经过十几年的工程实践，连拱隧道己在我国公路工程得到广泛应用。然而，作为一种新颖的结构形式，连拱隧道在应用过程中也存在不少问题。中隔墙是双连拱隧道结构受力的核心构件，受力十分复杂，是隧道应力集中部位(拉、压、弯、扭、剪力均有)，其结构受力要在隧道整体结构中进行调整。而中隔墙的力学行为和它的位移沉降指标直接关系到连拱隧道的总体稳定性。 研究方法与内容： （1）通过对国内外连拱隧道工程应用调查，分析不同断面形式和施工方法对中隔墙稳定性的影响。 （2）理论计算分析 选择实际隧道为原型，采用有限元数值计算方法对双连拱隧道施工过程及中隔墙内力和变形进行分析研究。分析不同施工工序条件下中隔墙应力变化规律、中隔墙稳定性以及两洞室开挖面合理间距。 （3）现场监控量测试验 依托工程为南京地铁一号线南延线安德门站～宁丹路站区间双连拱隧道，监测中隔墙内力以及变形情况。通过现场试验可以验证和完善理论分析所得的主要结论，同时可以反馈于理论计算及模型试验的测试结果的合理性。 主要研究成果： （1）连拱隧道在施工过程中处于偏压状态，其竖向应力从上到下呈台阶式收敛，先施工洞室一侧变化较大，中隔墙底部最大竖向应力出现在中隔墙的正下方。 （2）中隔墙在隧道施工过程中处于沉降状态；水平位移的最大值出现在中隔墙顶部，中部最小，但水平位移值较小，对中隔墙的稳定性影响不大；由于扰动次数较多，三导洞法相对于中导洞—台阶法引起的位移较大。 （3）随左洞掌子面的向前推进，掌子面后方的中墙产生整体向右的偏转，墙身中部向右侧鼓出，基部左墙趾向上抬起。当偏压明显时，应在墙体结构上采取相应的措施以提高墙体的稳定性，如降低墙体高度、加大下部结构尺寸或采取不对称结构，从而保证整体衬砌结构稳定与安全。 （4）采用三导洞施工方法下，左洞施工对中墙应力影响范围为18m，右洞施工对中墙应力影响范围为24m，从而得出两掌子面合理间距为单洞2倍跨度。

After more than ten years of engineering practice, the double-arch tunnel highway projects in China has been widely used. However, as the structure of a novel form of double-arch tunnel in the application process there are also many problems. In the wall is a double-arch tunnel structure by the force of the core components, the complexity of forces at the tunnel site of stress concentration (pull, pressure, bending, twisting, shearing both), its force structure to the overall structure of the tunnel adjustment. The wall of the mechanical behavior and its settlement indicators directly related to displacement double-arch tunnel to the overall stability. Methods and Content of researching: (1)Through the investigation of double-arch tunnel engineering to analysis the stability of Medium Partition in Double-arch tunnel in different forms and construction methods. (2)Theoretical calculation and analysis Choose the prototype of the actual tunnel, using the finite element numerical method of double-arch tunnel wall construction process and the internal force and deformation analysis. Analysis of different construction processes in the wall under the conditions of stress changes and stability in the Medium Partition as well as a reasonable distance between surface excavation. (3)Monitoring the volume of the test-site inspection Relying on the project for Nanjing Subway Line Extension Andre South Station ~ NingDan Road Station interval double-arch tunnel in the Medium Partition to monitor the situation of internal force and deformation. Can be verified through field trials and improve the theoretical analysis of the main conclusions, as well as feedback on the theoretical calculation and model test of the test results is reasonable. The main results: (1)The double-arch tunnels are in a bias state. The vertical stress was stepped from top to bottom convergence, changes in the side of the first large cavern construction, the largest in the Medium Partition at the bottom of the vertical stress in the septum Medium Partition below. (2)The Medium Partition is in the settlement status during the process of tunnel construction; the maximum horizontal displacement is at the top of the central minimum, but a relatively small horizontal displacement of the stability in the partition have little effect; as a result of a high number of disturbances, the three-hole method in the guide hole for the law - step method arising from the larger displacement. (3) with the working face of the left hole to move forward, working face of the rear wall of the right arising from the overall deflection, the wall to the right side of the centralUplift, the base of the left wall toe lifted up. When the apparent bias should be in the wall structure of the corresponding measures taken to improve the stability of the wall, such as reducing the wall height, the lower part of the structure to increase the size or asymmetric structure, in order to ensure the overall stability and security lining the structure. (4) Construction of a three-hole lead method, the left hole in the wall construction of the stress around the impact of the range of 18m, the construction of the right hole in the wall stress to 24m around the affected area, working face so as to arrive at a reasonable distance between the two single-hole 2 times the span.