新建隧道下穿既有隧道引起的隧-土相互作用研究

STUDY OF TUNNEL-SOIL INTERACTION INDUCEDBY TUNNELING UNDERLYING

基于隧道开挖下穿引起既有隧道变形的工况,获得了一种可计算既有隧道受力变形的解析方法。采用修正高斯公式解得既有隧道在盾构下穿作用下的附加应力,将既有隧道视为放置在Kerr地基上的无限长EulerBernoulli梁,结合隧道两端自由的情况获得上覆隧道受力变形响应。案例研究表明:与既有文献离心机试验比较,该方法计算结果符合离心机实测数据;与既有理论和可退化的Pasternak地基模型比较,该方法预测结果更贴近实测数据。进一步参数研究表明:双隧夹角的增大会引起既有隧道位移减小及弯矩增大;既有隧道的位移和弯矩会随着地层损失率的增大近似线性增大;既有隧道位移及弯矩会随着新建隧道埋深的增大逐渐减小。

Based on the condition of tunnel deformation caused by tunneling underlying,a theoretical solution is obtained to calculate the response of existing tunnels.The additional loading upon existing tunnel caused by tunneling underlying can be calculated by modified Gaussian formula.By treating the existing tunnel as Euler-Bernoulli beam lying on Kerr foundation model,the strain and stress response of the overlying tunnel can be obtained by considering the case of freedom at both ends of tunnel.Cases studies show that the solutions of the proposed method have better agreement with the centrifuge data than the existing centrifuge tests.Compared with existing theory and degraded Pasternak foundation model solution,the prediction of the proposed method is close to the measured data.Further study shows that the tunnel displacement decreases with the increment of the skew angle between two tunnels,but the tunnel bending moment increases.The displacement and bending moment of the tunnel increase approximately linearly with the volume loss.Displacement and bending moment of the tunnel decrease as the depth of new tunnel increases.