粒度对红砂岩力学性质影响规律与机制试验研究

Experimental Study of Influence Regularity and Mechanism of Particle Size on Mechanical Properties of Red Sandstone

为研究颗粒粒度对岩石力学特性的影响规律,对不同粒度红砂岩进行了单轴压缩与巴西劈裂拉伸试验。研究表明:红砂岩试验试件密度、单轴抗压强度、弹性模量和单轴抗拉强度最大离散系数分别为0.74%、6.65%、1.12%、9.64%,试验所用红砂岩试件均质性良好;当砂岩颗粒粒度较大时,砂岩单轴抗拉强度、单轴抗压强度、弹性模量等都呈现偏低特征,细粒红砂岩单轴抗压强度、弹性模量、单轴抗拉强度分别是粗粒红砂岩1.28倍、1.19倍、1.62倍。颗粒作为砂岩最基本构成单位,其大小差异导致砂岩内部空间结构的改变,造成其矿物成分、微细观组构特征呈现差异性,进而影响其宏观物理性质,最终决定不同粒度红砂岩石具有相异力学特性。

In order to study the influence regularity and mechanism of particle sizrock, uniaxial compression tests and Brazil splitting tests were carried out on red sandstone with different particle si-zes. The results show that the red sandstone specimens have good homogeneity, with the maximum dispersion coef-ficient of the density, uniaxial compressive strength; elastic modulus and uniaxial tensile strength being 0. 75% ,6.66% , 0.78% and 9. 64% respectively. The uniaxial compressive strength, elastic modulus and uniaxial tensile strength decrease with the increase of particle size. The uniaxial compressive strength, elastic modulus and uniaxialtensile strength of fine-grained red sandstone are 1. 28 times, 1. 19 times, and 1. 62 times of that of coarse grained red sandstone respectively. As the most basic unit of sandstone, particles have different sizes which give rise to the variety of sandstone internal spatial structure and the differences of mineral composition and micro structure charac-teristics , further affecting the macroscopic physical and mechanical properties and ultimately determining the differ-ent mechanical properties of red sandstone with different particle sizes.