A lot of shattering loose rock masses were created by the Wenchuan earthquake. In order to rationally evaluate the classification of the surrounding rock of newly built tunnels in these mountain areas, this paper analyzes, by way of site investigation, the features of shattered rock masses and their effects on the stability of surrounding rock. The shattered rock, which exhibits a more developed structural plane and poorer joining of interlamination after the effects of an intense seismic wave, has different features concerning hard rock and soft rock. The shattered hard rock is prone to centralized tension fissures and loosening, and the soft rock is prone to the volumetric deformation of loosening. Based on this, a three-level classification of shattered rock masses is proposed, e.g. Slight, moderate and intense. In addition, a revision program is presented in which the level of the classification is not lowered or only lowered by 0.5 for the slight shattered rock mass since it has little impact on the stability of the surrounding rock; the level of the classification is lowered by 0.5 to 1 for the moderate shattered rock mass since it has adverse effects on the stability of the surrounding rock; and the level of classification is lowered by 1 to 1.5 for the intense shattered rock mass since it has extremely adverse effects on the stability of the surrounding rock.%复合地层中盾构隧道开挖面稳定性一直是盾构隧道工程技术难点之一.新加坡地铁环线属于典型的复合地层,并首次大规模采用泥水平衡盾构施工.文章结合地铁环线C855标段,对复合地层泥水平衡盾构施工中开挖面的稳定性分析与泥水压力设定等问题进行了探讨,基于Anagnostou和Kovari提出的楔形体模型,引进稳定数Ns概念,对沿线开挖面的泥水压力进行了分析计算,综合考虑设备性能、周边环境条件、现场组织与实施等因素给出了泥水压力设定表；并针对工程实施过程中遇到的问题,如开挖面坍塌、泥水逃逸以及降水等情况进行了分析,成果可为其它类似工程提供借鉴与参考.
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