裂隙岩体非饱和水力应力耦合的不连续介质模型研究

目前对于裂隙岩体饱和水力应力耦合的研究取得了一些进展,但在很多工程领域不能简单地采用饱和渗流分析,而是要考虑岩体饱和-非饱和渗流、应力耦合作用对工程岩体的强度和稳定性的重要影响.因此在总结众多学者对裂隙岩体水力耦合研究成果的基础上,根据DDA力学计算和非饱和渗流计算原理,提出了基于非连续介质方法的--DDA方法的非饱和水力应力耦合模型;并给出了降雨入渗工况下的边坡水力耦合算例.计算结果表明,边坡稳定性随着降雨入渗时间的增加而减小,降雨强度越大,边坡稳定系数的降幅越大;考虑水力耦合时的边坡稳定性要小于不考虑水力耦合时的边坡稳定性,且在同一时刻,若降雨强度越大,考虑水力耦合与不考虑水力耦合的稳定系数差值越大.仿真试验和工程应用表明其计算成果是符合实践规律的,由此说明了所提出的水力耦合模型能正确反映裂隙岩体的水力学特性,验证了该模型是可行有效的,可付诸于实践.

STUDY ON DISCONTINUOUS MEDIUM MODEL FOR UNSATURATED HYDRO-MECHANICAL COUPLING OF FRACTURED ROCK MASSES

The characteristics of fluid flow in fractured rock masses are more complex than general porous medium flow in virtue of randomness,fuzziness of mechanical parameters and corresponding complex geomechanical environment.However,geotechnical engineering design,performance and safety assessment are often involved in fluid flow and hydro-mechanical coupling of fractured rock masses,making hydro-mechanical coupling of fractured rock masses being hot in mechanical investigation.In recent years,some advancements are achieved in saturated hydro-mechanical coupling,but saturated flow cannot be adopted simply in many practical projects.Therefore,most important influences of unsaturated hydro-mechanical coupling in fractured rock mass on strength and stability of the rock projects should be considered.Investigating productions for hydro-mechanical coupling of fractured rock masses by a good many scholars were generalized;and unsaturated hydro-mechanical coupling analysis model based on discontinuous medium method was put forward according to the mechanical calculation theory of discontinuous deformation analysis(DDA) and unsaturated fluid flow analysis.Taking reservoir rock slope as an example,the stability of rock slope was discussed with rainfall.The results indicate that rock slope stability is greatly reduced with increase of infiltration time of rainfall.The greater rainfall intensity is,the more greatly the stability coefficient of rock slope is reduced.Especially,the stability of the rock slope with/without considering coupling was different:the greater rainfall intensity was,the greater difference between two cases was.The calculation results achieved by numerical simulation and practical projects application agree well with those of in-situ tests,which illuminates that hydro-mechanical coupling model could reflect hydraulic characteristics of fractured rock masses.It is proven that the numerical model is feasible and valid in practical projects.