为了提高硬土层掘进效率，我队普遍采用了打土炮的办法，过去打土炮用的都是普通凿岩用的一字形钎子，有以下缺点：1．钎子不易转动，打一锤往往要用几倍的时间来转钎；2．土层在注水后很快就成了滞性很大的浓泥浆，必须取出钎子，掏出泥浆，才能注水再打，因此辅助时间增长；3．眼打到需要深度后，往往不易拔出，又费时间又费力； In order to improve the tunneling efficiency of hard soil, our team generally used the method of fighting the earthquakes. In the past, all the tools used for drilling the earth were the brazing stones used in ordinary rock drilling. The disadvantages were as follows: 1. Brake child is not easy to rotate, hammer often use several times to turn brazing; 2. Soon after the water injection, the soil layer became a thick slurry with a very large hysteresis. It was necessary to remove the brazing material and take out the slurry before it could be filled with water. Therefore, the auxiliary time increased. Eye hit the need depth, often difficult to pull out, but also time-consuming and laborious;