The blasting in the tunnel is easy to induce the instability of the slope at the entrance,especially the loose accumulation body.It is of great significance to study the analysis method of slope stability under blasting load for improving the construction method and design theory of tunnel entrance.Taking blasting load in the tunnel equivalent to the wave stress function,and based on the principle of the transfer coefficient method,the calculation method of the stability of the tunnel slope under the action of tunnel blasting excavation was established,and based on Qiaopingshan Tunnel of Yuxiang Expressway,the application research was carried out.The results show that under the blasting load of tunnel excavation,the dynamic stability coefficient of the accumulation slope at the tunnel entrance presents an attenuation sine wave change with time,reaches the minimum value at about 10 ms,and tends to the static stability coefficient after 0.2 s.Under the condition that the distance between the tunnel and the accumulation slope is equal to the span diameter of the tunnel and the slope angle is 25°,the maximum safe explosive amount per section is 6.5 kg.The larger the slope angle of the accumulation slope,the lower the variation range of the dynamic stability coefficient of the slope during the blasting excavation process.The smaller the thickness of the accumulation is,the easier the slope is to lose stability under dynamic disturbance.When the thickness of the accumulation does not exceed 2.5 m,the slope will lose stability during blasting.
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