Disaster Control Research Articles

Perceived Effectiveness and Responsibilities of the Forest Biological Disasters Control System of China: A Perspective of Government Administrators

Forest biological disaster control (FBDC) is appealing the attention in China and even across the world, while the control system plays a pivotal role in the entire control work. The survey-based comprehensive indicators system was developed to evaluate the perceived effectiveness of the entropy weight model and the perceived responsibilities of the FBDC system of China from the perspective of government administrators at the province-, prefecture-, and county- levels. Ordinary Least Square (OLS) and Simultaneous Equations Models (SEM) were further developed to quantitatively analyze the affecting factors of the perceived effectiveness. The results indicated that the perceived effectiveness of the FBDC system in China was relatively low, with a value of 47.18 (the range is 0–100). In specific, the county level has the highest value of 48.85, while the province level has the lowest value of 42.99. The major limiting factors perceived are the insufficiency of the funds and employees. In addition, the intelligentization level, the implementation of the quarantine enforcement, the infrastructure construction, and the involvement of the local communities also need to be further improved. The salary does not positively affect the perceived effectiveness, while administrators with higher education levels and ages usually have higher salaries. Furthermore, compared with the province- and prefecture-level agencies, the county-level agencies have higher perceived effectiveness and more perceived responsibilities with higher workloads. Thus, future policies are suggested to focus on diversifying the investment sources, refining the employee recruitment and promotion system, and paying more attention to the county-level agencies. The results of this study could help to enhance the understanding of the FBDC system of China, hence improving the control efficiency and reducing the economic loss caused by forest biological disasters in China.

Divergent hydrological responses to intensive production under different rainfall regimes: Evidence from long-term field observations

The progress in intensive production over recent decades have greatly altered land-use patterns, often resulting in simplified landscapes. Intensive production is particularly necessary in mountainous areas where arable land resources are scarce, but it is a pervasive concern that landscape simplification will increase pressure for mountain flood disaster control. In this study, rainfall, runoff and sediment process data from 1995 to 2015 were observed for a typical intensively developed mountainous watershed. Data were used to investigate the effects of intensive production on the hydrological response characteristics discharge, suspended sediment concentration, runoff depth, and sediment load under three different rainfall regimes, namely rainfall regimes I (long duration, light rainfall intensity), II (short duration, high rainfall intensity), and III (long duration, high amount). Orchard area in the watershed increased from 4.43 % to 37.44 % under intensive production from 1995 to 2015. Intensive production led to high-intensity land use as well as homogenization and simplification of the landscape, which inevitably caused changes in hydrological processes in the mountainous watershed. Intensive production resulted in a significant downward trend in runoff coefficients (p = 0.001) and sediment loads (p = 0.006) under the three different rainfall regimes. Average sediment concentration decreased significantly and continuously (2394 to 12.53 kg m−3) during the 20 years of the study, and average runoff fluctuated but decreased from 0.218 m3/s in 2000 to 0.093 m3/s in 2015. According to hysteresis analysis, the proportion of counterclockwise loop events decreased after intensive production but remained the dominant circulation mode (40 %). The proportion of events in eight-figure loops increased from 0.06 % before intensification to 25 %. The increase in complex circulation implied that development of intensive production increased the sources of sediment in the watershed. The study increases understanding of hydrological responses to intensive production in complex mountainous watersheds and provides practical references for sustainable watershed management and optimization of land use allocation.

Mechanism and Prevention Technologies of Reservoir Gas Disaster in Abandoned Oil Well of Coal Mine

