【摘要】 提出了动应力集中因子代表值的概念,以合理反映地震荷载作用下地下洞室围岩的动应力集中程度,并将动应力集中因子代表值,作为洞室地震响应的关键特征来衡量洞室地震响应的大小。应用显示有限差分法,讨论了地震动加速度幅值、洞室埋深、围岩岩体级别、衬砌混凝土厚度、衬砌混凝土强度等级与动应力集中因子代表值的相关关系。研究表明,动应力集中因子代表值与这5个因素均近似呈线性关系。在此基础上给出了有(无)衬砌支护结构两种情况的地震安全评价公式,提出了岩体地下洞室的地震安全评价方法。应用提出的评价方法,分别对唐山余震地震作用下溪洛渡水电站超大型地下洞室群的地震安全性进行了评价,所得结果与Dowding-Rozen及Sharma-Judd的评价方法结果一致。分析还表明,文中提出的岩体地下工程的地震安全评价方法的评价结果是偏于安全的。更多还原

【Abstract】 The concept of representative value of the dynamic stress concentration factor is proposed to describe the degree of dynamic stress concentration of underground openings under seismic loading. And the representative factor is employed to reflect the seismic response characteristic of underground openings. Based on explicit finite difference method, the relationship between five key factors: (1)acceleration amplitude of seismic wave, (2) overburden depth, (3) rock grade, (4) liner thickness and (5) concrete grade, and the representative factor has been investigated. It is shown that all these five factors appear approximate linear relationship with dynamic stress concentration factor. Accordingly, formulas of seismic safety assessment have been developed for both lined and unlined underground openings and a safety assessment method for underground engineering in rock under seismic loading has been proposed. The proposed assessment method is therewith applied to evaluate the safety of Xiluodu underground cavern groups subjected to Tangshan aftershock. It is demonstrated that the proposed method draws similar conclusions to Dowding-Rozen and Sharma-Judd’s methods. It also reveals that this method gives a relatively conservative assessment results.更多还原