Experimental Study on Sensitivity to Temperature Stress of the Permeability of Weakly Cemented Sandstone

In order to explore the meso-structural characteristics of weakly cemented sandstone and its permeability characteristics under multi-field coupling, SEM scanning electron microscopy and Top Industries rock triaxial remoter system have been used. On the basis of studying the microstructure of weakly cemented sandstone, the sensibility of its permeability to temperature and confining pressure is preliminarily study. The results show that the compaction effect of weakly cemented sandstone is poor, and the clastic particles are compacted and degenerated. It features concave-convex contact, and base cementation playing a main role. Because of the difference in pore structure, within the experimental range, when the temperature rises and the confining pressure increases, the influence of confining pressure on the mineral particles leads to the change of permeability. The confining pressure increases the plastic deformation of the intergranular particles. There is an irreversible phenomenon in the process of rising and falling of the confining pressure, while the effect of temperature on permeability is small. The three coupling surfaces of permeability, temperature and confining pressure of weakly cemented sand-stone with different granularities are developed, and the corresponding coupling equations are presented. Therefore, during construction in the weakly cemented stratum, substantial deformation of surrounding rock due to sensitivity of permeability to confining pressure should be avoided, and active support measures should be strengthened in the aquifer layer.