基于欧式距离的地铁隧道围岩韧性评估

Evaluation of Surrounding Rock Resilience of Subway Tunnel Based on Euclidean Distance

为进一步认识地铁隧道围岩的工程属性,结合韧性理论,提出地铁隧道围岩韧性的概念。构建地铁隧道围岩韧性的评估模型,引入欧式距离,对围岩韧性直观量化,并采用主客观结合的"二级赋权"方式对评估指标进行赋权。通过对围岩干扰前后各影响因素的归纳,从岩体性质、现场施工和设计方案3个影响方面出发,确定了8个围岩韧性评估指标。以南宁市某地铁车站为工程背景,对车站下5处隧道围岩进行韧性评估。编号1~5的5处隧道围岩韧性等级分别是2.57级, 2.87级, 2.62级, 2.28级和2.47级。评估结果显示同一地层的5处隧道围岩,尽管岩体的结构特征和地质特征相同,抗干扰、维持围岩平衡的能力也存在差别。基于欧式距离的地铁隧道围岩韧性的评估结果与工程实际情况相符,为地铁隧道围岩韧性评估提供新方法,并可根据每个评估指标对最终韧性等级结果的影响程度,采取有针对性的保护措施。

In order to further understand the properties of the surrounding rock of subway tunnels, the concept of surrounding rock resilience of subway tunnels is proposed in combination with the theory of resilience. The evaluation model of the surrounding rock resilience of the subway tunnel is constructed, and the Euclidean distance is introduced to visually quantify the resilience of the surrounding rock. The evaluation indicators are weighted by the combination of subjective and objective"secondary weight". Based on the induction of the influencing factors before and after the disturbance of the surrounding rock, eight evaluation indexes of surrounding rock resilience are determined in terms of rock mass properties, construction process and design scheme. With reference to a subway station in Nanning, the resilience evaluation of the surrounding rock of the five tunnels near the station is carried out. The resilience grades of the five surrounding rocks of No.1~5 are 2.57, 2.87, 2.62, 2.28 and 2.47 respectively. The results show that though the five tunnel surrounding rocks in the same stratum with the same structural and geological rock mass features, differences exist in their ability to resist disturbance and maintain the balance of surrounding rock. The evaluation results of the surrounding rock resilience of subway tunnels based on Euclidean distance are in accordance with the actual conditions of the project, which provides a new method for the evaluation of surrounding rock resilience of subway tunnels. Targeted protection measures can be taken based on the impact of each evaluation indicator on the final resilience rating results.