浅谈核三代技术风机用电机特点

根据核三代技术风机用电机的性能特点,对核三代技术风机用电机的关键技术以及创新性进行介绍。

Seismic stability of reinforced soil walls under bearing capacity failure by pseudo-dynamic method

In order to evaluate the seismic stability of reinforced soil walls against bearing capacity failure,the seismic safety factor of reinforced soil walls was determined by using pseudo-dynamic method,and calculated by considering different parameters,such as horizontal and vertical seismic acceleration coefficients,ratio of reinforcement length to wall height,back fill friction angle,foundation soil friction angle,soil reinforcement interface friction angle and surcharge.The parametric study shows that the seismic safety factor increases by 24-fold when the foundation soil friction angle varies from 25°to 45°,and increases by 2-fold when the soil reinforcement interface friction angle varies from 0 to 30°.That is to say,the bigger values the foundation soil and/or soil reinforcement interface friction angles have,the safer the reinforced soil walls become in the seismic design.The results were also compared with those obtained from pseudo-static method.It is found that there is a higher value of the safety factor by the present work.

Pseudo-Dynamic Testing for Seismic Performance Assessment of Buildings with Seismic Isolation System Using Scrap Tire Rubber Pad Isolators

Investigation of seismic performance of buildings with STRP （scrap tire rubber pad） seismic isolators by means of pseudo-dynamic tests and numerical simulation is presented. The isolated building is numerically modeled, while the base isolation layer is considered as the experimental substructure in the pseudo-dynamic tests. The test result verifies that the STRP isolator shows acceptable shear deformation performance predicted by the design methods, and demonstrated that seismic isolation using STRP works as a protective measure to provide enhanced seismic performance of the building indicated by the reduction of top floor absolute acceleration, drift and base shear as designated.

INFLUENCE OF UNCERTAINTY OF ROCK PROPERTIES ON SEISMIC RESPONSES OF REACTOR BUILDINGS

The influence of the dispersion and uncertainty of the dynamic shear wave velocity and Poisson＇s ratio of soil in a hard rock site was investigated on the seismic response of reactor building structure. The analysis is performed by considering the soil-structure interaction effects and based on the model of the reactor building in a typical pressurized water reactor nuclear power plant （NPP）. The numerical results show that for the typical floor selected, while the relative increment ratio of the dynamic shear wave velocity varies from -30% to 30% compared to the basis of 1 930 m/s, the relative variation of the horizontal response spectra peak value lies in the scope of ±10% for the internal structure, and the relative variation of the frequency corresponding to the spectra peak is 0.0% in most cases. The relative variation of the vertical response spectra peak value lies in the scope of - 10% to 22%, and the relative variation of the frequency corresponding to the Spectra peak lies in the scope of - 22% to 4%. The analysis indicates that the dynamic shear wave velocity and the Poisson＇s ratio of the rock would affect the seismic response of structure and the soil-structure interaction effects should be considered in seismic analysis and design of NPP even for a hard rock site.

Basic dynamic characteristics and seismic design of anchorage system

Based on some assumptions,the dynamic governing equation of anchorage system is established.The calculation formula of natural frequency and the corresponding vibration mode are deduced.Besides,the feasibility of the theoretical method is verified by using a specific example combined with other methods.It is found that the low-order natural frequency corresponds to the first mode of vibration,and the high-order natural frequency corresponds to the second mode of vibration,while the third mode happens only when the physical and mechanical parameters of anchorage system meet certain conditions.With the increasing of the order of natural frequency,the influence on the dynamic mechanical response of anchorage system decreases gradually.Additionally,a calculating method,which can find the dangerous area of anchorage engineering in different construction sites and avoid the unreasonable design of anchor that may cause resonance,is proposed to meet the seismic precautionary requirements.This method is verified to be feasible and effective by being applied to an actual project.The study of basic dynamic features of anchorage system can provide a theoretical guidance for anchor seismic design and fast evaluation of anchor design scheme.