Sand deposit-detecting method and its application in model test of sand flow

LI Wei(黎伟)^{1, 2}, FANG Ying-guang(房营光)^{1, 2}, MO Hai-hong(莫海鸿)^{1, 2}, GU Ren-guo(谷任国)^{1, 2}, CHEN Jun-sheng(陈俊生)^{1, 2}

(1. School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China;
2. State Key Laboratory of Subtropical Building Science (South China University of Technology),
Guangzhou 510640, China)

Abstract:Against the background of the sand-flow foundation treatment engineering of Guangzhou Zhoutouzui variable cross-section immersed tunnel, a kind of sand deposit-detecting method was devised on the basis of full-scale model test of sand-flow method. The real-time data of sand-deposit height and radius were obtained by the self-developed sand-deposit detectors. The test results show that the detecting method is simple and has high precision. In the use of sand-flow method, the sand-carrying capability of fluid is limited, and sand particles are all transported to the sand-deposit periphery through crater, gap and chutes after the sand deposit formed. The diffusion range of the particles outside the sand-deposit does not exceed 2.0 m. Severe sorting of sand particles is not observed because of the unique oblique-layered depositing process. The temporal and spatial distributions of gap and chutes directly affect the sand-deposit expansion, and the expansion trend of the average sand-deposit radius accords with quadratic time-history curve.

Key words:immersed tube tunnel; foundation treatment; model test of sand-flow method; sand deposit detecting; structural characteristics of sand-deposit