基于X-CT技术的气泡轻质土孔隙结构研究

Investigation on Void Structure of Foamed Light-Weight Soil with X-CT Scanning Technique

采用X-CT技术建立无掺土料气泡轻质土三维孔隙结构,基于统计分析研究了气泡轻质土孔隙体积、类型和球度的分布规律.结合无侧限抗压试验,探讨了气泡轻质土细观孔隙结构对其宏观力学性质的影响.结果表明:气泡轻质土中孔隙体积呈单峰分布,峰值出现在0.05~0.20mm3;气泡轻质土宏观密度越低,孔隙体积的分布范围越大;孔隙的球度呈单峰分布,峰值出现在0.15~0.35,绝大多数孔隙的外形呈极不规则状;气泡轻质土中联通类型孔隙占主导地位;孔隙体积与球度呈负相关,且与孔隙接触类型无关.对比分析气泡轻质土孔隙结构与无侧限抗压强度发现,在相近密度下,当孔隙球度提高7%或联通孔隙类型体积减小5%时,试样抗压强度与弹性模量均有10%以上的提升,且弹性模量的提升幅度更大.

X-CT scanning technique was adopted to obtain the void information of foamed light-weight soil without adding natural soil,including the void volumes,void contact relations and void sphericity as well as their distributions.After comparing the results of the void structure and unconfined compression test,the influence of foamed light-weight soil's void structure on its macroscopic mechanical behavior was explored.The results show that specimens with high density show a narrower volume range.The void volume shows a unimodal distribution,and the peak value is in range of 0.050.20mm3.Similarly,the void sphericity also shows a unimodal distribution with a peak value in range of 0.150.35,which indicates that void shape is highly irregular.Void sphericity is negatively correlated with void volume,and is independent on the void type.The comparison between X-CT data and unconfined compression test results shows that for the specimens with about the same density,when the void sphericity increases by 7%or the volume of connected void decreases by 5%,the compressive strength and elastic modulus of the specimens both are enhanced more than 10%,and modulus rises more significantly than unconfined compression strength.