摘要
针对泡沫土在工程应用中由于流动性不足导致的软弱夹层和透镜体,以及由于强度不够而引发的剪切裂缝和沉陷开裂等工程质量问题,开展一系列室内、现场的试验,分析了影响泡沫轻质土的抗压强度和流动性的主要因素,对现场浇筑过程中关键技术进行研究。结果表明:发泡剂类型、含量,水胶比,湿密度和矿粉、粉煤灰组分对泡沫轻质土流动性、成型后强度均有显著的影响。3种发泡剂所对应的轻质土土体强度基本表现为FLS-L-Ⅰ>FLS-S-Ⅰ>FLS-L-Ⅱ,流值随泡沫溶液含量的增大而减小,泡沫溶液质量分数宜控制在1.3%左右;水胶比越大流动性越强,而成型后泡沫土抗压强度越小,水胶比取值宜控制在0.55~0.65;湿密度与轻质土的抗压强度呈正相关而与其流值呈负相关,湿密度宜取550~650 kg/m^3;掺入一定的矿粉有助于提高泡沫土的强度,并存在15%的最佳掺量,而复掺粉煤灰将导致抗压强度的下降。施工关键技术控制方面,拌合时间、单层浇筑厚度及浇筑范围都对泡沫轻质土性能产生控制性影响,研究认为泡沫轻质土浇筑,单层浇筑厚度宜控制在0.3~0.6 m,单次最大浇筑距离宜控制在15m范围内。上述研究成果为今后泡沫土工程应用中关键技术的控制提供有益参考。
In light of engineering problems,such as weak interlayer and lenses,shear and sink cracks in the application of foamed lightweight soils,which are mainly attributed to construction mix proportion and pouring technology,a series of indoor and field tests were conducted to analyze the influence of different factors.These factors include physical and mechanical properties such as fluidity,bulk density,and compressive strength related to construction mix proportion and the key technologies in the on-site pouring process.The results showed that the type and content of foaming agent and the water-binder ratio have significant effects on the flow ability and strength of foamed lightweight soil.The flow value is increased with the increase in water-binder ratio and decrease in foaming agent content.However,the increase in water-binder ratio causes the compressive strength to decrease,and the optimum content of 1.3% for foaming agent content and the optimum range from 0.55 to 0.65 for the water-binder ratio are proposed.In addition,the mix of mineral power benefits the increase in compressive strength,and the optimum mass content of 15% is also advised,but the double mix of fly ash causes the compressive strength to decrease significantly.At the same time,the key technologies are pointed out,which have effects on the foam performance of lightweight soil in the on-site pouring process,such as the pouring wet density within 550-650 kg/m^3,the single grouting thickness within 0.3-0.6m and the optimum grouting distance range of 15 meters.The above research results provide useful references for key technologies in application of foamed lightweight soils in the future.
作者
黄学明
赵鲲鹏
王海波
吕伟华
刘泽龙
HUANG Xueming;ZHAO Kunpeng;WANG Haibo;LYU Weihua;LIU Zelong(Nanjing Forestry University,Nanjing 210037,China)
出处
《林业工程学报》
CSCD
北大核心
2019年第6期143-150,共8页
Journal of Forestry Engineering
基金
国家自然科学基金(51508279)
江苏省自然科学基金(BK20150885)
关键词
泡沫轻质土
配合比
浇筑技术
影响规律
foamed lightweight soils
construction mix proportion
pouring technology
influence rule