Abstract The reservoir gas disaster has distinct characteristics and is a key factor that threatens the safe and green mining of coal mines in the costorage area of coal and petroleum resources. In order to solve the problem of prevention and control of reservoir gas disasters in coal mines, the characteristics of oil-bed gas disasters in abandoned oil wells in coal mines were analyzed, and the oil-bed gas disaster mechanism of abandoned oil wells without isolation coal pillars was revealed to study the scope of gas disasters around oil wells under the influence of production. The research shows that: (1) abandoned oil well reservoir gas disasters have the characteristics of high gas pressure, high concentration, large lateral influence area, wide vertical sweep range, and frequent disasters, which seriously threaten the safety and green mining of coal mines; (2) divide the reservoir gas disaster of abandoned oil wells into the high-pressure gas disaster in the well and the disaster in the surrounding oil-bed gas enrichment area; (3) according to the numerical simulation results that the maximum damage depth of the coal seam mining floor is 38.6 m and the seepage height of high-pressure oil-bed gas is 40 m, the safety factor k is introduced, and the reservoir gas sweeping range of the abandoned oil well is determined to be 95.4 m below the coal seam to the surface; (4) the comprehensive prevention and control technical scheme of oil-bed gas for controlling high-pressure oil-bed gas in wells by ground plugging and downhole injection and injection of diluent to control enriched areas was proposed, which successfully solved the problem of safe and efficient exploitation of Shuangma coal mine in Ningdong coalfield by abandoned oil wells. The research results provide effective solutions for the realization of green mining in many coal mines in the costorage area of coal and oil resources in China and have important application value for the prevention and control of dynamic disasters in the costorage area of resources.

Intelligent prediction of rockburst in tunnels based on back propagation neural network integrated beetle antennae search algorithm.

Rockburst is one of the major engineering geological disasters of underground engineering. Accurate rockburst intensity level prediction is vital for disaster control during underground tunnel construction. In this work, a hybrid model integrating the back propagation neural network (BPNN) with beetle antennae search algorithm (BAS) has been developed for rockburst prediction. Before model building, 173 groups of rockburst dataset were collected. Six geological parameters are selected as predictors for rockburst, including the maximum tangential stress of the surrounding rock σθ, the uniaxial compressive strength of rock σc, the tensile strength of rock σt, the stress ratio σθ/σc, the rock brittleness ratio σc/σt, and the elastic energy index Wet. After preprocessed by outlier detection and synthetic minority oversampling technique (SMOTE), the new dataset was divided into training and test parts. BAS could optimize the weights and biases of BPNN from the training process. Then the established hybrid model was applied to the test samples with predicted accuracy of 94.3%, proving that the hybrid model has practical value in researching rockburst prediction.

Adsorption of CH4/CO2/N2 by different functional groups in coal

To explore the microscopic mechanism of gas adsorption by different functional groups in coal and provide theoretical support for the prevention and control of coal mine gas disasters, a slit-pore model and fragment model modified by different functional groups were built using Materials Studio software, based on density functional theory and the Monte Carlo method. The adsorption characteristics of seven different functional group models on the gas were analyzed, and the microscopic mechanism of adsorption performance of different functional groups on CH4/CO2/N2 was revealed. The results showed that the order of the electrophilic ability of each functional group fragment followed benzene ring > –OH > –CO > –O–CH3 > –COOH > –CH3 > –CH2–CH3, and the order of nucleophilic ability was benzene ring > –CH2–CH3 > –CH3 > –COOH > –OH > –CO > –O–CH3. After adding different functional groups to the surface of the complete activated carbon, the electrophilic ability and nucleophilic ability decreased. The adsorption capacity was affected by both gas properties and functional group structure. The adsorption heat was not only affected by the adsorption amount but also by the non-uniformity of the adsorbent surface. The oxygen-containing functional groups were beneficial to the adsorption of CO2 gas, and the aliphatic functional groups were committed to the adsorption of CH4 and N2.

Climate Change Characteristics of Typical Grassland in the Mongolian Plateau from 1978 to 2020

