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Background and Purpose: A high-altitude environment was known to have a negative effect on bone and lead to a higher incidence of hip fracture. However, the dependence of muscle composition on altitude is unclear. Thus, we aimed to compare muscle density and area in plateau and low altitude area and to determine the effect of the altitude on these outcomes. Methods: Community dwelling adults over 60 years old living in Beijing (elevation 50 m; 300 subjects,107 men and 193 women) or Kunming (elevation 2000 m; 218 subjects,83 men and 135 women) for more than 10 years were enrolled. Quantitative CT was performed in all subjects and cross-sectional area and attenuation measured in Hounsfield units (HU) were determined for the trunk, gluteus, and mid-thigh muscles. Results: Compared to Beijing, Kunming adults were slimmer (Beijing men vs Kunming men: 25.08 ± 2.62 vs 23.94 ± 3.10kg/m2, P =0.013; Beijing women vs Kunming women: 25.31 ± 3.1 vs 23.98 ± 3.54 kg/m2, P = 0.001) and had higher muscle density in the L2-trunk and gluteus maximus muscles after adjustment for age and BMI (L2-trunk muscles: Beijing men 29.99 ± 4.17 HU vs Kunming men 37.35 ± 4.25 HU, P < 0.0001; Beijing women 27.37 ± 3.76 HU vs Kunming women 31.51 ± 5.12 HU, P < 0.0001; Gluteus maximus muscle: Beijing men 35.11 ± 6.54 HU vs Kunming men 39.36 ± 4.39 HU, P = 0.0009; Beijing women 31.47 ± 6.26 HU vs Kunming women 34.20 ± 5.87 HU P =0.0375). Age was similar in both cohorts and no differences were observed in the gluteus medius and minimus muscle or the mid-thigh muscle, either in the area or density. Conclusions: Compared with Beijing, the adults in Kunming had higher muscle density of the gluteus maximus and L2 trunk muscles, showing that living at a higher altitude might be beneficial to muscle quality. [ABSTRACT FROM AUTHOR]

Malthusian population theory states that, when population growth exceeds the growth of the means of production, socioeconomic development will be hindered. This paper analyzes this issue from the perspective of uncoordinated urbanization. We used the data available for 262 cities at the prefecture level and above in China, for the years 2000, 2005, 2010, and 2015. We empirically investigated the relationship between uncoordinated urbanization and urban economic growth. We also examined how this relationship is affected by natural resource constraints. The research results show that there are temporal and spatial differences in the distribution of uncoordinated urbanization in China. From a temporal perspective, from 2000 to 2015, 45.61% of China's 262 cities show under‐urbanization, while 36.45% of cities show over‐urbanization. However, the number of cities with over‐urbanization is growing. From a spatial perspective, the number of cities in the northeastern region with over‐urbanization is declining. Conversely, the number of cities with over‐urbanization in Beijing in the central and southeastern coastal areas is increasing. Empirical research shows that uncoordinated urbanization and urban economic growth have an inverted U‐shaped relationship. Abundant natural resources can make the inverted U‐shaped curve of uncoordinated urbanization and economic growth flatter. The "resource curse" seems to occur only under high levels of uncoordinated urbanization (over‐urbanization). For some cities where there is under‐urbanization, abundant natural resources are conducive to urban economic growth. [ABSTRACT FROM AUTHOR]

