透明黏土盾构隧道开挖面失稳扩展过程和失稳特征研究  

Instability process and characteristics of the excavation face of shield tunnels using transparent clays

作　　者：雷华阳[1,2] 刘敏[1] 程泽宇 钟海晨 LEI Huayang;LIU Min;CHENG Zeyu;ZHONG Haichen(Department of Civil Engineering,Tianjin University,Tianjin 300354,China;Key Laboratory of Coast Civil Structure Safety of Ministry of Education,Tianjin University,Tianjin 300354,China)

机构地区：[1]天津大学建筑工程学院,天津300354 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300354

出　　处：《岩石力学与工程学报》2022年第6期1235-1245,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点研发计划项目(2017YFC0805402);同济大学土木工程防灾国家重点实验室开放基金项目(SLDRCE17–01)。

摘　　要：基于透明黏土盾构隧道开挖面失稳模型试验,探究开挖面失稳扩展过程和失稳特征。在验证透明黏土可用于盾构隧道开挖面失稳破坏试验研究的基础上,从土体运动的角度分析不同埋深比条件下开挖面失稳演化过程,研究失稳分阶段、分区和形态特征以及地表沉降变化规律。基于土体运动的变化,提出盾构开挖面失稳过程实质是开挖面正前方松动土体带动上方土体向隧道内部同步运动,伴随着周围土体受扰动产生运动,并不断扩展变化,最终土体快速滑移发生整体失稳。开挖面失稳呈现明显的分区特征,影响区域包括整体滑移形成的失稳区和产生明显位移形成的扰动区,并提出失稳区的确定标准。开挖面失稳滑移时,纵截面处失稳区土体向隧道内部“流动”,横截面处失稳区呈椭圆状形态。利用对数螺旋线模型和Torus模型对黏土体失稳形态进行描述时,模型底部拟合很好,上部的偏差均较大。开挖面整体失稳前的横截面地表沉降符合高斯沉降曲线,整体失稳后与高斯沉降曲线偏差较大。A series of shield tunnel face instability model tests using transparent clay were conducted to investigate the instability process and characteristics of the excavation face.It was verified that the transparent clay could be used for the experimental researches in shield tunnel face instability.The instability evolution process of the excavation face of shield tunnels was studied based on the soil movement under different cover depths to diameter ratios.The characteristics of staged collapse process,influencing zone and shape of the excavation face instability as well as the change of the surface settlement were discovered.In addition,the surface settlement under different collapse stages was studied.The nature of the excavation face instability is a gradual process of soil movement which can be described as three stages.The loosened clays in front of the tunnel face slipps into the tunnel vertically downward at an angle together with those in the upper portion in the initial deformational stage.The surrounding clays are disturbed and loosed continuously and the extent of the soil movement increases in the deformational-extended stage.The clays slipp rapidly and the overall face instability occurs in the collapse stage.The zoning characteristics refers to that the influencing zone of the face instability consists of the collapse zone caused by the overall clay collapse and the disturbed zone in which the clays exhibit obvious movement.A determination criterion of the collapse zone was proposed.The clays in the collapse zone flow into the shield tunnel in the longitudinal section and have an oval shape in the cross-section during the collapse stage.The traditional logarithmic spiral and Torus model contours fit well in the lower portion of the collapse zone but deviate in the upper portion of the collapse zone.The surface settlement in the cross-section conforms to the Gaussian settlement curve in the initial deformational stage and deformational-extended stage but deviates from the Gaussian settlement curve in t

关 键 词：土力学 透明土 盾构隧道 开挖面失稳 失稳过程 地表沉降 

分 类 号：TU43[建筑科学—岩土工程]