Typical grassland is the core of the Mongolian Plateau grassland belt, and is also an important ecological barrier in the north of China. It is of great significance to explore the real-time changes in grassland climate for the prevention and control of climate disasters, and for ecological protection. In this study, the spatial and temporal variation of temperature, precipitation and maximum wind speed in typical Mongolian Plateau grassland were studied using observation data from 16 meteorological stations from 1978 to 2020, using the linear trend method, cumulative anomaly method, Mann-Kendall test, sliding t-test and Morlet wavelet analysis. The results show that: (1) The typical grassland temperature has been increasing at a rate of 0.4 °C/10a (p < 0.001) over the past 40 years, with the most significant warming in spring and summer; a sudden change from low to high temperature occurred in 1992; the annual average temperature gradually increased from northeast to southwest, with significant warming in the southwest. (2) Annual precipitation decreased slightly at a rate of −2.39 mm/10a, with the most significant decrease in summer precipitation; a sudden change from more to less precipitation occurred in 1998; spatially, precipitation decreased gradually from east to west, with significant moisture reduction in its northern part. (3) The maximum wind speed decreased significantly at a rate of −0.33m/s/10a (p < 0.001), with the most pronounced decrease in spring; the maximum wind speed changed abruptly from strong to weak around 1991; spatially, the annual average maximum wind speed decreased gradually from northwest to southeast and northeast, with the most pronounced decrease in the south and northeast. (4) The wavelet analysis shows that the typical grassland area will still be in a warm, low-rainfall and weak-wind stage in the coming years. Using the above analysis, the typical grassland climate of the Mongolian Plateau has shown a clear trend of warm and dry, weak wind in the past 40 years.

Evaluation of Geological Disaster Sensitivity in Shuicheng District Based on the WOE-RF Model

To improve the prevention and control of geological disasters in Shuicheng District, 10 environmental factors—slope, slope direction, curvature, NDVI, stratum lithology, distance from fault, distance from river system, annual average rainfall, distance from road and land use—were selected as evaluation indicators by integrating factors such as landform, basic geology, hydrometeorology and engineering activities. Based on the weight of evidence, random forest, support vector machine and BP neural network algorithms were introduced to build WOE-RF, WOE-SVM and WOE-BPNN models. The sensitivity of Shuicheng District to geological disasters was evaluated using the GIS platform, and the region was divided into areas of extremely high, high, medium, low and extremely low sensitivity to geological disasters. By comparing and analyzing the ROC curve and the distribution law of the sensitivity index, the AUC evaluation accuracy of the WOE-RF, WOE-SVM and WOE-BPNN models was 0.836, 0.807 and 0.753, respectively; the WOE-RF model was shown to be the most effective. In the WOE-RF model, the extremely high-, high-, medium-, low- and extremely low-sensitivity areas accounted for 15.9%, 16.9%, 19.3%, 21.0% and 26.9% of the study area, respectively. The extremely high- and high-sensitivity areas are mainly concentrated in areas with large slopes, broken rock masses, river systems and intensive human engineering activity. These research results are consistent with the actual situation and can provide a reference for the prevention and control of geological disasters in this and similar mountainous areas.

Quantitative risk assessment of typhoon storm surge for multi-risk sources

Typhoon storm surge (TSS) is a complex marine disaster affected by multi-risk sources. Quantitative risk assessment is an important prerequisite for identifying risk areas and designing risk reduction strategies. This paper aims to propose a rapid, accurate, and comprehensive quantitative risk assessment method for TSS under multi-risk sources, including disaster occurrence probability and severity. First, identify the primary risk sources according to the disaster-causing mechanism of TSS. Then, based on the official public data from 1989 to 2020, the dependence structure among multi-risk sources is constructed using Copulas to calculate the probability of each superposition scenario. Meanwhile, build visual scenario databases employing Geographical Information System (GIS) techniques. Subsequently, the extent and depth of inundation are translated into economic risk and population risk using GIS and depth-damage functions. Finally, taking the “Mangkhut” as a case study, the method’s feasibility and accuracy are verified. The results show that the primary risk sources of TSS are storm tide, astronomical tide and coastal waves. The Gumbel Copula is optimal, with OLS (ordinary least squares) and D of 0.0186 and 0.1831, respectively. The probability assessment under different superposition scenarios indicates that the greatest threat of TSS in Guangzhou comes from the storm tide and the astronomical tide. As for the “Mangkhut” case study in Jiangmen City, the assesses occurrence probability is 0.0355%, the accuracy of economic risk assessment (except mariculture) is 95.28%, and the accuracy of population risk assessment is 98.60%. Residences and the disaster-bearing bodies in 0–3 m inundation depth are most severely affected by TSS disasters. Measures such as locating residential and important buildings away from the shoreline (at least 10 km) and ground (above 3 m), formulating disaster emergency plans, and developing the forecast and prevention of storm tides and astronomical tides will help ensure the safety of residents’ life and property. This paper provides an efficient and accurate method, which is of great significance for disaster control, sustainable development, and decision-making.

