爆破技术在顶管工程中的应用

Application of Blasting Technique in Pipe-jacking Engineering

介绍在全断面中风化花岗岩及局部岩层、局部软土复杂地质条件的顶管施工技术。为满足顶管穿越复杂地质条件的施工需求,对气压平衡式工具管进行了改进,对顶管穿越岩层段沿线软土地基采用深层搅拌桩进行加固处理,使之在顶管上部形成一个密封式的隔水、自立挡土层,并研制了适合在岩层中采用短进尺、多循环、光面爆破顶管掘进的施工方法。岩层爆破后,石渣体积较小,由人工逐段清除岩石,并在扩径部位回填砂土,然后逐段推进,使顶管成功穿越岩层。

This paper presents the pipe-jacking techniques under the complex geological condition of weathered granite at full section or with local rock stratum and local soft soil.To meet the requirement of complex geological condition for pipe-jacking engineering,the air-pressure balance type tool pipe is thereby improved and the soft-soil foundation along the rock section for pipe jacking is also reinforced using deep mixing pile to create a sealed and watertight self-supported earth retaining layer above the pushing pipe;for this purpose,the construction method for short drilling footage,multi-cycle operation and smooth blasting with pipe-jacking tunneling in rock stratum is therefore developed.The rock blasting will bring about small-volume rock ballast which can be removed manually section by section,and the diameter-enlarging area will be backfilled with sandy soil so as to advance the construction section by section,thus enabling the pushing pipe to pass rock stratum successfully.