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使用一种新的实验装置测量岩石样品的复杨氏模量。测量的频率范围为4赫—400赫,测量时的应变振幅接近10~(17)。在真空干燥的岩石中,可以忽略衰减和模量色散。在水饱和的砂岩、石灰岩和花岗岩中,由于应力弛豫引起了较大的衰减峰。其衰减和模量的数据可以由弛豫时间的Cole-Cole 分布来描述。因此,岩石的滞弹性满足克雷默斯—克罗尼格(Kramers-Kronjg)积分关系,发生在低频的应力弛豫具有窄分布的特征时间,应力弛豫是被热激发的,而且具有的激活能是16—22KJ/mol,激活能是氢键的特征。文中指出,模量亏损和衰减峰值随着各种不同的孔隙流体(水,酒精和 n—癸烷)而变化。实验结果可以解释为,空腔流体降低了形成岩石的矿物的表面自由能。弛豫过程包含着流体分子的运动。结合到表面的分子减少了表面能,因此也造成了岩石对频率的依赖性的减弱。
A new experimental setup was used to measure the complex Young’s modulus of rock samples. The measured frequency range is 4 Hz - 400 Hz, and the strain amplitude at the time of measurement is close to 10 ~ (17). In vacuum-dried rock, attenuation and modal dispersion can be neglected. In water-saturated sands, limestones and granites, large attenuation peaks are caused due to stress relaxation. The attenuation and modulus data can be described by the Cole-Cole distribution of relaxation time. Therefore, the rock’s inelasticity satisfies the Kramers-Kronjg integral relationship, occurs at low frequencies with a narrow distribution of stress relaxation time, and the stress relaxation is thermally excited and has The activation energy is 16-22 KJ / mol and the activation energy is a hydrogen bond. It is pointed out that the modulus loss and decay peaks vary with the different pore fluids (water, alcohol and n-decane). The experimental results can be interpreted as that the cavity fluid reduces the surface free energy of rock-forming minerals. The relaxation process involves the movement of fluid molecules. The molecules bound to the surface reduce the surface energy and thus also the frequency-dependent decrease of the rock.