Abstract:Based on the Yearbook of Meteorological Disasters in China （2004—2019）， the Tornado Dataset in China （2007—2016）， the media reports on tornado cases， and the research papers on tornadoes， a preliminary database of tornadoes in China from 2004 to 2019 was established， including information on the time， location， and intensity of tornado cases， etc.， and their spatiotemporal distribution characteristics were statistically analyzed. Subsequently， a 100 000-year stochastic simulation of tornadoes based on the tornado database was conducted using the Monte Carlo method. The annual frequency and spawn locations were simulated using the genesis model， the track parameters （such as intensity， direction， length， width， etc.） were simulated using the track model， and the wind speed variation was simulated using the wind speed model. Finally， the extreme wind speeds of tornadoes in various districts and counties in Jiangsu Province were predicted. The main results show that the distribution of tornado extreme wind speeds exhibits a pattern of higher values in the east and north， and lower values in the west and south. The tornado extreme wind speed in the downtown of Nanjing is significantly lower than that in other regions of Jiangsu Province， while that in Sheyang and Xiangshui Counties in Yancheng City is significantly higher compared to other regions in the province.

Abstract:By designing two types of connector perforated plate composite bridge deck structures suitable for different needs， experimental research is conducted on their mechanical properties. The main findings indicate that the failure of the composite bridge deck is marked by the diagonal tensile shear failure of the concrete slab at the variable cross-section of the shear span zone. The debonding gap of S1 specimen is relatively small throughout the loading process， because the bolted connection effectively suppresses the debonding deformation between the bottom plate and the concrete slab. The bending bearing capacity of S1 is 21% higher than that of K1， and the ultimate mid span deflection is 15.5% smaller than the latter， which can improve the overall stiffness of the composite bridge deck. Verification shows that when the contribution of perforated plates to bending capacity is neglected， the simplified calculation formula yields valid and conservative results， providing a reliable reference for design purposes.

Abstract:To minimum the impact on the facade of existing buildings avoid excessive occupation of structural space， a reinforcement method using the thin reinforced concrete （RC） columns with irregular cross-sections was proposed to enhance the integrity of existing masonry structures， focusing on the in-plane seismic behavior of masonry walls strengthened with externally added thin RC columns with irregular cross-sections. Four 1/2-scale clay brick masonry wall specimens with the same RC columns and different lengths were designed and fabricated. Pseudo-static cyclic loading tests were conducted to investigate the in-plane confining effect of the thin RC columns on the masonry walls. Subsequently， the discrete element method （DEM） was employed to numerically simulate the tested specimens and prototype walls. Existing DEM algorithms were modified， and based on the validated simulation methods， key parameters affecting the in-plane strengthening effectiveness of brick walls were analyzed. Both experimental and numerical results demonstrate that the proposed thin RC columns with irregular cross-sections could effectively improve the in-plane mechanical performance of brick walls. The strengthening walls exhibit significantly enhanced in-plane shear bearing and deformation capacities. From the perspective of enhancing the in-plane shear capacity of the wall， for a 240 mm thick brick wall， the effective confine length of two adjacent columns within the wall plane is no more than 7 200 mm.

Abstract:To evaluate the mechanical performance of naturally corroded reinforced concrete （RC） beams， bending tests were conducted on three RC beams that had been in service for 26 years in a marine environment， and the load-deformation full-process curves were obtained. Following the tests， the distribution of the cross-sectional area of corroded rebars along the longitudinal direction of the beams was captured employing 3D laser scanning technology. Based on this data， an analysis was performed on the bending failure modes， crack development， load-bearing capacity， and strain development of naturally corroded RC beams. The results indicate that the reinforcement corrosion in natural environments exhibits significant non-uniformity along the longitudinal direction， generally following a pattern of more severe corrosion at mid-span and less severe corrosion towards the ends. Moreover， longitudinal rebars in contact with stirrups exhibit reduced corrosion compared to adjacent positions， due to the protective effect of the stirrups. The failure mode of naturally corroded RC beams resembles that of uncorroded under-reinforced beams. However， substantial differences in corrosion degree among longitudinal rebars at the failure cross-section can lead to premature fracture of severely corroded rebars， causing redistribution of stress， which manifests as a “multi-stage” characteristic in the load-deflection curves. Compared with the least corroded specimen， the yield and ultimate loads of the most severely corroded specimen decreases by 18.1% and 14.7%， respectively. Additionally， the bending bearing capacity of the corroded RC beams， calculated by using the failure mode-based method， shows good agreement with the experimental results.

