顶管施工中管壁与围土间不同接触关系的冲击响应特征

Impact response characteristics under different contact relationships between pipe and soil in pipe-jacking construction

为研究冲击映像法在顶管施工泥浆套检测中的应用,根据顶进过程中的相互作用机理,将管壁与围土间的接触关系总结为4类:管壁–围土、管壁–空气–围土、管壁–水–围土、管壁–泥浆–围土,并通过数值仿真模拟了不同接触关系下冲击震源作用于管道内壁时的冲击响应波场特征。研究表明,不同接触关系下波形特征有较为明显的响应差异,通过分析波形的能量大小和频谱特性可判断出管道与围土之间的接触状态。当管壁与围土密实接触时,波形振幅较小且频谱分布窄;而当管壁与围土间有其他介质填充时,波形振幅较大,频谱中出现多个峰值。同时,现场检测试验分析结果显示,冲击响应强度能快速评价环形空间内介质可能的分布情况,并初步判定管壁与围土间的接触关系,再结合数值模拟规律即可更好地应用于实际工程检测中。

In order to study the application of impact image method in the detection of slurry for pipe-jacking construction,different contact relationships between pipe and surrounding soil are summarized into four categories according to the interaction mechanism during jacking:pipe-soil,pipe-air-soil,pipe-water-soil,and pipe-slurry-soil.The characteristics of the impact response wave field are simulated by numerical calculation when the impact source acts on the inner wall of the pipe under different contact relationships.The research shows that the contact relationships between pipe and surrounding soil can be determined by analyzing the energy and spectral characteristics of the waveform.When the pipe wall is in close contact with the soil,the waveform amplitude is small and the spectral distribution is narrow.When there is other medium filling,the amplitude of waveform is large,and multiple peaks appear in the spectrum.What’s more,the results of field tests show that the impact response intensity can quickly evaluate the possible distribution of the medium in the annular space and preliminarily determine the contact relationship between the pipe and the surrounding soil.Based on the numerical simulation law,the impact image method will be better applied to the practical detection.