广西典型膨胀土三向膨胀规律室内试验

Laboratory Test on 3-Dimensional Expansion Law of Typical Expansive Soil in Guangxi

采用自制的三向膨胀仪,以及与之相应的原状土取样器、重塑土制备器,以广西南宁、宁明4种典型膨胀土为研究对象,开展膨胀土三向膨胀率及膨胀力试验.试验结果表明:膨胀土三向吸水膨胀时程曲线分为快速、缓慢及趋于稳定3个阶段,并且3 h可完成膨胀的80%~90%;膨胀率及横向、竖向膨胀力存在明显差异,并随干密度增大而增大;在相同初始条件下,原状膨胀土与重塑膨胀土三向膨胀率存在明显差异,在相同初始水的质量分数条件下,竖向与横向膨胀力之比R 0随着干密度的增大而增大;试样吸水膨胀后水的质量分数均匀,试验方法可行,仪器测试数据可信.

The self-made 3-dimensional(3D)expansive instrument,the corresponding undisturbed soil sampler and remolded soil preparation device were used to carry out the 3D expansive rate and expansive force tests of expansive soils in Nanning and Ningming of Guangxi.The test results show that the time-history curve of 3D water absorption expansion of expansive soil can be divided into three stages:fast,slow and stable.80%-90%expansion finishes in 3 hours.There are obvious differences in expansion rate,lateral and vertical expansive forces,and the differences increase with the increase of dry density.Under the same initial conditions,there are obvious differences in the 3D expansive rate between undisturbed and remolded expansive soil.Under the condition of initial water content,the ratio of lateral to vertical expansion force R 0 increases with the increase of dry density.The test method is feasible,the data measured by the instrument is credible.