沪渝蓉高速铁路合宁段路基膨胀土填料改良试验研究  

Experimental Study on Improvement of Subgrade Expansive Soil Filler in Hefei-Nanjing Section of Shanghai-Chongqing-Chengdu High Speed Railway

作　　者：江涛[1] JIANG Tao(China Railway First Survey and Design Institute Group Co.Ltd.,Xi’an 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《铁道建筑》2022年第1期139-143,共5页Railway Engineering

摘　　要：针对沪渝蓉(上海—重庆—成都)高速铁路合肥地区膨胀土分布广泛且路基填料需远距离调配的问题,掺入水泥、熟石灰对膨胀土进行改良试验,通过界限含水率试验、颗粒分析、重型击实试验、饱和无侧限抗压强度试验、膨胀性试验、压缩试验、直剪快剪试验以及不固结不排水三轴试验对比分析水泥、熟石灰的改良效果。结果表明:随着水泥、熟石灰掺入比的增加,膨胀土的无侧限抗压强度明显提高;改良后土的各项膨胀性指标都有了较大幅度的减小,压缩系数减小和压缩模量增加明显,黏聚力和内摩擦角都有着不同程度的增大;熟石灰改良效果优于水泥改良;建议沪渝蓉高速铁路合宁段采用熟石灰进行膨胀土改良,基床底层改良土熟石灰掺入比建议采用6%,基床以下建议采用5%,改良土养护龄期为7 d。In order to solve the problem that expansive soil is widely distributed in Hefei area of Shanghai-ChongqingChengdu high speed railway and the subgrade filler needs to be allocated at a long distance,the experiment of improving expansive soil by adding cement and hydrated lime was carried out. The improvement effects of cement and hydrated lime were compared and analyzed by the limit moisture content test,particle analysis,heavy compaction test,saturation unconfined compressive strength test,expansion test,compression test,direct shear test and unconsolidated and undrained triaxial test. The results show that the unconfined compressive strength of expansive soil increases obviously with the increase of the mixing ratio of cement and hydrated lime. The swelling indexes of the improved soil decreased significantly,the compression coefficient decreased and the compression modulus increased obviously,and the cohesion and internal friction angle increased in varying degrees. The improvement effect of hydrated lime is better than that of cement. It is suggested that hydrated lime be used to improve expansive soil in Hefei-Nanjing section of Shanghai-Chongqing-Chengdu high speed railway. The hydrated lime mixing ratio of improved soil at the bottom of subgrade is recommended to be 6%,that below the subgrade is recommended to be 5%,and the curing age of improved soil is 7 d.

关 键 词：沪渝蓉高速铁路 路基 试验研究 填料 膨胀土 水泥改良 熟石灰改良 掺入比 

分 类 号：U213.1[交通运输工程—道路与铁道工程]