Vegetation significantly reduces the soil surface crack ratio and improves the soil crack resistance. The crack reduction ratio is positively correlated with both root weight and length density. In thicker vegetated soil layers, the final surface crack length noticeably declines.</p></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 2","pages":"Article 100068"},"PeriodicalIF":0.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929123000682/pdfft?md5=5ee08d7756668d880f909e435213d780&pid=1-s2.0-S2949929123000682-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139194823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil bioengineering using vegetation under climate change","authors":"Junjun Ni,&nbsp;Yang Xiao,&nbsp;Jinquan Shi,&nbsp;Jieling He","doi":"10.1016/j.bgtech.2023.100067","DOIUrl":"10.1016/j.bgtech.2023.100067","url":null,"abstract":"","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"2 1","pages":"Article 100067"},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2949929123000670/pdfft?md5=625ce60beba833c9a5df134e40a82bbf&pid=1-s2.0-S2949929123000670-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139019638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}