When a drill machine is working

energy of broking rock is produced from the action of torque and propulsion. The torque is resulted from the rotation of the bit

on which the propulsion is acting. When drilling conditions are certain

physical mechanical properties of rocks can be reflected from the energy consumed to break the rocks per unit volume. Based on this theory

advance geological drilling experiment has been performed on fault FK4+375.5 around the subsea tunnel across Qingdao Jiaozhou bay and the drilling parameters of tuff stratum and the variation of drilling energy with the displacement of bit are obtained. Parameters of a drill have been monitored in drilling process and analyzed using energy theory. The results show that

there is a good correlation between the drilling parameters of a digital drill machine and rock lithology. When surrounding rocks are integrated

hard and in the absence of fracture water

the drilling parameters are high. Conversely

when surrounding rocks are fractured

or in the presence of faults

fracture water and intercalated gouge

there are abrupt changes in the drilling rate

propulsion

rotational speed

torque and hit energy. The values of these parameters decrease markedly. The obtained results are consistent with core-drilling and advance geological prediction using tunnel seismic prediction (TSP). The above method is used in the classification of surrounding rock. According to the relation between energy curves and classification of surrounding rock

faults or fractured zones will appear in tuff stratum when the value of drilling energy is less than 0.95 kJ.