Simulation of strong earthquake characteristics of a scenario earthquake (MS7.5) based on the enlightenment of 2022 MS6.9 earthquake in Menyuan

The Menyuan area is an important transportation hub in the Hexi Corridor. The Menyuan MS6.9 earthquake that occurred on January 8, 2022 had a major impact on the local infrastructure and transportation of this region. Due to the high possibility of similar strong earthquakes occurring in this area in the future, preliminary assessment of the seismic intensity characteristics of destructive earthquakes in this region is essential for effective disaster control. This paper uses the empirical Green′s function (EGF) method as a numerical simulation tool to predict the ground motion intensity of Datong Autonomous County under the action of the scenario earthquake (MS7.5). Seismic records of aftershocks of the 2016 Menyuan MS6.4 earthquake were used as Green’s functions for this simulation. The uncertainties associated with various source parameters were considered, and 36 possible earthquake scenarios were simulated to obtain 72 sets of horizontal ground motions in Datong County. The obtained peak ground acceleration (PGA) vs. time histories of the horizontal ground motion were screened using the attenuation relationships provided by the fifth-edition of China's Seismic Ground Motion Parameter Zoning Map and the NGA-West2 dataset. Ultimately, 32 possible acceleration-time histories were selected for further analysis. The screened PGA values ranged from 78.8 to 153 cm/s2. The uncertainty associated with the initial rupture point was found to greatly affect the results of the earthquake simulation. The average acceleration spectrum of the selected acceleration-time history exceeded the expected spectrum of a intermediate earthquake, which means that buildings in Datong County might sustain some damage should the scenario earthquake occur. This research can provide reliable ground motion input for urban earthquake damage simulation and seismic design in Datong County. Growing the dataset of small earthquakes recorded in this region will facilitate the large-scale simulation of ground motions under different earthquake scenarios.

Sand control effect of HDPE sandbreak nets with different porosity structure

Straw checkerboard sand barriers with a porous structure that consists of a pervious upper portion and a dense lower portion are widely used to achieve great sand control effect. Considering this, and resolving the serious earth surface undercutting problem after HDPE sandbreak net checkboard barriers setting, the authors used HDPE (high-density polyethylene) materials to prepare new sandbreak materials with a similar porous structure. Through wind tunnel simulations and field sand control monitoring, we compared the sand control effect of three HDPE sandbreak nets with different porosity structure. Compared to the sandbreak net with uniform porosity structure, the three types of HDPE sandbreak nets with different porosity structure had poorer effect on reducing sand transport rates, but had longer effective protection distance before sandbreak nets at low wind velocity conditions (<12 m/s), longer effective protection distance at high wind velocity (>14 m/s) and longer effective protection distance between sandbreak nets at all experimental wind velocity conditions. Wind and sand control effect characteristics of HDPE sandbreak nets with different porosity structure provide an ideal material on semi-buried checkerboard sand barriers for sand stabilization. By contrast, uniform-type sandbreak nets are used as materials on high upright sand fences for sand blocking. These HDPE sandbreak nets can be used to replace traditional sandbreak materials and have a very high potential for widespread and popular application in aeolian sand disaster control.

Tidal Effect on Grouting in Karst Fracture with Flowing Water: Experimental Investigation and Its Application

To address the problem on grouting control of water inflow disaster in coastal area, a caisson-type grouting experimental system of a single fracture in flowing water under tidal action was developed independently. Through the tide simulation system, the tidal action of different intensity and frequency was effectively described. Tide simulation system, fracture system, grouting system, water supply system and information monitoring system were combined to realize the visualization of the whole grouting process under tidal action. Furthermore, the grouting experiments of a plate fracture under different tidal action were developed and the blocking mechanism under tidal action was revealed. The conclusions were as follow: 1) Under constant water head, the slurry had three typical diffusion patterns, which were circular distribution, double U-shaped distribution and elliptical distribution respectively. 2) Under tidal action, the pressure showed a periodic fluctuation growth, and the growth rate slowed down with the increase of fracture aperture. 3) Strong tidal action would promote the diffusion of and increased the outflow amount of slurry, which was not conducive to grouting. Based on the water inflow treatment project of limestone mine in Guangxi, Through the field grouting tests, the 2# water inflow point was blocked. The research results have a certain reference value for the technology optimization of grouting engineering in coastal areas.

