Abstract:In view of the current situation of the foreign military ground-penetrating weapons， the calculation method of equivalent contained explosion equivalent is given through the coupling factor of ground shock energy. By introducing the dimensionless energy factor， a criterion of damage zones based on the energy factor is proposed. Based on the classical elastic-plastic mechanics， the formulas for calculating the self-supporting capacity of surrounding rock and the pressure of surrounding rock are obtained. It is revealed that the essence of the self-supporting capacity of surrounding rock is the shear strength of surrounding rock， and the expansion of the plastic zone is conducive to the improvement of self-supporting capacity. Combined with the energy factor and the surrounding rock pressure under dynamic load， the calculation method for the minimum thickness of the safety protective layer of deep buried protection engineering under the coupling effect of ground shock and in-situ stress is given. The results show that the high in-situ stress increases the damage effect of the ground shock， and the range of the damage area is larger than that without considering the in-situ stress.

Abstract:The ground shock of earth-penetrating explosion poses a major threat to underground protection works. It is difficult for the existing experimental methods to establish a calculation method for the coupled ground shock effect of guided earth-penetrating bombs， hypervelocity kinetic energy bombs， and earth-penetrating nuclear bombs. In this paper， the relationship between the volume of the ground-penetrating explosion damage area and the coupled ground shock energy is revealed. According to the relationship between the radius of compression and damage areas of underground explosion and explosion equivalent， the correlation between the existing main coupling factors is clarified. A calculation method for coupling factors is proposed， which only needs two initial parameters， i.e.， the radius of the compression areas of the contact explosion and the closed explosion. The correctness of the method is verified from the aspects of energy coupling factor and equivalent coupling factor through comparative analysis with the existing nuclear test and numerical simulation results of foreign countries. Combined with the calculation of the packing factor， it shows that the coupling factor curve of the ground-penetrating nuclear explosion given by the United States has a good reliability. From the perspective of protection engineering against the ground shock effect of ground-penetrating explosion， it is more appropriate to use the equivalent coupling factor and packing factor. In this paper， the calculation formulas of the equivalent coupling factor and the packing factor of the earth-penetrating nuclear explosion are given.

Abstract:The smooth particle hydrodynamics method is used to construct an accurate and efficient axisymmetric smooth particle hydrodynamics （SPH） model in combination with the volume adaptive scheme （VAS） to realize the simulation of the process of underwater explosion including shock wave propagation and bubble pulsation. First， the phase of shock wave propagation is simulated to verify the accuracy of the axisymmetric SPH model by comparing with the empirical formula and theoretical value. Then， a typical double-bubble coupling problem in the bubble action phase is selected to analyze the bubble evolution and pressure-load dynamic characteristics. Finally， the influence of the distance parameter between two bubbles on the bubble interaction process is further discussed. The results imply that the axisymmetric SPH model in this paper is of high accuracy and can achieve detailed bubble capture and pressure load prediction for the underwater explosion process.

Abstract:In order to investigate the mechanism of the effect of ground impact disturbance generated by the blast action in the remote zone on the damage of deeply buried caverns， a similar simulation test was conducted using a ground impact effect simulation test device. A cube specimen with its side length of 1.3 m was used to simulate the entire process from ground stress loading （1 000 m burial depth）， cavern excavation to blast ground impact disturbance loading. During the test， sensors were placed inside the specimen and the cavern to monitor the change of stress， strain， displacement and damage inside the cavern. Damage phenomena such as debris crumbling out， fracture connectivity leading to block crumbling out， block slip and fault activation were reproduced by applying impact disturbance loads with different peak values on top of the specimen. Ultimately， preliminary safety thresholds for deeply buried cavern chambers were obtained. The damage mechanisms of fractured， block and fault-bearing rocks under different ground impact disturbances were obtained. Tests have proven that smaller dynamic disturbances can induce damage in deeply buried cavities. Moreover， the degree of chamber damage increases with the number of impact perturbations and the peak of impact load. The test results demonstrate that ground shock disturbances in the distant area of the explosion can still induce engineering hazards.

