三维裂隙岩体渗流广义混合模型及其应用

STUDY ON THE GENERALIZED MIXED MODEL FOR 3-D FRACTURED SEEPAGE FLOW

简述了裂隙岩体渗流离散模型与等效连续模型的优缺点，提出裂隙单元与岩体单元交界面上水头连续而允许流量不连续的观点，通过裂隙单元和岩体单元传导矩阵的组装，建立了三维裂隙岩体渗流广义混合模型。用子结构初流量法求解具有自由面的渗流问题。文中结合铜街子牛日溪１号碾压混凝土坝渗流进行了计算，结果表明该模型是合理的，可行的。

The paper surveys advantage and disadvantage of the discrete model and the equivalent continuous model for 3D fractured rockmass. It seems therefore necessary to present a new model of seepage in order to remedy the two models above. By the cubic law the paper assumes that the water head on the surface between fractured elements and rock elements is continuous and the discharge on the connecting surface is discontinuous. It is possible to construct the generalized mixed model of fractured rockmass by combining the transmission matrix of rockblock elements with that of fractured elements. Compared to the double media model, it is unnecessary for the mixed odel to lead into every attached parameter, and every node of the seepage nets has only one water head. The mixed model would be useful to analyse the seepage flow in both continuous media and discontinuous rockmass. For example, in order to calculate the uplift pressure on the dam bottom, itis possible to divide the dam foundation into two: the one close to the dam bottom is discrete media; the other is continuum media. Finally, the water head, on the nodes creates with mixed model. By the discussions above, it is definite to say that the mixed model is simple and active. Moreover, for the problem of determination of free face which will arise in the analysis of seepage flow, the substructural primery flow method is presented to locate the free face. The method is a kind of fixed nets method, and it is simple. Finally, the paper calculates the seepage field of the rollercompacted concrete dam No.1 on the Niu-ri-creek and the results show that the mixed model has rationality and practical values.