摘要
为准确掌握地铁盾构近接施工的风险等级,以近接既有隧道施工断面的地表沉降变形监测成果为基础,先分析研究其变形规律,再利用累计变形判据和变形速率判据实现近接施工的风险等级评估。实例分析表明:在近接施工段,地表变形具波动起伏特征,最大沉降量已达27.22 mm,说明近接施工对周围土体的扰动影响较为显著,但就现状变形而言,累计沉降量及变形速率均在预警值范围以内;同时,在近接施工风险等级评估过程中,各类风险判据的评估结果是不同的,侧面说明了近接施工风险评估判据应具多样性,且通过计算,得不同监测点的综合风险等级也存在一定差异,风险等级间于Ⅱ级~Ⅲ级,按不利原则,综合确定近接既有隧道段的施工风险等级为Ⅲ级,需提高监测频率,以切实保证施工安全。本次研究为合理评价近接施工风险等级提供了一种新的思路。
This work aims to accurately evaluate the close-spaced construction of subway shield tunnels.Based on the monitoring of surface settlement and deformation of close-spaced construction,the deformation law was analyzed,and the cumulative deformation criterion and deformation rate criterion were utilized to assess risk level.The case analysis shows that,in close-spaced construction section,the fluctuation of surface deformation can reach a maximum settlement of 27.22 mm,indicating that the close-spaced construction will significantly disturb the surrounding soil.In terms of the present deformation,the cumulative settlement and deformation rate are within the range of the early warning value.In assessing the risk level of close-spaced construction,different assessment results were obtained for various risk criteria.It is indicated that the risk assessment criteria for close-spaced construction should be diverse,and further calculation suggests different risk levels between levelsⅡandⅢ.According to the unfavorable principle,the risk level of close-spaced construction is comprehensively determined to be levelⅢ.It is necessary to increase the monitoring frequency to ensure the construction safety.This research provides a new idea for reasonably evaluating the risk level of close-spaced construction.
作者
李晓斌
白海军
LI Xiaobin;BAI Haijun(Shaanxi Railway Institute,Weinan,Shaanxi 714000;The Sixth Engineering Branch of China Railway Fourth BureauGroup Co.,Ltd.,Xi'an,Shaanxi 710000)
出处
《地质与勘探》
CAS
CSCD
北大核心
2022年第5期1108-1116,共9页
Geology and Exploration
基金
陕西铁路工程职业技术学院科研基金项目(编号:KY2020-59)资助。
关键词
近接施工
变形规律
累计变形
变形速率
风险等级
close-spaced construction
deformation law
cumulative deformation
deformation rate
risk level
