含铝固化剂固化软土的试验研究  

EXPERIMENTAL RESEARCH ON STABILIZED SOFT SOILS BY ALUMINA BEARING MODIFIER

作　　者：黄新[1] 许晟[1] 宁建国[1] 

机构地区：[1]北京航空航天大学土木工程系,北京100083

出　　处：《岩石力学与工程学报》2007年第1期156-161,共6页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50278007)

摘　　要：用普通硅酸盐水泥、石膏和一种含铝膨胀组分构成的复合固化剂(PC+G+Al固化剂),选取2种有代表性的试样,进行软土固化试验研究,并与单纯使用水泥(PC)和水泥-石膏(PC+G)固化剂加固软土的效果进行比较分析。研究结果表明:对2种试样,PC+G+Al固化剂加固效果优于其他2种固化剂;PC+G固化剂只对孔隙比大、含水率高的试样加固效果优于PC固化剂的加固效果。PC+G+Al和PC+G固化剂的水化物中都产生钙矾石,利用钙矾石生成的固相膨胀作用填充孔隙,而钙矾石的生成在固化土中是否产生增强效果,主要取决于钙矾石与水化硅酸钙凝胶生成过程的协调性。　The experimental investigation was carried out with the purpose of making a contrast of strength effects of two clay soil species stabilized by Portland cement（PC）,portland cement-gypsum（PC＋G） and compound modifier（PC＋G＋Al）,which consist of Portland cement,gypsum and alumina expansive agent.The result illustrates that the strength effect of stabilized soft soils differ strikingly due to their respective addition.PC＋G＋Al modifier in both stabilized soil samples produces more significant improvement in strength development than the other two modifiers.The PC＋G modifier produces positive effect on strength,compared with PC modifier,only in one stabilized soil sample,which is in high water content ratio and porosity and contains active soil mineralogical composition.Both PC＋G＋Al and PC＋G modifiers,in both soft soil samples,form ettringite in their hydrates.The formation of ettringite provides pronounced solid-phase expansion to fill up the porosity of soft soils.Whether the formation of ettringite enhances the strength of stabilized soil depends on the concordance in formation of ettringite and calcium silicate hydrate（CSH） gel.The strength of the stabilized soil samples increases markedly when the formation of ettringite is prior to the formation of CSH gel structure,which benefits the pore filling as well as mitigates the expansion damage to the CSH gel structure.

关 键 词：土力学 固化土 水化硅酸钙凝胶 协调性 强度 

分 类 号：TU43[建筑科学—岩土工程] TU528.042[建筑科学—土工工程]