Pub Date : 2025-06-01Epub Date: 2025-03-19DOI: 10.1016/j.bgtech.2025.100177
{"title":"Erratum regarding updating Declaration of Competing Interest statements in previously published articles","authors":"","doi":"10.1016/j.bgtech.2025.100177","DOIUrl":"10.1016/j.bgtech.2025.100177","url":null,"abstract":"","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 2","pages":"Article 100177"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697772","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}
Pub Date : 2025-06-01Epub Date: 2024-11-22DOI: 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.
{"title":"Impact behavior and strain rate effects of artificial limestone by MICP","authors":"Yaru Lv , Lin Wu , Zhigang Duan , Yuchen Su , Dongdong Zhang","doi":"10.1016/j.bgtech.2024.100154","DOIUrl":"10.1016/j.bgtech.2024.100154","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 2","pages":"Article 100154"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697771","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}
Pub Date : 2025-06-01Epub Date: 2024-05-23DOI: 10.1016/j.bgtech.2024.100105
Xinlei Zhang , Yue Sun , Yumin Chen , Lu Liu , Wenwen Li , Yi Han
The mineralization process of microbial-induced calcium carbonate precipitation (MICP) is influenced by many factors, and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for MICP technology. In this study, the uniformity of the saturated calcareous sand treated with MICP was investigated through one-dimensional calcareous sand column tests and model tests. The coefficient of variation was employed in one-dimensional sand column tests to investigate the impact of injection rate, cementation solution concentration, and number of injection cycles on the uniformity of the MICP treatment. Additionally, model tests were conducted to investigate the impact of injection pressure and methods on the treatment range and uniformity under three-dimensional seepage conditions. Test results demonstrate that the reinforcement strength and uniformity are significantly influenced by the injection rate of the cementation solution, with a rate of 3 mL/min, yielding a favorable treatment effect. Excessive concentration of the cementation solution can lead to significant non-uniformity and a reduction in the compressive strength of MICP-treated samples. Conversely, excessively low concentrations may result in decreased bonding efficiency. Among the four considered concentrations, 0.5 mol/L and 1 mol/L exhibit superior reinforcing effects. The morphological development of calcareous sandy foundation reinforcement is associated with the spatial distribution pattern of the bacterial solution, exhibiting a relatively larger reinforcement area in proximity to the lower region of the model and a gradually decreasing range towards the upper part. Under three-dimensional seepage conditions, in addition to the non-uniform radial cementation along the injection pipe, there is also vertical heterogeneity of cementation along the length of the injection pipe due to gravitational effects, resulting in preferential deposition of calcium carbonate at the lower section. The application of injection pressure and a double-pipe circulation injection method can mitigate the accumulation of bacterial solution and cementation solution at the bottom, thereby improving the reinforcement range and uniformity.
{"title":"Uniformity of microbial injection for reinforcing saturated calcareous sand: A multi-test approach","authors":"Xinlei Zhang , Yue Sun , Yumin Chen , Lu Liu , Wenwen Li , Yi Han","doi":"10.1016/j.bgtech.2024.100105","DOIUrl":"10.1016/j.bgtech.2024.100105","url":null,"abstract":"<div><div>The mineralization process of microbial-induced calcium carbonate precipitation (MICP) is influenced by many factors, and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for MICP technology. In this study, the uniformity of the saturated calcareous sand treated with MICP was investigated through one-dimensional calcareous sand column tests and model tests. The coefficient of variation was employed in one-dimensional sand column tests to investigate the impact of injection rate, cementation solution concentration, and number of injection cycles on the uniformity of the MICP treatment. Additionally, model tests were conducted to investigate the impact of injection pressure and methods on the treatment range and uniformity under three-dimensional seepage conditions. Test results demonstrate that the reinforcement strength and uniformity are significantly influenced by the injection rate of the cementation solution, with a rate of 3 mL/min, yielding a favorable treatment effect. Excessive concentration of the cementation