Modeling test of deep buried tunnel in soft and broken rock based on non-contact monitoring methods

A physical modelling test was carried out based on soft and broken surrounding rock tunnel.The formation and development process of temperature and displacement field were observed by two means of non-contact monitoring methods.The infrared thermal imager and the high-precision displacement monitoring system,the failure mechanism of the model was analyzed.Through the thermal imager,the excavation damage zone(EDZ)turned up in a low-temperature state along with the penetration of the full face excavation.By observing the temperature-time curves of the monitoring points in and out of EDZ,the temperature variation regularity in different area of the model emerged along the test process.The formation mechanism of the cracks which leaded to the destruction of the model was confirmed by the displacement nephogram and vector diagrams provided by the non-contact displacement monitoring.The formation and extension of the cracks connected EDZ and the roof collaps.The failure mechanism was analyzed reasonably by the combination of these two monitoring methods.