无充填周期性裂缝岩体的等效渗透系数（稿件编号：201600412）

为了研究无充填周期性裂缝岩体的渗流特性，建立了地下水流动分析模型，该模型假定裂缝和岩石交界面流速相等且剪应力连续。根据分析模型的边界条件，耦合Navier−Stokes方程和Brinkman-extended Darcy方程，推求出裂缝和岩石中水流的流速分布。结合线性Darcy定律，推导出无充填周期性裂缝岩体沿裂缝方向等效渗透系数的理论表达，该表达式揭示裂缝开度对等效渗透系数起控制作用。为进一步验证理论模型推求的成果，研制试验装置开展渗流试验。试验时用浇筑混凝土模拟岩石，用混凝土间缝隙模拟岩石裂缝。测得的平均渗透系数和理论计算得到的等效渗透系数在同一量级，且相差很小。试验结果验证了所推求等效渗透系数表达式的正确性和可靠性。

Equivalent Permeability Coefficient of Rock Mass Containing Periodic Fractures without Filling

In order to study the seepage characteristics of rock mass containing periodic fractures without filling, an analysis model for groundwater flow was built. In this model, two assumption conditions were given for the interface between rock and facture. One condition was that the velocity was equal and the other was that the shear stress was continuous. According to the given conditions, the velocity distribution in fractures was deduced using the Navier−Stokes equation and that in rocks was deduced using the Brinkman-extended Darcy equation. The equivalent permeability coefficient of the theoretic model, i.e. the rock mass containing periodic fractures without filling, was derived from the linear Darcy''s law. The derived explicit equation shows that the aperture of fracture plays an important role in the groundwater flow in rock mass. In addition, the laboratory seepage tests were performed to validate this model. During the testing process, concrete and fracture between two pieces of concretes were used to simulate rock and fracture respectively. The average permeability coefficient value measured by tests and the equivalent value calculated from the theoretical expression were in the same order of magnitude, and the error was very small. The test results validate the expression given in this study.