Abstract:As the burial depth increases， the stress redistribution of surrounding rock in deep engineering forms a supporting pressure zone after excavation， and a new fracture surface will be formed after failure. The stable support pressure zone is the loosening zone of the surrounding rock. The determination of the scope of the loosening zone of the surrounding rock and the study of the deformation and failure mechanism are related to the methods of the deformation stability control and support of the surrounding rock. In this paper， the equilibrium equation of the surrounding rock and the Taylor expansion method are used to obtain the initial radius of the loose zone， the Maxwell equation is used to characterize the evolution of defect stress in the rock mass， and the conditions for the cracking and failure of the loose zone of the surrounding rock are derived. The research results are of guiding significance to the stability analysis of underground roadways and the design of surrounding rock support.

Abstract:In order to study the dynamic response of steel plate-reinforced concrete shaft structure in soil before the formation of plastic hinge line under the action of conventional weapon explosion， based on the model experiment and finite element numerical simulation calculation method， the deformation process and characteristics of shaft structure under medium or long distance explosion were analyzed. The dimensionless circumferential relative displacement was determined as the criterion of structural deformation degree. The theoretical solution of the dynamic response of the shaft structure in soil under the explosion of conventional weapons was derived. The relationship between the dimensionless circumferential relative displacement calculated according to the elastic theory α1e and calculated by the finite element method α1p were analyzed ，and the influencing factors of the ratio α1p/α1e were discussed. The engineering algorithm of elastic-plastic dimensionless circumferential relative displacement α1p based on the elastic solution was constructed.The dimensionless circumferential relative displacement was proposed as the criterion of structural deformation degree， and the threshold value for the occurrence of plastic hinge line and the change of failure mode was determined as 3%. It was verified that the proposed theoretical calculation method can well calculate the dynamic response of steel plate-concrete shaft structure in elastic stage under conventional weapon explosion through the comparison between theoretical and numerical simulation results. The influence of the length-diameter ratio， the scale ratio of the structure and the mass of charge can be neglected. When the equivalent thickness-to-diameter ratio_e， the thickness ratio of steel plate to concrete are large and the relative height of the structure is small， α1e descreases and α1p/α1e increases. When α1e is equal， the plastic deformation of the structure， and α1p/α1e decreases， with the increase of concrete strength.

Abstract:Aimed at the cratering similarity of hypervelocity penetration， the relationship between the crater and the coupled ground shock energy， and the calculation method of the equivalent explosive yield， the similarity law of penetration crater is clarified and the formula of the ground shock energy based on crater volume is established. The relationship between the ground shock efficiency and the projectile kinetic energy， the length-diameter ratio of the projectile， and the material characteristics is obtained. The calculation methods for the equivalent yield of the penetration ground shock and the thickness of the safety protective layer are proposed. The results show that there is a scale effect in the volume of the penetration damage zone， which is proportional to the fourth power of the projectile radius， and that when other conditions remain unchanged， the ground shock energy efficiency increases with the increase of projectile mass， and decreases with the increase of projectile length-diameter ratio and density.

Abstract:This paper analyzed the necessity of anti-explosion resilience design for major projects， proposing the concept of anti-explosion resilience and design objective， based on which， corresponding resilience realization techniques concerning robustness improvement， decrease of indirect loss， and fast recovery were discussed for key civil infrastructures and military protection engineering. Moreover， it established a calculation model of resilience index based on the ratio of expected total loss to total project value， integrating the relationship between resilience and economy. Considering the resilience index and construction and restoration costs， it uesd the model to optimize the decision of resilience design program. Furthermore， it recommended development proposals， including strengthening anti-explosion resilience investigations on technic-support system of major projects， accelerating the research on resilience evaluation method of engineering anti-explosion toughness， accelerating the construction of data decision platform for anti-explosion resilience of major projects， and selecting major projects and conducting demonstration applications of anti-explosion resilience design to promote the development of relevant specifications.

Abstract:In this paper， the explosion damage assessment of prestressed concrete box girder is studied. First， the numerical analysis model of rectangular beam explosion is conducted， and the accuracy and reliability of the explosion numerical model is verified by the field test results. Then， based on the residual bearing capacity of the structure， the damage assessment criterion of box girder at explosion load is established. By analyzing the residual bearing capacity of box girders at explosion load， the P-I （pressure–impulse） curves of various damage degrees of box girders are determined. The results show that the concrete strength has a greater influence on the critical value of overpressure and impulse， while the yield strength of reinforcement has less influence. With the increase of damage grade， the influence amplitude of each parameter on P-I curve of box girder is different. Finally， the formula fitting of P-I curves of all damage grades of box girder with different concrete strength is performed， and the fitting parameter β is analyzed.

