煤渣基泡沫轻质土孔结构优化与浸水耐久性研究

Research on pore structure optimization and water immersion durability of cinder-based foam lightweight soil

为有效满足水工结构水下减载回填要求,以电厂煤渣为主要组分制备了煤渣基泡沫轻质土,并以相关物理力学性能指标作为表征依据,对煤渣基泡沫轻质土的浸水耐久性能进行系统研究,从而实现对煤渣基泡沫轻质土孔结构的优化。通过标准养护与浸水条件两种方式,对泡沫轻质土质量吸水率、抗压强度、软化系数等指标进行定期检测,以抗压强度与软化系数随浸水时间的变化规律来反映泡沫轻质土浸水耐久性能;根据不同养护龄期的检测结果,对影响煤渣基泡沫轻质土浸水耐久性的主要因素进行了系统研究,分析了质量吸水率、软化系数与密度等级、水泥掺量之间的关系,并在此基础上研究了煤渣基泡沫轻质土的浸水劣化机理。研究表明:随着密度等级和水泥掺量的提升,泡沫轻质土的质量吸水率和软化系数会降低,且相对于水泥掺量,密度等级对质量吸水率与软化系数的影响程度更高。研究成果可为煤渣基泡沫轻质土用于水下减载回填提供参考。

In order to meet the requirements for load reduction and backfilling at the top of the underwater immersed tube tunnel,the power plant cinder was used as the main component for the preparation and underwater backfilling of cinder-based foam lightweight soil.Based on the relevant physical and mechanical performance indicators as the characterization basis,the water immersion durability of cinder-based foam lightweight soil was systematically studied,so as to optimize the pore structure of cinder-based foam lightweight soil.Through standard curing and water immersion conditions,the mass water absorption,compressive strength,softening coefficient,etc.were checked regularly,and the variation of compressive strength and softening coefficient with immersion time was used to reflect durability of foamed lightweight soil.According to the test results of different curing ages,the main factors affecting the mass water absorption rate and softening coefficient of cinder-based foam lightweight soil were systematically studied,the relationship between mass water absorption,softening coefficient and density grade,cement content was analyzed.On this basis,the water immersion deterioration mechanism of cinder-based foam lightweight soil was analyzed.The relevant research results provide an important reference for the underwater backfilling of cinder-based foam lightweight soil.