冻融循环下风化砂改良膨胀土有荷膨胀率试验及模型预估

为研究风化砂改良膨胀土的有荷膨胀率与风化砂掺量、冻融循环次数之间的关系,通过向膨胀土中分别掺入0、10%、20%、30%、40%、50%的风化砂,经过0,1,3,6,9,12次冻融循环后,利用杠杆式固结仪进行25,50 k Pa下有荷膨胀率测试。试验结果表明:在同一掺砂比例下,风化砂改良膨胀土的有荷膨胀率随冻融循环次数的增大而减小,但变化的幅度各不相同;在同一冻融循环次数下,风化砂改良膨胀土的有荷膨胀率随掺砂比例的增大呈先增大后减小的变化趋势,且均在掺砂比例为10%时,有荷膨胀率达到最大。在同一掺砂比例下,当上覆荷载为25 k Pa时,风化砂改良膨胀土的有荷膨胀率与冻融循环次数之间呈对数函数衰减,当上覆荷载为50 k Pa时,风化砂改良膨胀土的有荷膨胀率与冻融循环次数之间呈线性下降关系。

THE LOADED SWELLING RATIO TEST AND MODEL PREDICTION OF WEATHERED SAND IMPROVED EXPANSIVE SOIL UNDER FREEZE-THAW CYCLES

This paper researched the qualitative and quantitative relationships among loaded swelling ratio of weathered sand improved expansive soil,weathered sand content and cycles of freeze-thaw tests by adding respectively 0,10%,20%,30%,40% and 50% of the weathered sand into the expansive soil. The loaded swelling ratio test under 25 k Pa and 50 k Pa was done with leveraged consolidation apparatus after 0,1,3,6,9,and 12 cycles of freezing and thawing.Test results showed that with the increasing of cycles of freeze-thaw,the loaded swelling ratio of weathered sand improved expansive soil decreased with different change magnitude under the same sand ratio. With the increasing of weathered sand proportion,the loaded swelling ratio first increased and then decreased under the same freeze-thaw cycles. When the content of sand was 10%,the loaded swelling ratio reached the maximum. The relationship between the loaded swelling ratio of weathered sand improved expansive soil and freeze-thaw cycles expressed a logarithmic function in the same sand ratio under the action of 25 k Pa overlying load,and linear function under 50 k Pa.