TBM Cutter Wear Under High-Strength Surrounding Rock Conditions: A Case Study from the Second Phase of the Northern Xinjiang Water Supply Project

Cutter wear is an important factor affecting the efficiency of tunnel boring machines (TBMs). In this paper, using a case study from the tunnel project of the XEVIII section of the second phase of the northern Xinjiang water supply project, cutter wear under conditions of high-strength (average strength 120 MPa) surrounding rock is studied. The results show that the cumulative wear of the center cutters and the front cutters increases exponentially with an increase of installation radius, and the cumulative wear of the edge cutters is affected by the installation angle, which increases at first and then decreases with an increase of the installation radius. The single cutter wear of the edge cutters is the largest, of the front cutters is the second largest, and of the center cutters is the smallest. With an increase of surrounding rock strength, the wear of the center cutters and front cutters increases exponentially, and the wear of the edge cutters increases based on a quadratic function per meter, while the cumulative wear per meter increases linearly. Volumetric mass loss increases exponentially with the increase of surrounding rock strength and Cerchar abrasion index and decreases logarithmically with the increase of cutter life index. When the surrounding rock strength is constant, when the revolutions per minute, torque, thrust, and penetration per revolution increase, the cutter wear per meter changes following a quadratic function, which first increases and then decreases. With the increase of penetration rate, the cutter wear per meter changes as a quadratic function, first decreasing and then increasing. Cutter wear is most sensitive to cutter head torque and thrust. In order to reduce cutter wear, it is suggested that cutter head torque should be limited to the range 1100–1300 kN m or 2100–2400 kN m, and the thrust should be limited to the range 9500–11,000 kN or 15,500–16,000 kN.