摘要
针对青海省某公路路基盐渍土开展了水泥窑粉尘改良试验。制备了不同改良剂掺量的试样,进行了UCS试验和水稳定性试验,同时在现场填筑了3个不同改良配比的试验段,测试了不同养护龄期下的CBR、回弹弯沉及贯入指数,获取了改良土物理力学指标随改良剂掺量及养护龄期的变化规律,探讨了采用CKD改良此地区盐渍土的方案。研究结果表明:采用CKD+水泥联合改良可以明显提高盐渍土的无侧限抗压强度,而且具有较好的水稳定性,3%水泥+20%CKD改良土经历4次干湿循环后的强度损失率低于15%;联合改良土CBR和刚度也有所增加,例如7 d养护后CBR增加10%~45%,14 d养护后CBR增加30%~70%,但联合改良发挥效果所需要的养护龄期相对水泥改良更长;从兼顾效果和成本的角度考虑,建议采用3%水泥+20%CKD改良土填筑下路堤,采用3%水泥+30%CKD改良土填筑上路堤。
This paper proposed study on cement kiln dust(CKD)improvment on subgrade salinized soil at a certain highway construction site.A series of improved soil specimens with different improver dosages were prepared.Uncofined Strenth(UCS)tests and water resistance ability tests were conducted.Morover,three subgrade sections for testing with different improved ratios were constructed in-site.CBR,resilience deflection and penetration index were measured.The variation rule of improved soil mechanic index with the improver dosage and curing time was acquired.The scheme of improving saline soil in this district by CKD was discussed.The results show that the combined improvement of CKD+cement can significantly improve the UCS of saline soil with ideal water resistance stability.The strength loss rate of 3%cement+20%CKD improved soil is less than 15%after four dry-wet cycles.CBR and stiffness are also increased.For example,after 7 day curing,CBR can be increased by 10%~45%,while CBR can be increased by 30%~70%after 14-day curing.However,the curing period required by combined improvement is longer than that of cement improvement.From the perspective of both effect and cost,it is suggested to use 3%cement+20%CKD to construct the lower embankment and 3%cement+30%CKD to construct the upper embankment.
作者
王来发
WANG Laifa(Qinghai Transportation Planning and Design Research Institute Co. LTD.,Xining,Qinghai 810000,China)
出处
《公路工程》
2021年第4期150-156,共7页
Highway Engineering
基金
青海省交通科技项目(2018-SF-139)。
关键词
公路路基
盐渍土
水泥窑粉尘
无侧限抗压强度
CBR
水稳定性
highway subgrade
salinized soil
cement kiln dust
unconfined compressive strength
CBR
water resistance ability
