Abstract:In order to improve the bearing capacity of complex joints of fully assembled steel-reinforced concrete composite columns and reduce the strength degradation degree of complex joints under load,the numerical simulation of the bearing capacity of complex joints of fully assembled steel-reinforced concrete composite columns was studied.Three kinds of complex joint specimens with shear span ratios of 2.2,2.6 and 3.0 were designed by using C40 concrete,HRB400 high-performance steel bars and M20 friction-type high-strength bolts,respectively.The bearing capacity of the three specimens was analyzed by actual loading test and three-dimensional finite element numerical simulation test.The analysis shows that among the three complex joint specimens,the yield load of the specimen with the shear span ratio of 2.2 reaches more than 190 kN,and the peak load and ultimate load remain more than 200 kN,and its bearing capacity is significantly higher than that of the other two specimens.In addition,the energy dissipation coefficient of the specimen with the shear span ratio of 2.2 is higher,which can maintain a high energy dissipation capacity during the loading process.Meanwhile,the strength degradation of the specimen is small,and the stress level of the specimen is maintained in a good state during the compression process.Therefore,the complex joints of fully assembled steel reinforced concrete composite columns with a shear span ratio of 2.2 can effectively guarantee the bearing capacity of the building.

Abstract:This study utilizes observational data from collocated accelerometers and seismometers at 61 earthquake early warning reference stations in Inner Mongolia.Under the assumption of negligible seismometer self-noise,a comparative analysis was performed using the probability density function(PDF)method to investigate the characteristics of background noise in terms of root mean square(RMS),power spectral density(PSD),and PDF.The results indicate that in the high-frequency band,variations in accelerometer RMS are strongly correlated with instrument models,whereas seismometer RMS variations are more closely linked to local environmental conditions.Moreover,accelerometer RMS values consistently exceed those of seismometers at the same station,which is primarily attributable to the higher intrinsic self-noise of accelerometers.In the mid-to-low frequency bands,seismometers demonstrate a superior capability in recording background noise,while accelerometers lack such capacity;both instruments exhibit relatively concentrated PSD distributions in the mid-frequency range.In the low-frequency band,seismometer performance is significantly affected by the velocity measurement principle,whereas accelerometers,which measure acceleration,remain unaffected.Analysis of instrument self-noise reveals a hierarchical pattern,with TDA-33M accelerometers exhibiting the lowest self-noise,followed by JS-A2,and QA-2g showing the highest noise levels.Consequently,this study recommends that future accelerometer designs prioritize the reduction of self-noise.

Abstract:The analysis of soft-sediment deformation structures is a crucial approach in paleoseismic studies.In re-cent years,the phenomenon of soft-sediment deformation in the Quaternary basins along the South China coast has garnered increasing attention.However,these soft-sediment deformation structures are often revealed through core samples,which have limited visibility and are susceptible to interference.Therefore,there is an urgent need for an appropriate method to identify the macroscopic structures and detailed characteristics of soft-sediment deformation.Micro-X-ray fluorescence(μ-XRF)mapping technology is capable of identifying the types and distribution charac-teristics of elements within samples,making it a direct and effective means for analyzing soft-sediment deformation structures in core samples.Although its application is still in its infancy,it merits further exploration.This study conducts an in-depth analysis of soft-sediment deformation structures in the late Pleistocene mottled clay layers of the South China coastal region,discusses the major elements that can effectively indicate such structures,and es-tablishes a μ-XRF analytical method suitable for soft-sediment deformation in the late Quaternary.The results indi-cate that the Fe element in the study area is a relatively stable and effective indicator for identifying soft-sediment deformation,with other elements playing a supportive role in discrimination.Furthermore,the pretreatment meth-od using epoxy resin to cure and polish samples significantly enhances the scanning quality of μ-XRF.This μ-XRF mapping analysis method can effectively assist in the macroscopic identification of soft-sediment deformation,re-veal its deformation details,and provide micro-scale technical support for the study of regional tectonical stability.

