热烈祝贺第八届海峡两岸隧道与地下工程学术及技术研讨会召开!青岛地铁近距离交叠隧道施工数值模拟与变形控制研究王渭明山东科技大学E-mail:wang@sdust.edu.cn提纲1、工程背景2、研究方案与技术路线3、研究内容与成果4、结论1、工程背景青岛地铁规划待建的地铁线为5条约115里,其中的交叠工程有20处(自身交叠13)。13处2、研究方案与技术路线正交实验设计原理安排优化数值模拟试验五因素对实验结果的影响程度分析既有隧道衬砌的位移回归曲线改进后的弹性地基梁模型推导出衬砌变形的计算公式与模拟计算结果进行对比分析工程加固措施模拟各种加固措施的加固作用效果制定控制变形的工程对策模拟研究三种不同的施工方法开挖新建隧道时围岩的变形规律3、主要研究内容与成果3.1、交叠隧道主影响因素正交数值分析3.2、既有隧道衬砌计算模型3.3、青岛交叠隧道变形规律研究3.4、交叠隧道变形特征与控制方法研究3.1、主影响因素正交数值分析3.1.1因素、水平、指标埋深H净距h围岩参数E、C、φ岩层表土层新线隧道既有隧道开挖方向地表①拱顶最大沉降量②拱底最大沉降量③拱顶最大下沉坡度④对拱底最大下沉坡度⑤地表最大沉降量⑥塑性破坏区体积⑦拱顶最大拉应力⑧拱顶最大拉应力指标FLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep3014ModelPerspective23:10:17MonMar242008Center:X:-3.553e-015Y:0.000e+000Z:-6.500e+000Rotation:X:20.000Y:0.000Z:50.000Dist:3.112e+002Mag.:1.95Ang.:22.500JobTitle:OverlappedShieldTunnelViewTitle:BlockGrouptunnel_2#_tun_1tunnel_2#_tun_2tunnel_2#_tun_3tunnel_2#_tun_4tunnel_1#_tun_1tunnel_1#_tun_2tunnel_1#_tun_3tunnel_1#_tun_4AxesLinestyleXYZ3.1.2模拟的实现既有线路隧道下部新建隧道模型交叠区加密段FLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep14655ModelPerspective16:54:32TueMar252008Center:X:-2.269e+001Y:3.525e+000Z:-8.810e+000Rotation:X:30.956Y:359.401Z:35.482Dist:2.772e+003Mag.:43.4Ang.:22.500JobTitle:OverlappedShieldTunnelViewTitle:SELGeometryMagfac=0.000e+000SELGeometryMagfac=0.000e+000BlockGrouptunnel_1#_liner_2tunnel_1#_liner_3BlockGrouptunnel_1#_liner_1SurfaceMagfac=0.000e+000SELGeometryMagfac=0.000e+000SELGeometryMagfac=0.000e+000钢筋砼支护实体单元模拟锚杆支护cable结构单元模拟初喷砼支护shell结构单元模拟开挖面初喷砼支护shell结构单元模拟隧道未开挖段3.1.3研究结论①拱顶最大沉降量EφChH⑤地表最大沉降量EφCHh②拱底最大沉降量EhHCφ⑥塑性破坏区体积φChEH③拱顶最大下沉坡度ECφhH⑦拱顶最大拉应力EhφCH④对拱底最大下沉坡度EhφCH⑧拱顶最大拉应力EhCφH(1)影响因子对考察指标的影响力排序既有隧道拱底变形槽与拱顶变形槽-16-9-2-40-30-20-10010203040既有隧道纵向位置坐标(m)竖向沉降量(mm)衬砌拱顶变形槽衬砌拱底变形槽BBFLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep54824ModelPerspective20:35:34SunApr202008Center:X:6.453e-001Y:-4.609e-001Z:6.380e+000Rotation:X:356.579Y:0.000Z:0.144Dist:3.113e+002Mag.:8.53Ang.:22.500PlaneOrigin:X:0.000e+000Y:1.000e-001Z:0.000e+000PlaneNormal:X:0.000e+000Y:1.000e+000Z:0.000e+000JobTitle:OverlappedShieldTunnelViewTitle:SurfacePlane:onMagfac=0.000e+000AAA-AFLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep54824ModelPerspective20:47:56SunApr202008Center:X:7.231e+000Y:-1.556e-001Z:-9.008e+000Rotation:X:270.000Y:359.745Z:90.000Dist:3.767e+002Mag.:2.59Ang.:22.500JobTitle:OverlappedShieldTunnelViewTitle:ContourofSMaxMagfac=0.000e+000GradientCalculation-1.2770e+005to-1.0000e+005-1.0000e+005to-5.0000e+004-5.0000e+004