真空联合堆载预压加固土体的工程地质性质

Engineering geological characters of soft soil by vacuum combined with surcharge pre-loading reinforcement

为解决一些软土不能满足工程建设要求的问题,必须对其进行加固处理。本文借助室内试验,对比江门软土加固前后的基本物理性质、物理化学性质和力学性质,借助扫描电镜(SEM)对比研究加固前后土体微结构和工程性质的变化。研究表明:加固后黏粒组含量明显减少,砂砾组和粉粒组含量明显增加,pH值降低,阳离子交换量大幅下降,Ca2+、CI-和HCO3-含量减小,其他离子含量变化不明显。加固过程增加了颗粒之间的连结力,力学性质明显提高。加固前软土的微结构以絮凝状结构为主,大孔隙较多;加固后以团粒状结构为主,粒内和粒间孔隙变小。真空联合堆载预压加固效果明显,软土工程性质明显提高,可以满足工程建设的需要。

In order to solve the problem of soft soil can not be satisfied with the demand of construction project, the reinforcement and improvement of soft soil＇s engineering characters are needed. The authors used laboratory tests to contrast the characters of unreinforced and reinforced soft soil in Jiangmen area, such as the basic physical, physical and chemical, and mechanical properties, and studied the micro-structural change of unreinforced and reinforced soil by scanning electron microscope. Clay group of reinforced soft soil were significantly reduced, gravel and silt groups increased, pH value and cation exchange capacity became lower, Ca^2＋ , CI^- and HCO3^- contents decreased, and the contents of other ions did not change obviously. Connectivity between the particles increased in reinforcement process, and mechanical properties increased simultaneously. Unreinforced soil was flocculation structure with more large pores, and reinforced soil was granular structure with smaller pores between grains. The consolidation affects of vacuum combined with surcharge pre-loading are obviously, the engineering nature of soft soil improved and met the construction needs.