生活垃圾焚烧炉渣在饱和状态下的强度特性

SHEAR STRENGTH OF SATURATED BOTTOM ASH FROM MUNICIPAL SOLID WASTE INCINERATOR( MSWI)

城市生活垃圾焚烧炉渣具有活性,饱和炉渣的剪切强度随时间增加而增加。本文采用常规三轴试验测试饱和炉渣的剪切强度,围压σ3分别为50k Pa、100k Pa、200k Pa和400k Pa,试样的干密度ρd分别为1.4g·cm^(-3)、1.5g·cm^(-3)和1.6g·cm^(-3),龄期t分别为3d、7d、14d和28d。三轴试验结果表明:饱和炉渣的破坏模式受龄期和围压的影响明显。围压小于200k Pa,龄期小于14d的试样表现为脆性破坏。在τ-σ坐标上,应力莫尔圆的包络线不是直线;炉渣在σ_1-σ_3坐标上表现为两段直线,分界点为σ_3=200k Pa,由σ_1-σ_3相关关系确定炉渣的内摩擦角和黏聚力更合理可信。

Shear strength of saturated MSWI bottom ash increases with age due to its activity. In this paper,shear strength of saturated MSWI bottom ash is measured using triaxial tests. The confining pressures are 50 k Pa,100 k Pa,200 k Pa and 400 k Pa, respectively. The dry densities of tested samples of saturated MSWI bottom ash are1. 4g·cm（-3）,1. 5g·cm（-3）and 1. 6g·cm（-3）. Their ages are 3d,7d,14 d and 28 d,respectively. The results of triaxial tests show that the failure modes of saturated MSWI bottom ash in triaxial tests are affected by cured ages and confining pressures. The samples with age less than 14 d undergo brittle failure at confining pressure less 200 k Pa.The envelope of Mohr-Coulomb criterion is not a straight line. Two straight lines exist in the plane of σ1-σ3 at demarcation point of σ3= 200 k Pa. Thus,the regressing maximum principal stress with minor principal stress is suitable to estimate shear strength parameters using triaxial tests.