Research on the Control of Mining Instability and Disaster in Crisscross Roadways

In order to solve the disaster caused by the instability of spatial crisscross roadways under the action of leading abutment pressure in the coal mine face, combined with a specific engineering example, the methods of theoretical analysis, numerical simulation and field measurement are adopted to simulate and analyze the stress mutual disturbance intensity and influence range of spatial crisscross roadways. The evolution law of the plastic zone in spatial crisscross roadways under the influence of mining is explored, and the key to mining instability control is made clear. The roof of the return air roadway, the shoulder angle of the two sides and the coal wall are the key parts of surrounding rock stability control. On this basis, the cooperative control scheme of changing the roadway section shape (straight wall semicircular arch), supporting (anchor cable and “U” section steel) and modifying (grouting) is put forward. Through the field measurement, within the influence range of the return air roadway, the displacement deformation of the top and bottom is less than 200 mm, which achieves the goal of roadway safety and stability. Furthermore, based on the theory of “butterfly plastic zone”, the mechanical mechanism of the overall instability of the spatial crisscross roadway is revealed; that is, during the advance of the working face, the advance mining stress is superimposed with the surrounding rock stress of the crisscross roadway, and the peak value of the partial stress of the surrounding rock mass of the crisscross roadway is increased. The expansion of the plastic zone is intensified, and beyond 7 m from the crisscross position, the shoulder angle of the two sides and the leading plastic zone of the coal wall of the working face are connected with each other, which leads to the overall failure and instability of the surrounding rock between the roadways at the intersection.

Analysis method of the water inrush and collapse in jointed rock mass tunnels: A case study

Water inrush disaster occurs easily when the tunnel is close to the water rich fault fracture zone. To clarify the disaster evolution process and the critical thickness of the water-resistant rock mass is the key problem of the prevention and control of water inrush disaster in jointed rock tunnel. However, the water inrush disaster in jointed rock tunnels involves solid-fluid interaction, and the conventional single-phase numerical method is difficult to realize the real simulation of the disaster. To solve this problem, we gave full play to the advantages of the discontinuous deformation analysis method (DDA) in simulating solid motion and the smoothed particle hydrodynamics method (SPH) in simulating fluid motion, and the two-dimensional DDA-SPH (2D DDA-SPH) method was used to simulation the solid-fluid interaction in the water inrush disasters. Firstly, the 2D DDA-SPH method was used to replicate the solitary wave experiment, named Scott Russell's wave generator, and the result of the simulation was almost the same with experiment, which verified the accuracy of 2D DDA-SPH method in simulating solid-fluid interaction dynamic problems. Secondly, taking the Yonglian Tunnel as the research object, we simulated the water inrush disaster in the F2 fault of Yonglian Tunnel under the condition of different thickness of water-resistant rock mass. Based on the results of the simulation, the critical thickness of water-resistant rock mass was determined, which was about 5m. Lastly, we analyzed the process of the water inrush disasters based on the movement state of the fluid near the water-resistant rock mass. And we divided the process of the water inrush disasters in the jointed rock mass into three stage, which were mutation stage, cataclysmic stage and stable stage, which provided a theoretical basis for the prevention and control of water inrush in jointed rock tunnel.