Nitrate (NO 3 −) is a key component of secondary inorganic aerosols and PM 2.5. However, the contributions of nitrogen oxides (NO x) emission sources to NO 3 − in PM 2.5 remain poorly constrained. This study measured nitrogen (N) isotopes of NO 3 − (hereafter as δ15N-NO 3 -) in PM 2.5 collected at Beijing in 2014. We observed that δ15N-NO 3 - values in PM 2.5 (−2.3‰ − 19.7‰; 7.3 ± 5.4‰ annually) were significantly higher in winter (11.9 ± 4.4‰) than in summer (2.2 ± 2.5‰). The δ15N differences between source NO x and NO 3 − in PM 2.5 (hereafter as Δ values) were estimated by a computation module as 7.8 ± 2.2‰ − 10.4 ± 1.6‰ (8.8 ± 2.4‰). Using the Δ values and δ15N values of NO x from major fossil (coal combustion, vehicle exhausts) and non-fossil sources (biomass burning, microbial N cycle), contributions of major NO x sources to NO 3 − in PM 2.5 were further estimated by the SIAR model. We found that seasonal variations of δ15N-NO 3 - values in PM 2.5 of Beijing were mainly caused by those of NO x contributions from coal combustion (38 ± 10% in winter, 20 ± 9% in summer). Annually, NO x from coal combustion, vehicle exhausts, biomass burning, and microbial N cycle contributed 28 ± 12%, 29 ± 17%, 27 ± 15%, and 16 ± 7% to NO 3 − in PM 2.5 , respectively, showing actually comparable contributions between non-fossil NO x (43 ± 16%) and fossil NO x (57 ± 21%). These results are useful for planning the reduction of NO x emissions in city environments and for elucidating relationships between regional NO x emissions and atmospheric NO 3 − pollution or deposition. Image 1 • δ15N-NO 3 - values of PM 2.5 in Beijing were higher in winter than in summer. • Seasonal δ15N-NO 3 - variations of PM 2.5 were mainly caused by those of NO x emission from coal combustion. • Fossil and non-fossil NO x sources contributed equally to NO 3 − of PM 2.5 in Beijing. Isotope partitioning of major nitrate sources in PM 2.5 [ABSTRACT FROM AUTHOR]

While residential coal/biomass burning might be a major and underappreciated emission source for PM2:5, especially during winter, it is not well constrained whether burning solid fuels contributes substantially to ambient volatile organic compounds (VOCs), which are precursors to secondary organic aerosols (SOAs) that typically have a higher contribution to particulate matter during winter haze events. In this study, ambient air samples were collected in 2014 from 25 October to 31 December at a rural site on the campus of the University of Chinese Academy of Sciences (UCAS) in northeastern Beijing for the analysis of VOCs. Since temporary intervention measures were implemented on 3-12 November to improve the air quality for the Asian-Pacific Economic Cooperation (APEC) summit held on 5-11 November in Beijing, and wintertime central heating started on 15 November in Beijing after the APEC summit, this sample collection period provided a good opportunity to study the influence of temporary control measures and wintertime heating on ambient VOCs. As a result of the temporary intervention measures implemented during 3--12 November (period II), the total mixing ratios of non-methane hydrocarbons averaged 11.25 ppb, approximately 50% lower than the values of 23.41 ppb in period I (25 October-2 November) and 21.71 ppb in period III (13 November-31 December). The ozone and SOA formation potentials decreased by ~ 50% and ~ 70 %, respectively, during period II relative to period I, with the larger decrease in SOA formation potentials attributed to more effective control over aromatic hydrocarbons mainly from solvent use. Back trajectory analysis revealed that the average mixing ratios of VOCs in southerly air masses were 2.3, 2.3 and 2.9 times those in northerly air masses during periods I, II and III, respectively; all VOC episodes occurred under the influence of southerly winds, suggesting much stronger emissions in the southern urbanized regions than in the northern rural areas. Based on a positive matrix factorization (PMF) receptor model, the altered contributions from traffic emissions and solvent use could explain 47.9% and 37.6% of the reduction in ambient VOCs, respectively, during period II relative to period I, indicating that the temporary control measures on vehicle emissions and solvent use were effective at lowering the ambient levels of VOCs. Coal/biomass burning, gasoline exhaust and industrial emissions were among the major sources, and they altogether contributed 60.3 %, 78.6% and 78.7% of the VOCs during periods I, II and III, respectively. Coal/biomass burning, mostly residential coal burning, became the dominant source, accounting for 45.1% of the VOCs during the wintertime heating period, with a specifically lower average contribution percentage in southerly air masses (38.2 %) than in northerly air masses (48.8 %). The results suggest that emission control in the industry and traffic sectors is more effective in lowering ambient reactive VOCs in non-heating seasons; however, during the winter heating season reducing emissions from residential burning of solid fuels would be of greater importance and would have health co-benefits from lowering both indoor and outdoor air pollution. [ABSTRACT FROM AUTHOR]