solution can lead to significant non-uniformity and a reduction in the compressive strength of MICP-treated samples. Conversely, excessively low concentrations may result in decreased bonding efficiency. Among the four considered concentrations, 0.5 mol/L and 1 mol/L exhibit superior reinforcing effects. The morphological development of calcareous sandy foundation reinforcement is associated with the spatial distribution pattern of the bacterial solution, exhibiting a relatively larger reinforcement area in proximity to the lower region of the model and a gradually decreasing range towards the upper part. Under three-dimensional seepage conditions, in addition to the non-uniform radial cementation along the injection pipe, there is also vertical heterogeneity of cementation along the length of the injection pipe due to gravitational effects, resulting in preferential deposition of calcium carbonate at the lower section. The application of injection pressure and a double-pipe circulation injection method can mitigate the accumulation of bacterial solution and cementation solution at the bottom, thereby improving the reinforcement range and uniformity.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 2","pages":"Article 100105"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141135975","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}
Pub Date : 2025-06-01Epub Date: 2024-09-07DOI: 10.1016/j.bgtech.2024.100136
Xiangwei Fang , Chao Chen , Ganggang Zhou , Zhixiong Chen , Chunyan Wang , Luqi Wang
The biocemented coral sand pile composite foundation represents an innovative foundation improvement technology, utilizing Microbially Induced Carbonate Precipitation (MICP) to consolidate a specific volume of coral sand within the foundation into piles with defined strength, thereby enabling them to collaboratively bear external loads with the surrounding unconsolidated coral sand. In this study, a series of shaking table model tests were conducted to explore the dynamic response of the biocemented coral sand pile composite foundation under varying seismic wave types and peak accelerations. The surface macroscopic phenomena, excess pore water pressure ratio, acceleration response, and vertical settlement were measured and analysed in detail. Test results show that seismic wave types play a decisive role in the macroscopic surface phenomena and the response of the excess pore water pressure ratio. The cumulative settlement of the upper structure under the action of Taft waves was about 1.5 times that of El Centro waves and Kobe waves. The most pronounced liquefaction phenomena were recorded under the Taft wave, followed by the El Centro wave, and subsequently the Kobe wave. An observed positive correlation was established between the liquefaction phenomenon and the Aristotelian intensity of the seismic waves. However, variations in seismic wave types exerted minimal influence on the acceleration amplification factor of the coral sand foundation. Analysis of the acceleration amplification factor revealed a triphasic pattern—initially increasing, subsequently decreasing, and finally increasing again—as burial depth increased, in relation to the peak value of the input acceleration. This study confirms that the biocemented coral sand pile composite foundation can effectively enhance the liquefaction resistance of coral sand foundations.
{"title":"Experimental investigation on response of biocemented coral sand pile composite foundation under seismic waves","authors":"Xiangwei Fang , Chao Chen , Ganggang Zhou , Zhixiong Chen , Chunyan Wang , Luqi Wang","doi":"10.1016/j.bgtech.2024.100136","DOIUrl":"10.1016/j.bgtech.2024.100136","url":null,"abstract":"<div><div>The biocemented coral sand pile composite foundation represents an innovative foundation improvement technology, utilizing Microbially Induced Carbonate Precipitation (MICP) to consolidate a specific volume of coral sand within the foundation into piles with defined strength, thereby enabling them to collaboratively bear external loads with the surrounding unconsolidated coral sand. In this study, a series of shaking table model tests were conducted to explore the dynamic response of the biocemented coral sand pile composite foundation under varying seismic wave types and peak accelerations. The surface macroscopic phenomena, excess pore water pressure ratio, acceleration response, and vertical settlement were measured and analysed in detail. Test results show that seismic wave types play a decisive role in the macroscopic surface phenomena and the response of the excess pore water pressure ratio. The cumulative settlement of the upper structure under the action of Taft waves was about 1.5 