摘要
为了研究含水率变化对粉质黏土隧道变形特征的影响,以杨宣高速公路大营坡隧道为研究对象,首先在调查现场灾害的基础上对施工现场取土样,按不同含水率配置重塑土样进行不固结不排水三轴压缩试验,得出土样的物理力学参数;其次采用数值模拟的方法对不同含水率和隧道埋深的粉质黏土地层公路隧道的围岩变形特征进行分析;最后根据现场监测数据揭示其变形特征并与数值模拟计算结果相互验证。结果表明:(1)含水率对土体破坏形式及最终破损形态有显著影响,当含水率不超过30%时,该地区粉质黏土破坏形式为剪切破坏,表现出应变软化特性;当含水率达到35%后,粉质黏土未产生剪切破坏,土样呈“腰鼓状”变形,表现出流变特性。(2)围岩变形随埋深增加而增大,含水率小于25%时为线性增加,达到30%后呈非线性指数式增加;在同样的埋深条件下,围岩变形随含水率增加而增大,且在含水率大于25%后急剧增加。(3)围岩变形具有变形量大、变形速度快、以竖向变形为主及受施工扰动影响大的特点,变形主要发生在上台阶开挖支护后,此时围岩变形速度最快,当初期支护封闭成环后围岩变形基本收敛。
To study the influence of water content variation on the deformation characteristics of silty clay tunnel,the Dayingpo tunnel on Yangliu-Xuanwei expressway was taken as the study object.First,on the basis of investigating site disaster,the soil samples were taken from the construction site.The unconsolidated undrained triaxial compression tests were carried out on the remolded soil samples according to the different water contents.The physical and mechanical parameters of soil samples were obtained.Second,the numerical simulation method was used to analyze the deformation characteristics of silty-clay-stratum highway tunnel surrounding rock with different water contents and tunnel burry depths.Finally,the deformation characteristics were revealed according to the field monitoring data,and were verified with the numerical simulation result.The result indicates that the water content has the significant effect on the failure type and final failure mode of soil.When the water content is less than 30%,the failure mode of silty clay in the area is shear failure,showing strain softening characteristics.When the water content reaches 35%,the silty clay does not produce shear failure,and the soil sample deforms in drum-shaped,showing rheological properties.The surrounding rock deformation increases with the increase of burry depth.When the water content is less than 25%,it increases linearly.When the water content reaches 30%,it increases exponentially.At the same burry depth,the surrounding rock deformation increases with the increase of water content,and increases sharply when the water content is over 25%.The surrounding rock deformation has the characteristics of large deformation,fast deformation speed,mainly vertical deformation,and significant influence by construction disturbance.The deformation mainly occurs after the excavation of support to upper bench,when the surrounding rock deformation speed is the fastest.When the initial support is closed into a ring,the surrounding rock deformation basically converges.
作者
敬雅文
张俊儒
徐剑
陈雪锋
卢锋
JING Ya-wen;ZHANG Jun-ru;XU Jian;CHEN Xue-feng;LU Feng(Key Laboratory of Transportation Tunnel Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,Hubei 430063,China;School of Emergency Management,Xihua University,Chengdu,Sichuan 610039,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第12期167-176,共10页
Journal of Highway and Transportation Research and Development
基金
高铁联合基金项目(U1934213)
四川省自然科学基金项目(2022NSFSC1025)。
关键词
隧道工程
变形特征
三轴压缩试验
粉质黏土
含水率
tunnel engineering
deformation characteristics
triaxial compression test
silty clay
water content
