小净距平行盾构隧道施工先行隧道管片附加应力监测研究

Field tests and researches on secondary stresses of advanced tunnel segments during parallel shield tunnels driving in close proximity

通过现场监测,研究揭示小净距平行盾构隧道施工中后行隧道掘进引起的先行隧道管片附加应力的变化规律。介绍了管片附加应力测点布置及监测方法,分析给出了管片附加应力动态变化规律,研究了附加应力与后行隧道掘进距离的关系,对管片附加应力的最大值和稳定值进行了统计分析。监测结果表明,当后行隧道掘进到监测断面附近时,附加应力有突变量,水平直径处环向受到压力作用,环向应力的量值比纵向应力大。以期能为评价小净距盾构隧道施工相互影响程度及该类盾构隧道设计、施工提供参考依据。

The change rules of the secondary stresses of advanced tunnel segment induced by parallel shield tunnels dirving in close proximity are studied by field tests.The layout of the measured points and the field test methods are introduced,and the change rules of the secondary stresses are analyzed.Furthermore,the relationship between the secondary stresses and the distance of the shield driving face to the measured section are studied.Statistical analyses of the maximum and the stabilized magnitudes of the secondary stresses are carried out.The results of the field tests show that there will be sharp change of the secondary stresses when the hind shield is driven to the measured section,the circumferential secondary stresses in the intersection of horizontal diameter with circumference of the tunnel will be laid,and the magnitudes of the circumferential secondary stresses will be greater than those of the longitudinal secondary stresses.The results may be applied to the quantitative assessment of the construction interaction of shield tunnels in close proximity and is regarded as references to the design and construction of this kind of shield tunnels.