铜坑矿地表塌陷区膏体处置体崩解特性试验研究

Experimental research on disintegration characteristics of subsidence paste backfill body of Tong-keng mine

利用自制的崩解率测试仪,配合SEM,CT等分析手段研究了废石掺量、水泥添加量对铜坑矿地表塌陷区膏体处置体崩解特性影响规律,探讨了处置体崩解机制。结果表明:在相同水泥添加量时,随废石掺量增加,处置体崩解率减小、崩解时间缩短。在相同废石掺量时,随水泥添加量增加,处置体崩解率大幅降低;将处置体崩解过程划分为吸水崩解、稳定崩解、崩解结束3个阶段;处置体的黏结力源于水泥水化产物形成的强度;处置体内部渗流是在渗透压力作用下,随机分布的开口通道与闭口通道不断扩展的结果;通道扩展的驱动力源于基质吸力,当处置体吸水后,通道中气–液相向固相不断传递力值,当力值大于胶结产物的黏结力后,处置体持续崩解。当力值小于黏结力时,处置体不发生崩解。

Using a backfill body disintegration rate tester along with SEM and CT analysis techniques, this paper examines the influence of waste rock incorporation proportion and cement introduction quantity upon the disintegration properties of the treated mass. The disintegration mechanism of the mass is also discussed. The results suggest： at given cement introduction quantity, the backfill body disintegration rate diminishes and its disintegration time shortens with an increasing refuse incorporation proportion. Also at a given waste rock incorporation proportion, the backfill body disintegration rate drops dramatically when the cement introduction quantity is increased. The disintegration process is subdivided into three phases including water absorption disintegration, steady disintegration, and disintegration termination. The treated mass derives it adhesion from the strength of the cement hydration products. The seepage flow is established inside the mass under the seepage pressure and is also the result of the randomly distributed open channels and the constant expansion of closed channels. Channel expansion is driven by attraction of the matrix, and when the backfill body absorbs water the gas-liquid phase transfers incessantly a force to the solid phase： the mass proceeds with disintegration if the force value is greater than the cementation adhesion, the mass does not disintegrate when the force value is less than the adhesion.