成渝客专新建中梁山隧道上穿既有襄渝铁路中梁山隧道，两者最短垂直距离仅2.9 m，为保证上穿隧道与既有隧道的施工运营安全，采用数值模拟和现场测试进行研究。研究结果表明： 既有隧道在新建上穿隧道开挖后整体呈上移趋势，最大垂直位移在拱顶处，达到7.10 mm，最大水平位移在起拱线位置，为1.73 mm，最大拉应力出现在起拱线内侧，最大压应力出现在拱顶内侧；提出既有隧道加固措施，并根据计算结果布设拱顶位移测点和水平收敛测线；监测结果的垂直位移基本一致、水平位移略小于计算值，但两者规律性趋于一致；证明了研究方法的可行性和正确性。

New Zhongliangshan tunnel on ChengduChongqing passengerdedicated railway crosses above existing Zhongliangshan tunnel on XiangyangChongqing railway, with the minimum vertical distance between the two tunnels being only 2.9 m. Numerical simulation and field tests are made so as to ensure the safety of the new tunnel and the existing tunnel. The study shows that the existing tunnel has an upward movement trend after the excavation of the abovecrossing tunnel; the maximum vertical displacement occurs at the tunnel crown, reaching 7.10 mm; the maximum horizontal displacement occurs at the spring line, reaching 1.73 mm; the maximum tensile stress appears at the inner side of the spring line; the maximum compressive stress appears at the inner side of the tunnel crown. Reinforcement measures for the existing tunnel is proposed and crown displacement monitoring points and horizontal convergence measuring lines are laid out according to the calculation results. The vertical displacement measured is close to the calculation value; the horizontal displacement measured is slightly less than the calculation value, but the regularity of the two values tends to be consistent. It proves that the research method is feasible and rational. 