【摘要】 基于爆炸地震波衰减过程将作用在滑体上的动荷载修正为随时间变化的波动应力,并将其引入传递系数法中,提出了考虑施工爆破荷载影响的滑坡传递系数法.利用该方法分析了宝鸡-天水高速渭河2号大桥17号桥台码头隧道洞口滑坡稳定性在隧道爆破施工中的变化特性.结果表明:隧道爆破施工产生的振动荷载使地表滑坡的稳定系数围绕天然条件下的稳定系数呈现衰减型波动变化;隧道爆破施工荷载作用下地表滑坡稳定系数衰减到天然工况量值所需时间及稳定系数变化值与所使用的爆破药量有关,药量越大,衰减时间越长,滑坡稳定系数变化值越大;码头滑坡在隧道施工爆破药量超过1000 kg后,滑坡稳定系数最小值降低到1.15以下,滑坡体在隧道爆破施工期间易于失稳,据此提出了隧道单炮施工药量取750kg的优化方案,实践证明该药量对该滑坡的稳定性未造成劣化影响.研究成果为有效评估隧道施工爆破对地表地质环境尤其是滑坡安全性具有积极意义.更多还原

【Abstract】 Correct dynamic load acting of landslide body was used as a time-dependent fluctuating stress and was introduced to the transfer coefficient method;a revised transfer coefficient method was established to consider the construction blasting load.Taking as an example the landslide at the mouth of Matou tunnel in the 17~# abutment of the 2rd bridge on the highway from Baoji to Tianshui,we analyzed the time behavior of the stability of landslide under action of tunnel construction,and the results showed that the vibration load by blasting construction in the tunnel made the stability coefficient of the landslide over the tunnel vary with fluctuations around the stability coefficient in the natural status.The stability coefficient variations of landslide and time attenuation for stability coefficient at blasting were calculated to reduce the impact in natural status,showing that therw was a high correlation with the amount of explosive used in the tunnel construction,i.e.bigger blasting doses and longer time of the attenuation would cause a bigger landslide stability coefficient variation.Landslide stability coefficient was depressed to lower than 1.15 when the blasting dose exceeded 1 000 kg,and the landslide was easy to be induced.According to this,the proposed prioritization scheme is that the blasting dose should be 750 kg,which was proved not to threaten a landslide.This is of very positive significance for evaluating the surface geological environment and even the surface landslide stability behavior.更多还原