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Quantitative Characterization of Macropore Structure of Granite Residual Soil QUE Yun, CAI Pei-chen, LI Xian Journal of Yangtze River Scientific Research Institute    2022, 39 (2): 82-88.   DOI: 10.11988/ckyyb.20200987 Abstract （250）      PDF（pc） （3094KB）（2392）       Knowledge map    Save In order to reveal the distribution law and shape characteristics of the macropore structure of granite residual soil, we quantified the round ratio, flatness, overall silhouette coefficient and fractal dimension of undisturbed granite residual soil in Fuzhou by using industrial CT scanning and ImageJ software. Our findings revealed that 1) over 80% of the macropores ranged 0.15-1 mm in diameter, and less than 20% of the macropores had a diameter greater than 1 mm. Ranging between 5.8%-22.7%, the macroporosity of granite residual soil first augmented and then reduced with the increase of soil depth. 2) Larger diameter of macropore resulted in a smaller round ratio. 3) The overall silhouette coefficient of four samples changed within 0.81-0.87, and such change attenuated with the increase of soil depth. 4) The macroporosity of granite residual soil is correlated with the fractal dimension; but the coefficients of such correlation of different samples varied distinctly. In summary, granite residual soil is of large porosity, small toughness, wide distribution of macropores, large difference in pore structure, and large dispersion of local pore flatness. Reference | Related Articles | Metrics | Comments（0）

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Identification and Physical Mechanical Property Comparison between Completely Decomposed Granite and Granite Residual Soil ZHOU Xiao-wen, LUO Xing-cai Journal of Yangtze River Scientific Research Institute    2022, 39 (4): 1-7.   DOI: 10.11988/ckyyb.20211331 Abstract （2092）      PDF（pc） （1853KB）（2326）       Knowledge map    Save Completely decomposed granite (CDG) and granite residual soil (GRS) are prone to trigger engineering accidents and geological disasters in South China. Despite that the weathering degree and engineering properties of CDG and GRS both vary remarkably, it is still a challenging task to distinguish CDG and GRS in practical geological investigation, in which the field geological appearance and the measured hit number of standard penetration test according to existing specification are taken as the major indicators for identification. In this paper, we discussed the relevant clauses about identifying CDG and GRS in some current specifications. In view of the difference in gradation between of CDG and GRS, i.e., the former is usually clayey sand, while the latter sand clay, we suggest to take grading characteristic as the subsidiary index of identifying CDG and GRS.According to physical properties test and triaxial shear test of soil samples from a foundation pit, we found that GRS sample had a larger pore ratio with a poor gradation lack of some intermediate particle sizes. Both the undisturbed CDG and GRS present initial structural features reflected by shear zone with strain localization in shear deformation, displaying drum-shear zone failure mode; the remolded samples present a standard drum-like failure mode. The friction angle of drainage shear of undisturbed CDG is slightly higher than that of GRS, and the cohesion obviously higher as CDG boasts a stronger structure; the cohesion of remolded CDG and remolded GRS are close due to the lack of original structure. Under low confining pressure, the structural strength of undisturbed soils contribute up to 60%-70% of the total shear strength, and the compression action of high confining pressure can completely destroy the initial structure of soils, in which case the structural strength will be eliminated. Reference | Related Articles | Metrics | Comments（0）

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Method of Three-dimensional Monitoring on Permafrost around Lake Draining Project on the Qinghai-Tibetan Plateau LANG Yong-biao, ZHENG Yun, JIN Wei, MU Yan-hu, CHAI Ming-tang Journal of Yangtze River Scientific Research Institute    2021, 38 (6): 45-51.   DOI: 10.11988/ckyyb.20200214 Abstract （276）      PDF（pc） （2374KB）（1877）       Knowledge map    Save Affected by climate warming and wetting, the number and area of lakes in the Qinghai-Tibetan Plateau have seen evident increases in recent years, resulting in lake overflow and even outbursts. Such threats to the security of lives and property of people and the safe operation of major engineering infrastructure can be alleviated by lake drainage project which diverts the overflow safely under control to the downstream area. However, in permafrost region, engineering activities and long-term water flow will lead to significant variations in hydrothermal regime. These variations will further affect local ecological environment and long-term stability of drainage projects. With the Yanhu Lake in Hoh Xil region as a background, we present a method combing InSAR, drone aerial photography, meteorological observation, ground temperature observation and geophysical exploration to establish a three-dimensional monitoring system on permafrost. The method considers the characteristics of permafrost in the region and the components of the drainage project. By using the present method, we could monitor synchronously the local meteorological conditions, the hydrothermal regimes of permafrost, and the stability of engineering structures. The monitoring work will provide data support for evaluating the impacts of drainage project on permafrost, and serve for prediction and early warning on the stability and service ability of engineering structures. The collected data will also offer important references for design, construction and maintaining of hydraulic infrastructure built on permafrost in the future. Reference | Related Articles | Metrics | Comments（0）

