Experimental study on acid dissolution damage characteristics of bedded limestone

Abstract

In southwest China, carbonate rocks are widely distributed. It has unique dissolution features which bring a lot of resistance to engineering constructions. In order to explore the dissolution damage regular of layered carbonate rocks in acidic water, a self-made flow dissolution system was used to conduct laboratory dissolution tests on limestone cores under four different conditions. The mass loss, the change of p-wave velocity, the mass concentration of Ca2+ and Mg2+ and the morphology of the core surface were obtained. Mass loss rate after dissolution of layered limestone was used to define the damage variation. Through multivariate statistical regression analysis, the relationship between four different arguments (bedding dip Angle, pH, velocity of flow, dissolution time) and dissolution damage variation was established. The results show that the dissolution damage of layered limestone has a good mathematical relationship between the four different arguments. The following conclusions can be drawn from the analysis: The time has a significant effect on the dissolution damage of bedded limestone, followed by the velocity and pH. Under the same acidic environment, the dissolution effect shows a rule of 90° >0° >45° >30° >75° >15° >60° for limestone with different bedding inclination angles. The bedded angle has less effect on the dissolution of limestone than other factors, but plays a decisive role in the surface dissolution morphology of rock samples. The results of this study can provide some reference for engineering practice and geological disaster control in limestone areas.

Keywords

• bedded limestone
• acid corrosion
• longitudinal wave velocity of rock
• dissolution damage
• dissolution damage variation