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UDEC离散单元法中关于裂隙岩体开挖模拟及水力全耦合分析模型,可用来分析裂隙岩体洞室开挖后,因围岩应力与水力耦合作用导致裂隙隙宽变化及渗流变化的过程。为了更为直观地了解耦合作用对裂隙岩体渗透特性的影响,本文以隧洞开挖为例,用开挖后隧洞内总涌水量来表征岩体的渗透特性。利用数值试验的方法,研究了块体边界、初始应力比、裂隙隙宽、裂隙夹角对开挖后隧洞内涌水量变化的影响,进而可以得出它们对裂隙岩体渗透性的影响。本文的主要结论为:随着块体尺寸和初始应力比的增大,隧洞内总涌水量减少;随着初始隙宽增大涌水量增大并当达到某一固定值后保持不变;隧洞涌水量在θ2/θ1=3.5,其中θ1=30°,即2组节理的夹角为75°处达到最大。
UDEC discrete element method for fractured rock mass excavation simulation and full hydraulic coupling analysis model can be used to analyze the fractured rock mass tunnel excavation, due to surrounding rock stress and hydraulic coupling caused by changes in fracture width and percolation process. In order to understand the effect of coupling on the permeability characteristics of fractured rock mass more intuitively, this paper takes tunnel excavation as an example to characterize the permeability characteristics of rock mass using the total water influx within the tunnel after excavation. The influence of block boundary, initial stress ratio, crack width and fracture angle on the variation of water inflow in the tunnel after excavation was studied by means of numerical experiments. The influence of these factors on the permeability of fractured rock mass was also studied. The main conclusions of this paper are as follows: With the increase of block size and initial stress ratio, the total water inflow in the tunnel decreases; the water inflow increases with the increase of initial gap width and remains unchanged after reaching a certain fixed value; The inflow rate is θ2 / θ1 = 3.5, where θ1 = 30 °, that is, the angle between two groups of joints reaches the maximum at 75 °.