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Research Advances in River Evolution and Ecological Regulation in the Downstream of the Three Gorges Reservior YAO Shi-ming, HU Cheng-wei, QU Geng Journal of Yangtze River Scientific Research Institute    2021, 38 (10): 16-26.   DOI: 10.11988/ckyyb.20210586 Abstract （323）      PDF（pc） （2236KB）（1698）       Knowledge map    Save Under the influences of natural conditions and human activities, the downstream rivers of the Three Gorges Reservior have been experiencing changes in flow and sediment conditions and river evolution, which in the meantime pose new demands for flood risk management, navigation, electricity generation, water supply and ecology. It is urgent to investigate the mechanisms underlying the water and sediment transport and river evolution in the downstream of the Three Gorges Reservior, and develop novel ecological regulation technologies, by which to promote the fusions of river regulation and ecology protection. In this paper we make a review on previous studies of water and sediment transport, river evolution, and ecological regulation in the downstream of Three Gorges Reservior. In view of the deficiencies of current studies, we put forward the direction and contents of future research: the spatio-temporal variation trend of water and sediment in the downstream channel of the Three Gorges Reservior, the interaction between the reconstruction of different river types and water-sediment transport, the habitat restoration technology for damaged river bank, the ecological reconstruction technology for embankment, and the eco-friendly methods and technologies for river regulation. Reference | Related Articles | Metrics | Comments（0）

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Research and Application of Intelligent Perception and Intelligent Management Technology for Dam Safety Monitoring HUANG Yue-wen, NIU Guang-li, LI Duan-you, HAN Xiao, ZHOU Hua-yan Journal of Yangtze River Scientific Research Institute    2021, 38 (10): 180-185.   DOI: 10.11988/ckyyb.20210589 Abstract （725）      PDF（pc） （1950KB）（1552）       Knowledge map    Save Monitoring on reservoir and dam safety is an important guarantee for the safe operation of project. It is urgent to improve the ability of dam safety monitoring by using the new generation of information technology. In this paper we systematically summarize the researches and applications made by Changjiang (Yangtze) River Research Institute in intelligent perception and intelligent management technology of dam safety monitoring in recent years. We built a unified data resource pool for dam safety monitoring by developing a series of intelligent sensors, intelligent acquisition units and Internet of things sensing platform, and developed a generalized safety monitoring cloud service system. We also built professional data mining platform and comprehensive visualization application to realize the full link application of data perception, transmission, management, analysis and display for dam safety monitoring, forming a full life cycle intelligent solution for dam safety monitoring. The research achievements have been applied in more than 100 water conservancy and hydropower projects, such as Wudongde, Xiluodu, Xiangjiaba and Datengxia hydropower stations, playing an important supporting role in ensuring the safety of project construction and operation. Reference | Related Articles | Metrics | Comments（0）

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Microplastic Pollution in the Yangtze River Basin: Status Quo and Control Measures LI Tian-cui, HUANG Xiao-long, WU Chen-xi, GUO Wen-si Journal of Yangtze River Scientific Research Institute    2021, 38 (6): 143-150.   DOI: 10.11988/ckyyb.20210057 Abstract （532）      PDF（pc） （1122KB）（1545）       Knowledge map    Save Microplastic pollution has attracted worldwide attention. The previous reports of microplastics pollution in the Yangtze River basin are summarized, and the spatial distribution and pollution characteristics are analyzed. Moreover, the adverse impacts of microplastics pollution in the Yangtze River basin are discussed, and corresponding prevention and control measures are put forward. Microplastics pollution in the Yangtze River is highly heterogeneous in spatial scale, with the abundance of microplastics in surface water ranging from tens to tens of thousands of ind/m3 and tens to tens of thousands of ind/kg in sediments. Compared with other basins in China and abroad, the Yangtze River Basin is subjected to a medium and low pollution level of microplastics, and the abundance of microplastics in lakes and reservoirs is generally higher than that in rivers. In addition, microplastics in water are mainly polyester, polyethylene and polypropylene, and fibers, fragments and films are dominant shapes. In the Yangtze River basin, the abundance of microplastics increased gradually from the upper reaches to the lower reaches, and from bank to ashore. To control microplastic pollution in the Yangtze River basin, laws and regulations need to be improved, sewage treatment capacity and management and disposal of plastic waste should be enhanced. Reference | Related Articles | Metrics | Comments（0）

