摘要
地铁盾构隧道施工会造成地基土体扰动,由此产生的土体刚度退化会影响地基土体的振动响应。为考虑近场施工扰动对后期隧道系统动力响应的影响,提出了一种静力有限元和2.5维动力有限元联合的求解方法。首先,基于饱和土的波动方程,推导了以土骨架位移u和孔隙水压力p表示的u-p格式的饱和土2.5维有限元表达式,结合拉伸函数构建完美匹配层边界,建立u-p格式下饱和地基下的2.5维有限元-完美匹配层动力模型。其次,采用静力有限元模拟隧道施工,确定由于盾构隧道施工扰动引起的地基土体剪切刚度退化值。最后,将退化的土体剪切刚度代入2.5维动力模型,实现施工扰动对系统动力响应的影响分析。基于该方法,探讨不同地基土体和隧道形状时盾构隧道开挖施工对地表振动响应的影响。结果表明:隧道施工会增大地表土体的竖向振动位移,距离隧道越近,隧道施工引起的地表竖向位移增量越大,最大值出现在隧道中心线处;圆形和矩形隧道下的振动响应小于椭圆形隧道。
Subway shield tunnel construction can cause disturbance to foundation soil body, and the generated soil body stiffness degradation can affect vibration response of foundation soil body. Here, to consider effects of near field construction disturbances on dynamic response of tunnel system in later stage, a solving method using the combination of static finite element and 2.5D dynamic finite element was proposed. Firstly, based on wave equation of saturated soil, a 2.5D finite element expression was derived for saturated soil in u-p form where u is soil skeleton displacement and p is pore water pressure. Combining tensile function, a perfectly matched layer boundary was constructed, and a 2.5D finite element-perfectly matched layer dynamic model for saturated soil foundation in u-p form was established. Secondly, the static finite element method was used to simulate tunnel construction to determine shear stiffness degradation value of foundation soil body caused by disturbance of shield tunnel construction. Finally, the degraded soil body shear stiffness was substituted into the 2.5D dynamic model to realize analysis of effects of construction disturbances on dynamic response of the system. Based on the proposed method, effects of shield tunnel excavation construction on ground surface vibration response were explored under different foundation soil bodies and tunnel shapes. The results showed that tunnel construction can increase vertical vibration displacements of surface soil body, the closer to tunnel the soil body, the larger the increment of its vertical displacement caused by tunnel construction, the maximum value appears at center line of tunnel;vibration responses under circular and rectangular tunnels are smaller than those under elliptical tunnels.
作者
苏光北
狄宏规
周顺华
郭慧吉
张小会
SU Guangbei;DI Honggui;ZHOU Shunhua;GUO Huiji;ZHANG Xiaohui(Key Laboratory of Road and Traffic Engineering of the Ministry of Education,Tongii University,Shanghai 201804,China;Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety,Tongii University,Shanghai 201804,China;The Technical Center of Shanghai Shentong Metro Group Co.,Ltd.,Shanghai 201103,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2023年第15期210-218,共9页
Journal of Vibration and Shock
基金
上海市自然科学基金面上项目(20ZR1459900)。
关键词
隧道施工
土体刚度退化
饱和土
完美匹配层
环境振动
tunnel construction
soil body stiffness degradation
saturated soil
perfectly matched layer
environmental vibration