Abstract:In order to investigate the mechanical characteristics of steel-steel fiber reinforced concrete （SFRC） composite deck under eccentric tension load in the main girder system， eccentric tension tests of normal concrete composite bridge deck and SFRC composite bridge deck specimens， together with finite element analyses based on the plastic damage model of materials were executed. The influence of SFRC on failure form， stiffness reduction and strain distribution of composite bridge deck under eccentric tension load were investigated. The test and numerical analysis results showed that， compared with normal concrete， SFRC presented characteristics of more cracks but smaller crack width during the development of tensile cracks. By observing the strain development and distribution of reinforcements， SFRC could continue to bear external load after cracking due to its tensile hardening property. After cracking， the contribution of SFRC to axial tensile stiffness and lateral bending stiffness of composite deck was significantly greater than that of normal concrete. When the maximum crack width was 0.10 mm and 0.20 mm， respectively， the contribution of SFRC to axial tensile stiffness of composite deck was 36% and 22%， while that of normal concrete was only 15% and 11%； the contribution of SFRC to lateral bending stiffness of composite deck was 41% and 27%， while that of normal concrete was only 29% and 17%. In addition， combined with theoretical derivation， the ultimate bearing capacity of composite deck under full section yield of steel was analyzed. The results showed that the contribution of SFRC and normal concrete to ultimate bearing capacity of composite deck was not significant.

Abstract:In order for the mode functions adopted in the formulation of dynamic response factor （DRF） or gust loaded factor （GLF） to fit better to the modes of real tall buildings and be easy for calculation， tall buildings with uniform cross sections are modeled as cantilever bending-shearing beams and a simplified fundamental vibration mode with high accuracy is adopted. A practical algorithm for the DRF of tall buildings based on the bending-shearing beam model and its simplified mode is proposed. Von Karman’s wind speed spectrum and Davenport’s spatial correlation function in frequency domain are adopted in the algorithm. The results of the DRF given by the algorithm are compared with those given by the Chinese wind loading code （GB50009—2012） through numerical examples. The result shows that the simplified algorithm for the DRF of tall buildings given in this paper considered the modal characteristics of different tall buildings， and are both accurate， simple to use， and easy to connect with main foreign wind loading codes.

Abstract:Based on the solution of multilayered fractional viscoelastic cross-anisotropic saturated soils， the boundary element-finite element coupling method is utilized to investigate the interaction between the plate and viscoelastic saturated soils. First， based on the Mindlin’s plate theory， the total stiffness matrix equation of the plate is obtained. Then， the precise integration solution of fractional viscoelastic saturated soils is introduced to obtain the flexibility matrix equation of soils. Finally， according to the coordination conditions of the plate-soil nodes， the solution of the interaction between the viscoelastic saturated soils and the plate is obtained. The proposed solution in this paper is verified by comparing with that of the literature. Moreover， the effects of the soil parameters and the reinforcement depth of soils on the time-dependent interaction between the raft and viscoelastic soils are analyzed.

Abstract:Rail surface rolling contact fatigue （RCF） crack propagation model based on state peridynamics was established to research the propagation of RCF crack and the formation process of spalling. It was found that the crack propagation path gradually turned towards into the internal rail with the accumulation of traffic tonnage in the case of single crack or cracks with distance longer than 1.5 mm between each other. The propagation rate gradually decreases with the increase of traffic tonnage and crack length. In the case of multiple cracks， the cracks propagated along their length direction below traffic tonnage of about 8.8 Mt. After the traffic exceeded 8.8 Mt， the secondary damage between cracks was formed especially between the cracks which their distance was less than 1.5 mm. If the distance between cracks was longer than 1.5 mm， the interaction among cracks was reduced. In the case of multiple cracks with adjacent distance less than 1.5 mm， the spalling occurred from the secondary damage when the increment of traffic tonnage reached a certain amount （>10.0 Mt）. At that time， the spalling depth was about over 1/2 depth of the crack.