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Latest Progress and Prospect of Technology on Control Equipment for Hydropower Units by Yangtze River Scientific Research Institute PAN Xi-he, HUANG Ye-hua, NIE Wei, FANG Bin-chen, YAN Guo-qiang, CHENG Yuan-chu Journal of Yangtze River Scientific Research Institute    2021, 38 (10): 192-198.   DOI: 10.11988/ckyyb.20210636 Abstract （242）      PDF（pc） （1465KB）（1461）       Knowledge map    Save At present, China’s hydropower industry has entered a new stage of high-quality development. In this paper we made a review on the technical status in two professional fields, namely, turbine governor and synchronous motor excitation. We introduced the progresses made in control theory research and regulation mode of special turbine, and expounded the main technical characteristics of dual-core excitation regulator. Moreover, we summarized the major achievements of Changjiang (Yangtze) River Scientific Research Institute in technology innovation, product innovation and industry standard formulation for hydropower unit control equipment in the past decade, and looked into the prospect of hydroturbine governor and synchronous motor excitation technology to make greater contribution to carbon peak and carbon neutrality goals. Hydroturbine governor and synchronous motor excitation should be autonomous and controllable, and must be improved in terms of reliability and intelligence. Reference | Related Articles | Metrics | Comments（0）

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Research on the Influence of Permeability on Deformation of Gravel Subgrade by a Hypoplastic Constitutive Model SUN Zi-yuan, TANG Yang, ZHAO Jian-yong, FAN Xuan Journal of Yangtze River Scientific Research Institute    2021, 38 (6): 86-92.   DOI: 10.11988/ckyyb.20200297 Abstract （208）      PDF（pc） （2838KB）（1414）       Knowledge map    Save It is an important premise of evaluating the stability of embankment foundation to analyze accurately the changes of internal structure and parameters of gravel soil materials under the action of permeability. With the crushing rock aggregates of limestone at Shuibuya project as the parent material, we prepared three groups of specimens with varied compactness by sieving test and compaction test. Through permeability deformation test, we investigated the effect of permeability on the loss of fine particles in the gravel soil and the permeability-induced deformation. By large scale triaxial test, we obtained the changes in strength and deformation parameters of gravel soil before and after extreme permeability action. Furthermore, we embedded the hypoplastic constitutive model into ABAQUS software to describe the stress-strain relationship of gravel soil before and after particle loss and calculated the settlement deformation before and after particle loss. The results can be used as reference for the engineering design for embankment foundation and calculation for permeability deformation. Reference | Related Articles | Metrics | Comments（0）

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Causes of Excessive Arsenic in Groundwater of Kuitun River Basin in Xinjiang SU Yan-peng, LI Qiao, TAO Hong-fei, HE Yu-jiang, LI Xian-wen, AIHEMAITI Mahemujiang Journal of Yangtze River Scientific Research Institute    2022, 39 (3): 54-59.   DOI: 10.11988/ckyyb.20201188 Abstract （1019）      PDF（pc） （1842KB）（1413）       Knowledge map    Save Kuitun River Basin in Xinjiang is the first endemic arsenic poisoned area in mainland China. The causes of excessive arsenic in the groundwater in Kuitun River Basin have not been clarified due to human activities and natural conditions. In the present research, we analyzed the main and trace element components in 51 groups of surface water and groundwater samples collected in 2017, as well as the particle size and chemical composition of 44 groups of sediment samples from two boreholes in typical high arsenic content area in 2019. Results unveiled that the concentration of arsenic in groundwater of Kuitun River Basin ranged from 10-887 μg/L, averaging 55.8 μg/L, and in sediment reaching 28.41 mg/kg to the maximum, which exceeded the standard (10 μg/L) largely. Siderite, calcium arsenate, manganese arsenate and other minerals distributed in the surrounding mountainous areas provided material sources for the excessive arsenic concentration in groundwater; strong evaporation and rock weathering further aggravated the arsenic concentration in groundwater; high pH and low Eh values of groundwater caused arsenate to desorb from the mineral surface and accumulate in groundwater. The reduction process of Fe/Mn oxide minerals in sediments and clay minerals released the coexisting arsenic, which is also the reason why arsenic in groundwater exceeded standard. Reference | Related Articles | Metrics | Comments（0）

