基于遗传算法的隧道围岩变形稳定可靠性分析

由于隧道的开挖,隧道围岩的初始应力状态将发生变化,围岩发生卸荷变形,并可能导致隧道的失稳。为了研究隧道开挖后围岩变形的可靠性,建立了隧道围岩变形可靠度指标计算模型,并用遗传算法进行求解。应用本文方法对一高速公路隧道围岩变形的可靠性进行分析。从结果可以看出,围岩的潜在破坏区域出现在拱顶和两侧拱肩区域,从这些区域的可靠度指标和破坏概率值可以看出,该隧道毛洞的拱顶下沉和拱肩收敛可靠度都满足不了规范的要求,要及时进行支护。

RELIABILITY ANALYSIS OF ROCK MASS DEFORMATION IN TUNNEL EXCAVATION BASED ON GENETIC ALGORITHM

The initial stress state and stability of the surrounding rock mass will change during tunnel excavation. The rock mass even may collapse due to over-size displacement. A new method is presented in this paper for reliability analysis of tunnel excavation. The genetic algorithm is put forward to calculate the reliability index and failure probability for the complexity of the model. The proposed method is applied to reliability analyzing of a practical expressway tunnel. The result shows that the potential break areas appear at vault and spandrel of the tunnel. The reliability indexes and failure probabilities of the vault settlement and spandrel convergent reflect that the reliability of the unsupported construction can't meet the requirement of the specification. The tunnel must be supported in time.