城市地铁穿越软流塑地层段的设计施工技术

软流塑地段围岩自稳能力极差，易坍塌，严重时可能发生突水涌泥现象，地层加固难度较大。通过已经成功修建的工程实例重点剖析城市地铁在穿越软流塑地层时的设计施工技术，重点对洞内注浆加固、软弱围岩仰拱超前、水平旋喷加固、冻结加固法等施工辅助工法进行介绍和比选。同时对软流塑淤泥质粉质黏土地层进行劈裂注浆的原理、可行性、加固范围与扩散半行、注浆压力、注浆量、浆体材料和配比、注浆效果等进行了研究。

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Collapses, even water ingressions or mud inflows may occur to the soft-flow plastic ground, due to its extremely poor self-supporting capability. Furthermore, there exist great difficulties in the consolidation of the soft-flow plastic ground. On basis of successful project cases, the author expounds the design and construction technology for urban Metro running tunnels in soft-flow plastic ground, including the comparison and selection of such assistant construetion methods as grouting inside tunnel, installing advance invert in soft ground section, horizontal jet grouting consolidation and freezing consolidation. Moreover, the author studies on the principle, feasibility, consolidation scope and diffusion radius, pressure, quantity, mortar material and mixing ratio and effects of splitting grouting in soft-flow plastic silty clay. The paper can provide reference for similar projects in the future.