摘要:
与单一膨润土相比,集成回填材料(新疆沸石与新疆膨润土混合物、安徽凹凸棒石与新疆膨润土混合物)能够提高防渗阻隔能力、热传导能力等,本文主要研究初始含水率、压制载荷、干密度、膨润土含量等因素对集成回填材料的膨胀率及膨胀力的影响.试验结果表明,初始含水量对集成回填材料的最终膨胀率和膨胀力影响不大,试样加水后体积迅速膨胀,2000 min后体积增长速度缓慢,直至体积保持不变.同等情况下,压制荷载为20 MPa比10 MPa时最终膨胀率和膨胀力大,说明压制载荷对集成回填材料的膨胀性能有所影响;在同一含水率、同一压制载荷20 MPa条件下,最终膨胀率和膨胀力随干密度的增大而增大,这是因为干密度越大,混合物间的颗粒联系越紧密,当遇水膨胀后对膨胀仪的反作用也大.最后还得出复合矿物中膨润土含量占集成回填材料的比例越大,其膨胀率和膨胀力越大.同等比例下,由于沸石为非粘土矿物,而凹凸棒石为粘土矿物并含有部分蒙脱石矿物对复合矿物的膨胀性能有所贡献,因此添加凹凸棒石比沸石更容易得到膨胀性能较好的集成回填材料.然而在实际工程中采用集成回填材料时还要综合考虑影响其它工程性能和阻滞性能的因素,选择适合的集成回填材料配比及工程参数为将来高放深地质处理核废物打好坚实的基础.
关键词:
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膨润土
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沸石
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凹凸棒石
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膨胀力
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膨胀率
Abstract:
Compared with the single bentonite,integrated backfill material (Xinjiang zeolite and Xinjiang bentonite mixture,Anhui attapulgite and Xinjiang bentonite mixture)could increase the thermal conductivity and seepage blocking ability etc..This paper mainly studied the impacts of initial water content,compaction load,dry density,bentonite content and so on of the expansion rate and expansion force in the integrated backfill material.The test result was that initial water content has little effect on the expansion and expansion pressure of final integrated backfill material.After adding water,the volume of the sample was rapidly expanding,and the volume growth rate of 2000 min was slow until the volume remains unchanged.Under the same circumstances,the final expansion volume and expansion force with the load 20MPa were higher than the one with load 10MPa.This indicated that the pressing load has an effect on the expansion performance of the integrated backfill material.In the same water content,the same press load 20MPa,the final the amount of swelling and swelling force increased with the increase of dry density.This was because the greater the dry density,the more closely the relationship between the particles of the mixture,when the water swelling in the expansion of the counter effect was also large.Finally,it was concluded that the ratio of bentonite content in compound mineral was larger than that of the integrated backfill material,and the bigger the expansion ratio and the expansion force were.Under the condition of equal proportions,due to zeolite for non clay minerals,and attapulgite clay mineral containing part of montmorillonite on mineral composite expansion properties contribute,so adding attapulgite were more likely to get expansion performance better of integrated backfill materials.However,considering the factors that affect the other engineering properties and block performance in the practical engineering using integrated backfill material,which chose suitable integrated backfill material proportioning and engineering parameters for high placed deep geological disposal of nuclear waste lay a good solid foundation.In the future.
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