厦门海底隧道类土质围岩水土作用研究

Study of water-soil interaction on similar soil surrounding rock in Xiamen Subsea Tunnel

以厦门海底隧道工程为例,通过室内试验研究了类土质围岩在水中的崩解情况,分析了崩解量与时间的关系,讨论了土样的均匀性、密实程度对崩解的影响;从水土作用方面分析了隧道掌子面局部失稳的原因。研究成果表明:土样的崩解与土体颗粒组成、密实程度有关,颗粒细且均匀、密实的土样崩解曲线呈3个阶段;不均匀或较松散的土样在17min内崩解基本完成,均匀致密的类土质围岩遇水发生完全崩解的时间较长,最长可达3h以上;水对围岩的软化及崩解作用,将降低围岩的稳定性及自支撑能力,因此,施工过程中必须加强排水工作并及时支护。

Taking Xiamen Subsea Tunnel engineering for example, the relation of disintegration content and time is analyzed through the laboratory test; the disintegration of similar soil surrounding rock in water and the influence of uniformity and density degree of soil samples on disintegration are discussed. The reason of unstability of tunnel face is analyzed from water-soil interaction. The research results show that disintegration of soil samples is related to granulation percentage and density degree; disintegration curve of uniform and compact soil samples has three phrases. Disintegration of non-uniform and incompact soil basically accomplishes in seventeen minutes; but non-uniform and compact soil samples need more minutes. Disintegration adds up to 100 percent as time flies. Drainage and duly shoring are necessary in construction process because the stability and self strength of surrounding rock will reduce due to intenerating from water and disintegrating.