Abstract:This paper carries out an experimental study on monitoring the hydraulic fracturing process of large-scale shale sample under the true triaxial loading by using the active ultrasonic based method combined with a passive acoustic emission technique.The paper used ultrasonic multiple scattering waves to monitor wave velocity changes and a template matching based acoustic emission method to detect the acoustic emission activities during the experiment.The results suggest that integrating active and passive monitoring methods allows us to observe a decrease in wave velocity approximately 36 seconds before hydraulic fracturing breakdown.A minimum velocity reduction of 0.035(-3.5%)occurred four seconds before the breakdown.During the same stage,inactive acoustic emissions are observed 12 seconds before the breakdown,while a large number of acoustic emissions occur at the time of the breakdown.We also observe a 40 s-long logarithm velocity recovery process after the breakdown.Meanwhile,the acoustic emission shows a relatively rapid power-law decay.These findings demonstrate that integrating active and passive monitoring methods effectively characterizes the evolution of the medium during hydraulic fracturing.This provides valuable support for laboratory studies on shale gas exploration and risk assessment.

Abstract:With the accelerated construction of cross-river and cross-sea bridges and the continuously increasing density of vessel traffic,ship-bridge collision incidents have become more frequent,posing severe threats to bridge structural safety and maritime traffic order.This paper systematically reviews the risk perception and assessment technologies for active bridge collision prevention,focusing on multi-source vessel target sensing technologies(AIS,visible light,infrared,radar,etc.)and their multi-source data fusion-based early warning mechanisms.Strategies for multimodal data fusion and ship collision risk assessment methods are analyzed.Current technical bottlenecks are summarized,and future research directions are proposed,including edge intelligence deployment,system-level collaborative integration,digital twin-based collision prevention frameworks,and standardized evaluation systems.This study aims to provide a theoretical foundation and technical support for resilient and intelligent bridge safety assurance.

Abstract:In order to meet the current needs of artificial intelligence development planning and big data management platform for earthquake prevention and disaster reduction,and to fully exploit the advantages of microservice architecture for system performance,availability,scalability,fault tolerance and security,an earthquake information trigger based on microservice architecture is designed.This system addresses the shortcomings of the existing system in the above dimensions.It provides stable,reliable and customized seismic event trigger for the downstream of seismic event data push,and provides data source for the big data service platform of earthquake prevention and disaster reduction and data support for subsequent research tasks.

Abstract:To analyze the pre-earthquake anomalies associated with the M5.0 earthquake in Beibu Gulf,a retrospective prediction study was conducted.Based on the earthquake catalog of Guangxi and adjacent regions,as well as geophysical observation data from the Guangdong-Guangxi border area,multiple methods—including seismic periodicity analysis,enhanced seismicity,earthquake swarm identification,seismic gap detection,and time-series analysis of geophysical observations,were applied to examine the anomalies preceding the M5.0 earthquake in Beibu Gulf on June 24,2023.The results show that this event belongs to an isolated earthquake sequence.Pre-earthquake anomalies include significant seismicity patterns,as well as fluid and geomagnetic anomalies.These findings provide a reference for post-earthquake trend assessment and strong earthquake prediction in the Guangxi region.

Abstract:In current marine seismic data processing,acquisition footprints caused by energy variations are difficult to be suppressed effectively,severely impacting the signal-to-noise ratio and resolution of target areas.This paper focused on energy-induced acquisition footprints and developed a novel acquisition footprint attenuation technology based on the Kriging algorithm.The core idea of this method is to apply the Kriging algorithm to statistically analyze the spatial correlation variations in seismic data volumes,thereby deriving a coefficient volume for removing acquisition footprints and achieving their suppression.The key innovation lies in modeling the regionalized seismic data as a combination of acquisition footprint noise factors and effective reflection signals.Each acquisition footprint factor of the data volume corresponds to a specific variogram,and the distinction between acquisition footprints and effective reflection signals in the variogram domain enables the prediction and attenuation of footprints.Application results in marine seismic data processing demonstrate that this fully data-driven method outperforms traditional approaches in footprint attenuation while better preserving effective reflections.It provides a new solution for acquisition footprint attenuation and holds significant potential for broader application.

