Experimental Investigation of the Physical Properties and Microstructure of Slate under Wetting and Drying Cycles Using Micro-CT and Ultrasonic Wave Velocity Tests

Abstract

Cyclic wetting and drying processes have been considered as important factors that accelerate the weathering process and have deteriorative effects on rock properties. In the present study, a fully nondestructive and noninvasive testing approach utilizing micro-CT and ultrasonic wave velocity tests was employed to investigate the microstructure of slate under wetting and drying cycles. We studied variations in the physical properties, including the dry weight and the velocities of P- and S-waves versus the number of wetting and drying cycles. The internal microstructural distributions were visualized and quantified by the 3D reconstruction and hybrid image segmentation of CT images. The degree of deterioration caused by wetting and drying cycles was reflected by exponential decreases of physical properties, including dry weight and velocities of the P- and S-waves. Parameters relating to the microfracture diameter, volume, etc. were quantified. The nondestructive and noninvasive testing approach utilizing micro-CT and ultrasonic wave velocity tests has potential for the detection and visualization of the internal microstructure of rock under wetting and drying cycles.

Study on Strength Damage Evolution Regulation of Sandstone under Cyclic Erosion

“…The figure displays the microscopic changes of the sample under peak stress conditions. The specific regulations are summarized as follows: (1) the particle displacement characteristics of the sample under different salt erosion 6 Geofluids cycles are shown in Figure 9(a). With the increase in cycle erosion times, clear penetrating unilateral oblique cracks appeared when T = 0/5/10.…”

“…When the crystallization pressure reaches the cementing strength of the cement, numerous microscopic cracks are generated in the sandstone, which leads to falling off of the sand surface [3,4]. The calcareous cement in the sandstone simultaneously reacts with the erosion solution to form novel salt products such as gypsum, causing the feldspar and other minerals in the sandstone particles to gradually degrade, causing chemical weathering [5][6][7]. The role of salt damage occurs simultaneously at the physical and chemical levels and is one of the primary factors that cause weathering on the surface of sandstone cave cultural relics.…”

In Situ Shear Test for Revealing the Mechanical Properties of the Gravelly Slip Zone Soil

“…To investigate the mechanical property of the gravelly slip zone soil, a group of in situ shear tests were conducted in the sliding zone of the Huangtupo landslide, which is volumetrically the largest reservoir landslide in the Three Gorges Reservoir area, having a volume of approximately 70 million m 3 [22,23]. The Huangtupo landslide is located in Badong County of Hubei Province in China (Figure 1a) on the south bank of the Yangtze River about 72 km upstream from the Three Gorges dam (Figure 1b).…”

“…The Riverside Slump I# has an average thickness of 69.4 m, an average N-S length of 770 m, a width of 475 m in the W-E direction, and a volume of approximately 23 million m 3 . The slide mass of the Riverside Slump I# mainly contains cataclastic rock, rock block, and rock fragments with clay [27].…”

“…The shear mechanical properties of slip zone soil play a key role in the deformation and failure of landslides [1][2][3]. In some geological conditions, the parent rocks, such as the limestone and argillaceous limestone, near the slip zone are not completely weathered during the process of formation and evolution of the landslide, and gravels formed in the slip zone [4][5][6].…”