For human health benefits it is crucial to see if carcinogenic air pollutants like polycyclic aromatic hydrocarbons (PAHs) are reduced accordingly along with the control of the criteria pollutants including fine particles (PM 2.5 ). A number of studies documented that enhanced temporary emission control during the 2014 Asia-Pacific Economic Cooperation summit (APEC) in Beijing resulted in substantial drops of observed ambient PM 2.5 , as well as PAHs, in urban areas of Beijing, yet it is not clear whether PM 2.5 -bound PAHs in the rural areas were also lowered during the APEC. Here filter-based PM 2.5 samples were collected at a rural site in northeast of Beijing, and analyzed for 25 PAHs before (Oct. 27-Nov. 2, 2014), during (Nov. 3–12, 2014) and after (Nov. 13, 2014–Jan. 14, 2015) the APEC. Observed concentrations of PM 2.5, OC and EC during the APEC dropped by about 30%, however, average PM 2.5 -bound PAHs and their incremental lifetime cancer risk (ILCR), 25.65 ng/m 3 and 3.2 × 10 −4 , remained almost unchanged when compared to that of 25.48 ng/m 3 and 3.5 × 10 −4 , respectively, before the APEC. After the APEC with the start of wintertime central heating in urban Beijing on Nov. 15, 2014, average total concentration of PAHs and their ILCR highly elevated and reached 118.25 ng/m 3 and 1.5 × 10 −3 , respectively. Source apportioning by positive matrix factorization (PMF) revealed that coal combustion was the largest source that contributed 63.2% (16.1 ng/m 3 ), 78.5% (20.1 ng/m 3 ) and 56.1% (66.3 ng/m 3 ) to the total PAHs before, during and after the APEC, respectively. Uncontrolled residential coal use during the APEC was found to be the reason for unabated levels of PAHs, and the largely aggravated PAHs after the APEC was resulted from increased coal consumption for wintertime residential heating. Our results suggested reducing emission from residential coal combustion is crucial to mitigate carcinogenic PAHs in ambient air, especially in rural areas. [ABSTRACT FROM AUTHOR]

• A method for coupling nighttime light data and energy statistics was developed. • The actual and simulated carbon emissions of energy consumption were assessed. • The carbon emission of long time series was reconstructed at grid scale. • Measures to reduce carbon dioxide emissions were proposed. The increase in carbon emissions exacerbates global warming and seriously threatens the sustainable development of human society. In China, energy statistics frequently suffer from missing and inconsistent data at the municipal or county level. Therefore, in the absence of statistical data, this study proposes a method of coupling nighttime light and energy consumption to invert carbon emissions at the grid scale, with high accuracy, which is suitable for spatial applications in developing countries in the context of the lack of energy-related carbon emission monitoring. We observed a good one-variable linear correlation between nighttime light and regional carbon emissions, with an average relative accuracy of 96.00%. The total carbon emission in Beijing-Tianjin-Hebei changed from 231 million tons in 2000 to 535 million tons in 2020. The overall carbon emission showed a "γ-shaped" pattern, with several high-density carbon emission centers. The hot spots spread from inland to the Bohai Coast and were concentrated in the "Beijing corridor Tianjin Tang", whereas the cold spots were mainly distributed in the northwest. The center of gravity of carbon emission shifted to the northeast, and Beijing and Tianjin considerably impacted the regional changes. [ABSTRACT FROM AUTHOR]

China faces the challenge of using limited farmland to feed more than 1.3 billion people. Accelerated urbanization has exacerbated this challenge by consuming a large quantity of high-quality farmland (HQF). It is therefore essential to assess the degree to which urban expansion has preferentially consumed HQF, and discern the mechanism behind this. We found urban areas in Beijing to expand at speeds of 48.97 km 2 /year, 21.89 km 2 /year, 62.30 km 2 /year and 20.32 km 2 /year during the periods 1986–1995, 1995–2000, 2000–2005 and 2005–2020, respectively. We developed an indicator of HQF consumption due to urban expansion, representing the ratio of HQF consumed to its proportion of overall farmland, and found its values were 2.21, 1.57, 1.99 and 1.10 for 1986–1995, 1995–2000, 2000–2005 and 2005–2020, respectively. Thus, although HQF has been overrepresented in the farmland consumed by Beijing's urbanization, this phenomenon has decreased over time. Centralized expansion has contributed greatly to consumption of HQF. Topography and distances to urban and water bodies determine the relative consumption of HQF in urbanization. [ABSTRACT FROM AUTHOR]

