不同养护温度下水泥改良风积沙无侧限抗压强度试验研究

为研究不同养护温度对水泥改良风积沙的影响,开展无侧限抗压强度试验。选用的养护温度为30℃,40℃,50℃,60℃,70℃和80℃,水泥掺量为4%和5%,压实系数为0.90和0.95。研究不同养护温度对水泥改良风积沙的应力应变曲线、无侧限抗压强度、峰值应变和刚度的影响。研究结果表明:随着养护温度升高,水泥改良风积沙的应力应变曲线左偏态特征越显著,无侧限抗压强度近似线性降低,峰值应变近似反比例降低,而刚度近似线性增大。与标准养护条件相比,水泥掺量5%,压实系数0.95的水泥改良风积沙在30℃,50℃和80℃养护条件下的无侧限抗压强度分别降低了1.1%,17.4%和40.6%,峰值应变分别降低了19.7%,31.8%和40.2%,刚度分别增大了18.0%,32.6%和77.9%。新疆塔克拉玛干沙漠夏季路基施工时,考虑70℃养护条件,掺量5%的水泥改良风积沙能满足铁路路基基床底层填料设计要求。本文研究成果对风积沙铁路路基基床设计和施工有借鉴意义。

Experimental study on unconfined compressive strength of cement-improved aeolian sand under different curing temperature

In order to study the effect of different curing temperature on cement-stabilized aeolian sand,a series of unconfined compressive strength tests were carried out.The curing temperatures for the specimens were 30℃,40℃,50℃,60℃,70℃and 80℃,respectively.The cement content was 4%and 5%and the degree of compaction was 0.90 and 0.95,respectively.The effects of different curing temperatures on the stress-strain curve,unconfined compressive strength,peak strain and stiffness of cement-stabilized aeolian sand were studied.The results show that,with the increase of curing temperature,the left skewness of the stress-strain curve of cement-stabilized aeolian sand becomes more obvious,the unconfined compressive strength decreases approximately linearly,the peak strain decreases approximately inversely,and the stiffness increases approximately linearly.Compared with standard curing condition,when the cement content is 5%and the degree of compaction is 0.95,the unconfined compressive strength of the cement-stabilized aeolian sand cured at 30℃,50℃and 80℃is reduced by 1.1%,17.4%and 40.6%,respectively.The peak strain is reduced by 19.7%,31.8%and 40.2%,respectively,and the stiffness is increased by 18.0%,32.6%and 77.9%,respectively.During summer construction in the Taklimakan Desert,considering the high temperature of 70℃,the cement-stabilized aeolian sand with 5%cement content can meet the design requirements of surface layer of the railway subgrade bed.The research results provide reference for the design and construction of railway subgrade filling using aeolian sand.