Abstract:To address the issues of delayed emergency response and increased risks and losses due to untimely identification of potential safety hazards in mines,this paper proposes a major mine disaster risk warning method based on a BES-RBF neural network.Kernel Principal Component Analysis(KPCA)is employed to extract features associated with mine disasters from complex mine data.The Radial Basis Function(RBF)neural network is adopted as the warning model for major mine disasters.The Bald Eagle Search(BES)algorithm is utilized to optimize the network parameters,thereby establishing an optimal network model.The extracted features are then used as inputs to the trained network,which outputs the relative risk value of mine disasters.This value is classified into different risk levels to achieve major mine disaster risk warning.Experimental results demonstrate that the proposed method achieves a high KS value while maintaining low CPU and memory occupancy.

Abstract:This study selects the large marshes on Plum Island,Massachusetts as a case.By using historical aerial images of 1974,2008 and 2021,the paper tracks the spatial pattern and temporal changes of salt marsh ponds and explores the impact of their expansion on the stability of the marsh plane.For this purpose,in this study,the boundaries of the pond were delineated and classified by area by using ArcGIS Pro,and key indicators such as the expansion rate,the direction of centroid migration and area change were calculated accordingly.The results show that over the past half century,these ponds have undergone a dynamic evolution process of expansion first and then partial recovery.The vegetation recovery in some local areas has even offset the area loss caused by expansion,showing a net recovery trend.Wind and wave erosion,freeze-thaw action and peat decomposition jointly drive the expansion and direction change of the pond.Map analysis further reveals that the vegetation restoration at the edge of the pond is closely related to the drainage effect of early ditching or tidal connectivity.Even under partially drained conditions,vegetation can gradually recover.Drawing on the mature research framework of the New England region has significant reference value for the management and restoration of salt marshes in China.

Abstract:The Enping Formation and Zhuhai Formation of Paleogene in Lufeng A Oilfield are affected by complex seismic sedimentary patterns,deep burial depths,and widely distributed high-speed limestone layers.The seismic data has narrow frequency band,low dominant frequency,and poor signal-to-noise ratio,making it difficult to overcome the challenges of high-resolution fine reservoir prediction,complex geological sedimentary pattern recognition,and solving oil-water conflicts faced by oilfield development.A set of fidelity and amplitude preservation high-resolution processing techniques has been developed for the characteristics of Paleogene seismic data in Lufeng A oilfield.Firstly,a combination of fidelity and amplitude preservation fine denoising is studied to provide effective signal-to-noise ratio for improving resolution;secondly,adaptive ghost wave suppression processing is performed to eliminate the notch response of ghost waves to the frequency band;then,based on the characteristics of shallow sea data,research on the prediction and suppression of multiple waves by multi-method prediction,multi-model and multi-domain joint adaptive subtraction is conducted;further research on effective Q-compensation processing for well-seismic contrast constraint is carried out;finally,research on pre-stack frequency band expansion processing is done in the imaging domain.By applying this scheme,high-resolution seismic data volumes were obtained,and the dominant frequencies of the Zhuhai Formation and Enping Formation were increased from 20 Hz to 35 Hz.The high-resolution seismic data finely characterized the distribution pattern of the sand bodies,ultimately explaining the problem of oil-water conflicts.This provides an example for improving the resolution of seismic data under the same geological conditions.

Abstract:According to the physical and mechanical property indicators of typical soil layers in Guangzhou in relevant references,and by using the inverse calculation of foundation bearing capacity formula,this paper determined some shear strength indicators,calculated the settlement of 84 groups of soil layer models,and obtained the settlement s of square plates with different width b under the corresponding load of foundation bearing capacity characteristic value and the distribution law of s/b value in various soil layers.The results show that when the width of the square pressing plate is in the range of 0.707 m to 2 m,the calculated value of the relative deformation value s/b corresponding to the characteristic value of the foundation bearing capacity has no obvious change.The calculated value of s/b of low compressibility soil of typical soil layers in Guangzhou is 0.005～0.010,the average value is 0.008,the standard deviation is 0.001,and the dispersion coefficient is 0.125.The calculated value of s/b of medium compressibility soil in the typical soil layers in Guangzhou is 0.008-0.021,the average value is 0.016,the standard deviation is 0.004,and the dispersion coefficient is 0.250.

