水位变化下浅埋盾构隧道开挖面渗透力与稳定性研究  

Study on seepage force and stability of shallow shield tunnel excavation face at the varied water level

作　　者：刘维正[1,2] 师嘉文 谭际鸣 董军 豆小天[3] LIU Weizheng;SHI Jiawen;TAN Jiming;DONG Jun;DOU Xiaotian(School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Research Center of High-Speed Railway Construction Technology,Changsha,410075,China;The 2nd Engineering Co.Ltd.,of China Railway Tunnel Group,Sanhe 065201,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]高速铁路建造技术国家工程研究中心,湖南长沙410075 [3]中铁隧道集团二处有限公司,河北三河065201

出　　处：《中南大学学报（自然科学版）》2024年第10期3833-3848,共16页Journal of Central South University:Science and Technology

基　　金：中铁隧道局集团科技创新计划项目(隧二研合2020-07);湖南省建设科技计划项目(KY202108)。

摘　　要：为分析临江地区透水地层浅埋盾构开挖面渗流作用下的稳定性,结合安庆市沿江东路管廊盾构段典型断面,建立浅埋盾构三维流固耦合数值模型,分析水位变化、土体力学性质对开挖面稳定性影响以及渗透力的变化规律,明确浅埋盾构渗透作用下开挖面的失稳形式,建立区别于传统破坏模型的圆台-弧转体数学模型,提出一种基于极限分析上限法且考虑渗透力作用的极限支护压力的计算方法,并与已有研究结果相对比,验证该方法的可行性;根据该方法分析水位、土体力学参数、盾构掘进参数对极限支护压力的影响。研究结果表明:黏聚力及内摩擦角增加会导致破坏区高度显著减小,而水位增加会导致破坏区高度及长度显著增加;开挖面上渗透力随开挖面与拱顶的距离增大而增大,渗透力随水位变化呈线性变化,平均渗透力随水位变化率为2.75 kN·m^(-3);极限支护压力随黏聚力、水位呈线性变化,随摩擦角呈非线性变化;结合开挖面前方土层土体力学性质,极限支护压力随水位变化率为5.11~5.75 kPa,与实测土仓压力变化率6.38 kPa较吻合,控制土仓压力在80 kPa以上时能有效保证开挖面稳定。In order to analyze the stability of the shallow buried shield excavation face under the influence of seepage force in the permeable strata in riverside area,combined with the typical section of the shield tunnel of the pipe gallery along the east river road in Anqing City,the three-dimensional fluid-solid coupling numerical model of the shallow buried shield was established,the influence of water level change and soil mechanical properties on the stability of the excavation face and the change pattern of seepage force were analyzed,the instability form of the excavation face with the permeability of the shallow buried shield was clarified,and the mathematical model of the round platform-arc rotation was established,which was different from the traditional failure model.Compared with the existing research,the feasibility of the method was verified,and the influence of water level,soil mass mechanics and shield tunneling parameters on the limit support pressure were analyzed.The results show that the height of the failure zone significant decreases with the increase of cohesion and internal friction angle,while the height and length of the failure zone increase with the increase of water level.The seepage force on the excavation surface increases with the increase of the distance from the vault,and the seepage force changes linearly with the water level,and the average seepage force change rate with the water level to 2.75 kN·m^(-3).Combined with the mechanical properties of the soil layer in front of excavation,the limit support pressure changes rate with the water level of 5.11-5.75 kPa,which is consistent with the measured soil silo pressure change rate of 6.38 kPa and the control of the soil silo pressure above 80 kPa can effectively keep the stability of the excavation face.

关 键 词：盾构开挖面 水位变化 渗透力 极限分析法 极限支护压力 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]