在胶州湾隧道工程中，为满足城市交通规划和区域交通疏导要求，采取设置地下分流匝道的设计方案。双车道匝道隧道与3车道主隧道在地下小角度交汇，形成分岔隧道。由于该分岔隧道段埋深浅、地层条件差、地面环境复杂，给设计和施工带来了不小的难度。通过工程类比、数值模拟分析等方法确定小净距隧道段范围，对变净距并行隧道中夹岩分区段采取扩挖换填混凝土、对拉锚杆等措施；在特大断面隧道段通过预注浆加固地层、加强初期支护，采用台阶分块开挖方案；施工中采用微震爆破技术，较好地保护了围岩，最终成功实现了此浅埋分岔隧道的快速施工。通过现场监控量测数据反馈分析，所采取的支护参数、工程措施、施工方案合理，确保了工程的安全、顺利建成。

A forked section is arranged in Jiaozhou Bay tunnel. Due to the shallow cover, poor geological conditions and complex ground surface environment of the forkedsection of the tunnel, there are great difficulties in the design and construction of the forkedsection. The range of the smallspaced tunnel section is determined by means of engineering analogy and numerical simulation. Concrete filling and tie bolts are adopted to reinforce the rock pillar of the smallspaced tunnel section. Pregrouting, primary support strengthening and bench excavating method are adopted for the large crosssection tunnel section. Microvibration blasting technology is adopted during the construction. In the end, rapid construction is achieved for the forkedsection. The monitoring results show that the support parameters, construction technologies and construction program adopted are rational and reliable.