Abstract: The pretreatment of boulders and bedrock before shield boring is discussed, with the boring of Bao’an Central Station to Fanshen Station section on Line 5 of Shenzhen Metro as an example. The details of the boulders and bedrock that may cause risks for shield boring are obtained by means of additional geological predictions. Countermeasures such as alignment adjustment and gradient adjustment, reinforcement and shield boring parameter control are taken to cope with the boulders and bedrock.In the end, successful boring is achieved and the construction schedule is guaranteed.

Key words: Metro, shield machine, bedrock, boulder, pretreatment, alignment adjustment, gradient adjustment, Soletanche grouting, boring parameter