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Hydrologic Cycle in the Source Area of Yangtze River: Research Status and Existing Problems CHANG Fu-xuan, HONG Xiao-feng Journal of Yangtze River Scientific Research Institute    2021, 38 (7): 1-6.   DOI: 10.11988/ckyyb.20201035 Abstract （361）      PDF（pc） （4760KB）（1399）       Knowledge map    Save Located in the hinterland of Qinghai-Tibet Plateau, the source region of the Yangtze River is featured with high altitude, low temperature, and harsh natural conditions. As a result, with the lack of hydrometeorological monitoring and basic data, study on the hydrological cycle in this region is inadequate. In this paper, the status of researches and observations of hydrologic cycle in the source region of Yangtze River is reviewed, and existing problems and challenges are expounded. First of all, the monitoring data could not meet research requirements due to insufficient monitoring stations and their unreasonable locations as well as difficulties in operating and maintaining equipment in such unfavorable circumstances. Research on the mechanism of hydrologic cycle needs to be deepened. Such mechanism involves the trend of water resources variation, runoff of underlying surface, groundwater transport, and etc. Moreover, the structure of hydrological simulation models should be enhanced, and the applicability and versatility await verification. Measures to tackle these problems are presented as follows: monitoring stations and platforms need to be upgraded by collaborative efforts from multi-departments and trans-disciplines; international corporation in scientific research can be intensified; information service and social benefits should be taken into consideration; prototype observation and fundamental theoretical research need to be improved. Innovations should also boost in terms of observation approach, atmospheric-solid-liquid water conversion, water balance, hydro-thermal coupling, hydrologic models for alpine area, as well as global climate change impact. Reference | Related Articles | Metrics | Comments（0）

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Research Progress on Mechanism of River Bank Collapse LÜ Qing-biao, ZHU Yong-hui, XIE Ya-guang, YUE Hong-yan Journal of Yangtze River Scientific Research Institute    2021, 38 (9): 7-13.   DOI: 10.11988/ckyyb.20200518 Abstract （285）      PDF（pc） （5637KB）（1396）       Knowledge map    Save On the basis of previous research results of river bank collapse, we reviewed the classifications of bank collapse types, summarized the influencing factors of river bank collapse into three categories inclusive of flow condition, river boundarycondition, and other factors. We further concluded the research progress of river bank collapse from aspects of numerical simulation and generalized model test. Furthermore, we analyzed and discussed the deficiencies of current research on the mechanism of river bank collapse. Such deficiencies are: factors are not considered comprehensively enough; numerical technologies lack perfection; and the accuracy of generalized model needs to be improved. Last but not the least, we put forward the key points and suggestions for future research work. Reference | Related Articles | Metrics | Comments（0）

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Salt Expansion and Frost Heave in Cooling Sulfate Saline Soil YING Sai, ZHOU Feng-xi, WEN Tao, WANG Shi-ji, CAO Ya-peng Journal of Yangtze River Scientific Research Institute    2021, 38 (6): 116-122.   DOI: 10.11988/ckyyb.20200358 Abstract （312）      PDF（pc） （1439KB）（1379）       Knowledge map    Save The aim of this study is to explore the connection between salt expansion and frost heave in cooling sulfate saline soil. Freezing deformation tests are conducted on sulfate saline soil samples to examine the variations of salt expansion and frost heave of soil under varying water and salt content. The salt expansion and frost heave are controlled by changing the water content and salt content in the freezing process. Freezing temperature is set as the demarcation point identifying between salt expansion and frost heave. Results reveal a duplicate effect between salt expansion and frost heave in the freezing process, i.e. there is no positive correlation between total deformation of samples and crystalline volume. Total deformation obeys the law of the balance of power between salt expansion and frost heave, which means that total deformation reaches the minimum when salt expansion deformation equals frost heave deformation. The curve between total deformation and ratio of salt expansion displays an M-shape. The research findings are of active significance for further understanding the mechanism, building models, and hazard prevention of salt expansion and frost heave. Reference | Related Articles | Metrics | Comments（0）

