When the resistive moment of surrounding soil is less than the torsional moment of eccentric jacking force, stability failure of pipeline occurs and pipes deviates from the designed axes.
管道失稳是由于管道周围土体提供的抵抗力矩小于偏心顶推力而产生的扭转力矩，造成管节偏离设计轴线。
2
According to coupling principle and excited force of shafting system, a model of coupled torsional-axial forced vibration can be constructed.
根据刚度耦合原理，并考虑轴系强迫激励进而建立了扭纵耦合强迫振动模型。
3
Performance of the coated tool and non-coated tool in cutting process is analyzed through measuring durability of the indexable insert turning tool and cutting force (torsional moment) of tap.