摘要
黄土隧道基底加固已成为防止隧道病害的一种常用手段。以傅家窑1隧道为依托,结合该隧道旋喷桩隧底加固实际,采用室内模型试验方法,对该隧道在开挖与浸水两阶段条件下的隧道受力与变形性状进行分析。结果表明:隧道开挖期,基底桩土应力比为1.1~1.2,贯通后,墙脚处桩土应力比为1.4左右,墙脚处加固桩承载性得到有效发挥。在浸水条件下,随着饱水锋面移至各测点位置处,各测点的围岩径向压力和切向应力均有一定程度增加,在饱水锋面移至桩底后,隧道基底承载能力减弱,出现整体下沉现象,各测点围岩径向压力和切向应力均出现降低。饱水锋面移至隧底时,隧底受到的基底压力最大,同时桩土应力比也达最大值,为1.1~1.9。饱水锋面移至桩底时,隧道发生急剧沉降,且沿隧底横向差异变形明显,易导致仰拱中部鼓起,严重时仰拱出现鼓起破坏。
Foundation bottom consolidation of loess tunnel has become a common means to prevent tunnel diseases.Based on Fujiayao #1 tunnel,combined with the actual situation of the tunnel bottom reinforcement with jet grouting piles,the force and deformation characteristics of the tunnel under the conditions of excavation and immersion are analyzed by indoor model test method. The results show that during the tunnel excavation period,the foundation pile-soil stress ratio is about 1.1–1.2. After penetration,the pile-soil stress ratio at the foot of the wall is about 1.4,and the bearing capacity of the reinforced pile at the foot of the wall is effectively brought into play. Under flooding conditions,as the saturated water front moves to the positions of each measuring point,the radial pressure and tangential stress of the surrounding rock at each measuring point increase to a certain extent. After the saturated front is moved to the bottom of the pile,the load-bearing capacity of the tunnel base is weakened,the overall sinking phenomenon appears,and the radial pressure and tangential stress of the surrounding rock at each measurement point are reduced. When the saturated water front moves to the bottom of the tunnel,the base pressure on the bottom of the tunnel is the largest,and the pile-soil stress ratio also reaches the maximum,about 1.1 to 1.9.When the saturated water front moves to the bottom of the pile,the tunnel undergoes rapid settlement,and the lateral deformation along the bottom of the tunnel is obvious,which easily causes the middle of the invert to bulge,and in severe cases,the invert is bulged and damaged.
作者
李又云
谢柯
孙永梅
李佳
LI Youyun;XIE Ke;SUN Yongmei;LI Jia(Key Laboratoty for Special Area Highway Engineering,Ministry of Education,Chang'an University,Xi'an,Shaanxi 710064,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2021年第S02期3334-3343,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51378004)
交通部西部建设项目(2014-318-J24-210)
陕西省自然科学基金项目(2130-2116-0351)。
关键词
隧道工程
黄土隧道
浸水
复合地基
模型试验
旋喷桩
tunnel engineering
loess tunnel
immersion
composite foundation
model test
jet grouting pile