摘要
城市地铁常采用盾构法施工,开挖面稳定对于隧道施工安全极为重要。水下或富水地层中修建隧道时,渗透力是影响开挖面极限支护力的一个关键因素,天然岩土体水力参数不确定性对开挖面附近渗透力具有较大影响。基于经典极限分析和随机场理论,引入饱和土有效应力原理,结合有限元空间离散和二次锥规划,建立了考虑孔隙水压力影响的随机数值极限分析方法。在此基础上,研究渗透系数空间变异性对富水地层盾构隧道开挖面稳定性的影响。结果表明,渗透系数非均匀性导致开挖面孔压梯度增大,渗透系数变异系数及竖向水平向渗透系数比的增加明显提高了维持开挖面稳定所需的支护力,互相关系数及自相关距离影响相对较小。研究结果对富水地层盾构隧道开挖面稳定性评估具有理论指导意义。
The shield method is commonly employed in the construction of urban subways, and the stability of the excavation surface is extremely important for the safety of tunnel construction. When constructing tunnels in submerged or water-rich strata, the seepage force is a key factor affecting the ultimate support force of excavation faces. Uncertainty of natural geotechnical material hydraulic parameters significantly impacts the seepage force near the face. Based on the classic limit analysis and the random field theory, the principle of effective stress in saturated soil is introduced, and the stochastic numerical limit analysis method considering the influence of pore water pressure is established by combining finite element spatial discretization and second-order cone programming.On this basis, the influence of spatial variability of permeability coefficient on the stability of shield tunnel face in water-rich strata is studied. The results show that the heterogeneity of the permeability coefficient leads to an increase in the pore pressure gradient at the face. The increase in the variation of permeability coefficient and the ratio of vertical to horizontal permeability coefficient significantly increases the support force required to maintain the face stability, and the effect of cross correlation coefficient and autocorrelation distance is relatively small. The present research can provide theoretical guidance for evaluating the face stability of tunnels in water-rich strata.
作者
袁帅
冯德旺
张森豪
邢运鹏
柯尊启
YUAN Shuai;FENG De-wang;ZHANG Sen-hao;XING Yun-peng;KE Zun-qi(School of Highway,Chang'an University,Xi'an,Shaanxi 710064,China;Wuhu Surveying and Mapping Design Institute Co.,Ltd.,Wuhu,Anhui 241000,China;Zhejiang Supervision on Highway and Water Transporation Construction Engineering Co.,Ltd,Hangzhou,Zhejiang 323000,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第11期3153-3162,共10页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51908053)
中央高校基本科研业务费项目(No.300102210209)。
关键词
隧道工程
开挖面稳定性
空间变异性
渗透力
极限分析
tunnel engineering
face stability
spatial variability
seepage force
limit analysis
