轻量土击实密度模型与工程特性（英文）

发布时间：2019-01-23 14:20

【摘要】：为了探索软夹杂土体压实机理,指导轻量土配方设计与压实施工,基于混合土物质结构组成及土体压缩变密的物理本质,建立了击实密度模型。试验发现模型预测值与实测湿密度基本一致,绝对误差仅有0.003~0.051 g/cm3,相对误差仅有0.282%~5.267%,证明击实密度模型可以准确预测混合土不同击实条件下的湿密度。EPS颗粒压缩率、混合土湿密度随击实次数增大而增大,增大趋势逐渐变缓;混合土孔隙比随击实次数增大而减小。在击实作用下,轻量土湿密度的提高是由土体的孔隙减少和EPS颗粒软夹杂的塑性压缩共同完成的。与砂土轻量土性质相似,粘土轻量土的湿密度、无侧限抗压强度随击实次数增大而增大。n=25击时,EPS颗粒压缩率范围6.13%~11.51%;n=94击时,EPS颗粒压缩率范围12.80%~14.87%。证明规范规定的击实次数与击实能量适合混合土的击实,不会导致EPS颗粒消泡。考虑到击实密度模型参数测定非常繁琐,根据工程实际情况,假设压实过程中土料含水量不变与压实后土颗粒-EPS颗粒之间的孔隙近似为0,进一步提出了简化击实密度模型,并且通过试验证明了简化模型完全适用于实际工程。
[Abstract]:In order to explore the compaction mechanism of soft mixed soil and guide the formulation design and compaction construction of lightweight soil, a compaction density model was established based on the composition of mixed soil material structure and the physical nature of soil compaction and densification. It is found that the predicted value of the model is basically consistent with the measured wet density. The absolute error is only 0.003g / cm ~ (-3), and the relative error is only 0.282 ~ 5.267g / cm ~ (-3). It is proved that the compaction density model can accurately predict the wet density of mixed soil under different compaction conditions. The EPS particle compression ratio and the wet density of mixed soil increase with the increase of compaction times and the increasing trend becomes slower. The porosity ratio of mixed soil decreases with the increase of compaction times. Under compaction, the increase of soil moisture density is due to the reduction of soil porosity and the plastic compression of soft inclusion of EPS particles. The wet density and unconfined compressive strength of the lightweight clay soil increase with the increase of compaction times, and the compression ratio of EPS particles increases in the range of 6.13 and 11.51 when the compaction times increase with the increase of compaction times. The compression ratio of EPS particles was 12.80% and 14.87% respectively. It is proved that the compaction times and compaction energy specified in the code are suitable for compaction of mixed soil, which will not result in the defoaming of EPS particles. Considering that the parameters of compaction density model are very complicated, according to the actual engineering situation, assuming that the soil material water content is invariable and the pore between soil particle and EPS particle after compaction is approximately 0, a simplified compaction density model is proposed. It is proved that the simplified model is suitable for practical engineering.
【作者单位】：西北农林科技大学水利与建筑工程学院;
【基金】：Project(2012JQ7013) supported by Natural Science Foundation of Shaanxi Province Project(Z109021108) supported by Special Matching Funds of Shaanxi Province Project(QN2012025) supported by the Fundamental Research Funds for the Central Universities PhD project(2011BSJJ084) supported by Research Foundation of Northwest A&F University
【分类号】：TU411

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