南京长江漫滩废弃粉土资源化利用击实试验研究

Research on compaction test effect of utilization of waste silt in Nanjing Yangtze River floodplain

为实现南京长江漫滩基坑开挖废弃粉土资源化利用,保证固化处理粉土达到最佳密实程度,基于室内击实试验和微观试验,研究了水泥、石灰固化废弃粉土的击实特性。试验表明:单掺水泥时,固化粉土的最大干密度随水泥掺量的增加先增大后减小,最佳含水率先减小后增大,拐点均在6%水泥掺量;固定6%水泥掺量下,固化土的最大干密度和最佳含水率均随石灰掺量的增加而减小。微观试验表明,在适当的固化剂作用下,粉土颗粒间孔隙被较好地填充密实,但添加剂过量则会导致孔隙增大,土体结构不密实,因此实际工程路基碾压施工中应控制水泥、石灰的掺量,并按击实试验结果控制含水率,以确保固化土达到最佳密实状态。

To realize the resource utilization of waste silt from foundation pit excavation of Nanjing Yangtze River floodplain and ensure the optimal compaction degree of solidified silt,the compaction characteristics of cement-lime solidified waste silt are studied based on laboratory compaction tests and microscopic tests.The results show that the maximum dry density of solidified silt increases first and then decreases with the increase of cement content,and the optimal water content decreases first and then increases with the increase of cement content.The inflectionpoint of cement content is 6%.The 6%cement content is chosen to investigate the influence of lime content,the maximum dry density and the optimum moisture content of solidified soil decrease with the increase of lime content.Micro experiments show that under the effect of proper additives,the space between silt particles is filled more closely,but leads to excessive additives porosity,soil structure is compact,so in roadbed rolling construction,the dosage of cement and lime should be controlled,the moisture content should be controlled by the compaction test results to realize the most compact structure of solidified soil.