淤泥在软土路基施工中的应用

Application of Muddy in Soft Soil Roadbed Construction

淤泥质土由于力学性能差,需经固化处理后才能应用到软土路基施工中。文章采用粉煤灰与生石灰作为固化剂,设计了5组固化土基层材料配比,通过室内试验,研究龄期、含水率、固化剂、干密度、孔隙比与无限侧抗压强度(UCS)、加州承载比(CBR)及压实度之间的关系,建立了考虑龄期、含水率的固化土无侧限抗压强度预测模型;设计对照试验,探究二灰土与固化土抵抗干湿循环的能力。结果表明:当固化剂生石灰和粉煤灰掺量均为7.5%时,淤泥固化土路基填料可以获得较高的UCS与CBR;随着龄期的增长,淤泥固化土路基填料土的孔隙比、含水率逐渐降低,无侧限抗压强度升高;淤泥固化土路基填料的UCS预测模型精准度高,预测模型R2=0.917 4;固化土相较于二灰土有着更强的抗干湿循环能力,且采用此淤泥固化剂固化淤泥铺筑试验路段,其强度与压实度完全符合规范要求,适于用作路基填料。

Due to its poor mechanical properties,muddy soil needs to be solidified before it can be used in soft soil roadbed construction.This paper uses fly ash and quicklime as stabilizing agents and designs five groups of stabilized soil subgrade material ratios.Through in-house experiments,the relationships between age,moisture content,stabilizing agent,dry density,void ratio,and unconfined compressive strength(UCS),California bearing ratio(CBR),and compaction degree were studied,and an unconfined compressive strength prediction model for stabilized soil considering age and moisture content was established.An experimental test was designed to investigate the ability of lime-ash soil and stabilized soil to resist dry-wet cycles.The results show that when the stabilizing agent dosage of quicklime and fly ash lime is 7.5%,the sludge stabilized soil subgrade filler can obtain higher UCS and CBR.As the age of the sludge stabilized soil subgrade fller increases,the void ratio and moisture content of the soil gradually de-crease,and the unconfined compressive strength increases.The UCS prediction model for sludge stabilized soil subgrade filler has a high precision,with R^(2)=0.9174.Compared with lime-ash soil,stabilized soil has stronger resistance to dry-wet cycles and is more suitable for use as subgrade filler.The trial section of sludge stabilized by this stabilizing agent is constructed,and its strength and compaction degree fully meet the requirements of the regulations.