皖中膨胀土的承载比(CBR)强度特性研究

针对皖中地区高速公路建设中遇到的膨胀土问题,选取合六叶高速公路典型土样开展了系统的承载比（CBR）特性试验研究,并在此基础上探讨了膨胀土作为路基填料的适用性。研究表明:（1）起始含水量对膨胀土CBR值影响显著,CBR最大值对应的含水量高于最佳含水量,且击实功越大,二者差值也越大;（2）CBR膨胀量随起始含水量增大而减小,起始含水量越低,CBR膨胀量就越大,路基的水稳性就越差;（3）当击实功较大时,膨胀土的最佳含水量较小,适合填筑的可变含水量范围较宽,建议现场施工控制采用重型击实标准;（4）在重型击实条件下,将弱膨胀土起始含水量控制在比最优含水量大2%⁴%范围内,能同时满足压实度和CBR值要求以用于填筑下路堤,中膨胀土作为路基填料时必须经过改性处理。研究结果对于在膨胀土地区进行公路建设具有参考意义。

CALIFORNIA BEARING RATIOS AND COMPACTION DEGREES OF ORIGINAL AND COMPACTED EXPANSIVE SOILS AS EXPRESSWAY SUBGRADE IN CENTRAL ANHUI PROVINCE

Aimed to address the expansive soil problem in highway construction in the centre of Anhui Province,typical soil specimens from the He-Liu-Ye expressway are chosen to carry out systematically experiments to study the characteristics of California Bearing Ratio(CBR) of expansive soils,and based on this the usability of expansive soils as subgrade materials is discussed.The research shows:(1)The initial water content affects the CBR value markedly,and the initial water content corresponding to the maximum CBR value is high than the optimal initial water content,and the discrepancy grows with the compaction work;(2)The CBR swell amount reduces when the initial water content increases.The CBR swell amount is higher as the initial water content is lower,and the roadbed water-stability is worse;(3)The optimal initial water content is lower when the compaction work is greater,and the range of variable water content suitable to pad is wider.So the heavy compaction standard is suggested in the site construction control;(4) In the condition of heavy compaction standard,the low-class expansive soil can meet both the compactioness request and the CBR request to pad the bottom of embankment,the middle-class expansive soil must be treated as roadbed padding materials.The results of the research could be referred to the construction of expressway in the expansive soil areas.