超固结比对合肥硬黏土剪胀特性的影响研究

Study on the effect of overconsolidation ratio on dilatancycharacteristics of Hefei hard clay

为了定量探讨超固结比(overconsolidation ratio,OCR)对合肥硬黏土剪胀性的影响,文章对合肥地区原状硬黏土进行三轴剪胀试验,并与重塑土试验结果进行对照;制备超固结比分别为1、2、4、8的重塑土进行三轴对比试验。结果表明:OCR为2.70~4.68的原状土,其最大体积剪胀率为1.1%~3.0%,在一定范围内,OCR与最大体积剪胀率呈抛物线关系;重塑土与同深度原状土相比,最大体积剪胀率降低33.3%~36.4%,且部分土样出现先剪缩后剪胀的现象;与原状土相比,OCR越大,重塑土的剪胀性降低程度越大,重塑土样的最大体积剪胀率降低5%~51%,在一定范围内,重塑土OCR与最大体积剪胀率之间存在较强线性关系。

In order to quantitatively explore the effect of overconsolidation ratio(OCR)on the dilatancy of Hefei hard clay,a triaxial dilatancy test was carried out on the undisturbed hard clay in Hefei area,and the results were compared with those of the remoulded soil.It shows that the maximum volume dilatancy rate of the undisturbed soil with an OCR of 2.7-4.68 is 1.1%-3.0%.Within a certain range,the OCR has a parabolic relationship with the maximum volume dilatancy rate.The maximum volume dilatancy rate of the remoulded soil is reduced by 33.3%-36.4%compared with that of the undisturbed soil,and some soil samples show the phenomenon of shear shrinkage before dilatancy.In addition,remoulded soils with OCRs of 1,2,4,and 8 were prepared for triaxial comparison tests.The test results show that the greater the OCR,the greater the reduction in the dilatancy of the remoulded soil,compared with that of the undisturbed soil.The maximum volume dilatancy rate of the remoulded soil is reduced by 5%-51%.Within a certain range,there is a strong linear relationship between the OCR and maximum volume dilatancy rate of the remoulded soil.