【摘要】 为了给广西地区隧道的设计与施工提供参考,针对隧道开挖对临近建筑物桩基产生不利影响的实际情况,开展了不同埋置位置隧道对群桩影响的离心模型试验。试验中选取的离心加速度为40g,目标地层损失比为2%,通过排水法控制地层损失,并分析隧道开挖引起的地表沉降、桩顶附加沉降、附加弯矩和附加轴力的变化规律。试验结果表明:隧道开挖完成后,较浅埋深双隧道共同引起的地表沉降大于深埋隧道;隧道开挖过程中,位于桩端处的隧道开挖引起的桩顶附加沉降大于桩端以上处,对桩基的变形较为不利;不同埋深隧道分段开挖所引起桩的附加弯矩和附加轴力分布及发展规律差异显著。更多还原

【Abstract】 To provide reference for tunnel design and construction in Guangxi,aimed at the situation that tunnelling inevitably induced negative effects on pile foundations of adjacent buildings,centrifuge modelling test was carried out to investigate the effects of tunnelling with different depths on existing pile group.In this test,centrifugal acceleration being 40 g,the water drainage method was adopted to control ground loss with target ground loss ratio of 2%.Meanwhile,variation laws of ground surface settlement,pile top additional settlement,additional bending moment and additional axial force induced by tunnelling were analyzed.The results show that after the tunnelling,ground surface settlement induced by twin tunnelling with shallow depth is greater than that induced by twin tunnelling with deep depth.In the process of tunnelling,additional settlement of pile top caused by tunnelling located at pile tip is greater than that caused by tunnelling located above pile tip,which is bad for the deformation of pilefoundation.There is a significant difference of the distribution and development law of additional moment and additional axial force of pile induced by segment tunnelling located at different depths.更多还原