干湿循环及固化工艺对固化土水稳特性和强度特性的影响

Effect of Wetting-drying Cycle and Solidification Process on Water Stability and Strength Characteristic of Solidified Soil

工程建设和河道清淤等工程的开展导致了大量废弃淤泥土的产生.废弃淤泥土资源化利用最有效的途径之一是对废弃淤泥土进行固化后作为路基或地基填料利用.本研究通过室内试验确定了最优固化剂配比,采用厂拌法、路拌法及就地固化法三种固化工艺将废弃淤泥土固化后在试验路段进行路基填筑,通过钻孔取芯的方法取回原状固化土试样进行浸水崩解试验和干湿循环试验.结果表明:三种固化工艺获得的固化土试样的水稳特性均较好.随着干湿循环次数的增加,厂拌法试样的强度衰减率及质量衰减率均较小;路拌法试样的质量前期发生折损,后期趋于稳定,最大质量衰减率为15.3%,最大强度衰减率为39.6%;就地固化法试样的质量折损最严重,最大质量衰减率为47.0%.通过三种固化工艺获得的固化土试样的抗干湿循环能力从高到低依次为:厂拌法试样>路拌法试样>就地固化法试样.厂拌法试样的无侧限抗压强度比路拌法试样大约一倍,这是因为厂拌法精度更高更均匀.

The development of engineering construction and river dredging project has led to the generation of a large number of waste sludge.It is one of the most effective ways to utilize waste sludge as filling material for subgrade or foundation after solidification.The optimal curing agent ratio was determined by laboratory tests in this study.Three solidification processes,namely plant mixing method,road mixing method and in-situ solidification method,were used to solidify the waste sludge and then the subgrade was filled in the experimental section after solidification.The undisturbed solidified soil samples were retrieved by drilling and core-taking method for immersion disintegration test and wetting-drying cycle test.The results show that the water stabilities of the samples prepared by three solidification processes are all quite well.With the increase of wetting-drying cycle numbers,the strength reduction rate and mass reduction rate of samples prepared by the plant mixing method are relatively small.The mass reduction of samples prepared by the road mixing method occurs in the early stage and tends to be stable in the later stage.The maximum mass reduction rate of samples prepared by the road mixing method is 15.3%,and the maximum strength reduction rate is 39.6%.The mass reduction of the samples prepared by the in-situ solidification method is the most serious,with the maximum mass reduction rate of 47.0%.The wetting-drying cycle resistances of the solidified soil samples obtained by the three solidification processes in the order of high to low are as follows:samples of plant mixing method>samples of road mixing method>samples of in-situ solidification method.The unconfined compression strength of the samples prepared by the plant mixing method is about twice that of the samples prepared by the road mixing method,because the plant mixing method is more accurate and uniform.