Abstract: For more than three decades, China has experienced large-scale expansion of construction land (i.e., land used for building structures and infrastructure) and a rapid loss of cultivated land, especially in metropolises. The present study assessed cultivated land loss due to construction occupation (i.e., the expansion of construction land) in Beijing. The effects of economic growth on cultivated land losses were also examined using a decoupling approach. It was found that the expansion of construction land in Beijing occupied an additional 845.2 km2, 304.5 km2 and 869.0 km2 of cultivated land during the periods 1986–1995, 1995–2000 and 2000–2005 respectively. During 1986–1995, cultivated land was mainly taken over by the expansion of urban areas, whereas during 1995–2000 it was mainly replaced by the expansion of rural settlements, and, during 2000–2005, by uses in the “other construction” land use category (e.g., roads, railways, or industrial facilities located apart from urban areas or rural settlements). Beijing's economy and population growth were prominently decoupled from cultivated land losses during 1995–2000, but became negative decoupled during 2000–2005. [Copyright &y& Elsevier]

The number of Beijing's civil vehicles is growing rapidly due to the great support of the automobile industry and the Chinese government and the increasing average per capita income of China's people. Exhaust emissions from vehicles have already become the main source of Beijing's air pollution. Based on the Long-range Energy Alternatives Planning System (LEAP), this article predicts the energy consumption and exhaust emissions from Beijing's civil vehicles. Also, we estimated the reduction potentials of China's new fuel consumption standards and exhaust pollutants standards that will be implemented from 2008 to 2020. Two scenarios were developed: “Business as Usual” (BAU) and “New Standard” (NS). In the BAU scenario, the Chinese government would do nothing to improve the fuel consumption standards and exhaust pollutants standards in the future. In the NS scenario, the Chinese government would implement more strict fuel consumption standards and exhaust pollutants standards for Beijing's civil vehicles. By comparing the results of the two scenarios for year 2020, the energy consumption will experience a reduction of 7.8%, and the exhaust pollutants CO, HC, NOX, PM, and the emissions of CO2 would decrease by 43.3%, 36.4%, 60.3%, 81.2%, and 7.8%, respectively. [ABSTRACT FROM AUTHOR]

In order to solve the problem of data loss in sensor data collection, this paper took the stem moisture data of plants as the object, and compared the filling value of missing data in the same data segment with different data filling methods to verify the validity and accuracy of the stem water filling data of the LSTM (Long Short-Term Memory) model. This paper compared the accuracy of missing stem water data for plants under different data filling methods to solve the problem of data loss in sensor data collection. Original stem moisture data was selected from Lagerstroemia Indica which was planted in the Haidian District of Beijing in June 2017. Part of the data which treated as missing data was manually deleted. Interpolation methods, time series statistical methods, the RNN (Recurrent Neural Network), and LSTM neural network were used to fill in the missing part and the filling results were compared with the original data. The result shows that the LSTM has more accurate performance than the RNN. The error values of the bidirectional LSTM model are the smallest among several models. The error values of the bidirectional LSTM are much lower than other methods. The MAPE (mean absolute percent error) of the bidirectional LSTM model is 1.813%. After increasing the length of the training data, the results further proved the effectiveness of the model. Further, in order to solve the problem of one-dimensional filling error accumulation, the LSTM model is used to conduct the multi-dimensional filling experiment with environmental data. After comparing the filling results of different environmental parameters, three environmental parameters of air humidity, photosynthetic active radiation, and soil temperature were selected as input. The results show that the multi-dimensional filling can greatly extend the sequence length while maintaining the accuracy, and make up for the defect that the one-dimensional filling accumulates errors with the increase of the sequence. The minimum MAPE of multidimensional filling is 1.499%. In conclusion, the data filling method based on LSTM neural network has a great advantage in filling the long-lost time series data which would provide a new idea for data filling. [ABSTRACT FROM AUTHOR]

