Abstract In order to investigate the fault F4–4 at the undersea tunnel in Jiaozhou Bay near Qingdao,an extendable testing system modeling water inrush in subsea tunnel overcoming the problems in the existing fluid-solid coupling model test was developed. The testing system composed of an extendable model bench,a water inflow acquisition and measurement device and an automatic water-level upgrading and loading device. The extendable model bench was made of high-strength steel and tempered glass. The steel structure members operated independently connecting with the glass room for observation,which made the testing process visible and the equipment attractive in appearance. The bench was made extendanle along the longitudinal dimension through the prefabricated bolt holes according to the test needs,achieving the simulation of different geological defects. The water inflow acquisition and measurement device was composed of the water inflow acquisition appliance,the aqueduct and the flow rate measurement sensors to monitor real-time water inflow. Meanwhile,two kinds of similar materials different in hydraulic property were developed according to the similarity conditions in fluid-solid coupling,and were proved to be suitable for simulating the fault and the normal surrounding rock. The information of multivariate precursors in real time water inrush tests such as the displacement,the stress and the seepage pressure was collected with the fiber grating sensors and the micro pressure cells. Model tests of water inrush in fault were carried out with the built model testing system. The variations of the displacement and the seepage of fault and surrounding rock mass were captured in the process of the water inrush and excavation process. Test results showed that the system was stable and reliable.
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Received: 03 December 2013
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