沉管隧道砂基础密实度无损检测方法研究

Nondestructive Testing for the Density of an Immersed Tunnel Foundation by the Sand-Flow Method

由于灌砂孔位置处的基槽深浅程度不一,以及灌砂压力与水砂比等各种因素的影响,沉管隧道基础灌砂后可能会出现砂盘局部不密实的情况,从而导致砂盘基础受力不均匀,引起管段结构开裂,并对沉管结构受力及接头防水等造成较大的影响。文章依托汾江路南延线沉管隧道工程,建造等比例试验模型,并通过对比试验研究,提出采用面波法和弹性波映像法综合检测沉管隧道砂基础的密实度。通过大量检测数据分析,提出沉管隧道砂基础密实度评判因子R,并建立评判因子与砂基础实测密实度对应的关系。该研究成果填补了现有沉管隧道砂基础密实度无损检测技术的空白,对沉管隧道安全施工及运营具有重要的意义。

Local non-compactness may occur in the sand foundation of an immersed tunnel after sand filling due to different trench depths, sand filling pressures and water-sand ratios, which may cause uneven loading on the sandfoundation, tunnel element cracking, or a great impact on the force bearing of the structure and joint waterproofing.Using the immersed tunnel of the south extension line on Fenjiang Road as an example, this paper establishes a rele-vant full-scale model, proposes a detection scheme for the density of a sand foundation through a contrast test（i.e.,adopting the surface wave method and elastic wave imaging method）, gives the evaluation factor of density（R） basedon an analysis of mass detection data, and builds a relationship between the evaluation factor and the sand founda-tion density.