非饱和土与混凝土界面摩擦特性试验

Experimental study of shearing behavior of interface between unsaturated soil and concrete

首先制备出具有不同孔隙比条件的土样,采用自制的灌注装置在土样上现浇混凝土,待混凝土硬化后先对土样进行饱和.然后再置入装有高进气值陶土板的压力板仪中,控制压制时间制成具有不同含水率的混凝土-非饱和土试样.最后将具有不同含水率的混凝土-非饱和土试样置入直剪仪中进行剪切试验,探讨土样含水率对界面摩擦剪切强度及极限剪切位移的影响.试验结果表明,在不同含水率的条件下,土与混凝土界面剪切强度在某种程度上遵循摩尔-库伦破坏准则,且粘性土具有一定的界面粘聚力;界面极限剪切强度随含水率的增大而减少;界面发生破坏时,对应的极限剪切位移随土体含水率的增大而增大;在不同法向应力条件下,试件界面极限剪切位移在1～5mm之间,发生破坏时的平均剪切位移约为3.62mm.

Firstly, the soil samples with different void ratio were prepared, then the cement was casted on the sample by self-made apparatus. When the cement was setting, the whole sample was saturated in a vaccum at first, and then it was put into the pressure plate apparatus to be unsaturated. The water content of samples were adjusted by being dewatered in different amount of time. The prepared samples were tested in direct shearing device, and the shear strength and ultimate shear displacement on the interface were studied by analyzing the test results. It was shown that the shear strength of the interface follows MorhColoumb law when the sample is of different water content;the shear strength increases while the water content of samples decreases. The ultimate shear displacement increases while the water content of samples increases. Under different normal stress, the ultimate shear displacement is from 1 mm to 5mm, and the average value is about 3.62 mm.