合安高速公路膨胀土掺石灰试验研究

在穿越膨胀土地区的高速公路路基修筑工程中,通常采用统一的掺灰率进行膨胀土性质改良。由于膨胀土工程性质的差别,采用相同的掺灰率处理是不合理的。文章对合安高速公路沿线肥西、庐江和桐城三地区膨胀土进行掺石灰试验研究,探讨掺石灰对膨胀土的胀缩性与强度的影响规律。试验研究结果表明:在膨胀土中掺入一定量的石灰可有效降低膨胀土的胀缩性;土体的最佳含水量随掺灰率的增大而增大,而其最大干密度则随掺灰率的增大而减小;土体的无侧限抗压强度随掺灰率的增加先增大,当达到峰值后,随掺灰率的继续增加而降低,存在一个最佳掺灰率点,肥西、庐江和桐城三地区膨胀土的最佳掺灰率分别为8%、8%和6%。文章最后从膨胀土地质成因角度分析了肥西、庐江与桐城三地区膨胀土工程性质差异的原因,为膨胀土研究提供了新的方法和思路。

Experimental Study on the Effect of Lime on Expansive Soils of He-an Expressway

During the construction of the embankment of expressway on expansive soils,the same lime ratio has been used to stabilize the expansive soils,this is an unscientific method.The paper studies the effect of lime added in expansive soils located in Feixi,Lujiang and Tongcheng areas along He-an expressway.Testing specimens were subjected to physical properties,compaction,free swell index and swell potential,swelling pressure,unconfined compressive strength tests in laboratory.The swell-shrinking test results show that add lime in expansive soil reduces the swell-shrinking potential.With the addition of lime,the optimum water content increased,while the maximum dry unit weight decreased.The unconfined compressive strength of lime-soil increases with the addition of lime at first,after it reaches the peak value,then decreases.At end of the paper,the physical and engineering diversities of the three different expansive soils were analyzed through geological methods,this is a new way in studying expansive soil.