海相沉积淤泥复合固化强度的试验研究

Experimental study on the composite solidified strength of littoral silt deposit

针对现有淤泥固化试验采用的固化剂相对单一的问题,为了系统研究多材料固化滨海沉积淤泥强度特性,以唐山南堡典型滨海沉积淤泥为研究对象,通过对比单掺、双掺及三掺等固化剪切强度,结合粉煤灰废物利用问题,系统研究了水泥、生石灰及粉煤灰等不同固化剂组合对滨海相沉积淤泥固化强度的影响。结果表明:不同固化剂对滨海相沉积淤泥抗剪强度影响的差异较为明显,抗剪强度基本随掺加固化剂的种类增加而增加,掺加6%生石灰、10%水泥和6%粉煤灰28 d龄期的固化淤泥抗剪强度最高,其黏聚力为238.4 kPa、内摩擦角为32.94°;抗剪强度指标的提高随龄期的变化存在差异,即淤泥单掺生石灰抗剪强度指标的提高主要在养护后期,施工中可适当增加闷料时间以使生石灰和淤泥颗粒反应充分;采用水泥来固化淤泥可在短期内明显提高强度,在高含水率的淤泥材料施工中有更好的工程效果;固化剂掺量相同情况下,抗剪强度随着龄期增长而增加。研究成果对滨海沉积淤泥的固化和工程应用具有参考价值。

Aiming at the problem of that the solidifying agent is relatively single for the silt solidifying experiment at present,meanwhile,for systematically studying the strength characteristics of the littoral silt deposit solidified with multi-material,the influences from different compositions of the influences from cement,quicklime,fly ash,etc.on the solidified strength of the littoral silt deposit are systematically studied herein through comparing the solidified shear strengths of single,double and three mixing schemes in combination with the waste utilization of fly ash by taking the typical littoral silt deposit in Nanpu of Tangshan as the study object.The result shows that the differences from the influences of different solidifying agents on the shear strength of the littoral silt deposit are more significant and the shear strength is basically increased along with the increase of the kinds of the mixtures of the solidifying agent,for which the shear strength of the solidified silt with the curing age of 28 d is the highest when adding 6%quicklime,10%cement and 6%fly ash,while its cohesion is 238.4 kPa,and the angle of internal friction is 32.94°.The change of the age-dependent increase of the shear strength index is different.That is to say,the shear strength index of the solidified silt singly mixed with quicklime is mainly increased in the later period of the curing,and then the enclosing time of the material can be appropriately increased for the sufficient reaction between the quicklime and silt particle during construction.The strength can be significantly increased by solidifying the silt with cement,from which the engineering effect is better in the construction of solidifying the silty material with high water content.Under the condition of the same mixing amount of the solidifying agent,the shear strength is increased along with the increase of the curing age.The study result has a referential value for the solidification of the littoral silt deposit and its engineering application.