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In the western and southwestern regions of China, under-construction and completed highspeed railway tunnels often suffer from elevated floor heave, which seriously threatens the construction progress and operational safety of the tunnels. This paper relies on the typical horizontally laminated carbonaceous shale stratum of the Xingshandong Tunnel to carry out a research on the mechanism of elevation of the base of the back arch. The model of the surrounding rock below the base of the elevated arch is simplified by applying the method of qualitative analysis by component testing and quantitative calculation by numerical simulation. The effects of different layer thicknesses, interlayer cohesion and material strength on the damage pattern of laminated rock masses are revealed, the causes of bottom bulging in horizontally laminated rock enclosures are analysed and corresponding bottom bulge control and disposal techniques are proposed. The results indicate: (1) The reduction in layer thickness reduces the ability of the laminated composite rock mass to resist deformation and damage, mainly manifested in the shortening of the elastic phase and the acceleration of the deformation rate; the reduction in the bond strength between layers destroys the integrity of the laminated composite rock mass, leading to the acceleration of the laminated rock mass into the single rock layer stress phase, but the effect on the deterioration of ultimate bearing capacity is not obvious;the reduction in the strength of the rock mass itself greatly reduces the load-bearing capacity of the laminated composite rock formation, causing the damage process to accelerate significantly and further deepening the extent and scope of the impact, which, combined with the numerical simulation results, further proves that the strength of the rock mass itself dominates the deformation and damage of the laminated rock mass. (3) The fatigue damage of train vibration, the weakening effect of groundwater aggregation and the long-term mechanical properties of the surrounding rock will all affect the stability of the elevation arch of the tunnel, and the order of deformation control effect is: deepening invert>base grouting>invert arch bolt. [ABSTRACT FROM AUTHOR]

Shimmy is one of the important factors affecting the ride comfort and lateral stability of straddle-type monorail vehicles with single-axle bogies (SMVS). To obtain the main parameters affecting SMVS shimmy, a global sensitivity analysis strategy for SMVS shimmy is proposed. The shimmy response surface model is constructed, and the sensitivity analysis of the shimmy response surface model is carried out by the Sobol method. Based on this, the shimmy factor model of SMVS is established by factor analysis method. A novel SMVS shimmy analysis method based on factor model is proposed. The shimmy factor model is verified by the dynamic model of SMVS. The results show that 11 main factors affecting the shimmy are obtained by sensitivity analysis. Through the dimension reduction technology of factor analysis, four main factors affecting SMVS shimmy are extracted. The complex coupling relationship between the shimmy factors of SMVS is revealed. The established shimmy factor model can effectively analyse the shimmy state of SMVS, and the dynamic simulation results also show consistency. This study not only proposes a new perspective to understand the SMVS shimmy mechanism, but also provides the foundation for further optimal design of monorail vehicle stability. [ABSTRACT FROM AUTHOR]

In order to study the influence of the space linkage system on the stability of the straddle-type monorail vehicle with single-axle bogies, the sensitivity analysis of the space linkage system is identified based on the Pearson coefficient method to determine the importance of each component of the single-axle bogies. The dynamics model of straddle-type monorail vehicle with single-axle bogies is established by the multi-rigid body dynamics. The Pearson analysis method is used to identify the key parameters of the space linkage system. Based on that, dynamic response optimization model of space bar system is developed to carry out a multi-objective suspension design optimization process. The results show that the maximum sensitivity parameter for the RMS value of yaw acceleration and pitch angle acceleration is the length of the longitudinal tow bar; there is a correlation of approximately 0.088 between the stiffness K and the damping coefficient C of the hydraulic shock absorber. After optimization the root mean square of lateral acceleration of the optimized single-axle bogie vehicle is reduced by 6.0%. [ABSTRACT FROM AUTHOR]

This paper firstly models the relationship between power companies, photovoltaic power generation, wind power generation networks, and users as a three-stage Steinberg game. In this game model, the power company is the dominant player and the leader of the entire game. Secondly, with the game model, a detailed analysis is carried out to obtain the optimal strategy of each game party. Finally, the simplified model was simulated and verified. The simulation result is consistent with the theoretical solution result. The research results of this paper have improved the level of energy services and innovated energy service models.

In order to solve the issues of all- terrain vehicle（ ATV） axle housing design process appears poor design efficiency and timeliness security,a reliability calculation method of certain type of all- terrain vehicle integral type axle housing based on the finite element method combined with the blind number theory is presented,the all- terrain vehicle axle housing design methods in full of uneven road is obtained by taking the integral type axle housing under the condition of the loaded with uneven road,wheels withstand the maximum tangential force,wheels withstand the maximum lateral force,and the axle housing conditions of stress and deformation as restriction. The simulation results show that based on the analysis of the results of finite element analysis,the calculation efficiency of the design of the all terrain vehicle axle housing is improved,combined with the load and the strength of the time- varying characteristics,a simple calculation method for the structure reliability of the all terrain vehicle axle housing by using blind number theory is provided.

Tunneling by means of shield or TBM is by now the advanced construction method, and the domestic application of them is relatively late compared with other countries. With the rapid development of national economy, other shield or TBM is progressed unprecedently, and will come to a peak in near future. This paper conducts a statistics of the shield tunnels in service, under construction and in planning from 2007 to 2021, and prospects the development of both tunnels. Shield and TBM tunneling reduce labor intensity, raise the quality and efficiency of tunneling, enhances work safety and improve working conditions, which are the effective way to alleviate the shortage of human resources and a long term solution to promote industrial upgrading. The modern and scientific shield and TBM methods will see broad application in China. [ABSTRACT FROM AUTHOR]