摘要
隧道运营后衬砌开裂的主要原因之一是由于衬砌受到了较大的局部水压作用。为解决局部水压显现明显地层中衬砌设计依据不足的问题,文章采用现场试验和数值模拟手段,研究局部水压作用下铁路单线隧道标准设计图的Ⅱ级围岩曲墙带底板衬砌形式和Ⅲ级围岩曲墙带仰拱衬砌形式的受力特征和安全性,并对衬砌安全系数提高措施的作用效果进行分析,提出了局部水压作用下衬砌的设计参数。研究结果表明:衬砌各部位的安全系数分布较离散,衬砌受局部水压作用的部位是薄弱部位;采用增大衬砌厚度和增加钢筋量的措施可明显提高钢筋混凝土衬砌的安全性,提高混凝土等级措施不能提高衬砌安全性;曲墙带仰拱衬砌的安全性明显优于曲墙带底板衬砌,通过增大衬砌厚度和增加钢筋量的措施,曲墙带底板衬砌最大能承受0.2 MPa水压,曲墙带仰拱衬砌最大能承受0.5 MPa水压力,在较大水压力作用下建议优先采用增大曲墙曲率的方法提高衬砌的安全性。
The high local water pressure applied on tunnel linings is one of the main reasons for lining cracking after operation. To address the insufficient theoretical design basis for linings that are subject to local water pressure, field tests and a numerical simulation method were used to study the mechanical characteristics and safety behaviors of linings under local water pressure in terms of the standard design drawings of a single-track railway tunnel, namely a curved wall with the floor in grade Ⅱ rock and a curved wall with the invert in grade Ⅲ rock. The effects of the measures to improve lining safety were analyzed, and the design parameters for the lining under local water pressure were put forward. The results show that： 1） the distribution of safety factors at various lining parts is much more scattered in the case of local water pressure, with the lining part subjected to local water pressure being the weak point; 2） the safety of the reinforced concrete lining can be improved by increasing the lining thickness and the amount of reinforcement rather than increasing the concrete grade; and 3） the safety of the curved wall with an invert is obviously better than that of the curved wall with a floor. By increasing the lining thickness and the amount of reinforcement, the lining lining structure of the curved wall with a floor and the curved wall with an invert can bear a water pressure of 0.2 MPa and 0.5 MPa, respectively. In the case of higher water pressure, it is recommended to increase the curvature of the curved wall to improve the lining safety.
出处
《现代隧道技术》
EI
CSCD
北大核心
2017年第3期8-16,25,共10页
Modern Tunnelling Technology
基金
铁道部科技开发计划项目重点课题(2008G030-E)
关键词
隧道工程
衬砌
局部水压
受力特征
设计参数
Tunnel engineering
Lining
Local water pressure
Mechanical characteristics
Design parameters
