【摘要】 为解决工程建设过程中废弃物堆积以及深窄基坑回填困难的问题，通过掺入聚羧酸减水剂、水泥、磷石膏以及水玻璃，以期将工程渣土进行流态化处理并用于基坑回填。通过流动度、无侧限抗压强度、干缩及微观试验，分析了不同外加剂对改良流态固化土流动性、强度与干缩性能的影响，并探讨了其改良机理。结果表明：掺入聚羧酸减水剂能够极大改善材料的流动性能，但随着水泥掺量的增加，流动度下降较快；磷石膏能够使试样在后期获得更高的强度，而水玻璃可以提高使试样的早期性能及干缩性能；随着水泥、磷石膏和水玻璃的掺入，各种水化产物填充土体中的孔隙，土体内部结构变得更为致密。此外，在现场选取试验段进行现场回填，验证了流态固化土作为基坑回填料的可行性。研究成果可为提高流态固化土性能以及配合比设计提供参考。更多还原

【Abstract】 To solve the problems of waste accumulation and deep and narrow backfilling of foundation pit in the construction process, by adding polycarboxylate superplasticizer(PCE), cement, phosphogypsum(PG) and water glass(WG), the engineering residue is improved into fluid solidified soil for foundation pit backfill. The effects of various admixtures on the fluidity, strength and drying shrinkage of the improved fluid solidified soil were studied through laboratory mobility test, unconfined compressive strength test, drying shrinkage test and microscopic test, and the improvement mechanism was analyzed. The results show that: The flow property of the material can be greatly improved by adding PCE, but the flow rate decreases rapidly with the increase of cement content. PG can make the sample obtain higher strength in the later stage, while water glass can improve the early performance and drying shrinkage property of the sample. With the incorporation of cement, PG and water glass, various hydration products fill the pores in the soil, and the internal structure of the soil becomes more dense. In addition, the feasibility of using fluid solidified soil as backfill for foundation pit is verified by selecting test section for field backfill. This paper can provide reference for improving the performance of fluid solidified soil and the design of mix ratio.更多还原