... pore forming efficiency,good quality,mo shock,noise or pollution,and high degree of mechanization Machine DrillingThe drilling rig is a kind ... ,the ZKL-30 Type hydraulic caterpillar type machine has high pore forming efficiency,good quality,mo shock,noise or pollution,and high ... performance than hammering and pile sinking methods for penetrating the sand and gravel layers,at the same time,it avoids ...