水泥土搅拌桩处理富集火山灰淤泥的适用性分析

Applicability of improvement of enrichment pozzolana muck using cement soil pile

水泥土搅拌桩已广泛应用于饱和软黏土的地基加固,但在处理富集火山灰淤泥方面鲜有研究和应用,而水泥、火山灰、淤泥混合体系的反应机理是水泥土搅拌桩能否适用于加固富集火山灰淤泥的决定因素。通过分析水泥-土体系和水泥-火山灰体系的反应机理,得出火山灰效应强度是水泥-土-火山灰体系后期强度增长的关键。针对富集火山灰淤泥结构特性,采用适宜的水泥土配比参数和合适的施工工艺进行现场试桩,结果表明,28 d龄期平均无侧限抗压强度远超设计要求,且在同龄期同水泥掺入比等条件下桩体强度远大于常规饱和软黏土中的水泥土桩体强度,水泥土搅拌桩在富集火山灰淤泥的地基加固方面是适用的。

Compared with widely used in reinforcement foundation of saturated soft soil,cement soil pile has less application on improvement of enrichment pozzolana muck.The reaction mechanism among cement,soil and pozzolana is the determining factor whether cement soil pile can be used in improvement of enrichment pozzolana muck.Based on the study and analysis of hydration mechanism of cement-soil gelation system and cement-pozzolana gelation system,we obtain that strength contribution by pozzolanic effect is the key factor for strength growth of cement-soil-pozzolana gelation system in the later hydration period.Aiming at structural characteristic of enrichment pozzolana muck and hydration mechanism,we test cement soil pile based on appropriate cement-soil design parameter and construction technology.The results show that 28 days unconfined compressive strength is much better than the design strength,and the pile strength is much better than the ordinary cement soil pile strength in soft soil under the same conditions.It means that cement soil pile is suitable for improvement of enrichment pozzolana muck foundation.