集成回填材料的渗透特性研究

本文在前人基础上改进渗透装置,通过自制多功能膨胀渗透仪在氮气加压为1.0 MPa条件下,测得沸石-膨润土-硫铁矿、凹凸棒石-膨润土-硫铁矿两组混合物在不同膨润土含量、压制载荷、压实密度、出水时间等条件下的渗透系数。实验结果表明:集成回填材料的渗透系数随时间的变化不大,基本满足达西定律。同一干密度和含水率条件下,不同混合物随着膨润土含量的增加,其渗透系数降低。膨润土含量占沸石混合物或者凹凸棒石混合物比例不小于60%时,二者混合物的渗透系数均满足高放废物处置中回填材料渗透系数小于7×10-10m/s的要求。但同等条件下,由于沸石为非粘性矿石,其具有孔隙大、渗透性好等特点,因此天然地下水在沸石混合物中比在凹凸棒石混合物中渗透得快。同一干密度和含水率条件下,不同混合物压实制样的载荷越大,其渗透系数越小,反之越大。压制载荷在50~100 MPa间时,混合物的渗透系数变化不大。通过进行混合物不同配比、不同影响因素对渗透特性影响的研究,为我国新型缓冲回填材料在未来地下工程中施工提供一定的理论依据。

The permeability characteristics of integrated backfill materials

In this study, the authors improved osmosis device on the basis of previous researches. Through the self-made multifunctional osmotic swelling meter in a nitrogen pressure of 1.0 MPa, and under different conditions of content, coefficient of load, compacted density, and water breakthrough time pressing, the authors obtained the permeability coefficient of zeolite-bentonite-pyrite mixture and attapulgite-stone-bentonite-pyrite mixture for two groups of samples. The results showed that the permeability of the integrated backfill material changed little with time, and was basically consistent with Darcy''s law. Under the same dry density and water content rate conditions, with the increase of the content of bentonite, the permeability coefficient of different mixed minerals decreased. When bentonite content proportion in zeolite mixture or attapulgite stone minerals was not less than 60%, the permeability coefficient satisfied the requirement of less than 7×10^-10 m/s permeability coefficient in high-level radioactive disposal of backfill material. Under the same conditions, because the zeolite is characterized by non-sticky property, large porosity, and good permeability, the water in the zeolite mixture permeated faster than that of the mixture. In the same dry density and water content rate, the greater the compaction of the loads of different mixtures, the smaller the permeability coefficient, and vice versa. From loads of 50~100 MPa, the permeability coefficient changed little. Thus, the study of the permeability characteristics of the mixture of different ratios and different influence factors, could provide a theoretical basis for the construction of a new type of cushion backfill material in the future.