大直径盾构隧道下穿南水北调干渠施工影响分析

以豫机城际铁路隧道下穿南水北调中线干渠为背景,通过FLAC3D三维数值模拟,对施工过程进行模拟,研究结果表明当隧道顶部距离干渠底部32.24 m开挖时,干渠结构相对稳定;当地层损失率控制在0.5%以内及覆土厚度大于2倍洞径时,地表沉降较小;随着地层损失率增大,地表沉降增大,随着覆土厚度增大,地表沉降减小。将数值模拟结果与经验公式预测结果进行比较,结果显示二者吻合度较高。

Analysis of large diameter shield tunneling crossing underneath existing trunk canal of South-to-North Water Transfer Project

The present article investigates the trunk canal of South-to-North Water Transfer Project constructed beneath the "Yu-ji" railway tunnel and crossing it. The three-dimensional numerical simulation FLAC3D is carried out to simulate the construction process,the results show that the canal structure is relatively stable when the distance between the top of the tunnel and the bottom of the trunk is about 32.24m. Besides the displacement becomes small when the ground loss rate is controlled at 0.5% or the overburden thickness is more than twice the diameters. It was also demonstrated that the displacement increases with the increase of ground loss rate,while it decreases along with the increase of soil thickness. The results of numerical simulation are compared with the empirical formula,and the results show that they are of high agreement.