粉煤灰作为地层时的工程特性研究较少,直接影响粉煤灰场地的勘察与设计。采用钻探、静力触探和十字板剪切试验相结合的方法研究湿排沉积粉煤灰层的工程特性。结果表明:沉积粉煤灰的静力触探曲线呈锯齿状,没有临界深度;锥尖阻力比粉质粘土和细砂小;侧壁摩阻力小于填筑粉质粘土、接近沉积粉质粘土、大于细砂;摩阻比小于填筑粉质黏土、大于沉积粉质粘土和细砂;比贯入阻力接近填筑粉质粘土、大于沉积粉质粘土;粉煤灰遇水软化,触探曲线在水位上下有明显的界面效应;十字板强度随深度加大而增大,具有明显的结构性;粉煤灰地层宜用双桥静力触探进行勘察。该粉煤灰的工程特性接近于粉土。
The engineering behavior of fly ash as stratum is studied seldom,which affects directly the exploration and design of the deposition fly ash site.The behavior of deposition fly ash was studied by drilling,cone penetration test and vane shear test.The results of study show that the fly ash cone penetration is the sawtooth form,and there is no critical depth for fly ash.The cone resistance of the fly ash is smaller than silty clay and sand,the friction resistance is smaller than filling silty clay,similar to deposition silty clay and more than fine sand,the friction ratio is smaller than filling silty clay,more than deposition silty clay and much more than fine sand,the specific penetration resistance is similar to filling silty clay,more than deposition silty clay.Fly ash with water will be soften,and there is a clear interface effect of fly ash penetration curve on the groundwater level.With obvious behavior of structure,vane strength of the fly ash increases with the depth increased.Even bridge cone penetration test should be used during geological exploration.The deposition fly ash is much similar to silt in character.