碱激发作用下海相软土固化研究

Solidification of Marine Soft Soil under Alkali Excitation

为提高工业废料电石渣、原状灰固化软土的作用效果,选择聚羧酸减水剂,硅酸钠、硫酸钠、三乙醇胺作为外加剂,采用无侧限抗压强度试验、X射线衍射、电镜扫描试验研究各外加剂间的协同作用。结果表明,0.1%质量分数的聚羧酸减水剂分别与3%(质量分数)硅酸钠、0.9%(质量分数)硫酸钠复配时能显著提高固化土强度,并确定硅酸钠与硫酸钠以1∶1双掺的复合早强剂。通过正交试验确定出减水剂、复合早强剂与工业废渣复配的最优配比。7 d、28 d龄期时,掺入复合早强剂的工业废渣固化软土比未掺时的强度增幅可达47%、77%。7 d龄期时,减水剂的分散效应在固化土中起主导作用,28 d龄期时,复合早强剂碱激发作用下的火山灰效应则更加明显。

In order to improve the effect of industrial waste calcium carbide slag and undisturbed ash on the solidification of soft soil,polycarboxylate superplasticizer,sodium silicate,sodium sulfate,and triethanolamine were selected as additives.The unconfined compressive strength test(UCS),X-ray diffraction(XRD),and scanning electron microscope(SEM)were used to study the synergistic effect of the additives.The results show that 0.1%(mass fraction)polycarboxylate superplasticizer combined with 3%(mass fraction)sodium silicate or 0.9%(mass fraction)sodium sulfate can significantly improve the strength of solidified soil,and the composite early strength agent with 1∶1 ratio of sodium silicate and sodium sulfate was determined.The optimum ratio of superplasticizer,composite early strength agent and industrial waste residue were determined by orthogonal test.At the age of 7 d and 28 d,the strength increase of the solidified soft soil with composite early strength agent is 47%and 77%higher than that without composite early strength agent.At the age of 7 d,the dispersion effect of superplasticizer plays a leading role in the solidified soil,while at the age of 28 d,the pozzolanic effect of composite early strength agent under alkali excitation is more obvious.