膨润土对土体微观孔隙结构特征影响的试验研究  

Experiment study on the effects of bentonite on the micropore structure characteristics of soil

作　　者：闫小庆[1,2] 房营光[1,2] 张平[1,2] 

机构地区：[1]华南理工大学土木与交通学院,广东广州510641 [2]亚热带建筑科学国家重点实验室,广东广州510641

出　　处：《岩土工程学报》2011年第8期1302-1307,共6页Chinese Journal of Geotechnical Engineering

基　　金：华南理工大学亚热带建筑科学国家重点实验室自主项目(2008ZA11)

摘　　要：土体的微观孔隙结构特征对其渗透性有着显著的影响,膨润土具有很强的防渗性能,在土中加入膨润土可改变其孔隙尺度分布和结构特征而降低土的渗透性。采用压汞仪法(MIP)试验研究了掺加不同比例的膨润土的细颗粒土的微观孔隙结构特征。试验结果表明:只要加入少量的膨润土便可使土体的大孔隙的数量急剧减少;随着膨润土的含量的增多,孔隙尺度分布逐渐发生变化,中孔隙的数量逐渐减少,小孔隙、微孔隙和超微孔隙的数量逐渐增多,孔隙分布密度函数由三峰态转变为双峰态,峰值所对应的孔隙直径减小。实验结果也证明了同一孔隙比的土样的孔隙特征的多样性,因此工程中采用的表达土的孔隙含量的宏观参数孔隙比并不能完整描述土体的孔隙特征,需要引入其他微观参数对土的孔隙特征进行描述。文中的研究对防渗工程设计与施工具有参考价值。The micropore structure characteristics have significant influence on permeability of the soil,and bentonite is high anti-seepage material,which is added into the soil to reduce the peamiability by changing the pore-scale distrbution and pore characteristics of the soil.The micropore structure characteristics of the soil added with different bentonite contents are measured by the mercury intrusion porosimetry（MIP）.The test results show that just adding a little bentonite can reduce the quantity of the large pore abruptly.With the increase of bentonite content,the pore-scale distribution changes gradually,the quantity of the middle pore increases,the quantities of the small pore,the micropore and the supermicro-pore increase gradually,and the pore size distribution density function changes from three-model to bi-model while the pore diameter size corresponding to the peak decreases.It is proved that the pore characteristics of the same void ratio are various according to the test results,so the void ratio which is a macroscope parameter can not represent the pore characteristics of the soil perfectly and it is necessary to introduce other microscope parameters to describe the pore characteristics of the soil.The conclusions have certain referential value for the design and construction of the anti-seepage（infiltration） projects.

关 键 词：膨润土 微细观孔隙 孔隙尺度 孔隙分布特征 压汞仪法 渗透性 

分 类 号：TU411[建筑科学—岩土工程]