基于DTS的地下连续墙浇筑完整性检测技术研究

Research on monitoring technology of casting integrity of diaphragm wall based on DTS

地下连续墙浇筑质量的检测是保证基坑开挖安全进行的关键。传统的墙体完整性检测方法均存在一定局限性。因此,本文基于分布式光纤温度感测技术(Distributed Temperature Sensing,DTS),将DTS测温光缆呈U型布设于地连墙中,通过检测混凝土产生水化热的升温过程来反映墙体浇筑的均匀性,进而对墙体的完整性进行定性判断。结合昆明市轨道交通4号线工程项目,对基坑开挖前的地连墙进行温度检测,并详细分析检测结果,定性判断出N-121墙体浇筑完整性较差,N-23墙体浇筑完整性较好。在基坑开挖过程中发现N-121墙体发生地下水渗漏现象,而N-23墙体无异常现象,证明了DTS用于地连墙浇筑质量检测是可行和有效的,利用该方法可为地连墙完整判断提供指导。

Monitoring the quality of the diaphragm wall is the key to ensure the safety of foundation pit excavation.Traditional integrity monitoring methods have some limitations.Therefore,based on Distributed Temperature Sensing(DTS),DTS temperature measurement cable is buried in the wall in U shape,which the uniformity of wall pouring by monitoring the hydration heat process generated by concrete.Then,the integrity of the wall is evaluated.Combining with the project of Kunming Rail Transit Line 4,the temperature of diaphragm wall before foundation pit excavation was monitored,and the monitoring results were analyzed detailedly.It is qualitatively judged that the casting integrality of N-121 wall is insignificant and that of N-23 wall is good.Groundwater seepage was found in N-121 wall during excavation of foundation pit,while there was no abnormal phenomenon in N-23 wall,which proved that DTS is feasible and effective for monitoring casting quality of diaphragm wall.This method can provide guidance for the casting integrity judgment of the diaphragm wall.