times that of El Centro waves and Kobe waves. The most pronounced liquefaction phenomena were recorded under the Taft wave, followed by the El Centro wave, and subsequently the Kobe wave. An observed positive correlation was established between the liquefaction phenomenon and the Aristotelian intensity of the seismic waves. However, variations in seismic wave types exerted minimal influence on the acceleration amplification factor of the coral sand foundation. Analysis of the acceleration amplification factor revealed a triphasic pattern—initially increasing, subsequently decreasing, and finally increasing again—as burial depth increased, in relation to the peak value of the input acceleration. This study confirms that the biocemented coral sand pile composite foundation can effectively enhance the liquefaction resistance of coral sand foundations.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 2","pages":"Article 100136"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697652","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}
Pub Date : 2025-03-01Epub Date: 2024-07-17DOI: 10.1016/j.bgtech.2024.100130
Hanlong Liu
With the increasing demand for buildings and infrastructures and the mounting challenges associated with the current construction technologies such as high emission, high pollution, and high energy consumption, the civil engineering profession is at the crossroad for a transformation or upgrading before it can be put into tasks for these challenges. Inspired by the concept of harmonious coexistence between humans and nature, a new concept, biogenic construction, for civil engineering is proposed in this paper. The definition of biogenic construction is given. The framework and four components of biogenic construction are established. These include microbial construction, plant construction, animal construction, and bioinspired construction. Examples of each component are given. A new construction system for creating a more eco-friendly, healthier, and more sustainable environment for future civil engineering developments is also proposed.
{"title":"Biogenic construction: The new era of civil engineering","authors":"Hanlong Liu","doi":"10.1016/j.bgtech.2024.100130","DOIUrl":"10.1016/j.bgtech.2024.100130","url":null,"abstract":"<div><div>With the increasing demand for buildings and infrastructures and the mounting challenges associated with the current construction technologies such as high emission, high pollution, and high energy consumption, the civil engineering profession is at the crossroad for a transformation or upgrading before it can be put into tasks for these challenges. Inspired by the concept of harmonious coexistence between humans and nature, a new concept, biogenic construction, for civil engineering is proposed in this paper. The definition of biogenic construction is given. The framework and four components of biogenic construction are established. These include microbial construction, plant construction, animal construction, and bioinspired construction. Examples of each component are given. A new construction system for creating a more eco-friendly, healthier, and more sustainable environment for future civil engineering developments is also proposed.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 1","pages":"Article 100130"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141842243","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}
Pub Date : 2025-03-01Epub Date: 2024-06-03DOI: 10.1016/j.bgtech.2024.100110
Yu Diao , Jitao Bai , Gang Zheng , Qingsong Hu , Pengjin Li , Xuanqi Liu , Wendi Hu , Jianyou Huang
With further investigation on biomineralization, biomimetic mineralization has been proposed in imitation of microorganism behavior, in which the mechanism of biomineralization is utilized for the control of the crystal growth to synthesize inorganic materials with special structures and superior physical-chemical properties. This review summarizes the recent advances in biomimetic-chemically induced carbonate precipitation (BCICP). BCICP is a biomimetic mineralization process induced by calcium carbonate crystal modifiers, which directly regulates the metathesis reaction of calcium salts with carbonates in soils to improve the soil properties. Several crystal modifiers for BCICP, including the aspartic acid (organic), the boric acid (inorganic), and the polyacrylic acid (polymer), are reviewed, and the biomimetic mineralization mechanism is introduced. In addition, current findings about BCICP in cementitious materials, soil reinforcement, dust suppression, as well as other fields are discussed, aiming to give deeper insights into the further development and application of BCICP.
