深部软岩隧道施工性态时空效应分析

随着我国交通事业的迅速发展,在深部岩体中修筑隧道工程已必不可少,随之而来的深部岩体所具有的特殊工程地质问题也更加突出。主要对深部软岩隧道工程中施工力学性态和变形时空效应进行三维非线性黏弹性数值模拟,并将计算结果与现场实测数据进行比较验证。研究结果表明,计入围岩流变效应,考虑深部软岩隧道时空效应影响,在作业面影响范围内,开挖面空间效应占主导因素,围岩应力随距作业面距离的加大而逐步释放;在此范围外,软弱岩体流变属性得以充分发挥。通过分析和施工实践证明,对于深埋软岩隧道应尽早施作衬护,以改善承载环范围内围岩受力,减少扰动,提高围岩自承能力;由于软岩流变效应显著,必须适时设置二次衬砌以承受来自围岩的后期流变压力,限制围岩大变形。研究成果丰富了地下工程施工力学理论,可应用于工程实践。

ANALYSIS OF TIME-SPACE EFFECTS OF CONSTRUCTION BEHAVIOR OF DEEP SOFT ROCK TUNNEL

With the rapid development of transportation,it is inevitable to excavate tunnel in the deep rock mass,and the problems of special engineering geology in deep rock mass will be much more distinct.The 3D nonlinear viscoelasticity numerical simulation and analysis are conducted on time-space effect of mechanical behaviors and deformation characteristics of deep soft rock mass during the tunnel construction;and the calculation results are compared with the field data.Considering rheological effect and time-space effect of deep soft rock tunnel,the results of show that the effect of excavation face is primary in the advancing face zone and the stress of surrounding rocks gradually releases from the excavation face.Rheological effect plays a key role out of the influence range of the spatial effect of excavation face.According to the characteristics of deep soft rock tunnel,support structure should be established as soon as possible in order to ameliorate the stress in surrounding rock circle,to reduce disturbance and to improve the self-bearing capability of the surrounding rock.Because of the distinct rheological property of soft and weak rocks,the secondary support structure must be established in time to bear the rheological pressure.Thus,the large displacement could be restricted by the secondary support structure.The present research enriches the theory of construction mechanics of underground structures and has wide application prospects in engineering.