越江盾构隧道纵向不均匀沉降控制指标值研究

Study on Values of Controlling Indexes of the Cross-River Shield Tunnel with Longitudinal Uneven Settlement

随着我国越来越多的越江隧道投入运营,由多种因素导致的隧道纵向不均匀沉降逐渐得到重视。为了保证车辆的正常运行以及越江隧道的结构安全,需要对隧道的纵向不均匀沉降进行控制,并提出合理的控制指标值。在修正的等效连续模型基础之上,笔者对纵向弯曲造成的越江隧道不均匀沉降的控制指标值进行了研究,同时,针对环向错台造成的越江隧道纵向不均匀沉降,研究了相对弯曲的合理取值。研究结果表明:当纵向曲率半径相同时,越江隧道的环缝张开量大于地铁隧道;在相同的环缝张开量条件下,越江隧道的纵向曲率半径随隧道直径的增大近似呈线性增长;当相对弯曲值相同时,越江隧道的错台量是地铁隧道的1.5至2倍。因此,相对于地铁隧道,应对越江隧道纵向不均匀沉降控制指标值提出更严格的限制。

With an increasing number of cross-river tunnels put into operation in China,uneven settlements in longitudinal directions of cross-river tunnels induced by various factors are receiving more and more attention. In order to ensure the normal running of vehicles as well as the structural safety of cross-river tunnels,it is necessary to control the longitudinal settlements of cross-river tunnels and to set reasonable values of controlling indexes. Based on a modified equivalent continuous model,the values of controlling indexes of the cross-river shield tunnel with uneven settlement caused by longitudinal bending are studied. At the same time,for the uneven settlements of cross-river tunnels caused by transverse dislocation,the reasonable value of relative bending is studied. The results show that：when longitudinal curvature radii are equal,the crack width of a cross-river tunnel segment joint is bigger than that of a metro tunnel segment joint; under the condition of a same crack width,the longitudinal curvature radius of a crossriver tunnel increases with the increase of its diameter in a nearly linear relation; when the values of relative bending are equal,the dislocation amount of a cross-river tunnel is 1.5 to 2 times as large as that of a metro tunnel. Therefore,compared with metro tunnels,stricter control values should be imposed on cross-river tunnels to prevent serious longitudinal uneven settlement.