In-situ measurements of TBM cutter temperature in Aspo Hard Rock Laboratory, Sweden

摘要

A boring machine usually breaks and excavates rock by means of the multi-cutters installed in its cutter head. During continuous rotation, the cutters continually break the rock beneath them. In field rock excavation this process always lasts several hours without stopping. The cutters themselves, therefore, become hotter and hotter as the process continues. If the temperature in the cutters is too high, the material properties of the cutters will be worsened, and in turn their surface wear will speed up. In addition, the mechanical properties of the rock beneath the cutters will possibly also be affected more or less due to the high temperature. Therefore, it is necessary to measure the actual cutter temperature of a boring machine, so that the influence of temperature on the boring machine can be considered in the design of boring machines.This note presents the results of in-situ cutter temperature measurements for a boring machine named Boretec DS 1.6 TBM. The boring machine was used for boring a series of vertical holes with a diameter of 1.8 m in the Aspo Hard Rock Laboratory in Sweden, where research is conducted underground in the field of nuclear waste repositories. The total designed maximum thrust of the boring machine was 2470 kN, and the rotation speed of the cutter head of the machine was 0-20 rpm. A total of 20 cutters (16 button cutters and four disc cutters) were installed in the cutter head during the in-situ measurements. The in-situ temperature measurements were performed in a front button cutter when a testing borehole was bored. The vacuum method was used to move the cuttings out of the borehole. The rock types in the area for in-situ measurements are mainly Aspo diorite and granite. Both rocks are fine-grained, massive and relatively homogeneous. In addition, no underground water appears during the in-situ measurements.