Abstract: The tunnel boring machine (TBM) has been developed for more than 100 years. With the changes in the excavation environment, the tunneling efficiency of TBM, which uses traditional tools as the main form of rock breaking, has become increasingly difficult to meet the requirements. Due to increasingly high construction requirements, a new combined rock breaking method is proposed, that is, a mechanical-hydraulic combined rock breaking method. This article is mainly from the approach of experiments. First, this paper studies the depth of grooves that can be formed by water jetting in cutting different rock types under different cutting parameters. Then, based on this experimental rule, the proposed water jetting adopts the method of repeatedly cutting in the same slot to increase the cutting depth. The experimental results show that: ①The higher the water jetting pressure, the slower the cutting speed and the greater the cutting depth. When cutting softer rock types, the target distance has a certain influence on the cutting depth. When cutting harder rock types, the target distance has a certain effect on the cutting depth. The impact is small. ②The repetitive cutting can effectively increase the cutting depth, but the increase in the cutting depth is related to the cutting parameters. The greater the water jetting pressure, the slower the cutting speed, the smaller the target distance, the greater the increase in the cutting depth. The experimental results have an important reference value for guiding the improvement of TBM and improving the tunneling efficiency.

Key words: Combined Rock Breaking, Cutting Depth, High-Pressure Water Jetting, Process Parameters, Influence Factors