水泥改良风积沙无侧限抗压强度影响因素分析

Influencing factors analysis on unconfined compressive strength of cemented aeolian sand

为了研究水泥掺量、压实系数、养护龄期等因素对水泥改良风积沙无侧限抗压强度的影响,开展一系列无侧限抗压强度试验。试验选取的水泥掺量为4%,5%,6%,9%和11%,养护龄期1,3,7,14,28,56和90 d,压实系数为0.90,0.93和0.95。试验结果表明,水泥掺量、压实系数、养护龄期以及水泥掺量与压实系数的交互作用对水泥改良风积沙无侧限抗压强度的影响都具有显著性。水泥改良风积沙的无侧限抗压强度随着水泥掺量的增大呈幂函数增大,水泥掺量从4%提升至11%时,试样的无侧限抗压强度提升了6.2~6.26倍;水泥掺量越大,无侧限抗压强度增长比越大。水泥改良风积沙的无侧限抗压强度随着压实系数的增大而增大,压实系数从0.90增大到0.95时,试样的无侧限抗压强度增大了20%~67%;但强度增长幅度随着压实系数增大而降低,低压实系数下的水泥增强效果更显著。随着养护龄期的增长,水泥改良风积沙的无侧限抗压强度呈双曲线函数增长,28 d龄期的无侧限抗压强度为7 d龄期的1.21~1.50倍,90 d龄期的无侧限抗压强度为7 d龄期的1.31~1.78倍,强度增长率随着养护龄期逐渐减小。建立了水泥改良风积沙无侧限抗压强度受水泥掺量、压实系数、养护龄期等因素影响的多元非线性预测模型,预测效果好。研究成果可以为风积沙地区铁路路基基床设计提供参考。

In order to study the influence of different factors on the unconfined compressive strength(UCS)of cemented aeolian sand(CAS),a series of UCS tests were carried out.The cement contents were 4%,5%,6%,9%and 11%,and the curing ages were 1,3,7,14,28,56 and 90 days,and the compaction coefficient(CC)were 0.90,0.93 and 0.95.The test results show that cement content,compaction coefficient,curing age and the interaction between cement content and compaction coefficient have significant effects on the UCS of CAS.The UCS of CAS increases in power function form with the increase of cement content.When the cement content increases from 4%to 11%,the UCS of samples increases by 6.2~6.26 times.The greater the cement content,the greater the growth rate of UCS.When the compaction coefficient increases from 0.90 to 0.95,the UCS of the specimens increases by 20%~67%,but the increase ratio of the UCS under 0.90 CC is greater than that under 0.95 CC,and the enhancement effect of cement under low CC is more significant than that under high CC.With the increase of curing age,the UCS of CAS increases with hyperbolic function.The UCS of CAS at 28d is 1.21~1.50 times of that at 7 d,and the UCS of CAS at 90 d is 1.31~1.78 times of that at 7 d.The strength growth rate decreases gradually with the curing age.A multivariate nonlinear strength prediction model including cement content,compaction coefficient and curing age was established,which can predict the UCS of cemented aeolian sand.The results can provide reference for the surface design of railway subgrade bed in aeolian sand area.