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为了研究渗透压及围压对岩体蠕变性的影响,对三峡库区巴东组二段粉砂质泥岩进行了不同围压和渗透压下的三轴蠕变实验。基于试验结果,在分析粉砂质泥岩的蠕变特性曲线基础上,探讨了围压和渗透压对岩体蠕变特性的影响过程和机理。最后,采用等时应力—应变曲线法和稳态蠕变速率法求得了粉砂质泥岩在不同围压和渗透压下的蠕变长期强度。结果表明:1粉砂质泥岩瞬时弹性模量随着偏应力等级的增加而减小,;2孔隙水压在蠕变初期能够减小轴向应变,但在蠕变后期由于其有利于裂纹扩展而增大了轴向应变;3渗透压缩短了岩石蠕变破坏的时间,使蠕变破坏呈现出一定的脆性特点;4渗透压的存在有利于岩石裂隙的扩展和贯通,因而降低了岩石蠕变的长期强度,但是围压的存在增大了蠕变长期强度。为深入认识和了解三峡库区粉砂质泥岩的流变力学特性提供重要的试验和理论依据。
In order to study the effects of infiltration pressure and confining pressure on the creep of rock masses, triaxial creep experiments under different confining pressures and seepage pressures were conducted on the second member of Badong Formation in the Three Gorges Reservoir. Based on the experimental results, based on the analysis of creep characteristics of silty mudstone, the influence of confining pressure and infiltration pressure on the creep characteristics of rock mass was investigated. Finally, the long-term creep creep strength of silty mudstone under different confining pressure and osmotic pressure is obtained by isochronous stress-strain curve method and steady-state creep rate method. The results show that: 1 The instantaneous elastic modulus of silty mudstone decreases with the increase of the deviatoric stress level; 2 The pore water pressure can reduce the axial strain at the early stage of creep, but due to its favorable crack propagation Which increases the axial strain. 3 The osmotic pressure shortens the time of the rock creep failure and makes the creep failure show a certain brittle characteristic. 4 The existence of osmotic pressure is conducive to the expansion and penetration of the rock fracture, thus reducing the rock creep Variable long-term strength, but the presence of confining pressure increases the creep long-term strength. It provides important experimental and theoretical basis for understanding and understanding rheological mechanical properties of silty mudstone in the Three Gorges reservoir area.