砒砂岩侵蚀的物理特性试验研究

Experimental Study of the Physical Characteristics of the Pisha Sandstone on Its Erosion

砒砂岩侵蚀较为强烈,研究其易蚀的岩性物理特性对于认识侵蚀岩性机理具有重要意义。利用现场灌砂法、粒度分析等方法,开展了砒砂岩原状样密度、微观结构和级配等物理特性试验研究。结果表明:砒砂岩干密度为1.36~1.58 g/cm^3,远小于一般砂岩的密度;砒砂岩孔隙率大、透水性强为砒砂岩易发生水蚀提供了结构条件;砒砂岩黏粒含量低,颗粒粒径小于0.500 mm的颗粒含量高,为砒砂岩易发生风蚀且风化速率快提供了几何条件;砒砂岩碱性较强,为砒砂岩在酸性雨水环境下发生水蚀提供了化学条件。因此,砒砂岩的物理特性是砒砂岩易发生强烈侵蚀的重要内因。

Pisha sandstone erosion is more intense. It is great significance to understand the erosion lithological mechanism through studying the erodible lithology physical properties. The Pisha sandstone physical properties such as the original density, its microstructure and graduation were tested. The sand filling method, grain size analysis and other methods were used. The results show that the density of original Pisha sandstone is in the range of 1.36-1.58 g/cm^3, which is much smaller than the rock density of the common sandstone. The larger porosity and the better water permeability are structural benefit for the water erosion of Pisha sandstone. The low clay content and the high content of particle diameter below 0.500 mm in the whole Pisha sandstone mass are geometrical benefit for the exposed sandstone with a faster weathering rate and a weaker wind erosion resistance. Furthermore, the strong alkali of Pisha sandstone is chemical benefit for the water erosion because of the acidic rain environment. Therefore, the physical characteristics of Pisha sandstone are the internal reasons for its erosion.