多刀破岩条件下滚刀载荷特性及刃形的影响OA

To ensure the safe and efficient operation of full-face tunnel boring machine(TBM)in complex terrains,it is essential to clarify the load characteristics of cutters in the multi-cutter collaborative rock-breaking condition and to analyze the performance of cutter profiles in different geological strata.Therefore,a numerical discrete element model based on the particle-flow method for the multi-cutter collaborative rock-breaking condition was established.The load characteristics of flat-tipped and circle-tipped cutters under varying rock strength and rotational speeds of cutterheads were investigated.Additionally,multi-cutter rock-breaking experiments were conducted to verify the accuracy of the numerical analysis results.The findings indicate that under a given penetration depth,the circle-tipped cutter exhibits a normal total thrust that is 23%-50%lower than that of the flat-tipped cutter,along with a reduction in rock-breaking volume and specific energy by 10%-20%.The load of cutters at different installation radii varies.The innermost and outermost cutters only collaborate in rock breaking with adjacent single-sided cutters,so the cutting force is approximately 30%higher than that of the adjacent cutter.Consequently,the mean and the standard deviation of cutting forces show a"W"-shaped distribution,with higher values at both ends and lower values in the middle as the installation radius increases.The mean and standard deviation of the normal forces for both cutter profiles are positively correlated.However,at the same level of normal thrust,the flat-tipped cutter exhibits a 37%-50%lower standard deviation of normal force,which means the circle-tipped cutter may lead to more severe vibrations.Additionally,the cutting forces for both types of cutters increase with an elevation in the rotational speed of the cutterhead.The flat-tipped cutter exhibits greater sensitivity to variations in the rotational speed.