摘要
为了从理论上确定土质隧道深浅埋的分界深度并阐明其与影响因素、经验值的关系,以卸荷拱为研究对象,通过引入卸荷拱跨中法向压力极限值为Rankine被动土压力的假定,建立了粘性土隧道和砂性土隧道深浅埋划分的定量判据和求解方程。理论分析表明,粘性土隧道中n值(深浅埋分界深度与压力拱高度的比值)与土体粘聚力、内摩擦角及隧道宽度有关,而砂性土隧道中n值仅与内摩擦角有关。n的理论取值范围为1.0～3.3,经验值在该取值范围内。通过与《人民防空工程设计规范》的对比表明,静荷载作用下的深浅埋分界深度比动荷载作用下的深浅埋分界深度更大。最后通过郑州-西安高速铁路客运专线的大断面黄土隧道工程实例验证了本文方法的可靠性。
In order to determine the dividing depth of shallow earth tunnel and deep earth tunnel quantitatively, the unloading arch is studied in theory. Based on the assumption that the horizontal pressure limit of midspan is Ran- kine＇ s passive earth pressure for unloading arch in critical depth, the quantitative criterion of the dividing depth and solution equations was established in clayey and sandy soil tufinel. Theoretical analysis shows that the ratio { n ） of the dividing depth to pressure arch height is related to the cohesion, internal friction angle, and the width of tunnel in clayey soil while the ratio n is only related to the internal friction angle for sandy soil tunnel. The theoretical range of n value is 1.0 ~ 3.0 and the empirical value is just within the range. A comparison with ＂Code for design on civil air defense works＂ shows that the dividing depth under static load is greater than that under dynamic load. Finally, the presented theory is applied to large cross-section loess tunnels of high-speed railway from Zhengzhou to Xi ＇ an and the result is well agreed with practice.
出处
《地下空间与工程学报》
CSCD
北大核心
2012年第1期37-42,128,共7页
Chinese Journal of Underground Space and Engineering
关键词
分界深度
深埋隧道
浅埋隧道
卸荷拱
承载力
dividing depth
deep tunnel
shallow tunnel
unloading arch
bearing capacity
