深埋隧道开挖引起围岩应力释放与重分配，周围岩体与支护结构力学特性发生复杂变化，会造成围岩大变形和塑性破坏。开展深埋隧道围岩稳定性与力学特性研究，无论是对本学科的发展，还是对地下空间的有效合理开发、施工优化和确保工程顺利进行，均有十分重要的意义。 本文以沪蓉西高速公路夹活岩深埋隧道为依托工程，以现场量测资料为依据，结合FLAC3D有限差分软件数值模拟，对深埋隧道施工力学特性进行研究，并将实测数据与模拟结果对比分析，研究深埋隧道的围岩变形破坏机理。笔者阐述了有限差分法模拟地下工程施工过程的基本原理。对隧道开挖过程进行有限差分三维数值仿真模拟，得出:隧道掘进过程中锚杆受力曲线；隧道掌子面的两侧和掘进前方10-20m范围内出现压应力集中区，拱腰及拱脚出现剪应力集中区，在拱顶和底板以张拉性破坏为主，拱腰和拱脚以剪切破坏为主；拱顶下沉与周边位移随着掘进位移速度逐渐减小，当掘进至25m，围岩位移曲线逐渐趋于稳定；在深埋隧道中初期支护承担90%以上的围岩压力，二次衬砌作为安全储备；确定了深埋隧道不同断面的二次衬砌最佳支护时间。夹活岩隧道监测数据表明：在该深埋隧道设计支护条件下，拱顶下沉和周边位移量均在预留变形量之内，符合公路隧道设计规范要求。 结合监控量测和数值模拟分析成果，得出夹活岩深埋隧道围岩变形破坏机理及变形特征，并分析该隧道发生拱顶冒落和边墙混凝土剥落的现象的主要原因及解决措施。深入探讨了深埋隧道围岩的变形破坏机制，为深埋隧道的理论研究、优化设计和施工提供了依据和实践经验。

The excavation of the deep-buried tunnels makes the stress of the surrounding rock release and re-distribution, Surrounding rock mass and the supporting structure of mechanical properties occur complex changes, it will cause damage to large deformation and plasticity.So research deep-buried tunnel stability and the mechanical characteristics all have significance not only in the development of the disciplines but also in underground space for the effective and rational development, optimization and construction to ensure the smooth conduct of the project. This paper depends on deep-buried tunnel(Jiahuoyan Tunnel),through measured information at construction field, combined the finite difference software FLAC3D numerical simulation,study on the dynamic construction mechanics feature of intersection part of deep buried tunnel. Through comparative analysis the measured data and simulation results,to probe the deep-lying tunnel mechanism of rock deformation and failure.Elaborate the finite difference method on underground engineering simulation of the basic principles of the construction process. The process of tunnel excavation on the finite-difference simulation of three-dimensional numerical, Concluded that: the process of tunnel boring bolt force curve; Both sides of the tunnel working face and the driving range in front of 10-20m appear pressure stress concentration zone, lumbar arch and arch foot appear shear stress concentration zone, in the vault and floor damage to the main tension, waist and foot arch arch to the main shear failure; dome surrounding the sinking and displacement as the tunneling rate of displacement decreases; when driving to 25m, surrounding rock displacement curve gradually stabilized; deep-buried tunnel in the early commitment to support more than 90% of the rock pressure, secondary lining as a safety reserve; determine the best supporting time of defferent sections of the secondary lining. The tunnel folder monitoring data show that:in the design of its support conditions, the dome surrounding the sinking and displacement all in the scope of deformation reserved. content with the design specifications. Combination of monitoring and measuring the results of numerical simulation analysis, propose failure mechanism of rock deformation and deformation characteristics of Jiahuoyan tunnel.analysis of the tunnel roof and side-wall of concrete falling off of the main reasons for the phenomenon and solutions.More in-depth exploration of the deep tunnel of the deformation and damage mechanisms, provide the basis and practical experience for the oretical studies of deep-lying tunnels ,optimize the design and construction.