高速铁路路基粗粒土B组填料剪胀特性的大型三轴试验研究

Large-scale triaxial test study on shear dilatancy of subgrade filler of group B coarse-grained soil of high speed railway

采用大型三轴试验剪切仪，对高速铁路路基粗粒土 B 组填料的剪胀特性进行试验研究。结果表明：围压和粗粒含量对粗粒土 B 组填料的剪胀性有显著影响，整体表现为粗粒含量低或围压高时剪缩，粗粒含量高且围压低时先剪缩后剪胀；当围压小于200 kPa，粗粒含量大于49．31％时，粗粒土 B 组填料存在明显的剪胀趋势，且围压越低、粗粒含量越高，剪胀时轴向应变越小。验证了轴向应变ε21与侧向应变ε3的二次函数对粗粒土 B 组填料的适应性，并在此基础上根据试验结果建立粗粒土 B 组填料关于粗粒含量、围压的剪胀判据方程。ROWE 剪胀方程能很好地反映粗粒土 B 组填料剪胀特性，参数K 可取7～12。

In order to study the dilatancy effect of group B coarse -grained soil using as high speed railway sub-grade filler,a series of group B coarse -grained soils tests were executed by the large scale triaxial shearing ap-paratus.Tests results show that both the confining pressure and coarse particle contents have obvious influences on the dilatancy of the group B coarse -grained soil.When the confining pressure is lower or coarse particle con-tents is higher,the group B coarse -grained soil amples shows shearing shrinkage.When the confining pressure are higher and coarse particle contents is lower,the group B coarse -grained soil amples shows dilatancy in the tests.Moreover,the group B coarse -grained soil contract first and then dilate during shearing when the confi-ning pressure is lower.When the confining pressure is less than 200 kPa and coarse particle contents is more than 49.31%,the group B coarse -grained soil shows obvious dilatancy tendency.Applicability of quadratic function between axial strain ε21 and lateral strain ε3 is convinced for the group B coarse -grained soil,and an experiential dilatancy criterion which is available for the group B coarse -grained soils,was set forward.The Rowe dilatancy law can commendably reflect the dilatancy of group B coarse -grained soil,and the shearing di-latancy coefficient K of Rowe is identified as 7 ~12.