Development and Application of a Three-Dimensional Geo-Mechanical Model Test System Under Hydro-Mechanical Coupling

Abstract

To study the surrounding rock stability, water inrush mechanism and support control of the deeply buried tunnel under hydro-mechanical coupling, a hydro-mechanical coupled geo-mechanical model test system is developed, and it is mainly composed of a high-pressure sealed model test chamber, a built-in high hydraulic servo loading system, a high seepage pressure omni-directional loading system, an inclined geologic structure fabrication system and a high precision integrated test system. The internal field of the model test apparatus is 1.0 m in length, 1.0 m in width and 1.0 m in height. It has good sealing and can be tilted at any angle. This model test system can realize the coupling loading of real three-dimensional in-situ stress and seepage pressure, and it adopts the loading mode that the seepage pressure changes with the depth gradient. And it can prepare the inclined geological structure with arbitrary dip angle. A model test of tunnel excavation and support in the Xianglushan diversion tunnel, which is located in Yunnan, China, was carried out by using this model test system. The variations in displacement, stress, seepage pressure and contact pressure are obtained. The results demonstrate that the apparatus is effective, reliable and practical and provide theoretical support for the project.