隧道纵向变形曲线与围岩特征曲线耦合分析

发布时间：2018-03-20 18:08

本文选题：隧道　切入点：围岩　出处：《岩土工程学报》2014年04期 　论文类型：期刊论文

【摘要】：目前,多数关于开挖面空间效应的研究仅采用弹性与理想弹塑性模型进行分析。然而,具有不同地质强度指标(GSI)的岩体呈现不同的峰后破坏模式,应采用合适的力学模型计算表征空间效应的隧道纵向变形曲线。同时,可将相同模型下围岩特征曲线与之进行耦合,从而指导隧道支护设计。提出了一种简便的基于有限差分法的分析方法,该法可计算Hoek-Brown与Mohr-Column屈服准则下,采用理想弹塑性、弹脆塑性、应变软化模型的隧道纵向变形曲线与围岩特征曲线。利用已有研究成果,验证了方法的合理性,并比较了不同GSI范围与不同力学模型下开挖面后部某一位置处的虚拟支撑力。结果表明:GSI越大,3种模型下对应的虚拟支撑力差别越大,更应如实考虑岩体峰后力学行为;GSI中等或较高时,离开挖面距离小于约0.8倍洞径时,理想弹塑性模型设计偏于保守,但大于此距离时情况相反。
[Abstract]:At present, most of the researches on spatial effect of excavating face are only analyzed by elastic and ideal elastic-plastic models. However, the rock mass with different geological strength indexes (GSI) presents different post-peak failure modes. A suitable mechanical model should be used to calculate the longitudinal deformation curve of the tunnel which represents the spatial effect. At the same time, the characteristic curve of surrounding rock under the same model can be coupled with it. A simple analysis method based on finite difference method is proposed. The method can be used to calculate the ideal elastic-plastic and elastic-brittle ductility under Hoek-Brown and Mohr-Column yield criteria. The longitudinal deformation curve and surrounding rock characteristic curve of strain softening model are used to verify the rationality of the method. The virtual support forces at a certain position at the rear of the excavated surface under different GSI ranges and different mechanical models are compared. The results show that the greater the ratio of the three models is, the greater the difference of the virtual support forces in the three models is. When the mechanical behavior of rock mass after peak is medium or high and the distance from excavation surface is less than 0.8 times, the design of ideal elastoplastic model is conservative, but when the distance is greater than this distance, the design of ideal elastoplastic model is conservative.
【作者单位】：华中科技大学岩土与地下工程研究所;
【基金】：新世纪优秀人才支持计划资助项目(NCET-06-619)
【分类号】：U451.2

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