Experimental investigation of the seepage failure between bulkheads and surrounding rocks in deep underground mines

• Published in: Bulletin of engineering geology and the environment Vol. 81; no. 9
• Main Authors: Hang, Yuan, Sui, Wanghua, Yuan, Shichong
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2022
• Subjects: Earth and Environmental Science; Earth Sciences; Foundations; Geoecology/Natural Processes; Geoengineering; Geotechnical Engineering & Applied Earth Sciences; Hydraulics; Nature Conservation; Original Paper; Deep underground mine; Failure criterion; Water retention bulkhead; Scale model test; Seepage failure
• ISSN: 1435-9529; 1435-9537
• DOI: 10.1007/s10064-022-02859-w

This paper presents an experimental investigation of seepage failure between water retention bulkheads and surrounding rocks. Water retention bulkheads are commonly used to prevent and control water inrush in underground mines. However, water seepage or even water inrush still occurs because bulkheads are traditionally designed for structural integrity and stability with little consideration of seepage failure and the permeabilities of surrounding rocks. To address the issue of water seepage in the strata surrounding the bulkheads, a scale model test was developed to simulate the seepage failure process in homogeneous surrounding rock and surrounding rock with a fractured zone with high water pressures in deep underground mine. The results revealed the occurrence of seepage and changes of pore water pressure in the surrounding rocks, which were first divided into five stages due to the blocking effects of bulkheads. Seepage or seepage failure can occur through and around bulkheads, especially when a fractured zone exists around the roadway. Therefore, a criterion for predicting seepage failure was put forward and verified with experimental results. Specifically, when the ratio of the critical hydraulic gradient to the stable hydraulic gradient is greater than the water retaining safety coefficient of the bulkhead, the bulkheads will fail to retain water. The safety coefficient is determined to be 0.6 according to the statistics of bulkhead engineering practices in underground coal mines. This work indicated that seepage stability must be demonstrated when designing and constructing a water retention bulkhead, in addition to considering the mechanical strength and stability.