挤压性围岩隧道变形潜势的判定

Determination of Deformation Potential of Squeezed Surrounding Rock Tunnel

研究目的:挤压性围岩隧道的工程难点主要是变形潜势的判定,以往主要利用岩石(岩体)的强度应力比来评价围岩的变形潜势,理论上概念明确,但在挤压影响严重段,围岩地应力和岩体强度很难实测,且受构造作用影响,岩体的强度时高时低、变化频繁,具有很大的不确定性,现场难以据此进行变形潜势判定。因此,有必要进一步研究变形潜势的判定方法,便于施工现场操作。研究结论:(1)勘察阶段可按岩石单轴抗压强度和最大初始地应力值之比对挤压性围岩变形潜势进行宏观预判;(2)设计阶段可按岩石(岩体)的强度应力比来评价围岩的变形潜势,划分变形等级,进行预设计;(3)施工阶段可按围岩完整程度和开挖后变形速率对变形潜势进一步进行判定;(4)变形速率可作为主要评价指标,对支护参数与围岩的适应性进行评价,动态调整支护参数;(5)本研究结论可为铁路挤压性围岩隧道的设计与施工提供思路和方法。

Research purposes： The engineering difficulties of squeezed surrounding rock tunnel are mainly the determination of deformation potential. The deformation potential of surrounding rock was mainly evaluated by the strength- stress ratio of the rock （rock mass） in the past, the concept is clear, but when severely affected by the extrusion, surrounding rock stress and rock mass strength is difficult to test, and affected by the tectonic setting, the strength of the rock mass changes frequently and uncertainly, it is difficult to determine deformation potential accordingly. Therefore, it is necessary to further study the deformation potential determination method, which is convenient for site operation. Research conclusions ： （ 1 ） In the exploration stage, the deformation potential of squeezed surrounding rock is estimated by the ratio of the uniaxial compressive strength of rock to the maximum initial ground stress value. （2） In the design stage, the deformation potential of surrounding rock was evaluated by the strength - stress ratio of rock （ rock body） , and the deformation grade was divided for the preliminary design. （3） In the construction stage, the deformation potential is further determined by the integrity of surrounding rock and the deformation rate after excavation. （4） The deformation rate can be used as the main evaluation index to evaluate the supporting parameters and the adaptability of surrounding rocks, and dynamically adjust the supporting parameters. （5） The research results can provide ideas and methods for the design and construction of railway compressive surrounding rock tunnel.