深圳福永填埋固化污泥土的工程性质研究

摘要

深圳福永污泥填埋场位于深圳国际机场拟建T4航站楼扩建区中部,填埋场内堆积了大量的固化污泥土,是机场地基处理遇到的难题.为了查清固化污泥土的岩土工程性质,对填埋污泥进行了物质成分分析、微观结构观察、室内外力学试验等.结果表明:固化污泥土中含片状的粘土矿物颗粒、未定型的水化硅酸钙(CSH)、针状的钙矾石以及结构松散的有机絮凝体;土颗粒间孔隙多,孔隙较大(1~6 μm),存在大量的微孔隙;固化污泥土具有低密度、低土粒密度、高含水率、高孔隙比、高液塑限等特点;土体十字板抗剪强度值为13.8~23.7 kPa,强度随固结应力的增加而大幅增加;地基承载力特征值为78.9 kPa,变形模量为4.1 MPa,重塑后压缩系数a1-2为3.073 MPa-1.%The Fuyong sludge landfill site is located in the middle of the extension area of Shenzen International Airport,where it is going to build the T4 terminal.There is a great amount of solidified sludge soil landfilled in this site,which is a difficult problem for airport foundation improvement.In order to find out the geotechnical engineering properties of the solidified sludge soil,experiments including component analysis,microstructure observation,laboratory soil tests and in-situ tests were performed in this study.The results showed that the solidified sludge soil contained flake clay mineral particles,unshaped hydrated calcium silicate (CSH),needle like ettringite and loose structure organic matters;there were a lot of voids between the soil particals including macrovoid(1~6 μm) and microvoid;the solidified sludge soil had characters of low density,low soil particle density,high water content,high void ratio,high liquid limit and high plastic limit;the vane shear strength of the soil was 13.8~23.7 kPa and its strength increased greatly with the increase of the consolidation stress;the characteristic value of foundation bearing capacity was 78.9 kPa and the deformation modulus was 4.1 MPa,but the compression coefficient of the remolded soil was 3.073 MPa-1.