As the most important manifestation of the activities of the life service industry, the reasonable layout of spatial agglomeration and dispersion of the accommodation and catering industry plays an important role in guiding the spatial structure of the urban industry and population. Applying the contour tree and location quotient index methods, based on points of interest (POI) data of the accommodation and catering industry in Beijing and on the identification of the spatial structure and cluster center of the accommodation and catering industry, we investigated the distribution and agglomeration characteristics of the urban accommodation and catering industry from the perspective of industrial spatial differentiation. The results show that: (1) the accommodation and catering industry in Beijing presents a polycentric agglomeration pattern in space, mainly distributed within a radius of 20 km from the city center and on a relatively large scale; areas beyond this distance contain isolated single cluster centers. (2) From the perspective of the industry, the cluster centers close to the core area of the city are characterized by the agglomeration of multiple advantageous industries, while those in the outer suburbs of the city are more prominent in a single industry. (3) From the perspective of the location quotient of cluster centers, the leisure catering industries are mainly located close to the urban centers. On the contrary, the cluster centers in the outer suburbs and counties are relatively small and dominated by restaurants and fast food industries. Commercial accommodation businesses are mainly distributed in the transportation hub centers and in entertainment and leisure areas. [ABSTRACT FROM AUTHOR]

In 2014, China launched its latest urbanization strategy, the National New-type Urbanization Plan, to promote scientific and reasonable urbanization modes. China's new-type urbanization policy not only affects urban development, but will also have significant impacts on the lives of hundreds of millions of Chinese farmers as well as on the use modes of rural settlements. A thorough analysis of the impacts of new-type urbanization policies on the pattern evolution of rural settlements is therefore critical for developing and proposing a science-based layout scheme of rural settlements and for guiding the development and evolution of rural settlements in a reasonable manner. In this paper, we use the Tongzhou District of Beijing, one of China's new-type urbanization pilot areas, as an example. Applying the CLUE-S model to analyze the impacts of new-type urbanization policies, we simulate the potential influences of the implementation of these policies on the pattern evolution of rural settlements. Based on the results, the implementation of new-type urbanization policies has significant influences on both urban and rural population migration, mainly through the reform of the household registration system. The results further suggest that these policies have significant impacts on the land use scale as well as on the spatial patterns of rural settlements. By 2030, under the scenario of new-type urbanization, the land use scale of rural settlements in Tongzhou District would increase by 0.79% compared with that under the scenario of conventional urbanization. In terms of spatial distribution under new-type urbanization, land use of rural settlements would mainly compete with that of urban land and grassland. We conclude that the spatial distribution of rural settlements in Tongzhou District can be improved and better regulated via reasonable planning. • Simulated rural settlement pattern evolution in the Tongzhou District of Beijing. • Contexts and policies of China's new-type urbanization plan (NUP) were reviewed. • CLUE-S was used to analyze the impacts of NUP on rural settlement. • Household registration system reform impacts the utilization of rural settlement. • Rural settlement increase by 0.79% under NUP compared to conventional urbanization. [ABSTRACT FROM AUTHOR]

• Operation modes of pumping and recharging well are studied by physical simulation. • The modes are continuous heating/cooling, summer then winter, winter then summer. • Experiments were performed based on heating/cooling duration in three cities. • Suggestions for long-term operation and improved system reliability are provided. • The results guide the application and operation of pumping and recharging wells. A pumping and recharging well (PRW) system is an important single well groundwater heat pump system that is being used increasingly in practical projects such as in renewable energy utilization systems. In this study, we investigated four different PRW operation modes based on the heating and cooling periods in Shenyang, Beijing, and Shanghai using the physical simulation experimental sandbox of a single well groundwater heat pump that can accurately reflect actual physical phenomena. In the experiment, the duration of the operating conditions is distributed according to heating, air conditioning, and recovery seasons. The experiments were conducted under four conditions: continuous heating (CH), continuous cooling (CC), first summer then winter (SW), and first winter then summer (WS). In the heating/cooling load-dominant areas, the results show that an aquifer cannot be restored to its original state during the natural recovery period. In the CH/CC conditions, the cumulative heat absorption and rejection in six cycles decreases by 23.0% and 6.0%, respectively. The results also show that the PRW is more sensitive in the heating mode and heat absorption is more difficult than heat rejection. In the CH condition, the effect of the initial disturbance on the aquifer is more evident. The reduction in the cumulative heat in the second operating cycle is 57.1% of the total reduction in the six cycles. Thus, it is necessary to continue recharging the aquifer over time based on the building load to ensure long-term reliable operation of the system. In the heating/cooling load-dominant districts, the use of the SW operation mode can improve system stability. The results of the study offer valuable practical reference for implementing PRWs and can be applied to aquifer energy storage. [ABSTRACT FROM AUTHOR]

