Predicting Erosion-Induced Water Inrush of Karst Collapse Pillars Using Inverse Velocity Theory

Abstract

Although the impact of Karst Collapse Pillars (KCPs) on water inrush has been widely recognized and studied, few have investigated the fluid-solid interaction, the particles migration inside KCPs, and the evolution feature of water inrush channels. Moreover, an effective approach to reliably predict the water inrush time has yet to be developed. In this work, a suite of fully coupled governing equations considering the processes of water flow, fracture erosion, and the change of rock permeability due to erosion were presented. The inverse velocity theory was then introduced to predict the water inrush time under different geological and flow conditions. The impact of four different controlling factors on the fracture geometry change, water flow, and inrush time was discussed in detail. The results showed that the inverse velocity theory was capable of predicting the occurrences of water inrush under different conditions, and the time of water inrush had a power relationship with the rock heterogeneity, water pressure, and initial particle concentration and an exponential relationship with the initial fracture apertures. The general approach developed in this work can be extended to other engineering applications such as the tunneling and tailing dam erosion.

Effects of Initial Porosity and Water Pressure on Seepage-Erosion Properties of Water Inrush in Completely Weathered Granite

“…In recent years, a large number of tunnels have been constructed in unfavorable geology such as completely weathered granite, karst, and fault [1][2][3][4], causing various challenges to the geotechnical engineers, for example, collapse [5], land subsidence [6], groundwater inflow [7,8], and total environmental hazards [9]. The completely weathered granite, one of the typical unfavorable geologies, is widely distributed in subtropical, tropical, and humid temperature zones [10][11][12].…”

Floor Failure Evolution Mechanism for a Fully Mechanized Longwall Mining Face above a Confined Aquifer

“…Many researchers in China and abroad have investigated mining floor failure laws and water inrush controls. Yao et al [4] presented a suite of fully coupled governing equations to determine fracture erosion and changes in rock permeability. To determine the hydraulic conductivity of a rock formation between a deeply buried coal seam and an aquifer, Huang et al [5] conducted four water injection tests at the Baodian Coal Mine.…”

Quantitative Evaluation of Karst Developmental Differences Based on Improved Analytic Hierarchy Process and Multidimensional Extension Matter Element Model

“…Lancia et al [12] conducted combined experiments and a hydrogeological evaluation method to determine the water-conducting characteristics of karstdeveloped rock masses; the limits of continuum modeling for karst media were addressed by combining two methods. Yao et al [13] established a fully coupled antivelocity theoretical control model based on factors such as water flow, karst fissure erosion characteristics, and permeability change and used it to predict the karst water inrush time under different geological conditions; the results showed that the inverse velocity theory is capable of predicting the occurrence of water inrush under different conditions. Sauro et al [14] conducted detailed statistics on the distribution and direction of karst development in southern Italy and analyzed the differences in karst development under different geological structures.…”