胶结充填体固化与开挖矿体垂直应力匹配特征

Match between the solidification of the cemented backfill and the vertical stress in the excavated ore body

以某铀矿山中和后的堆浸尾渣为骨料,制备了渣浆体积分数为78%,80%和83%,灰渣比为1∶6,1∶8,1∶10,1∶15,1∶20,1∶25,1∶30的尾渣胶结充填料试样,经不同养护时间后,测定了它们的单轴抗压强度;建立了尾渣胶结充填体固化强度与养护时间的关系。结果表明,最终强度值、强度响应系数、强度增长稳定时间和初始强度(t=3)等力学参数能定量描述不同尾渣胶结充填体的强度随养护时间的变化特征。引入能量匹配系数表征岩体开挖释放比能与充填体变形比能关系,得到上向进路胶结充填采矿法中一步骤充填体固化时间与二步骤矿体回采时间匹配与矿岩容重、矿岩埋深、矿岩弹性模量、充填体灰渣比、渣浆体积分数和养护时间密切相关。采用某铀矿山工程实例验证了本研究结果。

Samples, with slurry concentrations 1 ： 8, 1 ： 10, 1 ： 15, 1：20, 1：25 and 1 ：30 of 78%, 80% and 83%, cement-tailing ratios of 1 ： 6, and different curing time, were prepared by using the neutralized uranium tailings from heap leaching as the aggregate, and the uniaxial compressive strengths for the samples were measured. The relationships between the cemented tailings strength and the curing time were established by experimental data fitting. The results showed that the mechanical parameters for the relationships, such as final strength of cemented tailings, strength response factor, time needed for strength stability and primary strength （t=3） can quantitatively describe the variation of the cemented railings strength over the curing time. Energy match coefficient was proposed to show the energy den- sity relationship between the excavation and the backfill deformation. Calculation equation showed that the reasonable match time correlated closely with volume density of rock mass, depth of the ore body, elastic modulus of rock mass, cement-tailing ratio, slurry concentration and curing time. This new ap- proach was verified by a uranium mine.