elasticity module

Using additives can improve the mechanical properties of soils of construction projects such as irrigation canals. The materials such as sand, in addition to improving soil conditions, are compatible with the environment. So, in recent decades, the utilization of sandy soils in the construct of irrigation networks has been extended. In this study, the effect of size and amount of sand on the strength characteristics of lime treated soils. In this way, at first, to determine the best soil-lime mixture, the soil was mixed by different amount of lime and unconfined compressive strength of these has been investigated. The highest unconfined compressive strength was achieved by adding 7 percent lime to the soil. Then, a set of tests conducted on coarse (D50= 1.4 mm), medium (D50= 0.45 mm) and fine (D50= 0.22 mm) and by applying 5, 10 and 15 percent of sand to lime-clay mixture in three replicates. The unconfined compressive strength was performed on the specimen at curing time of 7, 14 and 28 days. Results showed that adding 5 percent of coarse sand to clay–lime mixture can increase compressive strength and elasticity module about 13 percent and 16 percent, respectively, on average. In addition, adding medium and fine sands can cause to deteriorate soil’s strength and elasticity module.

Soil strength and elasticity modules are important parameters in the engineering characteristics of soils. Bearing capacity is increased by soil strength. Elasticity module determines the potential of soil deformation. In this experiment، stabilization of problematic clay soils using sands were investigated. The samples were prepared with variable soil moisture and compaction، and were tested in single-axis compression apparatus in the soil mechanics laboratory of Shahid Chamran University (SCU) in Khuzistan province. The samples were tested with soil moistures as follows: optimum humidity; 2% and 4% less than optimum; and 2% and 4% more than optimum moisture. The compaction of applied، R. C، were equal to 85، 95 and 100 percents. Using the obtained data، the soil strength and elasticity modules were calculated. Our findings show that for all in clay and sandy-clay samples tested increasing moisture lead to decrease of soil strength. However، reduction of soil strength in the sandyclay sample is more than problematic clay soils samples. Results of these experiments regarding the moisture change from 4% less than optimum to 4% more than optimum، decreased soil strength of problematic clay soil، approximate 84%، while، for sandy-clay soil it was about 93 percents. Moreover، decreasing of elasticity module in sandy clay samples with 100% compaction and 13% moisture is approximately 51 percents.