to0.0000e+0000.0000e+000to5.0000e+0045.0000e+004to1.0000e+0051.0000e+005to1.5000e+0051.5000e+005to2.0000e+0052.0000e+005to2.1523e+005Interval=5.0e+004AxesLinestyleXYZFLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep54824ModelPerspective21:04:35SunApr202008Center:X:-4.632e+000Y:-1.556e-001Z:-9.008e+000Rotation:X:270.000Y:359.745Z:270.000Dist:3.767e+002Mag.:2.59Ang.:22.500JobTitle:OverlappedShieldTunnelViewTitle:ContourofSMaxMagfac=0.000e+000GradientCalculation-1.2770e+005to-1.0000e+005-1.0000e+005to-5.0000e+004-5.0000e+004to0.0000e+0000.0000e+000to5.0000e+0045.0000e+004to1.0000e+0051.0000e+005to1.5000e+0051.5000e+005to2.0000e+0052.0000e+005to2.1523e+005Interval=5.0e+004AxesLinestyleXYZFLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep54824ModelPerspective21:02:39SunApr202008Center:X:2.565e+000Y:1.207e+000Z:-9.021e+000Rotation:X:90.000Y:0.480Z:90.000Dist:6.067e+002Mag.:3.81Ang.:22.500JobTitle:OverlappedShieldTunnelViewTitle:ContourofSMaxMagfac=0.000e+000GradientCalculation-8.9905e+003to0.0000e+0000.0000e+000to1.0000e+0051.0000e+005to2.0000e+0052.0000e+005to3.0000e+0053.0000e+005to4.0000e+0054.0000e+005to5.0000e+0055.0000e+005to5.4446e+005Interval=1.0e+005AxesLinestyleXYZB-BFLAC3D3.00ItascaConsultingGroup,Inc.Minneapolis,MNUSAStep54824ModelPerspective20:54:15SunApr202008Center:X:2.565e+000Y:1.207e+000Z:-9.021e+000Rotation:X:90.000Y:0.480Z:270.000Dist:6.067e+002Mag.:3.81Ang.:22.500JobTitle:OverlappedShieldTunnelViewTitle:ContourofSMaxMagfac=0.000e+000GradientCalculation-8.9905e+003to0.0000e+0000.0000e+000to1.0000e+0051.0000e+005to2.0000e+0052.0000e+005to3.0000e+0053.0000e+005to4.0000e+0054.0000e+005to5.0000e+0055.0000e+005to5.4446e+005Interval=1.0e+005AxesLinestyleXYZ既有隧道衬砌拱底拱顶最大拉应力云图(2)新隧道开挖引起既有隧道衬砌拱底最大沉降量的回归公式1xH350tanxEC2xh12312233122212320.771261940.5068414-11.85241448-0.102395996-0.1341451740.0286143040.00974783-0.0311126180.881466945-0.000535166Sxxxxxxxxxxxx拱底式中:•建立模型弹性地基梁模型,假设梁底面与地基表面始终紧密相贴,即地基的沉陷或隆起与梁的挠度处处相等新线隧道既有隧道衬砌弹性梁模型3.2、既有隧道衬砌计算模型•求解AB段:可由初参数法求出BC段:k=044zdyEIbdx432123424zbyxAxAxAxAEI32123326zbxAxAxAEI212(62)2zbMEIxAxAEI1(6)zbQEIxAEIBC段边界条件:B点:C点:对称:O点(中点):1ByS1B1CyS1CBCMMBCQQOyS0O•结论其中:S1、分别为新隧道开挖引起的既有隧道衬砌拱底变形槽反弯点处的沉降量和最大坡度角。为了防止衬砌开裂破坏,应该提前在既有隧道施工时,在衬砌变形槽反弯点处设置变形缝。2241(2)(2)32384zzbbSSllalaEIEI21(2)8zbllaEI13.3、交叠隧道变形规律研究近距离交叠隧道的开挖会对地层产生两次施工强扰动,进而会显著增大地表的变形,同时地面沉降区的变形形态也会发生复杂变化,从单条隧道开挖的地表沉降槽向复杂的沉降漏斗转变。•地表沉降漏斗的形成过程仿真模拟•模拟数据分析先开挖下部隧道,后开挖上部隧道先开挖上部隧道,后开挖上部隧道-25-20-15-10-50-30-24-18