穿黄隧洞内衬混凝土环向应力参数敏感性分析

Parameter sensitivity analysis of hoop stress of inside liner of yellow-river-crossing tunnel

为了研究设垫层的预应力复合衬砌结构内衬混凝土的结构内力对垫层材料参数以及预应力损失计算参数的敏感性情况,以南水北调中线穿黄工程为背景,采用有限元软件ANSYS建立了盾构输水隧洞预应力复合衬砌结构的整体三维有限元模型,拟定了不同垫层弹性模量、不同预应力筋与孔道壁的摩擦系数、不同管道局部偏差摩擦系数、不同张拉控制应力、不同锚具变形和钢筋内缩值等一系列工况,以内衬管壁混凝土环向应力为敏感性分析指标,运用上述模型计算了内衬管壁混凝土在不同工况下的环向应力的变化情况。计算分析结果表明:在设计参数水平下,内衬管壁混凝土全断面受压,预应力效果良好;内衬管壁混凝土环向应力受张拉控制应力以及预应力筋与孔道壁的摩擦系数影响较大,受锚具变形和钢筋内缩值影响较小,管道局部偏差摩擦系数对管壁混凝土环向应力几乎没有影响;垫层弹性模量越大,管壁混凝土环向压应力越小,采用弹性模量较小的垫层能够提高预应力效果,改善内衬混凝土的受力状况。

The sensitivity of structural internal force of the prestressed composite linings with cushion layer for water conveyance shield tunnel to Cushion layer material parameters and calculation parameters of prestressing loss were studied.By using of the finite element software ANSYS,the whole three-dimensional finite element model of the prestressed composite linings with cushion layer for water conveyance shield tunnel was established with the Yellow-River-crossing tunnel in the Middle Route Project of South-to-North Water Diversion as the background.Analysis cases of different cushion layer modulus,friction coefficient of prestressed steel and channel wall,local deviation friction coefficient of strand channel,stretching control stress,anchorage deformation and steel shrinking value were programmed.Using hoop stress of inside liner as the Sensitivity analysis indicators,the hoop stress of inside liner were calculated at different cases with the above mentioned model.The calculation and analysis results reveal that the whole section of inside liner is compressed and the prestressing effect is satisfactory.Stretching control stress and friction coefficient of prestressed steel and channel wall have a big influence on hoop stress of inside liner.The hoop stress of inside liner is less affected to the anchorage deformation and steel shrinking value and the local deviation friction coefficient of strand channel has no effect on it.The greater of the cushion layer modulus,the hoop compressive stress of inside liner is smaller.So,the effect of prestressing and the force condition of inside liner can be improved by using the cushion layer whose modulus is smaller.