砂砾改良高液限粉土物理力学特性试验研究

Experimental study on physical and mechanical properties of high liquid limit silt improved by gravel

高液限粉土的稳定性很差,路基工程中往往需要采取各类措施加以改良。通过向有机质高液限粉土中掺加砂砾,开展一系列基本物性试验以研究不同砂土配合比对改良土的物理力学性质的影响规律。结果表明:掺砂可以显著改善有机质高液限粉土的可塑性,降低其液塑限与塑性指数,且掺砂量对塑限影响更显著,对液限的影响程度相对较低;随着砂土配合比的增大,改良土的最优含水率先迅速降低而后趋于平缓,最大干密度先迅速增大而后同样趋于平缓;随着砂土配合比的增大,改良土的吸水膨胀量逐渐降低,吸水量先增高后降低,CBR逐渐增大;且当砂土配合比为1∶1时,CBR值可以达到10.39%,满足路基填筑要求。

The stability of the high liquid limit silt is very poor,and it needs to be improved in the roadbed engineering.A series of basic physical property tests were carried out by mixing different contents of gravel into the organic matter high liquid limit silt to study the influence of different mix ratios of gravel and soil on the physical and mechanical properties of the improved soil.The results show that gravel mixing can significantly improve the plasticity of high-liquid-limit silt and reduce the liquid-plastic limit and the plasticity index of high-liquid-limit silt.And the amount of gravel has a more significant impact on the plastic limit,and the impact on the liquid limit is relatively low.With the increase of the gravel-soil mix ratio,the optimal moisture content of the improved soil first decreases rapidly and then tends to level off,and the maximum dry density first increases rapidly and then also tends to level off;With the increase of the gravel-soil mix ratio,the water-absorbing swelling capacity of the modified soil gradually decreases,the water absorption first increases and then decreases,and the CBR gradually increases,and when the gravel-soil mix ratio is 1∶1,the value of CBR can reach 10.39%which satisfies the requirement of subgrade filling.