掺绿砂改良膨胀土室内试验研究

绿砂高额的处理费用与其具有的再利用潜力相比，使绿砂再利用的研究得到重视，尤其对公路路基改良具有很大的利用潜力。针对膨胀土路基的胀缩问题，围绕绿砂及膨胀土-绿砂混合物进行一系列室内土工试验，探讨绿砂作为公路膨胀土路基改良剂的可行性。在不同含水率及不同配比条件下，对绿砂以及绿砂改良后膨胀土的基本物理性质、击实特性、力学特性等进行室内对比试验分析。分析结果表明，绿砂改良膨胀土试样的强度主要取决于试样的含水率、掺砂率；随着掺砂率的增加，塑性指数逐渐降低，最佳含水率也随之减小，最大干密度增大的幅度变化很小，无侧限抗压强度先降低而后提高，其后又降低。

Laboratory test study of properties of expansive soil improved by waste foundry sand

The high cost of handling and the potential reuses of waste foundry sands made the research on waste foundry sands reuse to be attached importance, which is especially beneficial to the improved soil for roadbed. A laboratory testing program was conducted on waste foundry sand and expansive soil-foundry sand mixtures to assess their applicability as improver aimed at the swell-shrink characteristics of the roadbed. The mixtures were compacted in the laboratory at a variety of moisture contents and waste foundry sand content; and the basic physical properties, compaction properties, and mechanical properties were analyzed. The results of the study show that the strength of the mixture is highly dependent on the waste foundry sand content and water content at compaction. Along with increasing waste foundry sand content, plastic index and optimum moisture content gradually decreased; the marginal increment of maximum dry density changed little; and the unconfined compression strength increased at first, then decreased.