摘要
工程实践中,采用"先挖后支"模式开挖的矿山法土质隧道,开挖进尺基本依靠经验确定,存在很大安全隐患。在考虑未支护段长度的基础上,采用水平微分单元法分析了开挖面前方土体内的应力分布,得到了计算开挖面稳定性的理论公式。研究表明:与传统的筒仓楔形体模型假设的开挖面前方土体水平应力均匀分布模式不同,土体水平应力呈近似呈抛物线分布;通过与模型试验结果和传统的筒仓楔形体模型方法的对比分析,验证了本文计算方法的合理性;开挖面在未到达筒仓楔形体模型所假设的开挖面整体失稳前,开挖面就已经发生了局部失稳,采用筒仓楔形体模型确定的极限稳定支护力是不安全的。
It is dangerous that excavation footage is determined by experience in mining method tunnel with pattern of supporting at first and excavating behind. In this paper,a new formulation is proposed for calculating the horizontal earth pressure in front of work face with horizontal differential element method.It takes into account free span behind the work face. The research results show that the horizontal earth pressure is not uniform assumed by traditional silo wedge model but parabolic. In order to check the accuracy of the proposed formulation,the predictions from the equation are compared with existing model test results and values from the traditional silo wedge. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict the average support pressure to stabilize the work face. The validity of the traditional wedge model is doubtful because local instability is occurred before global stability that assumed by the existing model.
作者
李博平
武军
张笈玮
王飞
刘孟波
LI Boping;WU Jun;ZHANG Jiwei;WANG Fei;LIU Mengbo(Troop No. 63926 of Chinese People＇ s Liberation Army, Beijing 100192, China;Shanxi Yuantong Coal Mining Engineering Design Co. , Ltd. , Taiyuan, Shanxi 030012, China;Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China)
出处
《施工技术》
CAS
2018年第10期105-108,共4页
Construction Technology