Abstract:This paper proposes an long short-term memory （LSTM） traffic anomaly detection model based on the attention mechanism， which uses the overall traffic grid point data to predict the future traffic flow at various points in order to achieve the purpose of anomaly detection. By evaluating the simulation data， the Attention-LSTM model has a better detection effect. Furthermore， this paper uses the SKAB dataset to test the anomaly detection ability of the model， and obtains good results. Finally， this paper conducts experiments on the actual GPS signal data of Shanghai taxis， empirically analyzes some of the actual traffic anomalies detected， and proves the effectiveness of the model in detecting actual traffic anomalies.

Abstract:High-salt wastewater treatment is the one hot research field in the environmental industry. Its characteristics of high organic matter， high salt content， and high hardness limit the wastewater treatment process. Thermal evaporation is necessary since the national requirement of pollutants， i.e.， ‘Zero Emission’ is proposed. The scaling problem of heat exchanger has brought huge problems to the industrial production chain. How to solve the scaling problem of heat exchanger and put forward effective scale inhibition technology for high salt wastewater has， therefore， become a research hotspot. This paper mainly introduces the scaling mechanism and influencing factors of high salt wastewater in industrial treatment. It also summarizes and analyzes the existing scale inhibition technologies， so as to provide theoretical support for future research of scaling， descaling， and scale inhibition of high salt wastewater heat exchangers.

Abstract:In order to improve the switching quality of the dual-motor electric mode to parallel hybrid mode transition process of a new series-parallel hybrid power system， and ensure the adaptability of the mode switching strategy in different vehicle driving states and driver input， two mode switching control strategies of smooth starting and dynamic starting were proposed. First， the dynamic model of the series-parallel hybrid system was established， and the mode switching process from electric mode to parallel hybrid mode was analyzed to determine the control objectives and control strategies in different stages of mode switching. Then， taking the vehicle driving comfort and engine starting time as the optimization indexes， the optimal engine cranking speed curve was solved through dynamic programming， and an engine starting model predictive optimization control strategy was proposed to calculate the clutch friction torque online. The engine tracked the target optimal speed curve， and the torque fluctuation at the output was compensated by the motor. The results of the simulation and hardware in loop bench test show that the two mode switching control strategies can meet different driving requirements and have good a driving comfort.

Abstract:To avoid the risk of lateral instability of the vehicle， based on the independent controllability of the four-wheel drive/braking torque of the four-wheel independent drive electric vehicle， a fuzzy sliding mode direct yaw moment control strategy with a two-layer structure of an upper controller and a lower controller was proposed. In the upper controller， a fuzzy sliding mode controller was used to calculate the total required yaw moment and distribute the longitudinal forces of the four wheels. In the lower controller， the tire longitudinal force was transformed into the control of tire slip rate， and the tire longitudinal force was realized by controlling the torque of the four wheels. The simulation results show that the fuzzy sliding mode direct yaw moment control strategy can ensure the lateral stability of the vehicle under various road conditions， and can weaken the system chattering caused by the traditional sliding mode controller.

Abstract:A kind of combined cooling heating and power （CCHP） system considering multi-energy collaborative supply consisting of photovoltaic power，wind power，natural gas， and grid power is developed in this paper. By using the independent CCHP system as the measurement benchmark， investment and operation cost， primary energy utilization， as well as carbon dioxide emission are incorporated to formulate multi- objective optimization function. For electrical， heating， and cooling loads on the three kinds of annual typical days such as winter， summer， and transitional seasons， the collaborative optimization study on device capacity sizing and operation strategy including FEL （following the electrical loads） and FTL （following the thermal loads） is conducted. Due to simultaneous existence of the continuous and combinatorial optimization， a bi-level optimization algorithm of multi-objective particle swarm is proposed. In addition， the orthogonal experimental analysis for the impact of critical system parameters on the optimal result is performed. The results show that compared with the independent CCHP system， the proposed CCHP system considering photovoltaic-wind-gas-power collaborative energy supply has a significantly better performance in economy， energy saving， and environmental protection.