دانلود رایگان مقاله انگلیسی تاثیر ریزساختار ترکیبات سنگی و ویژگی های منفی بر خواص مکانیک سنگ آن - الزویر 2018

abstract

This paper is to study the influence of composition, microstructure and pore characteristics on the rock mechanical properties. Five kinds of sandstone compositions were analyzed by using X-ray diffraction instrument. And the microstructure was observed by using scanning electron microscope. Then the pore distribution characteristic was investigated by using the low field nuclear magnetic resonance equipment. Finally, the uniaxial compression test was carried out to investigate the mechanical characteristics by using RMT150C mechanics experimental system and the uniaxial compressive strength, Poisson’s ratio and elastic modulus were obtained. Compared to the analysis of the composition, structure and pore distribution and mechanical properties of the five kinds of sandstones, the relationship among composition, structure, pore distribution and mechanical properties was obtained. The results show that the composition, microstructure, pore distribution and mechanical properties of sandstone are closely related. With the decrease of feldspar and quartz particles, the compressive strength and elastic modulus increase, while the porosity decreases.

5. Conclusions

(1) The major component minerals of five kinds of sandstones are quartz and feldspar. Major cement materials are clay minerals, carbonate, ironic, analcime, and sulfate; analcime dominates group A, clay minerals dominate groups B and C, sulfate dominates group D, and carbonate dominates group E.

(2) There are difference in cementing quality among the five kinds of sandstones. From group A to group E, cementing quality increases, but the particle diameter and pore diameter are getting smaller and smaller, and the number of pores is less and less.

(3) The porosity decreases from group A to group E. The porosities for group A, group B, group C, group D, and group E are.7.6%, 5.9%, 4.4%, 3.0%, 1.6%, respectively.

(4) The composition of sandstone is closely related to its rock mechanics properties. Quartz and feldspar are important factors affecting the rock mechanics properties. However, the cement content of sandstone and the type of cement also play a decisive role in its mechanical characteristics.

(5) The cementing quality, grain size, and quantity and size of pores all affect the rock mechanics properties of sandstone. The better the cementing quality, the larger the UCS. The smaller the grain size, the higher the UCS. The smaller and the less the number of pore, the higher the UCS.

(6) Porosity is closely related to the rock mechanics properties of sandstone. Decreasing porosity will increase UCS. There is a trend of negative relationship between Young’s Modulus and porosity.