黄土盾构隧道开挖围岩扰动特性模型试验研究  

Model tests on disturbance characteristics of surrounding rock of loess shield tunnels during excavation

作　　者：韩兴博[1,2] 陈子明 叶飞[1,2] 梁晓明 冯浩岚 夏天晗 HAN Xingbo;CHEN Ziming;YE Fei;LIANG Xiaoming;FENG Haolan;XIA Tianhan(School of Highway Engineering,Chang'an University,Xi'an 710064,China;Research Center on Safety of Highway Large Structure Engineering,Ministry of Education,Chang'an University,Xi'an 710064,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]长安大学公路大型结构安全教育部工程研究中心,陕西西安710064 [3]西南交通大学土木工程学院,四川成都610031

出　　处：《岩土工程学报》2024年第5期968-977,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52108360);长安大学中央高校基本科研业务费专项资金资助项目(300102213206);中国博士后科学基金项目(2020M683398)。

摘　　要：为了探究不同含水率和埋深等工况下的黄土盾构隧道开挖对围岩的扰动作用特征,采用相似模型试验,首先通过三轴试验测定了不同含水率下原状黄土物理参数及强度指标,通过大量试配得到了不同含水率下与原状黄土强度指标参数相似的试验用土。其后,考虑盾构隧道盾尾间隙特征,开展不同含水率及埋深等组合工况下盾构开挖模拟试验,通过微型土压力传感器、百分表等监测元件以及数字图像技术等手段,分析了不同工况下地层变形、地表沉降和围岩应力的变化规律。研究发现:含水率较低时,围岩的自稳能力强;含水率越高,埋深越大,开挖对地层的扰动作用也越大;地表最大沉降值与含水率呈正相关,与埋深呈负相关;围岩剩余应力随含水率和埋深的增大而增大,但当含水率增大至一定值(26.6%)时,围岩剩余应力骤减;基于不同含水率下的围岩应力及变形发展规律,可将黄土含水率分为自稳、形变以及松动含水率,基于含水率和埋深引起的围岩松动情况,可将不同工况下的黄土盾构隧道围岩压力作用模式按照形变压力和松动压力计算,以更加适应黄土地层的特性。In order to explore the disturbance characteristics of the surrounding rock by excavation of loess shield tunnels under different water contents and buried depths,the similarity model tests are carried out.Firstly,the physical parameters and strength indexes of the undisturbed loess under different water contents are measured by the triaxial tests.Through a large number of tests,the test soil with similar strength indexes of the undisturbed loess with different water contents is obtained.Then,considering the characteristics of shield tail gap of shield tunnels,the simulated tests on the shield excavation under different water contents and buried depths are carried out.The variation laws of stratum deformation,surface settlement and rock stress under different working conditions are analyzed by means of the monitoring components such as micro-earth pressure sensors,dial indicator and digital image technology.It is found that the self-stabilizing capability of the surrounding rock is strong when the water content is low.The higher the water content,the greater the buried depth,the greater the disturbance of excavation to the stratum.The maximum ground settlement is positively correlated with the water content and negatively correlated with the buried depth.The residual stress of the surrounding rock increases with the increase of the water content and buried depth,but when the water content increases to a certain value(26.6%),the residual stress of the surrounding rock decreases sharply.Based on the development law of the stress and deformation of the surrounding rock under different water contents,the water content of loess can be divided into self-stabilization,deformation and loosening water contents.Based on the loosening of the surrounding rock caused by the water content and buried depth,the pressure action mode of the surrounding rock of loess shield tunnel under different working conditions can be calculated according to the deformation pressure and loosening pressure,so as to better adapt to the characteri

关 键 词：黄土盾构隧道 相似模型试验 含水率 埋深 围岩变形 应力 

分 类 号：TU411[建筑科学—岩土工程]