Abstract:To achieve damage-free and reversible reinforcement of ancient wooden columns， this paper proposes a strengthening method of wooden columns with high-performance bamboo-based composites constrained by steel strips. Additionally， it conducts axial compression tests on 6 circular medium-length wooden columns. The experimental results show that the load-bearing capacity of wooden columns strengthened with high-performance bamboo-based composites are significantly increased， with a range of 22.0%~97.6%. The stiffness of the specimens increased by approximately 18.9%~57.3% after reinforcement. However， the lateral constraint effect of the steel strip on the core column is not significant. Based on the experimental results， the type and thickness of reinforcement materials are used as test variables to analyze the failure mode， load bearing capacity， and deformation performance of strengthened circular medium-length wooden columns. An extended parameter analysis is conducted through finite element simulation， and a calculation model for the compressive bearing capacity of wooden columns under different stress states is established. The calculation formula for the load bearing capacity of the circular medium-length wooden columns strengthened with high-performance bamboo-based composites is derived. The errors between the calculated and tested results are within 13%. The findings of this study can provide theoretical guidance for the reinforcement design and related analysis of ancient wooden columns.

Abstract:Calculating the annual probability of slope failure is crucial for landslide risk assessment. In this paper， an efficient method for calculating the annual probability of slope failure under rainfall conditions is proposed considering both uncertainties of rainfall and soil parameters. First， according to the theory of seepage and strength of unsaturated soil， the limit equilibrium method is used to obtain safety factors of the slope under a given rainfall event. Then， the slope stability analysis is regarded as a binary classification problem， and the support vector machine is used to build a surrogate model to predict the slope failure. With the surrogate model， the failure probabilities of the slope under different rainfall conditions are analyzed to construct the fragility surface. The annual most dangerous rainfall is identified based on the maximum slope failure probability. Finally， according to the total probability theorem， the Monte Carlo simulation is used to estimate the average failure probability of a slope under the annual most dangerous rainfall， i.e.， the annual probability of rainfall-induced slope failure. The proposed method is applied to study the annual probability of rainfall-induced slope failure in a certain region. The results show that the probability of slope failure for a given rainfall intensity increases nonlinearly with rainfall duration. As the rainfall intensity increases， the probability of slope failure increases. The annual most dangerous rainfall is more intense and longer in duration than normal rainfall but has a lower likelihood of occurrence. The annual probability of slope failure is proportional to the average number of rainfall events per year and is more sensitive to effective cohesion and friction angle. The method proposed in this paper can provide an efficient tool for rainfall-induced landslide risk assessment.

Abstract:This paper proposes a method for the system reliability analysis of high concrete-faced rockfill dam （CFRD）， considering creep effects and hydro-mechanical coupling. To obtain the joint failure probability of CFRD in multiple failure modes， the total probability formula is used to express the failure probability of the dam system as the product of the failure probability of the face slab and the conditional probability of seepage failure after slab failure. The instantaneous deformation， consolidation deformation， and long-term creep are calculated by the Duncan-chang E-B model， the Biot consolidation theory， and an improved Merchant model， respectively. Considering the uncertainty of the parameters and the time factors of rockfill creep and reservoir water level fluctuation， the system reliability of the dam is calculated. The method is applied to the 233 m high Shuibuya CFRD. The results show that the consolidation deformation is completed in the construction and initial storage stages， and the deformation produced during the operation of the dam is mainly creep deformation. During the initial storage， the slab failure probability and the seepage failure probability after the slab failure increase sharply， resulting in an obvious reduction in the reliability of the dam system. During operation， the increase in creep deformation leads to a gradual decrease in the reliability of the slab and the dam system. As the creep deformation gradually converges， the reliability of the dam system tends to be stable after a slow decline.

