School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Sensors (Basel). 2020 Jan 23;20(3):638. doi: 10.3390/s20030638.
As a portion of intact rock separating joint surfaces, rock bridge plays a significant role in the stability of rock slopes. This paper aims to investigate the effect of different rock bridges on the mechanical properties and failure mode of rock slope by means of the direct shear test and acoustic emission technique. Field conditions were simulated in direct shear tests which were carried out on specimens with rock bridges at different continuity rates, normal stress, arrangements, and joint angles. Experimental results indicate that the strength of specimens is controlled by the rock bridge and the structural plane. The rock bridge contributes to the strength of the specimen, while the through plane weakens the strength of the specimen. The increase of normal stress can weaken the stress concentration near the tip of the rock bridge and improve the shear resistance of the specimen. The different arrangement of rock bridge has little effect on the normal displacement of the specimen, and has a great influence on the shear strength. The shear capacity of the specimen is related to the angle of the crack, and the angle of the crack is approximately proportional to the peak shear strength. For the specimens with different joint occurrence, the mode of crack propagation at the initial stage is basically the same, and the specimen is finally damaged due to the generation of through cracks in the core area of rock bridge. The instantaneous release of the huge energy generated during the experiment along the shear direction is the root cause of the sudden failure of the rock bridge. The formation, aggregation, and transfixion process of rock bridge is of concern and has been experimentally investigated in this paper for the prevention and control of the locked section rock slope with sudden disasters.
作为分隔节理面的完整岩石的一部分，岩桥在岩石边坡的稳定性中起着重要作用。本文旨在通过直剪试验和声发射技术研究不同岩桥对岩石边坡力学性质和破坏模式的影响。在直剪试验中模拟了现场条件，对具有不同连续性率、法向应力、布置和节理角度的岩桥试件进行了试验。试验结果表明，试件的强度受岩桥和结构面控制。岩桥有助于试件的强度，而贯穿面削弱了试件的强度。法向应力的增加可以削弱岩桥尖端附近的应力集中，并提高试件的抗剪能力。岩桥的不同布置对试件的法向位移影响不大，但对剪切强度有很大影响。试件的剪切容量与裂缝的角度有关，裂缝的角度与峰值剪切强度大致成正比。对于具有不同节理出现的试件，初始阶段的裂缝扩展模式基本相同，由于岩桥核心区域贯穿裂缝的产生，试件最终损坏。实验过程中沿剪切方向瞬间释放的巨大能量是岩桥突然失效的根本原因。岩桥的形成、聚集和贯穿过程是关注的焦点，本文通过实验对锁固段岩质边坡突发性灾害的防治进行了研究。
