The Yangtze Three Gorges Project (TGP) is the key backbone project to develop and harness the Yangtze river in China. As the largest water conservancy project in the world with the earth and rock excavation amounting ...The Yangtze Three Gorges Project (TGP) is the key backbone project to develop and harness the Yangtze river in China. As the largest water conservancy project in the world with the earth and rock excavation amounting up to 102.83×10 6 m 3, it is, therefore, the largest project on a scale of geomechanical engineering. The involvement of numerous domestic and foreign research institutes in the scientific research has promoted the development of geomechanics. Some rock and soil mechanical issues arising during construction of the Three Gorges Project are discussed in this article.展开更多
In recent years, with the rapid development of China's economy and the acceleration of the urbanization process, the demand for infrastructure construction has become higher and higher, thus ensuring the sustainab...In recent years, with the rapid development of China's economy and the acceleration of the urbanization process, the demand for infrastructure construction has become higher and higher, thus ensuring the sustainable development of the national economy and the circulation of commodities. Therefore, the construction quality of soft foundation is an important factor affecting the quality of highway bridge engineering in our country. Soft foundation is an important potential safety hazard in highway and bridge construction. Its water content is above 70%, and it has low foundation bearing capacity, permeability, compressibility, viscosity and other characteristics. If not paid attention to in the construction process, it will not only affect the overall use effect of the project, but also cause uneven settlement, instability, collapse and other problems, causing serious consequences. Therefore, it is necessary to adopt appropriate technical measures in highway, bridge and other projects. Therefore, in highway bridge construction, technical personnel should strengthen the control of the soft soil foundation in time, understand the influence of the current soft soil foundation on the bridge structure from the perspective of soft soil foundation treatment, fully understand the engineering requirements, and master the technical key points of construction at the same time, improve the construction treatment technology of the soft soil foundation of the road bridge, and guarantee the construction quality. In order to further improve the quality of highway and bridge construction, the feasibility analysis scheme of soft foundation reinforcement technology is formulated. Based on the characteristics of soft foundation and the problems in construction technology, this paper discusses its specific application.展开更多
Nanoparticles ( 100 nm) are becoming more prevalent in residential and industrial uses and may enter the environment through wastewater. Although lab studies have shown that nanoparticles can be toxic to various organ...Nanoparticles ( 100 nm) are becoming more prevalent in residential and industrial uses and may enter the environment through wastewater. Although lab studies have shown that nanoparticles can be toxic to various organisms, limited research has been done on the effects of nanoparticles in the environment. Environmental conditions such as pH and ionic strength are known to alter the biotoxicity of nanoparticles, but these effects are not well understood. The objectives of this research were to determine the impacts of silver nanoparticles (AgNP) on zebrafish in the pseudo-natural environment of a lab-scale constructed wetland, and to investigate wastewater remediation through soil and water treatment residual (WTR) adsorption of AgNPs. Concurrently, the effect of particle size on AgNP sorption was examined. Researchers exposed adult zebrafish in a lab-scale constructed wetland to concentrations of AgNP ranging from 0 - 50 mg AgNP/L and compared them to negative controls with no silver exposure and to positive controls with exposure to silver nitrate. The results suggest that aggregated AgNP do not impact zebrafish. Separately, sorption experiments were carried out examining three media - a wetland soil, a silt loam soil, and a WTR - in their capacity to remove AgNPs from water. The silt loam retained less AgNPs from solution than did the wetland soil or the WTR. In the WTR AgNPs were associated with sand size particles (2 mm - 0.05 mm), but in the wetland soil and silt loam, approximately half of the AgNPs were associated with the sand-sized particles, while the rest were associated with silt sized (~0.05 mm) or smaller particles. The larger sorption capacity of the wetland soil and WTR was attributed to their higher carbon content. The sorption data indicate that AgNPs adsorbed to soil and WTRs and support the idea that natural and constructed wetlands can remove AgNPs from wastewater.展开更多
To treat the relationship between project construction and ecological environment and effectively prevent new soil erosion during the construction, according to the project layout, soil erosion distribution as well as...To treat the relationship between project construction and ecological environment and effectively prevent new soil erosion during the construction, according to the project layout, soil erosion distribution as well as natural and socio-economic conditions, the control measures of newly increased soil erosion along the project were carried out based on site survey and analysis of relevant information. In addition, adhering to the prin- ciple of partition prevention and treatment, some guiding prevention and control measures of the natural zone passed by the project and soil erosion control district were determined, which provided scientific references and technical support for the rational layout of water and soil conservation and ecological restoration measures in Dina 2 gas field.展开更多
Plenty of inorganic nitrogen in wastewater can cause the eutrophication in water bodies, so it is an important task to remove nitrogen. Purification role was realized by absorption, filtration, depositon, evaporation,...Plenty of inorganic nitrogen in wastewater can cause the eutrophication in water bodies, so it is an important task to remove nitrogen. Purification role was realized by absorption, filtration, depositon, evaporation, nitrification and denitrification of microbes. Although the studies of Phragmites austrilis bed in the constructed wetland are popular, the purification performances of constructed wetland filled by saline-alkali soil substrate are less reported. In the paper, the purification efficiency of nitrogen with Phragmites austrilis bed in the constructed wetland filled by saline-alkali soil substrate was discussed through a simulation study. Results to date indicated that the first order plug flow model was adequate to describe the nitrogen removal. The experiment showed that the diminishing concentration of TN, NO 2-N, NO 3-N, NH 4-N were closely related to hydrological retention time (HRT), the correlation coefficient was R 2=0.98499, R 2=0.9911, R 2=0.89407 and R 2=0.95459, respectively. According to the data, the most suitable hydrological retention time (HRT) for this kind of constructed wetland should be determined to 4 days. In addition, the experiment showed the purification efficiency of nitrogen has very broad range and drastic vibration, TN (17%-79%), NO 2-N (33%-98%), NO 3-N(13%-93%), NH 4-N (28%-64%). The study will promote wetland’s design and operation procedures in large saline-alkaline soil areas.展开更多
文摘The Yangtze Three Gorges Project (TGP) is the key backbone project to develop and harness the Yangtze river in China. As the largest water conservancy project in the world with the earth and rock excavation amounting up to 102.83×10 6 m 3, it is, therefore, the largest project on a scale of geomechanical engineering. The involvement of numerous domestic and foreign research institutes in the scientific research has promoted the development of geomechanics. Some rock and soil mechanical issues arising during construction of the Three Gorges Project are discussed in this article.
