土体圆柱孔破损结构演化特性研究

The Structural Evolution Characteristics of Images of Cylindrical-Pore-Damaged Soil

取南水北调中线工程陶岔引水渠坡的膨胀土做试样,利用与电子计算机断层扫描X-Ray CT机配套使用的土工三轴仪,对圆柱孔破损重塑膨胀土样进行控制吸力为100kPa、200kPa和净围压为50kPa、100kPa、200kPa的CT-三轴压缩试验,通过CT扫描设备获得试验过程中土样内部破损结构的实时演化情况.试验结果表明:净围压在孔洞结构演化中发挥重要作用,净围压越大,CT数均值ME越大,破损孔洞面积缩小越明显,试样整体被压密;方差值SD越小,试样结构性趋于均匀.从ME值和SD值的变化可以看出,试验过程中试样逐渐被压密,破损结构有一定的修复.

The expansive soils were taken as the test specimen from the site of the Central Line Project of South-to-North Water Diversion.The remolded expansive soil samples with cylindrical pore damage were tested by a multifunctional X-ray CT-triaxial apparatus.The tests were carried out under a control suction of 100 kPa or 200 kPa,and a net cell pressure of 50 kPa,100kPa or 200 kPa.The evolution of the internal structural damage was observed real-timely by the CT scanning equipment.The results showed that net confining pressure played a significant role during pore structure evolution.As net confining pressure increased,the ME value increased,which suggested that the damaged pores shrank and the overall sample was compacted.As the SD value decreased,the sample structure tended to be more uniform.The changes in MEand SDindicated that in the initial stage of the tests the tested sample was gradually compacted and the damaged structure was repaired to a certain extent.