土岩复合地层盾构滚刀冲击荷载及振动响应分析

Analysis of Impact Load and Vibration Response of Shield Disc Cutters in Soil-rock Composite Strata

盾构在土岩复合地层中掘进时,由于地层的不均匀性,刀具在土岩交界面会受到明显的冲击荷载,进而引起刀盘的强烈振动,对盾构设备安全及环境产生不利影响。基于济南地铁R2线某区间的实际施工情况,利用三维动力数值方法,建立滚刀切削复合地层的有限元模型,分析了不同贯入度、切削速度及岩层硬度等条件下滚刀的冲击荷载响应以及冲击荷载响应与各因素的相关关系;对典型工况下的荷载响应时程曲线进行傅里叶变换,得到了单滚刀冲击荷载响应的频率分布特点。结果表明:(1)单滚刀所受垂直力与贯入度、切削速度、岩层硬度均呈正相关关系;(2)滚刀荷载频率主要分布在0~20 Hz的范围内,随着贯入度、切割速度、岩层硬度的增大,滚刀荷载在低频范围内的振幅有所提升,且在50 Hz左右存在少量分布。

When the shield machine drives in the soil-rock composite strata,the cutters will be subjected to im⁃pact loads at the soil-rock interface due to the uneven properties of ground,causing the strong vibration of the cut⁃terhead,threatening the stability of the shield machine and surrounding environment.Based on the actual construc⁃tion situation of a running tunnel of the Jinan metro line R2,three-dimensional dynamic numerical method is used to build the finite element model of single disc cutter cutting composite strata under different conditions.Then the impact load response of single disc cutter and the relationship between the impact load and influencing factors are analyzed under different conditions of penetration,cutting speed and rock hardness.The frequency distribution char⁃acteristics of the impact load response of single disc cutter are obtained by Fourier transform of time-history curve of load response under typical working conditions.The results shows that the vertical force on a single disc cutter is positive correlated with the penetration,cutting speed and rock hardness;the frequencies of loads on the disc cutter are mainly distributed in the range of 0-20 Hz,with increase of the penetration,cutting speed and rock hardness,the amplitude of low-frequency load increases while a small amount of load frequency being distributed around 50 Hz.