Abstract:Seawater sea sand recycled aggregate concrete （SSRAC） with different recycled coarse aggregate replacement ratios and salinities were designed to explore its carbonation characteristics. The results from carbonation depth measurements and thermogravimetric analysis showed that the carbonation rate could be increased by 81.23% with 4% salinity and 100% recycled aggregate replacement ratio， Additionally， the carbon absorption of seawater sea sand mortar increased by up to 14.33%. Carbonation also improved the concrete compressive strength. Based on the test results， a prediction model for the carbonated concrete strength was developed. Using this model， the total carbon emission （C_E） and carbon absorption （C_AS） over the whole lifecycle were calculated， and the net carbon emission （C_EF） was defined and calculated. The analysis showed that the ratio of net carbon emission to total carbon emission （C_EF/C_E） for SSRAC decreased from 61.37% （in ordinary concrete） to 26.93%， demonstrating strong potential as a low carbon material.

Abstract:To investigate the influence of sudden changes in light， temperature， humidity， wind speed， and other environmental factors on the physical and mental state of expedition members during a sea voyage to Antarctica lasting for several weeks， as well as the rules governing human adaptation to these changes， field measurements and sea voyage surveys were conducted on Xuelong and Xuelong 2. Subjective questionnaires were used to assess the light environment in different cabin spaces and the sleep and mood of expedition members in various stages of the voyage. A design strategy for the cabin light environment was then proposed. The findings indicate that the cabin spaces are affected by insufficient natural light and outdated， inadequately vivid colors. The sleep quality score of Xuelong members exhibits a gradual decline， while that of Xuelong 2 initially decreases but later increases. At the end of the voyage， the sleep quality score of Xuelong 2 is significantly higher than that of Xuelong （p<0.05）. The members on Xuelong primarily experiences sleep disturbances and irritability， whereas those on Xuelong 2 encounters motion sickness， loneliness， and nervousness. Approximately 83% of the members expressed a desire to incorporate colored lighting in the cabin. The analysis of the relationship between light environment and sleep and mood indicates that targeted optimization of cabin lighting can help to improve the quality of the living and working environment of the expedition members during the voyage.

Abstract:Knowledge graph neural recommendation algorithm （KGCN） is used to assess hazmat road transportation risks in real time， aiming to reduce the probability of risks and avoid terrible accidents by detecting high-risk factors detected timely and adjusting the transportation status in advance based on real-time risk assessment report on hazmat road transportation. A knowledge graph describing hazmat road transportation accidents is constructed and embedded into a recommendation algorithm based on graph neural networks （GNN）， so that the probability of risk factors causing an accident is evaluated and a specialized risk assessment is given for each hazardous material road transport incident. The method simplifies real-time data processing operations and overcomes the difficulties of real-time data sparsity. Taking the cargo road transportation alarm data including 54 097 items as an example for calculation， the AUC value is calculated to be stable at around 0.83， indicating that the calculation results are reliable.

Abstract:To address the current limitation of using a single threshold for the calibration of servo steel support axial force， an elastic foundation beam model was employed to simplify the excavation support structure. A variable “concentrated force” approach， considering the ultimate bearing capacity of the support as the upper limit， was adopted to simulate the servo steel support. A finite element analysis model was developed using ABAQUS software combined with a genetic algorithm for joint computation， proposing a combined solution method for the dynamic setting of servo steel strut axial force. Utilizing the servo steel strut’s dynamic force adjustment function and based on the dynamic axial force setting method proposed in this paper， the optimal force reference value can be determined through objective function setting， providing reference guidelines for technical staff to regulate servo steel strut’s support forces， thereby contributing to the realization of the high-quality development goals of “active regulation， micro-deformation control” in excavation engineering .

Abstract:To solve the problem of choosing grinding mode by experience in the rail grinding process of high-speed railway turnout， the parametric expressions of rail profile and grinding wheel were established， taking the CMC-16 turnout grinding vehicle as the research object. The rail grinding process was simulated using Matlab numerical calculation， and the angle distribution and action results of nine grinding modes commonly used in turnout grinding vehicles were analyzed. Based on this， with the design principle of realizing the best match between the theoretical grinding rail profile and the target one， an improved method of rail grinding scheme of turnout grinding vehicle was proposed. The results show that the proposed method is based on the common mode of grinding vehicle. During field trials， the maximum difference in grinding amount between the actual profile and theoretical profile was 0.16 mm， within the grinding range of -10° to 55°. The profiles were essentially identical， indicating that the method can avoid the problems of uncontrollable grinding mode and over-reliance on human experience. The grinding scheme designed by this method consists of the grinding mode serial number of each operation， which can be directly input to the operators of the field grinding vehicle， and is more suitable for field practical application.

