Rock-breaking mechanism of TBM with different types of cutter tools and estimation of thrust force

The rock-breaking mechanism and the coupling effect rules between the cutter tool and the surrounding rock are studied in order to resolve the TBM construction problems of cutter breaking rock, such as security, reliability and efficiency. The optimal cutter spacings for some common rocks, such as red sandstone, limestone and granite, are put forward based on the theoretical analysis and experimental results from the experimental platform for the function between disc cutter and rock. A formula for the optimal cutter spacing is deduced while the rock strength is under 40～170 MPa. Meanwhile, the mechanism of rock-breaking under single-tool and multi-tool is improved. Considering the impact of various factors, a new method for estimating the total thrust force and cutter-head torque of compound TBM is proposed, and it is proved to be more scientific and accurate through practical projects. The test results can be used to select and arrange the cutters, to design thrust force and torque, to reduce the manufacturing cost of TBM and to increase the efficiency of construction.