The effect of seismic action on stability of saline soil subgrade in cold region based on isothermal stratification method

With the change of seasons, the shear strength of saline soil subgrade filler will change with the change of external temperature, which will aggravate the adverse effects of seismic on the subgrade. To explore the influence of seismic action on the stability of saline soil subgrade under the influence of temperature on the strength of saline soil subgrade filler, this paper first carried out saline soil shear tests at different temperatures to obtain the influence of temperature on the shear strength of saline soil. Then, the temperature field of the saline soil subgrade was simulated, and then based on the subgrade isothermal stratification model and FLAC3D, the displacement and acceleration amplification effects of seismic action on the shady slope, sunny slope and subgrade of saline soil subgrade in different months were analyzed. The following conclusions were finally drawn: under the action of seismic, In the process of the change of subgrade temperature of Qarhan-Golmud Expressway between 7.7°C and 27°C, the change of saline soil cohesion is the main factor affecting the stability of subgrade slope, and the maximum and minimum values of subgrade surface settlement appear in September and June of each year,respectively. In August, the differences of settlement between the shady slope and the sunny slope shoulder of the subgrade were the largest, and the acceleration of the shady slope and the sunny slope and the inside of the subgrade changed most significantly in the vertical direction. Special attention should be paid to the seismic early warning in the above key months;In the range from both sides of the shoulder to the centerline of the roadbed,the acceleration amplification effect starts to increase significantly from about 3m from the centerline of the roadbed to the centerline, so it is necessary to pay attention to the seismic design of this range.

Progress,problems and prospects for standardization of greenhouse-related technologies

In recent years,the scale of greenhouse grows rapidly and steadily in China,which promotes the development of greenhouse technology and the demand for standardized technology.However,the standardization process of greenhouse industry in China has been facing with the problem of unbalanced development with the practical standard system for many years.To solve these problems,the most characteristic greenhouse designs used in China contributing to this work are presented in detail.And the development of standard system and the standardization efforts of them are summarized and analyzed in relationship to the data presented in this paper.In this way the origin of greenhouse standard system in China and context of the system development and standardization of greenhouse structure are clarified.It was also found that the development and iterative update of greenhouse standard system are under the influences of enterprises which as the participation of standard constitutors were proved to play an important role in promoting the standardization development of greenhouse.The outcome of this work may be utilized to perfect the greenhouse standardization system and improve the greenhouse standardization efficiency that dominate the facility agriculture in China.

Key technologies of the emergency platform in China

An emergency platform is an informatization support platform for disaster information perception,disaster situa-tional awareness,and emergency decision command.This is a key tool for ensuring the efficiency and effectiveness of emergency responses.Numerous large countries have conducted in-depth research on the key technologies of emergency platforms.Over the past 20 years,with the reform of emergency management mechanisms,China has developed two generations of emergency platform systems.This paper reviews the two generations of emergency platforms and summarizes their key technologies including multi-source-based monitoring and early warning,multi-hazard risk assessment,“scenario-response”-based decision support,synthetical forecasting based on in-cident chain,and emergency common operational picture(COP)for command and dispatch.Future research directions for the next generation emergency platforms are also proposed.