After analyzing the propagation of stress wave at different angles of inclination, strength parameters and the group number of structural plane. The results of research are summarized as follows: Due to the change of propagation direction in structural planes with different angles of inclination, the original propagation rule of stress wave changes too, the peak velocity of the monitory point gets relatively flat as the strength parameters of structural plane turn greater. Stress wave repeatedly refracts and reflects in many groups of structural plane, then the appropriate dynamic characteristics of the wave no longer maintains as the number of group increases or decreases. By analyzing and verifying the slope instance, the test result provides a reference for studying dynamic response rules.

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A sealing grease plays a crucial role in the sealing of shield tails. Its pumpability and pressure sealing resistant sealing performance are greatly affected by the fiber content. In this study, discrete element method models were used to simulate the pressure-resistant tests of sealing grease in order to investigate the influence of viscosity grade and fiber’s aspect ratio on the optimum fiber content of sealing grease. Meanwhile, the rationality of the optimum fiber number determined based on the sealing performance was verified with the unbalanced force and fiber area proportion obtained in the simulation, of which the variation curves with the increasing fiber number were practically identical. The simulation results elucidated that the viscosity of grease had little effect on the optimum fiber content for sealing grease. However, the increase in viscosity can improve the sealing effect, and increasing the fiber’s aspect ratio can reduce the fiber number to reach a specific seal state. Based on the analysis of the total number of fiber spheres for the models with different fiber’s respect ratios, it can be concluded that the sealing grease sample made of the same fiber material and quality can reach the same seal state and seal effect, independent on fiber’s aspect ratio.

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