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Typical Pollutants in Waters along the Riverbank of the Yangtze River Middle Mainstream: Species Identification and Source Analysis TANG Hai-bin, DAI Yan-ran, FAN Yao-cheng, LEI Lei, SONG Xiao-yong, CUN De-shou, HAN Jian, LIANG Wei Journal of Yangtze River Scientific Research Institute    2021, 38 (6): 151-159.   DOI: 10.11988/ckyyb.20210067 Abstract （413）      PDF（pc） （2238KB）（1344）       Knowledge map    Save To identify the major pollutants in the surface waters along the riverbank of the Yangtze River middle mainstream and explore their temporal and spatial distribution, we conducted a survey on five typical types of riverbanks which have been exploited for agriculture and fishery, industrial production, port logistics, river crossing transportation, and urban living. We selected Yichang, Wuhan, and Huangshi in the middle mainstream of the Yangtze River as three representative segments. According to the Environmental Quality Standard for Surface Water (GB 3838—2002) and the Standard for Drinking Water Quality (GB 5749—2006), we found that the main pollutants were total nitrogen (TN), total phosphorus (TP), ammonia nitrogen (NH3-N), iron (Fe) and manganese (Mn). All the monitored pollutants presented a similar pattern of spatial variation, with the lowest annual mean concentration in Wuhan and the highest in Yichang. However, the temporal variations in conventional pollutants and heavy metals were different. For the conventional pollutants, the lowest mean concentration was found in summer while the highest value was in autumn. For heavy metals, the relatively higher concentrations were observed in autumn and winter, whereas the lower value was in spring. Along the middle mainstream of the Yangtze River, the riverbank exploited for urban living suffered from the most severe pollution, with annual mean concentrations of TN, TP, NH3-N, Fe and Mn across the three segments amounting to 11.58, 0.83, 5.83 mg/L, 351.67 , 147.66 μ g/L respectively, which exceeded the standard by 11.58, 4.15, 5.85, 1.17, and 1.48 folds. A total of 8 kinds of pyrethroid pesticides, 33 kinds of organophosphorus pesticides and 12 kinds of organochlorine pesticides were detected in the surface water along the agriculture and fishery riverbank. Besides, 13 polycyclic aromatic hydrocarbons (PAHs) were detected along the riverbank exploited for industrial production, with tetramethrin, tetraethyl pyrophosphate (TEPP), 4.4′- dichlorodiphenyltrichloroethane (DDT), and indeno (1, 2, 3-cd) pyrene as the major compositions, yet all lower than standard. The results of sources apportionment of PAHs showed that the PAHs stemmed from wood, coal and a small amount of oil. These research findings would contribute to the rational development and structural optimization of riverbanks, and better protecting the Yangtze River with providing useful data. Reference | Related Articles | Metrics | Comments（0）

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Research Status and Progress of Cohesive Sediment Flocculation LI Jie, YANG Wen-jun, JING Si-yu, CHEN Yue Journal of Yangtze River Scientific Research Institute    2022, 39 (4): 8-13.   DOI: 10.11988/ckyyb.20201353 Abstract （303）      PDF（pc） （1207KB）（1341）       Knowledge map    Save Study on the flocculation mechanism of cohesive sediment is of great significance to the treatment of deposition in estuaries, reservoirs and waterways and water environment protection. In this paper, we made a review on the equipment and methods used in numerical simulation, field observation and laboratory experiment of cohesive sediment flocculation, and also expounded the research achievements of sediment flocculation under the influences of turbulent shear rate, salinity, suspended sediment concentration and organic matters. Researches in the following fields are still inadequate: three-dimensional observation of floc structure, in-situ observation of flocculation in high-concentration water, sediment flocculation influenced by multi-factor, and the quantitative relation between flow turbulence structure and flocculation characteristics. Researches need to be strengthened in the following aspects: developing flocculation observation device; quantifying the corresponding relation between flow turbulence structure and flocculation characteristics; multi-factor coupling experiment; and three-dimensional structure observation of floc. Reference | Related Articles | Metrics | Comments（0）

