Influence of Shield Cutter Layered Configuration and Cutting Parameters on the Fracture Mechanism of Hollow Pipe Piles
(1. Ningbo Service Chief Station of Construction Safety & Quality, Ningbo 315040; 2. Construction branch of Ningbo Rail Transit Group Co. Ltd, Ningbo 315101; 3. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044; 4. CCCC Tunnel Engineering Company Limited, Beijing 100088)
Abstract：
To explore the dynamic damage and fracture process of hollow reinforced concrete pipe piles under the cutting action of shield cutters, a dynamic model for shield cutter groups cutting reinforced concrete pipe piles is established with the Ningbo Metro Line 7 tunnel project as the engineering background. The effect of cutter layered configuration and cutting parameters on cutting performance is investigated. The research results show: (1) When cutters are arranged in layers, the first layer rippers locally fracture the concrete and effectively cut the reinforcement cage. When cutters are arranged with uniform high difference configuration, a penetrating crack appears at the middle of the hollow pipe pile, and the cracking expands into a large-scale fracture, causing the reinforcement cage to lose its constraint and deform, which cannot be effectively cut. (2) When the cutter cuts the first main reinforcement, the reinforcement cage is constrained by the relatively intact concrete, and the instantaneous impact load is the largest, which represents the most unfavorable condition. The impact load peak for the layered cutter configura? tion is much smaller than that for the uniform high difference configuration. (3) As the cutting speed increases, the peak impact load increases significantly due to the strain rate effect of the concrete. The increase in penetration leads to an overall higher cutting load, but the impact on the peak impact load is relatively small, as the rebar diameter is small and breaks completely in a single cut. (4) Engineering practice shows that when the cutter head rotation speed is maintained at 0.9 r/min and the penetration is maintained between 20~40 mm/r, the thrust during the cutting process fluctuates around 15 500 kN, with a peak value of only 18 000 kN, and the torque remains around 800 kN·m.
WU Weisong1 LIANG Tianyi2 CAI Zhe2 FANG Yingran3 YAN Tao4 LIU Xiaohai4 LI Xinggao3
.Influence of Shield Cutter Layered Configuration and Cutting Parameters on the Fracture Mechanism of Hollow Pipe Piles[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(2): 172-182
2025, Vol. 62 