水泥改良西藏林芝地区粉土路用性能试验研究

为解决西藏林芝地区路基填料问题,对林芝地区粉土进行水泥改良处理并进行击实试验、CBR试验、无侧限抗压强度试验和冻胀融沉试验,研究不同水泥掺量对改良土的最大干密度、最优含水率、CBR值以及冻融循环下改良土的物理力学性质的影响。试验结果表明:不同掺量的水泥改良粉土的最优含水率几乎不变,最大干密度随掺量增加缓慢增大;在冻融循环作用下水泥改良粉土仍为脆性破坏模式,水泥改良粉土的第5次冻融后和第10次冻融后的单轴应力应变曲线几乎趋于重合,在实际工程中可以以冻融循环5次后的强度作为水泥改良土的设计参考强度;在考虑冻融循环作用下,西藏林芝深厚粉土区域二级公路上路床粉土填料的最优水泥掺量为4%以上。

Experimental study on performance of silt road in Linzhi area

In order to solve the problem of roadbed packing in Linzhi area of Tibet,the silt is improved by cement in the area. The maximum dry density,the optimum water cut rate,the CBR value and the physical properties of the modified soil under different freezing and thawing cycles are studied by the compaction test,the CBR test,the unconfined compressive strength test and the frost heave sedimentation test. The results show that:The optimum moisture content of cement with different content is almost constant,and the maximum dry density increases slowly with the increase of content;Under the action of freeze-thaw cycle,the cement improved silt is still brittle failure mode,and the uniaxial stress-strain curve of the cement-modified silt is almost coincident,so in the actual project the strength of the cement frozen after 5 times can be taken as a modified soil design reference strength;Considering the effect of freeze-thaw cycle,the optimal cement content of the silt filler on the secondary road of Linzhi deep silty area in Tibet is more than 4%.