But appropriate the blasting parameters of medium deep blasting in hard rock tunnel is always a technical problem need to be solved.

而合理的硬岩巷道中深孔掘进爆破参数则一直是需要研究解决的技术难题。

youdao

But appropriate the blasting parameters of medium deep blasting in hard rock tunnel is always a technical problem need to be solved.

而合理的硬岩巷道中深孔掘进爆破参数则一直是需要研究解决的技术难题。

youdao