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鉴于公路膨胀土路基的合理覆土深度的确定是膨胀土路基设计的一个关键问题,以小溪塔至鸦鹊岭一级公路改建工程膨胀土路基处理为背景,对采用风化砂改良后的膨胀土做了膨胀力试验及在不同上覆荷载作用下的有荷膨胀率试验,即对原膨胀土及膨胀土中掺入10%、20%、30%、40%、50%的风化砂,分别在杠杆式标准固结仪上做膨胀力试验,并在杠杆式标准固结仪上按0、12.5、25.0、37.5、50.0、75.0kPa做六级加载试验。试验结果表明,随着风化砂掺量的增加,膨胀力显著下降,同一掺砂比例下掺砂土的膨胀率与上覆荷载常对数呈线性关系,同一上覆荷载作用下掺砂土的膨胀率随掺砂比例的增加先增大后减小,可推断不同深度处膨胀土可能发生的变形量,进而确定工程上处理膨胀土时需覆土的深度。
In view of the determination of the reasonable depth of soil cover for expansive highway embankment is a key issue in the design of expansive soil embankment. Based on the treatment of expansive soil subgrade of the Yixi Tower to Crowbone Ridge Class I Highway, The expansive force test and the test of load expansion under different overburden were done, that is, the weathered sand mixed with 10%, 20%, 30%, 40% and 50% of the original expansive soil and expansive soil respectively In the lever standard consolidation instrument to do the expansion force test, and in the lever standard consolidation instrument at 0,12.5,25.0,37.5,50.0,75.0kPa do six loading test. The test results show that with the increase of the amount of weathered sand, the expansive force decreases significantly. The swelling rate of the sand mixed with the same sand content has a linear relationship with the constant logarithm of the overlying load. Under the same overburden, The expansion rate increases first and then decreases with the increase of the proportion of mixed sand, which can be deduced the possible deformation of the expansive soil at different depths, and then determine the depth of soil covering engineering expansive soil.