The present study investigates the dynamic response characteristics during the shield cutting pile process. The dynamic response induced by shield cutting pile impact load was solved by combining numerical simulation and theoretical analysis with the background of the shield crossing group pile project of Nanjing Metro Line 10. Concurrently, vibration sensors were installed on the cutterhead to monitor the dynamic response of the shield cutting pile. The results of the study indicate that: (1) When the shield cuts the reinforced concrete pile foundation at a low speed of approximately 5 mm/s, the thrust and torque changes are small, and the thrust and torque show obvious hysteresis because the pile foundation is cylindrical and the cutting section increases slowly. The peak thrust and torque are about 1.3 times and 1.25 times the initial value. (2) As demonstrated by the simulation results, the rebar incision presents a compression-tension fracture under the action of multiple cuts by the cutter. Under the impact loading, multiple dynamic response waveforms appear at the cutterhead bearing position with peaks close to 0.6g. (3) The measured data show that under the impact load, the time domain curve of cutterhead vibration acceleration shows several consecutive peaks with an interval of about 0.1 s and an amplitude of 0.5g. The measured impact response waveform is highly consistent with the theoretical solution and they verify each other. The waveform can be used as a typical characteristic of continuous cutting of steel bars by multiple cutters. (4) During the whole pile cutting process, the acceleration response and peak value are significantly higher, and the maximum intensity is about twice as high as when cutting clay ground. After this, the response will undergo a rapid decline.

During slurry shield tunneling in the sandy pebble stratum, the slurry discharge pipeline will transport a large number of the large irregular pebbles, generating unstable turbulence, which causes difficulties to the determination of the pipeline pressure loss. This study designed a circulating flow test device, and the slurry used in the experiment is CMC transparent viscous slurry. And the study established a numerical model using the computational fluid dynamics-discrete element method (CFD-DEM) coupling approach. Taking pebbles with a particle size of 5~80 mm as the research object, the study investigated the effects of pebble particle size distribution, slurry velocity, pebble volume fraction, and pipeline inclination angle on the pressure loss along the pipeline, respectively. The results indicate that the pressure loss along the pipeline increases exponentially with the increase of slurry velocity under the same particle size distribution, pebble volume fraction, and pipeline inclination angle. And for horizontal pipelines, the effect of pebble particle size distribution on the pressure loss along the pipeline is not significant. In addition, for the low slurry velocity (v＜2 m/s), the pressure loss along the pipeline increases linearly with the increase of pebble volume fraction. And for the high slurry velocity (v ≥ 2.0 m/s), the pressure loss along the pipeline increases exponentially with the increase of pebble volume fraction. For inclined and vertical pipelines, the pressure loss along the pipeline firstly increases slowly with the increase of the pipeline inclination angle, and then increases sharply under the same particle size distribution, pebble volume fraction and slurry velocity, and the pipeline inclination angle at the turning point is 60°. In addition, under the action of mud buoyancy and turbulence, it is difficult for large-size pebbles to overcome their own gravity and reach a state of complete suspension. Therefore, large-size pebbles mainly move along the lower wall of the pipeline, and the pressure at the elbow of the pipeline is obviously stratified.