摘要
目前,有些黄土公路隧道受到地形限制只能采取小净距隧道形式,为了更好地解决彼此开挖相互受影响带来的安全隐患问题,笔者开展了6组基于先加载后开洞思路的离心模型试验,研究了不同净距和间距的组合下双洞效应黄土公路隧道地表及地层的变形规律。试验结果表明:间距保持1D时,随着净距的增大,双洞间的相互影响程度明显减弱,先行洞开挖对后行洞的次生扰动逐级递减;地表沉降轮廓由单核心盆地演变为多核心盆地,地层变形曲线从V形发展为W形;压力拱效应明显且成拱高度随两隧体净距的增加而升高。间距变为2D时,无论净距如何取值,地表和地层沉降的最大值都会在右侧隧道中心线附近出现,右侧隧道上覆土体变得更为敏感。净距2D间距2D时,地表和地层沉降均在右侧先行隧道拱顶上方出现6组工况下的最大沉降值,评定为最不利工况;间距1D净距取1.5D和2D时,两隧体间均可形成自稳的宽底承载土柱体。因此,小净距黄土公路隧道合理净距取值范围为1.5D^2D,相应的掌子面间距宜控制在1D内。
In order to understand the deformation rule of loess road tunnel under the influence of double-hole effect more comprehensively,six groups of model tests were carried out systematically with the centrifuge model test device,based on the thinking of first loading and then punching,and the influence of different combination of spacing and interval on the ground surface and stratum deformation of the loess road tunnel was studied. The test results showed that,to keep interval 1D,with the increase of double-holes spacing,the degree of the mutual influence between two holes would recede,the surface and stratum deformation changed from＂V＂shape for single core basin into＂W＂shape for multi-cores basin gradually. There exists the pressure arch effect,and the height of the pressure arch increases with the increase of double holes clear distance. The influence degree of the anterior holes on the subsequent tunnel will recede gradually with the increase of double-hole spacing. On spacing 2D and interval 2D condition,the surface and stratum’s subsidence value on the right anterior hole all became the maximun among these six working conditions,so this condition was evaluted as the worst one; keeping the interval as 1D,the spacing as 1.5D and 2D,the steady wide-base bearing soil column between holes can be formed,so the reasonable spacing between two holes of closely spacing loess road tunnel should be 1.5D ~ 2D,and the reasonable face interval should keep 1D.
出处
《地下空间与工程学报》
CSCD
北大核心
2016年第2期306-313,共8页
Chinese Journal of Underground Space and Engineering
基金
中央高校基本科研业务费专项资金(CHD2012ZD019)
长安大学基础研究支持计划专项基金
关键词
黄土隧道
双洞效应
模型试验
地表沉降
地层变形
loess tunnel
double-hole effect
model test
surface settlement
stratum deformation
