# Experimental Study on the Pre-Peak Mechanical and Seepage Characteristics of Granite
###### Abstract
The eigenvalue of the dissipation energy steadily increased with the increase in the confining pressure. The above researchers have conducted many positive investigations on the progressive failure analysis of rocks, but there are few reports on the pre-peak progressive failure analysis of rocks. With the increasing depletion of land-based mineral resources, the exploitation of marine mineral resources has become a new direction of development. Compared with the exploitation of land-based mineral resources, due to the threat of the underlying seawater, the exploitation of marine mineral resources is very complex [15]. In recent years, stress-permeability coupling has also gradually become prevalent, and many researchers have conducted a lot of research in the field of fluid-solid coupling. [PERSON] et al. [16] found that with an increase in effective stress, the permeability and porosity of granite decrease gradually. The relationship between effective stress and permeability can be described via the exponential and power law. [PERSON] et al. [17] showed that the permeability with stress differences showed four stages: slow decline, smooth development, slow increase, and rapid increase. [PERSON] et al. [18] carried out stress-seepage coupling tests under different pore pressures and found that the permeability of granite increased with the increase in the initial pressure difference. [PERSON] et al. [19] and [PERSON] et al. [20] studied the evolution of the permeability of brittle intact rocks during conventional triaxial compression tests, revealing the coupling mechanism between rock permeability and damage processes. The effects of seepage pressure, confining pressure, and rock microstructure on permeability evolution have been investigated [17; 21; 22]. Some tests have shown that deviatoric stress leads to the development and expansion of cracks in brittle rocks, leading to a significant increase in permeability [19; 23]. [PERSON] et al. [24] conducted solid-flow coupling tests on calcareous sedimentary rocks and proposed a corresponding weakening mechanism based on the law of the evolutionary process of permeability and microstructures. [PERSON] et al. [11] found that the peak permeability of sandstone lagged behind the peak stress under different seepage pressures and showed a sudden jump near the peak stress. Most of the previous studies have focused on the effects of seepage pressure, confining pressure, and microstructure on rock permeability, and little has been reported on the evolution of pre-peak stress-permeability, which is of engineering concern. In summary, there are few studies on granite's mechanical and seepage pre-peak characteristics. The MTS815 rock triaxial seepage test system was employed to test the triaxial compression-seepage conditions under different confining pressures to reveal granite's mechanical and seepage pre-peak characteristics. Based on the test results, stress sensitivity analyses were carried out to show the permeability stress sensitivity of granite under different confining pressures. The results of this study will be helpful for the establishment of a coupled flow-solid model for the safe mining of bedrock deposits on the seabed of Sanshandao and provide corresponding data support.