裂隙岩体渗流与三维应力耦合的理论与实验研究

THEORETIC AND EXPERIMENTAL STUDIES OF THE COUPLING OF SEEPAGE FLOW AND 3D STRESSES IN FRACTURED ROCK MASSES

围绕裂隙岩体渗流与应力之间的关系问题,从理论出发,经过合理的建模和严密的推演,得出裂隙岩体渗流与三维应力的耦合方程。该方程经过了大量的三轴实验数据的验证,解决了裂隙岩体受到的侧向应力对其渗流是否有影响这一岩石力学学科中争议很大的问题。指出了裂隙侧向应力引起的裂隙侧向变形是影响裂隙岩体渗流的主要因素,其影响符合负指数规律。同时,还分析了裂隙组的渗流问题。

The coupling equation of the seepage flow in fractured rock masses and 3D stress is concluded. The physical models and strict related equations of rock mass under 3D stresses are proposed by joining the tectonic characteristics of the fracture in rock. In the model, it is supposed that the fracture in rock is composed of two body matrixes and the fracture is filled by soft material, whose elastic modulus is much less than that of the body matrixes. Under 3D stresses, the coupling deformation of fillings and body matrixes makes the fillings denser and the permeability coefficient of the fracture decrease, in which the lateral deformations of the fracture plays significant role. The lateral deformations of the body matrixes are equal to the lateral deformations of the fillings in the fracture when the fracture is very narrow. Meanwhile, the density of the fillings in the fracture will be changed with the lateral deformation and consequently the permeability coefficient of the fracture. The deduced calculation formula of permeability coefficient is examined by large amount of triaxial experimental data of coal and limestone. The simplified calculation formula of permeability coefficient with only normal stress is same as the traditional one. It is concluded that the lateral deformations caused by the lateral stresses have important effects on the fracture seepage, the relation of which is in the form of a negative exponent law. The permeability law in the group of fractures is also analyzed.