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Influence of Freeze-Thaw Cycles on Mechanical Properties and Fracture Evolution of Cement-Soil SUN Tao Journal of Yangtze River Scientific Research Institute    2021, 38 (8): 127-132.   DOI: 10.11988/ckyyb.20200485 Abstract （236）      PDF（pc） （4563KB）（1335）       Knowledge map    Save In the aim of understanding the changes of cement-reinforced silty soft soil under freeze-thaw cycles, we conducted triaxial compression tests, CT scanning, and SEM scanning on cement-soil specimens undergone 0-10 times of cyclic freezing and thawing to examine the mechanical properties and microstructural damage of soil specimens. Results revealed that the stress-strain curves of cement-soil displayed strain hardening features. With the increase of freeze-thaw cycles, the cohesion and internal friction angle shrank in exponential and linear trends, respectively. Binary results of CT scanning images manifested that the crack rate rose exponentially with the increase of freeze-thaw cycles. During cyclic freezing and thawing, the change of fracture rate synchronized with those of strength indicators. Moreover, from SEM scanning we observed losses of cementitious agents in the cement-soil and decay of compactness among particles, which led to the expansion of cracks and degradation of mechanical properties. Reference | Related Articles | Metrics | Comments（0）

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Risk Assessment of Water Diversion Tunnel Collapse Based on Entropy Theory and Extension Cloud Model LI Yan, JIN Chun-ling, GONG Li, TIAN Jie, ZHU Gui-yong Journal of Yangtze River Scientific Research Institute    2022, 39 (2): 70-76.   DOI: 10.11988/ckyyb.20201177 Abstract （209）      PDF（pc） （3825KB）（1323）       Knowledge map    Save The aim of this research is to effectively prevent water diversion tunnel from collapse during construction. According to previous research results and engineering practice, an index system for assessing the collapse risk of water diversion tunnel was established. The preference ratio method (PRM) and anti-entropy weight (AEW) were employed to analyze the weight of each index factor. Moreover, in consideration of the uncertainty of risk factors and the fuzziness of assessment rating, a risk assessment model for diversion tunnel collapse was constructed based on entropy theory and extension cloud model. The collapse risks of nine typical segments of the single line diversion tunnel of Dongguan branch in the Pearl River Delta water resources allocation project were assessed as case study. Results demonstrated that: the collapse risk level of diversion tunnel GS19+590-GS20+050, GS20+050-GS21+340, GS22+226-GS22+553 and GS24+911-GS26+035 segments was grade II, implying moderate risk; the risk level of GS21+340-GS22+226,GS22+553-GS23+788,GS23+788-GS24+911,GS26+035-GS27+700, and GS27+700-GS28+061 segments is grade III, indicating high risk. The assessment results are consistent with the actual situation of the project, which verifies the practicability and effectiveness of the method in tunnel collapse risk assessment. Reference | Related Articles | Metrics | Comments（0）

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Application of Vertical Penetration Stratified Sampling Technique in Liquid-Plastic Limit Combined Testing XUE Kai-xi, ZHOU Chao-hui, TIAN Xing-hua, DUO Hui-hui, DING Chen, CAO Kai, QI Xiao-hong Journal of Yangtze River Scientific Research Institute    2022, 39 (1): 114-121.   DOI: 10.11988/ckyyb.20200939 Abstract （241）      PDF（pc） （1431KB）（1313）       Knowledge map    Save In geotechnical engineering practice, the specific classification of a clay soil is generally determined by measuring its liquidity and plasticity index, and the basic engineering properties of the soil are determined accordingly. However, the liquid-plasticity limit (LPL) method recommended in the Standard for Geotechnical Test Methods (GB/T 50123—2019) has some shortcomings as the soil samples produced by the method differ significantly in dry density, which makes the data points obtained during the test discrete in the double logarithmic coordinate axis. In this paper, a new test method, the vertical penetration stratified sampling liquid-plastic limit joint test method, is developed by improving the liquid-plastic limit joint test method recommended in the national standard. The proposed method is more rigorous in the preparation of soil samples and shows a good linear relationship on the double logarithmic axis. The boundary moisture content of four soil samples, namely, reticulated red soil, brown caliche, silt loam and tidal soil, is tested in house to verify the uniformity of dry density and the richness of moisture content distribution levels of the prepared samples. Comparison between the proposed method and standard-recommended method as well as plate shear test result further verify the rationality of the present method. Reference | Related Articles | Metrics | Comments（0）