To describe the epidemiologic, clinical, laboratory, and radiological characteristics and prognoses of COVID-19 confirmed patients in a single center in Beijing, China. The study retrospectively included 19 patients with nucleic acid-confirmed SARS-CoV-2 infection at our hospital from January 20 to March 5, 2020. The final follow-up date was March 14, 2020. The epidemiologic and clinical information was obtained through direct communication with the patients or their family members. Laboratory results retrieved from medical records and radiological images were analyzed both qualitatively by two senior chest radiologists as well as quantitatively via an artificial intelligence software. We identified 5 family clusters (13/19, 68.4%) from the study cohort. All cases had good clinical prognoses and were either mild (3/19) or moderate (16/19) clinical types. Fever (15/19, 78.9%) and dry cough (11/19, 57.9%) were common symptoms. Two patients received negative results for more than three consecutive viral nucleic acid tests. The longest interval between an initial CT abnormal finding and a confirmed diagnosis was 30 days. One patient's nucleic acid test turned positive on the follow-up examination after discharge. The presence of radiological abnormalities was non-specific for the diagnosis of COVID-19. COVID-19 patients with mild or no clinical symptoms are common in Beijing, China. Radiological abnormalities are mostly non-specific and massive CT examinations for COVID-19 screening should be avoided. Analyses of the contact histories of diagnosed cases in combination with clinical, radiological and laboratory findings are crucial for the early detection of COVID-19. Close monitoring after discharge is also recommended. [ABSTRACT FROM AUTHOR]

Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) at heights of 3, 15, 32, 64, and 102 m above the ground on the Institute of Atmospheric Physics (IAP) tower in central Beijing during the winter of 2016 and the summer of 2017. Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone. Isoprene mixing ratios were the highest at the 32 m in summer (1.64 ± 0.66 ppbV) and at 15 m in winter (1.41 ± 0.64 ppbV) with decreasing concentrations to the ground and to the 102 m, indicating emission from the tree canopy of the surrounding parks. Monoterpene mixing ratios were the highest at the 3 m height in both the winter (0.71 ± 0.42 ppbV) and summer (0.16 ± 0.10 ppbV) with a gradual decreasing trend to 102 m, indicting an emission from near the ground level. The lowest isoprene and monoterpene mixing ratios all occurred at 102 m, which were 0.71 ± 0.42 ppbV (winter) and 1.35 ± 0.51 ppbV (summer) for isoprene, and 0.42 ± 0.22 ppbV (winter) and 0.07 ± 0.06 ppbV (summer) for monoterpenes. Isoprene in the summer and monoterpenes in the winter, as observed at the five heights, showed significant mutual correlations. In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m, suggesting possible anthropogenic sources. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• The characteristics and intrinsic cause of leakage disease at the junction between the shaft and shield tunnel is found. • The structural leakage disease mechanism of the tunnel junction site is proved by numerical simulation. • The new cement-based grouting material and the rapid treatment method for leakage disease are put forward. Tunnel leakage disease will seriously affect the metro operation and threaten the safety of passengers. Therefore, this study investigates the mechanism of structural leakage disease at the junction between the shaft and shield tunnel through the operational tunnel in the Beijing area. Firstly, the characteristics and intrinsic cause of the leakage are analyzed by ground penetrating radar, endoscope detection, and total station. The field inspection indicates that the water-rich cavity caused by the rise of groundwater is the main external environmental factor inducing structural leakage. The uneven deformation of the junction between the shield segments and ring beam and the deterioration of the ring beam structure are the main reasons for the waterproof layer failure, which further lead to structural leakage. In addition, numerical simulations are carried out to study the leakage mechanism of the junction structure under the effects of structural uneven deformation and ring beam deterioration. The numerical results show that the leakage caused by uneven deformation of tunnel junction is significant. Especially, the water-rich cavity near the ring beam will aggravate structural leakage. Furthermore, the deterioration of the ring beam structure has a more significant effect on the structural leakage, and the leakage mainly occurs in the ring beam and ring beam-segment joints. This finding is basically consistent with the actual leakage situation. In addition, the rapid treatment method for plugging water-rich cavities and structural defects is proposed, and a new cement-based material with good non-dispersible underwater properties is developed. The surface observation and internal detection show that the rapid treatment method effectively controls structural leakage. This research can provide a reference for future similar leakage and disease control projects of metro subways in operation. [ABSTRACT FROM AUTHOR]