高速公路软岩隧道复合支护机理的FLAC解析

结合软弱围岩隧道工程地质和支护设计特点 ,应用有限差分方法 ( FLAC)模拟研究了软岩隧道受力变形特征和围岩收敛曲线 ,并分析了复合支护结构中一次支护和二次支护结构的作用机理及作用效果。研究结果表明 ,软岩隧道开挖和一次支护后围岩支护压力随拱顶位移增加而连续减小 ,预测的最大位移均发生在隧道拱顶。但是 ,在同样支护压力下 ,考虑软岩流变特征的收敛曲线的拱顶位移要大得多 ,必须及时设置二次支护。另外二次支护结构还将起到承受流变压力的作用

FLAC analysis of composite support mechanism in weak rock tunnel of freeway

According to the characteristics of engineering geology and support design in weak rock tunnel, a finite difference method for fast lagrange analysis code(FLAC) was applied to simulate the deformation characteristics and convergence curves of weak rock tunnel in the paper.Then the mechanism and effect of first support and second support in composite support were discussed. The results of the study show that the support pressure of rock mass continuously reduced with increasing of displacement of arch crest after excavation and first support of soft rock tunnel. The maximum of predicting displacement is occurred in arch crest of the tunnel. However, under the same support pressure, displacement of arch crest considering soft rock rheological property is larger than that of no considering soft rock rheological property. Therefore, the second support must be established on time.