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2018/19 eLife Ambassadors progra

EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working

THE WORK-OUTS TO OPTIMIZE THE EFFICIENCY FOOTWORK – A CASE STUDY FOR TALENTED FEMALE TABLE TENNIS ATHLETES AT THE AGE OF 14-15 IN VINH LONG PROVINCE, VIETNAM

The purpose of this study was to build up and evaluate the application of work-outs about the efficiency of footwork for talented female table tennis athletes. 08 healthy female talented table tennis athletes at the age of 14-15 in Vinh Long province were chosen to participate in the 8-week pre-season training. Results indicated that the 20 work-outs were selected to improve the efficiency footwork through the basis of training principle, participant’ characteristics, previous studies, and expert interviews. Besides, there were significant differences in all 06 tests to evaluate the footwork ability after the experiment. Moreover, the percentage of change indicated increased, from the objective perspective, we found that the growth rate was still at the moderate level (from 2.72% to 6.07%). Therefore, it is necessary to apply the 20 work-outs more flexibly and closely to improve the efficiency of footwork in different training phases next year. It was concluded that the application of the 20 work-outs about the efficiency of footwork had positive effects on female talented table tennis athletes. Future studies should be conducted on a group of males, diverse in training levels, and/or on the other sports group that need to promote footwork ability.   Article visualizations