阳安二线膨胀土填料改良研究

拟建阳安二线沿线膨胀土广泛分布,膨胀土不能直接作为路基填料,如果选取合格填料,运距较远、投资大,而且挖方地段的膨胀土又得弃掉、占地多,极不经济。通过选取现场两处代表性取土场取样,生石灰粉作添加剂,按4%、6%、8%、10%四个级别的掺入比做室内改良试验,试验表明:生石灰掺入比大于4%改良后,能达到消除膨胀性的目的,改良土有较好的水稳性和较高的强度,能满足设计要求;改良土较原膨胀土有较高的抗压强度和剪切强度,且随生石灰的掺入比增加而增大;得出了路基不同部位、不同膨胀级别膨胀土的生石灰粉掺入比,为阳安二线路基填料设计提供了理论依据。

Study on Improvement of Expansive Soil Filler of YangAn Railway Second Line

The expansive soil is widely distributed in the proposed Yang An second line and the expansive soil can not be directly used as roadbed filler. If other qualified filling material is used the haul distance will be longer with heavy investment,waste of excavated expansive soil and more land coverage. A test is conducted with two representative field soil samples and lime powder as additive in 4%,6%,8% and10% of four levels of incorporation for improvement. Test results show that the soil improvement with mixing ratio greater than 4% can eliminate the swelling,and the improved soil has good water stability and higher strength and meets the design requirements. Compared with the original expansive soil,the improved soil has higher compressive strength and shear strength with the increase of the lime mixing ratio. The mixing ratios for different part of subgrade and different grade of expansive soil are obtained,providing theoretical reference for the design of Yang An second-line subgrade filler.