引黄工程国际Ⅰ标新奥法施工爆破对隧洞围岩扰动影响的试验研究

Experiment Study in the Influence of Blasting of the NATM Construction on the Disturbance of Surrounding Rock in No.1 International Bid of the YRDP

围岩是隧洞最基本的支护结构成分，如何看待围岩、处理围岩是新奥法设计施工全过程中最首要的问题。岩体开挖后引起围岩承载力下降，其主要原因就是爆破的影响。为保护岩体天然承载力，减轻和消除因爆破给围岩带来的损伤，引黄国际Ⅰ标地下工程爆破参数优化试验与分析，提出了优化的隧洞光面爆破与松动爆破参数及在施工中应注意的有关问题，以保证围岩开挖后轮廓面光滑平整，并且最大限度地保护围岩少受扰动，致使新奥法施工顺利进行。并通过爆破振动的观测与分析，得出了只要按优化爆破参数开挖施工，并把最大单响药量控制在３０ｋｇ左右，爆破振动就不会对本洞１０ｍ以远以及距２０ｍ的相邻隧洞的围岩产生任何危害影响。

Surrounding rock is the most basic part of support structure of tunnel,and how to treat it is the most important problem in the whole stage of design and construction of the NATM.The main cause for the declining of the bearing capacity of surrounding rock after its being excavated is the influence of blasting.In this paper,in order to preserve the natural bearing capacity of rock body,ensure the smoothness and neatness of profile after excavation,make the disturbance of blasting on surrounding rock down to minimum and make the NATM construction to be smoothly underway,the experiment study on the influence of blasting disturbance to surrounding rock is done.The optimal parameters for smooth wall blasting and for loosening blasting and some relevant problems,to which care should be taken in the construction are presented.Finally.the conclusion shows that the blasting vibration will not exercise any harmful influence on the surrounding rock beyond 10 m distance for the tunnel where the blasting is carried on provided that the optimal parameters of blasting are adopted in the excavation of the tunnel and that the blasting power of single bang blasting is controlled to be about 30 kg in weight at the most.The blasting experiment introduced here was made by over 20 times and finished in April,1998.