摘要
以上海地铁为背景,探讨施工扰动造成隧道固结沉降的估算方法。将问题简化为平面应变问题;采用无量纲参数η和D反映盾构施工的松动效应与挤压效应,认为隧道沉降是松动效应与挤压效应共同作用的结果。采用镜像法对地层损失(松动效应)造成的隧道上浮量进行研究;采用柱孔扩张理论对挤压效应造成隧道固结沉降量进行研究,通过计算土体中各点应力增量得到各点的超孔隙水压力,进而得到挤压效应造成的扰动范围H;通过分层总和法计算挤压效应造成的隧道最终固结沉降量;利用平均固结度得到t时刻固结沉降量;将松动效应与挤压效应造成隧道竖向位移相加,得到施工扰动造成隧道固结沉降量。结果表明:地层损失造成的隧道上浮量与参数η成正比;挤压效应造成的隧道固结沉降量与参数D成指数关系;当D<0.3ln(1.34η+1.31)时,隧道表现为上浮;当D>0.3ln(1.34η+1.31)时,隧道表现为下沉。
The estimation method of consolidation settlement of tunnel structure due to shield tunnel construction was discussed with Shanghai subways as the background.The solution assumed plane strain conditions.The impact of shield tunnel construction on surrounding soil was classified as loosening effect and squeezing effect,which were reflected by η and D.The tunnel settlement was seen as combination of the loosening effect and squeezing effect.The floating displacement of tunnel caused by ground loss was studied with the mirror method.And the consolidation settlement of tunnel caused by squeezing effect was studied by using the column cavity expansion theory.The excess pore pressure of each point of soil was obtained by calculating the stress increment of soil,and then the range of disturbance was obtained.The ultimate consolidation settlement of tunnel was calculated by using the splitting summation method,and the consolidation settlement at any time was also calculated.The consolidation settlement of tunnel due to shield construction disturbance was obtained by summarizing the vertical displacements of tunnel due to the loosening effect and the squeezing effect.The study shows as follows： The floating displacement of tunnel caused by ground loss is proportional to η;the consolidation settlement of tunnel caused by squeezing effect has exponential relationship with D;the tunnel will float when D0.3ln（1.34η＋1.31）,and drop when D0.3ln（1.34η＋1.31）.
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2012年第11期115-121,共7页
Journal of the China Railway Society
基金
云南省应用基础研究计划(2008ZC028M)
关键词
盾构隧道
施工扰动
地层损失
挤压效应
固结沉降
shield tunnel
construction disturbance
ground loss
squeezing effect
consolidation settlement