文摘In recent years, with the rapid development of China's economy and the acceleration of the urbanization process, the demand for infrastructure construction has become higher and higher, thus ensuring the sustainable development of the national economy and the circulation of commodities. Therefore, the construction quality of soft foundation is an important factor affecting the quality of highway bridge engineering in our country. Soft foundation is an important potential safety hazard in highway and bridge construction. Its water content is above 70%, and it has low foundation bearing capacity, permeability, compressibility, viscosity and other characteristics. If not paid attention to in the construction process, it will not only affect the overall use effect of the project, but also cause uneven settlement, instability, collapse and other problems, causing serious consequences. Therefore, it is necessary to adopt appropriate technical measures in highway, bridge and other projects. Therefore, in highway bridge construction, technical personnel should strengthen the control of the soft soil foundation in time, understand the influence of the current soft soil foundation on the bridge structure from the perspective of soft soil foundation treatment, fully understand the engineering requirements, and master the technical key points of construction at the same time, improve the construction treatment technology of the soft soil foundation of the road bridge, and guarantee the construction quality. In order to further improve the quality of highway and bridge construction, the feasibility analysis scheme of soft foundation reinforcement technology is formulated. Based on the characteristics of soft foundation and the problems in construction technology, this paper discusses its specific application.
文摘Nanoparticles ( 100 nm) are becoming more prevalent in residential and industrial uses and may enter the environment through wastewater. Although lab studies have shown that nanoparticles can be toxic to various organisms, limited research has been done on the effects of nanoparticles in the environment. Environmental conditions such as pH and ionic strength are known to alter the biotoxicity of nanoparticles, but these effects are not well understood. The objectives of this research were to determine the impacts of silver nanoparticles (AgNP) on zebrafish in the pseudo-natural environment of a lab-scale constructed wetland, and to investigate wastewater remediation through soil and water treatment residual (WTR) adsorption of AgNPs. Concurrently, the effect of particle size on AgNP sorption was examined. Researchers exposed adult zebrafish in a lab-scale constructed wetland to concentrations of AgNP ranging from 0 - 50 mg AgNP/L and compared them to negative controls with no silver exposure and to positive controls with exposure to silver nitrate. The results suggest that aggregated AgNP do not impact zebrafish. Separately, sorption experiments were carried out examining three media - a wetland soil, a silt loam soil, and a WTR - in their capacity to remove AgNPs from water. The silt loam retained less AgNPs from solution than did the wetland soil or the WTR. In the WTR AgNPs were associated with sand size particles (2 mm - 0.05 mm), but in the wetland soil and silt loam, approximately half of the AgNPs were associated with the sand-sized particles, while the rest were associated with silt sized (~0.05 mm) or smaller particles. The larger sorption capacity of the wetland soil and WTR was attributed to their higher carbon content. The sorption data indicate that AgNPs adsorbed to soil and WTRs and support the idea that natural and constructed wetlands can remove AgNPs from wastewater.
文摘To treat the relationship between project construction and ecological environment and effectively prevent new soil erosion during the construction, according to the project layout, soil erosion distribution as well as natural and socio-economic conditions, the control measures of newly increased soil erosion along the project were carried out based on site survey and analysis of relevant information. In addition, adhering to the prin- ciple of partition prevention and treatment, some guiding prevention and control measures of the natural zone passed by the project and soil erosion control district were determined, which provided scientific references and technical support for the rational layout of water and soil conservation and ecological restoration measures in Dina 2 gas field.
基金NortheastInstituteofGeographyAgriculturalEcology,CAS .(KZCX3 SW NA 13 )
文摘Plenty of inorganic nitrogen in wastewater can cause the eutrophication in water bodies, so it is an important task to remove nitrogen. Purification role was realized by absorption, filtration, depositon, evaporation, nitrification and denitrification of microbes. Although the studies of Phragmites austrilis bed in the constructed wetland are popular, the purification performances of constructed wetland filled by saline-alkali soil substrate are less reported. In the paper, the purification efficiency of nitrogen with Phragmites austrilis bed in the constructed wetland filled by saline-alkali soil substrate was discussed through a simulation study. Results to date indicated that the first order plug flow model was adequate to describe the nitrogen removal. The experiment showed that the diminishing concentration of TN, NO 2-N, NO 3-N, NH 4-N were closely related to hydrological retention time (HRT), the correlation coefficient was R 2=0.98499, R 2=0.9911, R 2=0.89407 and R 2=0.95459, respectively. According to the data, the most suitable hydrological retention time (HRT) for this kind of constructed wetland should be determined to 4 days. In addition, the experiment showed the purification efficiency of nitrogen has very broad range and drastic vibration, TN (17%-79%), NO 2-N (33%-98%), NO 3-N(13%-93%), NH 4-N (28%-64%). The study will promote wetland’s design and operation procedures in large saline-alkaline soil areas.
