中文摘要：

传统意义上，平行导洞的作用在于为正洞开挖探明地质，并通过一系列横通道实现正洞“长隧短打”。此工艺不仅具有分部开挖的特点，还可利用导洞解决排水问题，导洞挖通后，还可改善洞内通风条件。研究的堡镇隧道右线出口高地应力环境下软弱围岩中的平行导洞，围岩变形量大，变形速率大，变形持续时间长，隧道破坏严重。主要表现为拱顶下沉、边墙内挤、喷混凝土剥落、钢拱架扭曲、底鼓及仰拱开裂翘起、衬砌开裂等，变形破坏具有不均匀性和不对称性。与平导围岩变形特征相反，平导扩挖时的变形特征具有均匀性和对称性。从工程岩体二次演化、应力场二次演化以及平导围岩和平导扩挖围岩变形破坏特征等方面进行分析，提出了平行导洞在穿越高地应力软岩中能释放应力、减弱正洞围岩变形的破坏程度。

英文摘要：

In tradition, parallel pilot is used for exploring geologic condition before excavation tunnel, and adding working face through cross entryway. It performs not only cutting partial section, but also settling drain problem. After parallel pilot is cut through, it can improve ventilating condition. Research on the parallel pilot of right line outlet in Baozhen tunnel, the monitoring data shows that deformation was rapid with long duration, intense deformation and serious failure happened. For example, roof subsidence, wall crushing, shotcrete flaking, S-shape twisted steel support, broken lining, floor upheaval, invert crazing and lots of cracks distributed everywhere, the deformation characters of surrounding rocks present inhomogeneity and asymmetry. Reverse to pilot, the deformation characters of enlarging pilot present homogeneity and symmetry. Analyzing through twice evolution of surrounding rocks and earth stress as well as deformation characteristics, draw a conclusion that parallel pilot can release stress and reduce deformation during tunnel construction in soft rock with high earth stress.