Abstract:The water depth in Lufeng Sag of the Pearl River Mouth Basin is relatively shallow and the terrain is relatively flat.Two sets of high-velocity limestone strata are widely developed in the Pearl River Formation in this area.The strong reflection coefficient interfaces formed by the strong impedance difference between the sea surface,seafloor,and limestone strata readily generate multiples with high energy.In addition,the short-period multiples formed in shallow water areas interfere with effective reflections,affecting shallow,medium,and deep strata,which significantly increases the difficulty of seismic interpretation.The unique geological characteristics of this area result in strong multiple energy and complex multiple types,making it difficult to effectively suppress them by conventional methods.Based on the geological characteristics of the area,this study takes the gentle slope zone of Lufeng 15 Depression in the eastern part of the basin as an example and adopts a targeted combination multiple suppression approach for shallow water areas.First,the Model Shallow Water Demultiple(MWD)method is used to suppress water-layer-related multiples,especially short-period multiples.Then,the 3D Surface Related Multiple Elimination(3D SRME)method is applied to suppress long-period multiples related to the sea surface,particularly those associated with the limestone interface,as well as some interbed multiples.Finally,the high-resolution Radon transform is applied on common reflection point gathers to suppress residual multiples.The results show that the combined MWD+3D SRME+Radon method can effectively suppress short-period water-layer multiples,long-period limestone-interface-related multiples,and some interbed multiples,significantly improving the signal-to-noise ratio and imaging quality of seismic data,and providing an important reference for areas with similar geological backgrounds.

Abstract:Based on the field deformation measurement data of metro tunnels and side excavation foundation pits,a tunnel deformation prediction method for metro protected areas based on Bayesian dynamic linear model(BDLM)is proposed.Firstly,the BDLM prediction model is established for the horizontal deformation of the excavated foundation pit next to the tunnel,and then the prediction results of the foundation pit deformation are used as regression variables to establish the prediction results of tunnel deformation,and finally the real-time and accurate prediction of the deformation of the metro tunnel protection area is realized.Taking the measured data of a certain section of Hangzhou Metro Line 1 with metro excavation as an example,the effectiveness of the method is verified.The results show that the proposed BDLM prediction method can accurately predict the horizontal deformation of the foundation pit and the tunnel deformation of the metro protection area in the short term,and effectively measure the uncertainty in the model,and give the confidence interval of the prediction results.

Abstract:This paper explores the audience cognitive efficiency and behavioral response patterns of short video platforms in the dissemination of earthquake disaster information,and provides a basis for optimizing the emergency communication strategy.This paper constructed a research model based on social cognition theory and uses and satisfaction theory,empirically analyzed the data of 380 residents in earthquake-prone areas by questionnaire survey method,and verified the hypotheses by correlation analysis,ANOVA and regression analysis.The results show that the frequency of using short videos significantly improves the audience's understanding speed and key point memory(cognitive efficiency)of disaster information;the content released by government agencies is more effective in triggering risk-avoidance behaviors than the content of ordinary users;the education level positively regulates the audience's willingness to actively verify information.Short video platforms have significant real-time communication advantages,but content authority and public media literacy need to be strengthened.

