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.