岩体力学参数对隧道围岩稳定性的影响分析

Effect of Rock Mechanical Parameters on Stability of Tunnel Surrounding Rocks

文章采用正交数值模拟试验方法研究了岩体力学参数对隧道水平收敛、拱顶下沉量和塑性区因子的影响。选取6个因素(弹性模量、泊松比、内摩擦角、抗拉强度、内聚力和密度)、3个水平的正交试验方案,采用方差分析方法对试验结果进行分析。结果表明:影响水平收敛量因素的程度大小的次序为内聚力、弹性模量、内摩擦角、抗拉强度、泊松比;影响拱顶下沉量因素的程度大小的次序为内聚力、内摩擦角、弹性模量、抗拉强度、泊松比;影响塑性区因子因素的程度大小的主次顺序为内摩擦角、内聚力,而密度对隧道围岩稳定性几乎没有影响;改变任一岩体力学参数,试验结果与正交试验结果吻合;考虑隧道围岩稳定性,应当对隧道开挖后的水平收敛量、拱顶下沉量和塑性区因子等进行综合考虑。针对三泉隧道V级围岩段施工,提出合理支护方式,并通过数值分析和现场监控量测验证了围岩处于稳定状态。

The effects of mechanical parameters of rock mass on horizontal convergence, crown settlement and fac? tor of plastic zone were studied by an orthogonal numerical simulation test. The 6 factors (elastic modulus, poisson ratio, internal friction angle, tensile strength, cohesion and density) and the orthogonal test program of three level were selected, and the test results were analyzed by ANOVA. The results show that the horizontal convergence is affected by the following factors in a sequence of cohesioin, elastic modulus, internal friction angle, tensile strength and Poisson ratio;the crown settlement is affected by the following factors in a sequence of cohesion, internal friction, elastic modulus, tensile strength and Poisson ratio;the plastic zone is affected by the following factors in a sequence of internal friction angle and cohesion, while the density has little effect on stability of tunnel surrounding rocks;the test results agree with the results from orthogonal test in condition of change of any mechanical parameter of tock mass;a comprehensive consideration should be given to the horizontal convergence, crown settlement and plastic zone after tunnel excavation in view of stability of tunnel surrounding rocks. Reasonable support method was proposed regarding the construction of Sanquan tunnel with the surrounding rock of grade V, and it proves that the surrounding rocks are stable by numerical analysis and site monitoring and measurement.