Abstract:A numerical model is proposed to accurately and efficiently separate the pulsating pressure of side windows in the frequency range of 100~10 000 Hz to address the problem of interior noise caused by pulsating pressure at side windows in high-speed driving conditions. First， the shear stress transfer delayed detached-eddy simulation （SST-DDES） turbulence model is used to simulate and analyze the external flow field of the vehicle body. The analysis model for the external flow field of the entire vehicle is established the turbulence cloud map， the velocity streamline map， and the pressure cloud map at side windows are analyzed， which are compared with the wind tunnel test analysis. The simulation results are in good agreement with the wind tunnel test. The excitation characteristics of side window fluctuating surface pressure is studied based on the improved periodogram method. By analyzing the wavenumber frequency spectrum characteristics， a numerical model is established to separate the convective and acoustic components of fluctuating surface pressure. Based on the interpolation accuracy analysis of fluctuating surface pressure data points， the convective and acoustic components in the frequency range of 100~10 000 Hz are analyzed， and the analysis results and solution time are compared with those of the commercial software VA One. The accuracy and computational efficiency of the numerical model for fluctuating surface pressure separation are validated.

Abstract:To address the limitations of traditional geophysical methods in effectively predicting the distribution of low-permeability sweet spots in deep continental formations， a high-precision geological sweet spots prediction method based on artificial intelligence （AI） is proposed， providing reliable guidance for optimizing fracturing schemes and deploying well locations. This multi-step AI-driven approach incorporates XGBoost algorithm for constructing an improved empirical quality index （RQI） for low-permeability reservoirs， bee colony algorithm deep neural network for 1D well-point RQI curve prediction， and improved CNN algorithm based on Dropout strategy for spatial three-dimensional RQI distribution prediction.This methodology breaks through the limitations of traditional sweet spots prediction techniques， achieving multi-scale intelligent prediction from 1D to 3D while significantly improving the accuracy of low-permeability reservoir characterization. The application in a certain oil field shows that this method effectively overcomes the influence of various unfavorable factors and significantly improves the accuracy of geological sweet spots prediction compared to traditional methods.

Abstract:The Songze and Liangzhu Cultures are characterized by the abundant and exquisite jade artifacts unearthed. The characteristics of unearthed jade artifacts， especially their sources， have become significant scientific questions drawing attention from the fields of earth science， archaeologyand cultural heritage. Based on the exploration of the geological processes that jade may undergo during burial and the potential changes that may occur， and the discussion about the regional geological prospecting and the innovative integrated research， it is suggested that the sources of jade artifacts unearthed from Songze and Liangzhu Cultures， while not excluding the possibility of “source from afar”， should primarily focus on “local resourcing”. The key to future breakthroughs lies， first and foremost， in the innovation of research routes and methods. In addition， it is essential to further deepen the comprehensive study of geological processes during the burial stage of jade artifacts. Moreover， it is essential to strengthen regional geological prospecting efforts， along with interdisciplinary collaborative research.

Abstract:To accurately quantify the real-life usage cost of power batteries over their entire lifecycle， provide consumers with transparent long-term vehicle cost references， and offer a scientific basis for society to assess the economic benefits and sustainability of electric vehicle adoption， this paper， taking electric vehicles equipped with lithium iron phosphate batteries as a case study， constructs consumer total cost models of power batteries in fast and slow charging modes. The influencing factors on consumer total costs of power batteries in these two charging modes and the relationships between total costs and these factors are investigated. Taking the conversion between the number of the individual cycles of power batteries and the driving distance of electric vehicles into account， it incorporates the capacity degradation of power batteries into the model. To validate the effectiveness of the model， it conducts an instance analysis of the total cost. The findings show that the actual capacity retention rate of power batteries is the most critical factor affecting total consumer cost.