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Developments of Rock Mechanics in Hydraulic Engineering and Their Applications by Yangtze River Scientific Research Institute WU Ai-qing Journal of Yangtze River Scientific Research Institute    2021, 38 (10): 104-111.   DOI: 10.11988/ckyyb.20210677 Abstract （349）      PDF（pc） （1228KB）（1310）       Knowledge map    Save Based on the achievements of the rock mechanics major by professionals in Changjiang (Yangtze) River Scientific Research Institute in the past decade, this paper presents a review on the new developments of rock mechanics in hydraulic engineering and their applications. The contents include: fundamental theories and numerical methods, testing methods and technologies for rock mechanics, geo-stress measurement technique and methods for stress field simulations,geophysical and advanced detection technologies for rock masses,anchor support and reinforcement technologies for rock masses and structures, and their applications and practices in rock engineering. The forthcoming challenges in terms of understanding, utilizing and reinforcing rock masses in the profession of rock mechanics in hydraulic engineering are also expounded. The core issues of future research include: nonlinear properties of rock mechanics, continuous-discontinuous media mechanics, evaluation of cross-scale mechanical properties,multi-field coupling,and rock mechanics under dynamic conditions of high seismic intensity, etc. Reference | Related Articles | Metrics | Comments（0）

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Scientific Research of Water and Soil Conservation in the Yangtze River Basin:Retrospect and Prospect LIU Ji-gen, DING Wen-feng, HUANG Jin-quan Journal of Yangtze River Scientific Research Institute    2021, 38 (10): 54-59.   DOI: 10.11988/ckyyb.20210678 Abstract （302）      PDF（pc） （1293KB）（1307）       Knowledge map    Save Since the 1980s, notable progress has been made in scientific research of water and soil conservation in the Yangtze River Basin, providing scientific evidence to understanding the current situation of soil erosion in the basin, formulating soil and water conservation policy and planning, and implementing soil and water conservation. At present, China is in the crucial period of promoting the construction of ecological civilization. In view of this, we sum up the development process of soil and water conservation research, the key points and highlights of basic theory and key technology, as well as the construction of scientific research platform in the Yangtze River Basin. But overall, the scientific research foundation of soil and water conservation in the Yangtze River Basin is still relatively weak, the theoretical research still lags behind the practice of soil and water conservation. By clarifying future research priorities, that is, the dynamic mechanism and process of soil erosion, erosion prevention mechanism and applicability of soil and water conservation measures, restoration mechanism and technology research and development of degraded ecosystem, ecological process and effectiveness evaluation of major ecological treatment projects, our research would be of great significance to strengthening science and technology innovation and promoting the development of soil and water conservation in the Yangtze River Basin. Reference | Related Articles | Metrics | Comments（0）

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Researches and Practices on River & Sediment and River Regulation & Flood Control of the Yangtze River DONG Yao-hua Journal of Yangtze River Scientific Research Institute    2021, 38 (10): 7-15.   DOI: 10.11988/ckyyb.20210571 Abstract （300）      PDF（pc） （2252KB）（1307）       Knowledge map    Save Researches and practices on river & sediment and river regulation & flood control of the Yangtze River are comprehensively reviewed in terms of three aspects: theoretical researches on river & sediment, researches of river modeling and special study on flow & sediment, and practical application of river regulation & flood control. First, theoretical researches on river & sediment includes: river classification and morphology research such as stream-order gradation, river segmentation and river-regime-fitted grid, as well as sediment characteristics and movement while of demarcating grain size of river sediment, changes in runoff and sediment load, and methodological contrast between sediment budget and morphological change. Second, researches of river modeling and special study on flow & sediment consists of modeling on river flow and sediment transport and special studies on river and sediment, in which the modeling researches include development, applications and key technologies of river models, while the special studies give examples of essential features and numerical modeling of bend flow, features of cavity flow and sediment transportation and influence of physical model distortion, and impact of shoreline and island utilization on river-lake functions. Third, practical applications of river regulation & flood control comprises researches on large hydro-engineerings (e.g. Three Gorges Project, Gezhouba Project, and South-to-North Water Diversion Project), researches on major issues of river regulation, and practical application of flood control of the Yangtze River. Last but not the least, issues such as river research based on sediment, sediment research unlimited to river, and interaction between river and sediment should be enhanced, while interactive connection and achievement transformation between theoretical researches on river and sediment and practical application for river regulation and flood control should be also strengthened. Reference | Related Articles | Metrics | Comments（0）