Optimization of coalbed methane recovery from extraction borehole using novel plastic spraying material: A field application and evaluation

High-quality gas extraction is confronting enormous difficulties due to the leakage of air from the roadway through the coal wall into the extraction system, particularly in the boreholes along the coal seam. In this work, a new set of material and technology for coal wall spraying and sealing was developed to block the air leakage channel and enhance the concentration of extracted gas. The material has excellent air-tightness, resilience, and flame retardancy, and the feasibility of the implementation of the technology was demonstrated by the application in Hexi Coal Mine. The results showed that: the gas-extracted concentration was lower than 10% after 70 days under the conventional borehole sealing method. However, the new material and technology could increase gas-extracted concentration by 26.9∼43.7% with a maximum increase multiple of 4.090 times. Moreover, the average gas-extracted concentration can be increased to 76.7% and maintain a relatively stable state for 80 days. This technology could not only reduce the air leakage, but also strengthen the internal and external pressure difference of the borehole, so that more gas can be extracted at a high concentration, which is expected to provide a reference for the gas disaster control and high-quality gas source guarantee.

Effect of a newly synthesized anionic Gemini surfactant composite fracturing system on the wettability of coking coal

To improve the wetting effect of the fracturing fluid on coal, a sulfonate Gemini surfactant (Gemini-3OH) was synthesized from nonyl phenol through a double ether and sulfonation reaction. It was mixed with an appropriate amount of cationic cellulose (JR400) to form a fracturing fluid composite system (Gemini-3OH/JR400). The optimum concentration ratio of the composite system was determined using a surface tension test. The mechanism of action of water, Gemini-3OH and Gemini-3OH/JR400 composite system on the coal surface was analyzed by means of FTIR, XPS, industrial analysis, and SEM, along with microscopic observations, contact angle measurements, and molecular dynamics simulations. The results showed that Gemini-3OH/JR400 had a lower critical micelle concentration and surface tension, and had the greatest impact on the coal structure and functional group content. The contact angles of Gemini-3OH/JR400 at the moment of contact with coal and at 60 s were 33.12° and 19.76°, respectively. Finally, molecular dynamics simulations further verified that Gemini-3OH/JR400 had a better wetting effect on coal. This study provides a new concept for wetting coal bodies by water injection and fracturing in coal seams, and hence, can help in the prevention and control of mining accidents and disasters.

Evaluation of comprehensive treatment effect of geotechnical and ecological engineering for debris flow: case of Wenchuan County, Sichuan Province

As a crucial link in debris flow disaster control, control engineering can be divided into geotechnical engineering and ecological engineering. Geotechnical engineering is less affected by climate and can play an immediate role in the treatment of debris flow in a short time. Ecological engineering has obvious regulating effect on surface runoff and erosion. Furthermore, there are few discussions on comprehensive treatment effect between geotechnical engineering and ecological engineering for debris flow. Therefore, taking the debris flow gullies with control engineering implemented in Wenchuan area of Sichuan Province as the research object, this paper puts forward an evaluation method of treatment effect comprehensively considering the geotechnical engineering and ecological engineering. It is mainly based on the impact of engineering on the formation conditions of debris flow and the damage of projects. The comprehensive treatment effect of geotechnical and ecological engineering for debris flow is analyzed. The corresponding evaluation indexes are extracted, including 5 first-class evaluation indexes such as landform factor and water source factor, as well as 11 s-class evaluation indexes such as the peak flow reduction rate, the sediment retention ratio and the LAI ratio. The Fuzzy-AHP method is used to establish the evaluation model of treatment effect. The evaluation results are graded. It is considered that the treatment effect of other debris flow gullies is medium or above except that two gullies are poor. The evaluation results are consistent with the actual investigation, which provides a reference for the control of debris flow in this area.

