海南高液限土结合水试验研究

Experimental study on high liquid limited soil bound water in Hainan

为了确定高液限土结合水及其合适的测试方法,为进一步开展高液限土压实机理研究提供基础,在海南万洋高速公路选取高液限土,分别采用容量瓶法和等温吸附法进行了结合水对比试验研究。试验结果表明,容量瓶法测试结果大于等温吸附法试验结果,两种方法测得结合水含量均随粒径的减小而增大,即细粒>原土>粗粒;容量瓶法测得细粒土样的强结合水含量是粗粒土的2.57倍,等温吸附法测得的细粒土样的强结合水含量是粗粒土的2.11倍;高液限土结合水的密度、水合比重均随结合水含量的增多而降低。等温吸附法自水汽中吸附结合水,因黏土堆积及其成团聚体的特点,水分子仅被吸附在黏粒表面,所以试验结果势必偏小。而容量瓶法从液体水中吸附结合水的过程更符合原状土的实际情况,因此建议采用容量瓶法测高液限土的结合水含量。

In order to ascertain the bound water of high liquid limit soil and its proper testing method,this research provides a basis for further research on compaction mechanism of high liquid limit soil,selection of high liquid limit soil in Hainan Wan Yang Expressway,unit-weight method and isothermal adsorption method were used to study the bound water test.The results show that the unit-weight method test results are greater than the isothermal adsorption test results.The bound water content measured by two methods increases with the decrease of particle size,fine particles>original soil>coarse particles.The strong binding water content of the fine-grained soil samples measured by the unit-weight method was 2.57 times that of the coarse-grained soil,and the strong binding water content of the fine-grained soil samples measured by the isothermal adsorption method was 2.12 times that of the coarse-grained soil.The hydration specific gravity of the high liquid limit soil and the density of the bound water all decrease with the increase of the adsorption bound water.Adsorption of water from water vapor by isothermal adsorption,because clay is stacked and has aggregates,water molecules are only adsorbed on the surface of the clay,so the test results must be small,the process of adsorption and binding of water from liquid water by unit-weight method is more consistent with the actual situation of raw soil.It is recommended to test the bound water content of high liquid limit soil by unit-weight method.