基于模糊综合评判的护盾式TBM施工围岩稳定性分类

Stability Classification of Tunnel Surrounding Rock During Shield TBM Construction Based on Fuzzy Comprehensive Evaluation

针对传统分类方法难以对围岩稳定性进行评价的问题,以护盾式全断面隧掘进机(TBM)施工隧洞的围岩稳定性评价为目标,在研究护盾式TBM施工特点的基础上,参照国内、外常用的围岩分类方法,选择了岩石的回弹值、刀盘推力、刀盘扭矩、片状岩渣含量、地下水渗流量和最大主应力与洞轴线的夹角作为围岩稳定性评判因素。采用模糊综合评判方法,建立围岩稳定性多因素评判模型,通过确定评判因素的权重向量选取隶属函数,进而对围岩稳定性进行定量评判,并将之应用到某工程双护盾TBM施工的围岩稳定性评判中。结果表明:序号1、2、3和4洞段对应的较稳定、较稳定、局部稳定性差和不稳定的最大隶属度分别为0.494、0.403、0.388、0.442,分别对应Ⅱ、Ⅱ、Ⅲ和Ⅳ类围岩;模糊综合评判方法合理,评判结果较为可靠。研究成果对护盾式TBM施工的围岩稳定性评价、围岩分类及支护方式选择等具有参考价值。

Considering the difficulty of the traditional method in the classification and evaluation of surrounding rock stability of TBM tunnel,a new system of stability classification of the surrounding rock with shield TBM tunnel is developed.Based on the characters of a shield TBM construction and some regular classification methods,the evaluation factors were selected,including rock rebound value,cutterhead thrust,cutterhead torque,content of rock chips cut by TBM,groundwater flow and angle between the maximum principal stress and the tunnel axis.The multi-factor model of a stability analysis of surrounding rock was established by using fuzzy comprehensive evaluation method.The surrounding rock stability was quantitatively assessed by determining weight vector of impact factors and by selecting membership functions.This method was applied to the stability evaluation of tunnel surrounding rocks during a double shield TBM construction.The results showed that the tunnel sections of No.1,2,3 and 4 were relatively stable,relatively stable,local stabile,and instable respectively.Their maximum membership degrees were 0.494,0.403,0.388,and 0.442,corresponding to the surrounding rocks ofⅡ,Ⅱ,ⅢandⅣ.The developed method based on fuzzy comprehensive evaluation is reasonable,and the evaluation result is reliable.The research results have reference value for surrounding rock stability evaluation,surrounding rock classification,and support mode selection of shield TBM construction.