Based on the convergence confinement method, yielding support has become an important means to control large deformations of soft rock. However, it is not sufficient to adopt a single yield for different failure processes of the surrounding rock. This study investigated the zonal deformation and failure mechanism of surrounding rock during open tunnel boring machine (TBM) excavation of inclined shafts under conditions of low strength, high stress, and pore water. In addition, to achieve coupling between the surrounding rock and support system, a new stage control device was designed. The device was composed of a sleeve, cone, and tray. It could realize two or multiple yielding stages and obtain different yielding pressures and lengths by adjusting the parameters of each component according to the field conditions. The device was successfully applied in an excavation project of an open TBM in the inclined shaft of the Kekegai coal mine. The monitoring results indicated that the ratio of the maximum and minimum surrounding rock pressures in the conventional support section was 1.7 and 1.5, and that in the test section was 1.5 and 1.4, respectively. Compared with the conventional support design, the stress of the bolt was smaller and more uniform after the new stage control device was adopted. The monitoring results also indicated a reduction in the deformation of the surrounding rock, and there were no significant local deformations. Simultaneously, the crack in the surrounding rock in the test area was reduced, and the range of the loose zone was reduced from 2.5 to 2 m. The results showed that the new stage control support technology exhibited a good control effect on the surrounding rock and aided the TBM in realizing fast driving.

中文翻译：

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富水弱胶结软岩开敞式TBM隧道衬砌支护新型阶段控制装置


基于收敛约束方法的让压支护已成为控制软岩大变形的重要手段。然而，对于围岩的不同破坏过程采用单一屈服强度是不够的。研究了低强度、高应力和孔隙水条件下露天隧道掘进机（TBM）开挖斜井过程中围岩的分区变形和破坏机制。此外，为了实现围岩与支护系统的耦合，设计了新型的阶段控制装置。该装置由套筒、锥体和托盘组成。根据现场情况调整各部件参数，可实现两级或多级屈服，获得不同的屈服压力和长度。该装置成功应用于可可盖煤矿斜井露天TBM掘进工程。监测结果表明，常规支护段最大围岩压力与最小围岩压力之比分别为1.7和1.5，试验段最大围岩压力与最小围岩压力之比分别为1.5和1.4。与传统支撑设计相比，采用新型阶段控制装置后，螺栓受力更小、更均匀。监测结果还表明，围岩变形有所减少，没有出现明显的局部变形。同时，试验区围岩裂缝减少，松动带范围由2.5减少至2 m。结果表明，新型阶段控制支撑技术对围岩表现出良好的控制效果，辅助TBM实现快速掘进。