Abstract:Granite residual soils are widely distributed in Guangdong Province,China,exhibiting unique engi-neering properties that significantly influence slope stability.This study focuses on a tower-foundation slope com-posed of granite residual soil in Guangdong,where the strength reduction method in Midas GTS/NX was employed to simulate slope stability under extreme rainfall conditions.Numerical simulations revealed that the safety factor of the slope decreased to 0.985 under extreme rainfall,indicating significant stability degradation.Laboratory permea-bility tests demonstrated that the second soil layer possesses a relatively high permeability coefficient.Subsequent seepage-stress coupling analysis further revealed that this layer preferentially forms dominant seepage channels,inducing increased permeability and pore water pressure in the underlying soil.Meanwhile,the combined effects of tower-foundation loading and seepage-induced water pressure generated stress concentration and throughgoing plas-tic zones in the mid-lower slope,ultimately triggering instability mechanisms.This study elucidates the spatiotem-poral coupling mechanisms between rainfall-induced seepage path evolution and stress field responses,particularly identifying the critical safety threshold for the slope toe region under synergistic load-seepage interactions.The find-ings provide a novel analytical framework for stability assessment and mitigation design of granite residual soil slopes under similar geological conditions.

Abstract:Absrtact:Three high-resolution seismic reflection profiles obtained from shallow seismic exploration were used to analyze the shallow strata and the basic characteristics of the fault.The results show that the shallow strata of the Xushui fault are in a horizontal shape,with little variation in overall thickness;The Xushui fault strikes east-west and dips north with an apparent dip of 59°-77°and a fault drop of 3-14 m.The shallowest upper break point can be identified with a burial depth of 42 m.Combined with drilling verification,it is considered that Xushui fault is an active fault in the early and middle Pleistocene.

Abstract:In order to further play the disaster reduction effect of earthquake early warning and improve the ability of earthquake emergency response,based on the emergency response requirements of major earthquakes in Yunnan Province,the emergency wake-up mechanism of earthquake early warning in Yunnan Province is proposed.The technologies of sending rules,automatic matching of epicenter latitude and longitude,and identification of affected areas are studied,and the emergency wake-up system of earthquake early warning is constructed.Based on the number list,the push of the earthquake early warning message is realized.By forcing the message to reach the user,the display form that must be displayed is provided,and the efficient emergency wake-up service is realized.The analysis of the test and exercise results shows that the average release time is less than 18 s,which indicates that the technical architecture and release process of the earthquake early warning emergency wake-up system are feasible.

Abstract:Under the background of rapid development of assembled buildings,a new modular integrated construction sandwich shear wall was composed of two"L"prefabricated wall panels with cast-in-place concrete in the middle is proposed to address the impact of shear wall connection reliability on structural performance.Comparison of the seismic performance of the two sandwich shear walls and cast-in-place shear wall through low cycle repeated load test showed that the specimens showed bending and shear damage characteristics,and the sandwich shear wall produces cracks along the joints,which are finally divided into several parts.The ultimate bearing capacity of the sandwich shear wall(average value of 1,968.41 kN)is lower than that of the cast-in-place shear wall(2,130.95 kN)by 7.62%,and the ductility coefficient of the sandwich shear wall(2.18)is lower than that of the cast-in-place shear wall(2.18)by 2.75%.The sandwich shear wall shows better energy dissipation capacity as compared to cast-in-place shear wall.

Abstract:From March 8 to 29,1966,there were five earthquakes above 6 magnitude in Xingtai area,including Ningjin 7.2 earthquake,which caused more than 8000 deaths.The Xingtai earthquake swarm occurred in the Shulu Depression in the south-central North China Plain.Previous data suggest that the boundary and internal faults of Shulu Depression are not active in the late Quaternary.The seismogenic structure of the 1966 Xingtai earthquake may be a hidden deep strike-slip fault,which is not related to the shallow pre-existing faults.The recent shallow seismic exploration work carried out in the Shulu Depression and its vicinity reveals that faults with shallow burial depth of upper breakpoints may be developed inside the Depression.Based on the results of the latest shallow seismic exploration work,this paper uses the borehole joint profile detection method,combined with the chronology test,to detect the breakpoints revealed by the shallow exploration in detail and analyze the age of fault activity.The detection results reveal that a steeply dipping active fault since the late Pleistocene—Xinhexi fault is also developed on the west side of the Xinhe fault on the eastern boundary of the Shulu Depression,which may be connected up and down with the deep steeply dipping strike-slip fault revealed by the early detection data.The detection results provide key information for the analysis and discussion of the seismogenic structure of the 1966 Xingtai M7.2 earthquake.