摘要
为研究极软岩隧道车行横洞交叉段施工力学特性,以大梁山特长公路隧道V级极软围岩段为依托,采用现场试验结合数值模拟试验分析其空间效应。研究断面现场监测结果表明:6个断面在深度为1 m、2m和3 m处内部围岩位移受横洞开挖影响较小,可忽略不计。拱腰和拱脚处钢支撑内力在横洞开挖后小幅增大,影响区集中于拱腰及以下部位,对拱顶部位影响较小。远离横洞侧拱脚、拱腰及拱顶处围岩压力与层间压力所受开挖影响很小,而近横洞侧拱腰处影响相对较大,在施工中应值得注意。数值试验结果表明,混凝土应力受横洞开挖影响主要表现为压应力增大,产生压应力增大区;围岩塑性区在开挖前有一定程度增大和区域改变,锚杆轴应力施工前后变化不大。
Based on the Daliangshan super-long tunnel constructed in V-grade rock mass,combining the in-situ test and numerical simulation test,the construction mechanics at the intersection of the horizontal adit in large-span and super-long highway tunnel in soft rock were studied.The in-situ monitoring results indicated that:the internal displacement at different depths in 6 study sections was slightly affected by adit excavation,which can be neglected.The inner force in steel support in tunnel hance and arch foot increased slightly after the excavation.In term of the influence area,it mainly concentrates on the hance and the following parts,which has little influence on the vault.Surrounding rock pressure and interlayer pressure in arch foot,hance and hance from the side of the adit was influenced slightly,while that in near side was influenced seriously.It should be worth paying attention to this situation in construction.The numerical results show that the influence of adit excavation on concrete stress is mainly manifested by increase of compressive stress and corresponding extension area.The plastic zone of the surrounding rock increases to a certain extent and some changes happened in distribution area,and the stress of the anchor shaft has little change before and after adit construction.
作者
陈旭元
CHEN Xuyuan(School of Civil Engineering,Jiangsu College of Engineering and Technology,Nantong,Jiangsu 226300,China)
出处
《公路工程》
北大核心
2019年第1期227-233,共7页
Highway Engineering
关键词
隧道工程
极软岩
车行横洞
现场监测
有限元
力学特性
tunnel engineering
extremely soft rock
horizontal adit
in-situ monitoring
FEM
spatial mechanics
