饱和-失水循环作用下蚀变岩劣化规律研究

LABORATORY STUDY ON DETERIORATION LAW OF ALTERED ROCK UNDER EFFECT OF WATER SATURATION-DEHYDRATION CIRCULATION

为了研究水岩作用对蚀变岩劣化破坏的损伤机理,选取某边坡蚀变岩样为试验对象,对不同饱和-失水次数的蚀变岩进行了岩石力学试验。建立了数学关系式来表达水岩作用对蚀变岩力学性质的劣化规律,借助损伤率的概念分析了循环次数对蚀变岩力学性质的损伤作用。试验结果表明:在水岩作用下蚀变岩的力学性质产生了明显的劣化现象,随着循环次数的增多劣化效果越明显;当岩石的蚀变风化程度相同时,抗拉强度劣化程度最大,弹性模量次之,单轴抗压强度最小;在不同饱和-失水循环次数下,蚀变岩抗拉强度、弹性模量随次数的增加迅速减小,单轴抗压强度出现持续减小的现象;蚀变、风化程度越高的岩石对水岩作用表现出越强的敏感性,随着饱和-失水循环次数的增加,蚀变岩的劣化现象趋于稳定,抗拉强度的损伤率最大达到63%,弹性模量60%,单轴抗压强度48%。

This paper aims to examine the effect of water-rock interaction on mechanical property of altered rock.Rock samples from the slope are selected. Rock mechanics testing is carried out to examine the effect of different saturation-dehydration frequencies. The function is established to describe the variation pattern of mechanical properties of altered rock with the circulating effect. The influence of mechanical properties of altered rock with different circulating times is analyzed,using the concept of damage rate. The project result indicates that the mechanical properties of the altered rocks are obviously weakened by water-rock interaction. With the increase of water-rock interaction,the phenomenon is more obvious. With different circulating times,the tensile strength and the modulus of elasticity decay rapidly while the peak intensity is decaying continuously. When the degree of alteration of all rock has no difference,the degree of deterioration of tensile strength is the biggest,followed by the modulus of elasticity and minimum uniaxial compressive strength. As the degree of alteration and fragmentation increases,the degree of damage increases regarding the water-rock interaction to the mechanical properties of rock.The damage rate of tensile strength can reach 63%,the modulus of elasticity can reach 60%,as the present of peak intensity is 48%. And with the increase of saturation-dehydration circulation,the deterioration phenomenon of altered rocks is stable.