含石量对砂卵石土的颗粒破碎及强度与变形的影响研究

Influence of gravel content on particle breakage,strength and deformation of sandy pebble soil

为探究含石量对不同围压下砂卵石土的颗粒破碎及抗剪强度与变形特性的影响,利用室内大型三轴试验仪开展了固结排水剪切试验。试验设计了0~100%之间5级含石量,在0.5 MPa、1.5 MPa、2.5 MPa三种不同围压条件下进行固结排水三轴剪切试验。基于试验结果,分析了含石量及围压对砂卵石土抗剪强度和剪胀、剪缩特性的影响,并分析了相应的颗粒破碎情况。试验结果表明,在相同含石量下,砂卵石土抗剪强度随着围压的升高不断增加,体变初期表现为明显剪缩,之后剪胀性随围压升高而降低,颗粒破碎率随围压升高而增加;在相同围压下,含石量在50%~75%时,颗粒破碎率最大,并出现最大抗剪强度,而围压越高,试样剪胀越不明显。

In order to explore the influence of gravel contents on particle breakage,the shear strength and deformation characteristics of sandy pebble soil,the CD test was carried out by using a large-scale triaxial test system.Five gravel contents between 0%and 100%were used as samples for CD tests under three different confining pressures of 0.5MPa,1.5MPa and 2.5MPa.Based on the test results,the effects of gravel content and confining pressure on the shear strength,dilatancy and shrinkage of sandy pebble soil are analyzed,and the variation of particle breakage under the same conditions is analyzed.The test results show that the shear strength of sandy pebble soil increases with the increase of confining pressure under the same gravel content.Moreover,the initial stage of bulk deformation is rapid shear shrinkage,and then the dilatancy decreases with the increase of confining pressure,while the particle breakage rate increases with the increase of confining pressure.Under the same confining pressure,when the gravel content is between50%and 75%,the soil skeleton plays a major role and the maximum shear strength appears.The higher the confining pressure is,the less obvious the dilatancy of the sample is.