Rock Breaking Performance of TBM Disc Cutter Assisted by High-Pressure Water Jet

Abstract

A high-pressure water jet can break rock efficiently, which is of great potential to overcome the problems of a tunnel boring machine (TBM) in full-face hard rock tunnel digging, such as low digging efficiency and high disc cutter wear rate. Therefore, this paper presented a new tunneling method that is a TBM coupled with a high-pressure water jet. The rock failure mechanism under the coupled forces of a disc cutter and water jet was analyzed at first. Then, the finite element method (FEM) and smoothed particle hydrodynamics (SPH) method were used to establish a numerical model of rock broken by the disc cutter and water jet. Effects of parameters on rock breaking performance were studied based on the numerical model. Moreover, an experiment of the water jet cutting marble was carried out to verify the reliability of the numerical simulation. Results showed that the high-pressure water jet can increase the TBM digging efficiency and decrease the forces and wear rate of the disc cutter. The optimum nozzle diameter is 1.5 mm, while the optimum jet velocity is 224.5 m/s in this simulation. The results can provide theoretical guidance and data support for designing the most efficient system of a TBM with a water jet for digging a full-face hard rock tunnel.

Numerical study on the rock breaking mechanism of high-pressure water jet-assisted TBM digging technique based on 2D-DEM modelling

“…It can be found that when the disc cutter is in contact with the rock sample, a stress concentration zone with mainly compressive stress will be generated beneath the disc cutter, and the farther away from the disc cutter, the smaller the degree of stress concentration, and the stress transfer to the position of the precutting slit is blocked, which is caused by the decompression effect of the precutting slit (Tan et al, 2012). As can be seen from the figure, due to the effect of the precutting slit tip, the bottom of the precutting slit also distributes the relative stress concentration zone (Wang et al, 2020), and the stress concentration zone tends to develop along the bottom of the precutting slit from beneath the disc cutter. Therefore, it appears that the stress concentration degree beneath the disc cutter is high on the precutting slit side and low on the non-precutting slit side, which is most significant when the precutting slit depth H is 30 mm and 40 mm.…”

Reduction of Cracks in Marble Appeared at Hydro-Abrasive Jet Cutting Using Taguchi Method

“…It is most often composed of calcite-CaCO 3 or dolomite-CaMg(CO 3 ) 2 , by recrystallization. The main properties of marble are: porosity (%), density (g/cm 3 ), compressive strength (MPa), flexural strength (MPa), Amsler abrasion wear (mm/1000 m), hardness (Mohs), Young's modulus (GPa), fracture toughness (MPa/m) [2,14] and largely depend on the area from which it comes.…”

“…A recent research study [13] proposes an approach to the complex process of cutting hard rock, analyzing and evaluating the intensity of the disintegration of abrasive materials in the process of cutting AWJ, during the creation of the abrasive jet. Some current processing models on abrasive water jet machines used in the analysis of the behavior of various materials, including rock type are presented in the papers [14][15][16], but in the field of marble cutting by AWJ process research is limited.…”

Numerical and Experimental Study on Crushing Properties of Hard Coal Using Impacting-Cutting Technique

“…For hard coal seams, there are currently some new coalcrushing technologies, which are classified according to their working principles and can be divided into jet crushing [7][8][9], jet-assisted mechanical crushing [10][11][12][13], special-shaped pick crushing [14,15], and laser crushing [16,17]. In recent years, these methods were carried out fruitfully by scholars.…”