渣土改良为流动化回填土的应用

针对城市管网基槽开挖产生大量渣土难以处理、基槽回填缺乏良质回填土的问题,提出了将渣土改良为流动化回填土原位使用的技术并进行了示范工程应用。通过室内测量流动性和强度得出:流动性随着用水量增加显著增加,强度随着固化材料掺量和养护龄期增加而增加。水固比和灰砂比可以作为流动化回填土配比指标参数,当水固比为0.63、灰砂比为0.15时,流动化回填土流动值为242 mm,且具备早强性能,1 d强度可达98 kPa, 28 d强度可达390 kPa,满足流动化回填土设计要求。在东莞茅洲河治理管网埋设工程中将渣土改良成流动化回填土后成功浇筑回填管网并实测了应用效果,使用室内试验得到的配方,现场工程施工得到顺利开展。现场开挖渣土经过使用上述配比进行拌和浇筑后,流动值在188～218 mm之间,28 d强度在324～362 kPa之间,完全满足管网回填土要求。

Research on application of residue soil-based flowable fill

Aiming at the problems that a large amount of slag sludge is difficult to be treated in the excavation of urban pipe network and the backfilling of the basement is lacking in good quality backfilling, the technology of improving the slag sludge to the flowable fill for in-situ use is studied and applied in a demonstration project. Measurements of the fluidity and the strength by indoor experiments indicates that the fluidity increases significantly with the increase of water consumption, and the strength increases with the increase of the amount of solidified material and the age of curing. The water-solid ratio and the lime-sand ratio can be used as the ratio index parameters of the fluidized backfill. When the water-solid ratio is 0. 63 and the lime-sand ratio is 0. 15, the flowable fill has a fluidity value of 242 mm, and it has the early-strength performance, which can reach 98 kPa in one day and 390 kPa in 28 days, meeting the design of fluidized backfill. This paper discusses the application and effect of this technology in engineering in combination with the pipe network embedding project in the management of Maozhou River in Dongguan. Through the on-site construction and the follow-up inspection, it shows that the slag excavated on site is mixed with the above ratio, the flow value is between 188-218 mm, and the strength at 28 d is between 324-362 kPa, fully meeting the requirements of pipe network backfill.