Development of similar materials with different tension-compression ratios and evaluation of TBM excavation

Studying the disturbance patterns of surrounding rock and soil during TBM excavation holds great significance in ensuring the safe construction of tunnels. Geomechanical model testing serves as an effective approach for such research. However, the current model tests suffer from lengthy curing times of rock similar materials and the simplification of tunneling simulation devices. To address these issues, this paper presents an innovative approach by preparing a rock similar material with early strength and good brittleness and utilizing a self-developed scaled TBM testing machine for rock breaking simulations. The conducted tests demonstrate that an increased content of sulphoaluminate cement significantly enhances the compressive-tensile ratio of the rock-like similar materials, thus indicating the excellent performance of the developed materials. The impact zone of TBM tunneling primarily encompasses the surrounding rock within 0.5D in front of the tunnel face and 2D at the rear. The proposed method for similar material preparation and the model test device put forward in this paper can serve as valuable references for similar tunneling experiments.