西南某水电站坝址区风化花岗岩工程地质性质分析

The physical and mechanical properties of weathered granite in the foundation of a hydropower station in southwest China

文章对西南某大型水电站坝址区深厚层全风化和强风化花岗岩进行研究。将全、强风化花岗岩物理、水理及力学性质与新鲜岩体相应性质进行比较,并分析了花岗岩风化后吸水性增大、岩体软化、抗压抗剪强度减小的成因。对强风化花岗岩与新鲜花岗岩抗压强度进行了比较;拟合了风化花岗岩弹模、变形模量值与新鲜花岗岩相应模量的变化百分比关系曲线。研究结果表明：强风化花岗岩的干抗压强度为新鲜岩体的1/4-1/3,湿抗压强度为新鲜岩体的1/4-1/5;岩体弹性模量和变形模量与岩体的风化程度成反比例线性关系。

It is well known that the weathered action has declined the physical and mechanical property of rock, so the research on the relationship between the physical and mechanical property and the extent of weathering of the rock in large hydropower stations has great effects on how to choose the norm of the characteristics of the weathered rock and the parameters of the mechanics. The paper studied the completely-weathered and highly-weathered granite in the deep and thick stratum in the foundation of a great hydropower station in southwest, and it also analyze the characteristics of the granite such as its increase of absorption, soften and the decrease of shear strength after it weathered. And compared the compressive strength between the highly-weathered and fresh granite, simulated the percentage the trend of deformation modulus and elastic modulus of weathered-granite and fresh granite. The results showed that the compressive strength of highly-weathered granite when it is dry is 1/4 - 1/3 of the fresh, the compressive strength of highly-weathered granite when it is wet is 1/4 - 1/5 of the fresh, moreover, the elastic modulus and deformation modulus is linear and inverse ratio to the degree of the rock weathered.