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金川矿区井巷围岩多属不良岩层,地质构造复杂,岩体软弱松散,地应力高,围岩形态变化大,而且具有显著的流变特征。因此采用传统的支护方法,并不能保证巷道的稳定。围岩变形是能集中而真实地反映围岩的受力状态和稳定程度的。因此变形量测所得的变形值、变形速率和时间效应是指导喷锚施作,评定围岩稳定程度的重要依据。塑性流变特征明显的大变形巷道中采用二次喷锚支护是解决这类岩体巷道维护的一个有效途径。初始支护应尽可能快地施作,充分利用支护的及时性、固结性和密封性,以迅速加固松散岩体,控制围岩初期的剧烈变形,并使围岩应力得到进一步释放,减轻支护结构的负担。二次支护则应有足够的滞后时间,只有在围岩变形速率明显下降时施作二次支护,才能取得最良好的效果。由此可见,必须十分重视现场监测,切实掌握围岩力学形态的变化,研究岩体的变形和破坏规律,探索围岩结构和工程结构的相互作用,进行岩体稳定性评价,这是提高喷锚支护可靠性的直接而有效的方法。
The surrounding rock in tunnels of Jinchuan Mine is mostly an unfavorable rock formation, with complex geological structure, weak and loose rock mass, high geostress, and large changes in the morphology of the surrounding rock, and it also has significant rheological features. Therefore, using traditional support methods does not guarantee the stability of the roadway. Surrounding rock deformation can concentrate and truly reflect the stress state and stability of surrounding rock. Therefore, the deformation value, deformation rate and time effect obtained by deformation measurement are the important basis for guiding the application of spray anchor and assessing the stability of surrounding rock. The use of secondary spray-anchor support in large deformation tunnels with obvious plastic rheological characteristics is an effective way to solve the maintenance of such rock roadway. The initial support should be applied as soon as possible to make full use of the timeliness, consolidation and sealing of the support to quickly reinforce the loose rock mass, control the intense initial deformation of the surrounding rock, and further release the stress of the surrounding rock. Reduce the burden on the support structure. The secondary support should have sufficient lag time. Only when the deformation rate of the surrounding rock is significantly reduced, secondary support can be used to achieve the best results. Therefore, we must pay great attention to on-site monitoring, effectively grasp the changes in the mechanical morphology of surrounding rock, study the laws of rock deformation and damage, explore the interaction between surrounding rock structure and engineering structure, and evaluate the stability of rock mass. A direct and effective method of anchorage support reliability.