{"title":"Development and optimization of biomimetic-chemically induced carbonate precipitation: A review of recent research","authors":"Yu Diao , Jitao Bai , Gang Zheng , Qingsong Hu , Pengjin Li , Xuanqi Liu , Wendi Hu , Jianyou Huang","doi":"10.1016/j.bgtech.2024.100110","DOIUrl":"10.1016/j.bgtech.2024.100110","url":null,"abstract":"<div><div>With further investigation on biomineralization, biomimetic mineralization has been proposed in imitation of microorganism behavior, in which the mechanism of biomineralization is utilized for the control of the crystal growth to synthesize inorganic materials with special structures and superior physical-chemical properties. This review summarizes the recent advances in biomimetic-chemically induced carbonate precipitation (BCICP). BCICP is a biomimetic mineralization process induced by calcium carbonate crystal modifiers, which directly regulates the metathesis reaction of calcium salts with carbonates in soils to improve the soil properties. Several crystal modifiers for BCICP, including the aspartic acid (organic), the boric acid (inorganic), and the polyacrylic acid (polymer), are reviewed, and the biomimetic mineralization mechanism is introduced. In addition, current findings about BCICP in cementitious materials, soil reinforcement, dust suppression, as well as other fields are discussed, aiming to give deeper insights into the further development and application of BCICP.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 1","pages":"Article 100110"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141279618","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}
Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids. Particularly, the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance. Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete. This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection, thus enhancing the performance and durability of concrete blocks. Enzyme induced carbonate precipitation (EICP) is one of the promising bio-cement methods. Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media. The treated blocks were tested for water absorption, ultrasonic pulse velocity (UPV) measurements, unconfined compressive strength (UCS), thermal performance, and scanning electron microscopy (SEM). The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55% reduction in water absorption, a 15% higher UCS and a 6.7% higher UPV when compared with control blocks. The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete. Although most of the posttreatment strategies investigated herein were found to be operative, a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media (CM). With the successful demonstration, the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.
{"title":"Evaluating the performance and durability of concrete paving blocks enhanced by bio-cement posttreatment","authors":"Navaratnam Rathivarman , Sivakumar Yutharshan , Alakenthiran Kabishangar , Vignarajah Janani , Sivakumar Gowthaman , Thiloththama Hiranya Kumari Nawarathna , Meiqi Chen , Satoru Kawasaki","doi":"10.1016/j.bgtech.2024.100103","DOIUrl":"10.1016/j.bgtech.2024.100103","url":null,"abstract":"<div><div>Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids. Particularly, the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance. Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete. This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection, thus enhancing the performance and durability of concrete blocks. Enzyme induced carbonate precipitation (EICP) is one of the promising bio-cement methods. Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media. The treated blocks were tested for water absorption, ultrasonic pulse velocity (UPV) measurements, unconfined compressive strength (UCS), thermal performance, and scanning electron microscopy (SEM). The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55% reduction in water absorption, a 15% higher UCS and a 6.7% higher UPV when compared with control blocks. The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete. Although most of the posttreatment strategies investigated herein were found to be operative, a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media (CM). With the successful demonstration, the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 1","pages":"Article 100103"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722190","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}
Pub Date : 2025-03-01Epub Date: 2024-07-25DOI: 10.1016/j.bgtech.2024.100121
Zhengjun Mao , Xu Ma , Mimi Geng , Munan Wang , Guangsheng Gao , Yanshan Tian
Repeated wet swelling and dry shrinkage of soil leads to the gradual occurrence of cracks and the formation of a complex fracture network. In order to study the development characteristics and quantitative analysis of cracks in root-soil complex in different growth periods under dry-wet cycles, the alfalfa root-loess complex was investigated during different growth periods under different dry-wet cycles, and a dry-wet cycle experiment was conducted. The crack rate, relative area, average width, total length, and the cracks fractal dimension in the root-soil complex were extracted; the crack development characteristics of plain soil were analyzed under the PG-DWC (dry-wet cycle caused by plant water management during plant growth period), as well as the crack development characteristics of root-soil complex under PG-DWC and EC-DWC (the dry-wet cycles caused by extreme natural conditions such as continuous rain); the effects of plant roots and dry-wet cycles on soil cracks were discussed. The results showed that the average crack width, crack rate, relative crack area, and total crack length of the alfalfa root-loess complex were higher than those of the plain soil during PG-DWC. The result indicated that compared with plain soil during PG-DWC, the presence of plant roots in alfalfa root-soil complex in the same growth period promoted the cracks development to some extent. The alfalfa root-soil complex crack parameters during different growth periods were relatively stable during PG-DWC (0 dry-wet cycle). During EC-DWC (1, 3, and 5 dry-wet cycles), the alfalfa root-loess complex crack parameters increased with the number of dry-wet cycles during different growth periods. Unlike PG-DWC, the EC-DWC accelerated crack development, and the degree of crack development increased with the number of dry-wet cycles. The existence of plant roots promoted crack development and expansion in the root-soil complex to a certain extent, and the dry-wet cycle certainly promoted crack development and expansion in the root-soil complex. This result contradicts the improvement in the root-soil complex's macro-mechanical properties during plant growth, due to differences in the mechanical properties of roots and soil. The research results will provide reference for the root soil complex crack development law and the design of slope protection by vegetation.
