Hoek-Brown准则在初始地应力场评估中的应用研究

Application Research on Hoek-Brown Criterion in Initial Ground Stress Field Evaluation

以基于岩体波速的Hoek-Brown准则为理论基础,根据岩体的稳定性条件建立了初始地应力场中水平地应力σH取值范围的计算模型,并通过已有的地应力测量数据验证了计算模型的合理性。在该计算模型的基础上,对平均水平地应力σ_(Hmean)、水平地应力和垂直地应力的比值σ_H/σ_V、侧压系数λ沿深度h的分布特征进行了研究,从岩体稳定性的角度较合理的解释了σ_H/σ_V在地层中的分布现象。在给定σ_(Hmean)和λ沿h分布的边界条件的基础上,建立了σ_(Hmean)和h之间、λ和h之间的非线性函数关系式,并将后者应用于工程实例中的初始地应力场计算。结果表明:在此初始地应力场条件下模拟出的岩体开挖后的应力和位移分布与现场地质调查情况基本相符,在地应力资料缺乏的情况下为初始地应力场评估提供了新的思路和方法。

Based on the theory of Hoek-Brown criterion of rock mass wave velocity, a calculation model of the values range of horizontal geostress （σH） in initial ground stress field was built according to the stability condition of rock mass, and the rationality of the calculation model was proved by the existing in-situ stress measurements data. Based on the calculation model, studies about distribution characteristics of average horizontal geostress （σHmean） , ratio of horizontal geostress and vertical geostress （σH/σV）, coefficient of horizontal pressure （λ） all distribute along depth （h） were carried out. A reasonable explanation of the distributing phenomenon of σH/σV in stratum was given from the perspective of rock mass stability. Based on the given boundary conditions of σ Hmean and A along h,the nonlinear function relations between both σ Hmean and h,λ and h were built,and the latter was applied to calculate the initial ground stress field in the engineering example. The results show that, the stress and displacement distribution in the slope after excavation simulated by the initial ground stress field is consistent with geological investigation situation. New ideas and methods about evaluating initial ground stress field are given in the case of lack of in-situ stress data.