RISK ASSESSMENT OF GEOLOGICAL DISASTERS ALONG THE G213 MAOXIAN-WENCHUAN SECTION BASED ON GF-6 DATA

Abstract. China is a country prone to natural disasters, and roads are easily damaged in natural disasters. As the infrastructure of people's production and life and the lifeline of post-disaster rescue, roads play a very important role. There are many previous studies on geological disasters risk assessment, but few special researches on highway geological disasters risk assessment, especially quantitative risk assessment combined with remote sensing images. Therefore, the risk assessment of geological disasters along the road is of great significance for the prevention and control of geological disasters and the protection of life and property safety. Based on GF-6 data and other geographic data, this study used the comprehensive evaluation method to realize the geological disasters risk assessment of the Maoxian-Wenchuan section along the G213 line, and analysed and discussed the causes and spatial distribution of geological disasters along the G213 line. Our study presents several key findings, (1) The order of impact degree of each impact factor is road network density, soil erosion, slope, human activities, vegetation coverage, rainfall, and slope aspect, among them, the road network density factor plays a leading role, and the aspect factor is the least impact factor; (2) The geological disasters risk in the study area is divided into five categories: extremely low risk, low risk, medium risk, high risk, and extremely high risk. In general, the geological disasters risk of the research road section is relatively high, and the risk area division is consistent with the historical disaster point data. The research results can provide reference for the smooth development and implementation of road geological disasters risk assessment in the mountainous areas in southwestern China.

City Models and Preventive Planning Strategies for Resilient Cities in Germany

In the face of the Covid-19 crisis, the city model of the new Leipzig Charter of the EU was re-evaluated. The existing urban development model of a mixed and compact city is to be mainly maintained because the urban density or building typology does not influence the spread of Covid-19. But the pandemic has made it clear how important green space and recreation areas are for inner city residential areas. This green space also becomes more important regarding climate adaptation measures to provide cooler air and ventilation. In the framework of the Leipzig Charter of the EU, the German ministry for building adopted the memorandum on Urban Resilience in May 2021. Resilience in this context means that we should not only repair the damage of disasters but also adapt to future crises and make our cities more resilient and sustainable. For this, we need to strengthen preventive strategies in urban development planning connected with urban renewal approaches and ask for extended city models. Planning shapes the future, including counteracting undesirable scenarios with preventive planning. In this sense, future planning and disaster control have common objectives—they take an interdisciplinary approach to prepare for future change, they want to anticipate and prevent danger, protect and expand the infrastructure, and serve the common good. In this article, I will point out how integrated urban development concepts should be extended with aspects of urban resilience, and which city models are important for the future.

The Key Technology of Oblique Photogrammetry of Assembled Buildings by UAV

In order to ensure the disaster control during infrastructure construction and operation, a method of tilt photogrammetry of prefabricated buildings using UAV is proposed. A comparative study of the key steps in the 3D construction process of building (structure) was carried out, and a set of 3D morphology construction method based on UAV tilt photogrammetry was proposed, and the key steps were optimized to realize automation and visualization in the process of model construction. The experimental results show that in the application case of a school district, the error of the three directions is distributed between -4 cm and 4 cm, accounting for 74%, and that between -2 cm and 2 cm, accounting for 37%; the root mean square error of the three directions was calculated to be 4.0 cm, 3.8 cm, and 2.8 cm, respectively. In an engineering application case, the error size of the three directions distributed between -4 cm and 4 cm accounted for 74%, and that between -2 cm and 2 cm accounted for 50%; the root mean square error of the three directions was calculated as 2.3 cm, 2.5 cm, and 3.3 cm, respectively. Conclusion. This method can not only obtain high-precision 3D models of urban complex and single buildings, but also meet the requirements of digital city construction for 3D model construction and obtain clear and high-precision digital land surface model.

Relationship between desorption amount and temperature variation in the process of coal gas desorption

Coal bed methane (CBM) is a clean energy source and its main component is methane, however, due to the complex conditions of its occurrence, its content detection is inaccurate and its utilization is not efficient. To further investigate the desorption and diffusion of methane in coal seams, this study uses an experimental system to investigate the desorption volume and temperature variations of gas desorption at different equilibrium pressures for three different particle sizes of coal samples. The results show that the desorption process is a heat absorption and cooling process, which is mainly influenced by the equilibrium pressure and the particle size of the coal samples. The amount of desorption and the absolute desorption temperature variation increases with increasing equilibrium pressure and increases with decreasing particle size of the coal sample. The desorption temperature variation at a desorption time of approximately 3000 s is close to the minimum. There is a linear relationship between the gas desorption volume and the absolute desorption temperature variation, which can be used to predict the desorption volume using the absolute desorption temperature variation. This will assist in the accurate measurement of coal bed methane content and the prevention and control of coal mine gas disasters.