{"title":"Development characteristics and quantitative analysis of cracks in root-soil complex during different growth periods under dry-wet cycles","authors":"Zhengjun Mao , Xu Ma , Mimi Geng , Munan Wang , Guangsheng Gao , Yanshan Tian","doi":"10.1016/j.bgtech.2024.100121","DOIUrl":"10.1016/j.bgtech.2024.100121","url":null,"abstract":"<div><div>Repeated wet swelling and dry shrinkage of soil leads to the gradual occurrence of cracks and the formation of a complex fracture network. In order to study the development characteristics and quantitative analysis of cracks in root-soil complex in different growth periods under dry-wet cycles, the alfalfa root-loess complex was investigated during different growth periods under different dry-wet cycles, and a dry-wet cycle experiment was conducted. The crack rate, relative area, average width, total length, and the cracks fractal dimension in the root-soil complex were extracted; the crack development characteristics of plain soil were analyzed under the PG-DWC (dry-wet cycle caused by plant water management during plant growth period), as well as the crack development characteristics of root-soil complex under PG-DWC and EC-DWC (the dry-wet cycles caused by extreme natural conditions such as continuous rain); the effects of plant roots and dry-wet cycles on soil cracks were discussed. The results showed that the average crack width, crack rate, relative crack area, and total crack length of the alfalfa root-loess complex were higher than those of the plain soil during PG-DWC. The result indicated that compared with plain soil during PG-DWC, the presence of plant roots in alfalfa root-soil complex in the same growth period promoted the cracks development to some extent. The alfalfa root-soil complex crack parameters during different growth periods were relatively stable during PG-DWC (0 dry-wet cycle). During EC-DWC (1, 3, and 5 dry-wet cycles), the alfalfa root-loess complex crack parameters increased with the number of dry-wet cycles during different growth periods. Unlike PG-DWC, the EC-DWC accelerated crack development, and the degree of crack development increased with the number of dry-wet cycles. The existence of plant roots promoted crack development and expansion in the root-soil complex to a certain extent, and the dry-wet cycle certainly promoted crack development and expansion in the root-soil complex. This result contradicts the improvement in the root-soil complex's macro-mechanical properties during plant growth, due to differences in the mechanical properties of roots and soil. The research results will provide reference for the root soil complex crack development law and the design of slope protection by vegetation.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 1","pages":"Article 100121"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839789","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}
Pub Date : 2025-03-01Epub Date: 2024-10-22DOI: 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 Dr and total unit weight γt) 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 Dr and total unit weight γt) 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.
{"title":"Physical property of MICP-treated calcareous sand under seawater conditions by CPTU","authors":"Kemeng Yu, Yuling Ran, Jie Shi, Menglan Duan, Zhongkun Ouyang","doi":"10.1016/j.bgtech.2024.100131","DOIUrl":"10.1016/j.bgtech.2024.100131","url":null,"abstract":"<div><div>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 <em>D</em><sub>r</sub> and total unit weight <em>γ</em><sub>t</sub>) 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 <em>D</em><sub>r</sub> and total unit weight <em>γ</em><sub>t</sub>) 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.</div></div>","PeriodicalId":100175,"journal":{"name":"Biogeotechnics","volume":"3 1","pages":"Article 100131"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722192","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号