| dc.description.abstract | First, static triaxial tests were carried out to realize the basic properties of sand. From the experimental results, it is revealed that the peak deviator stress is reached when the axial strain of specimen is about 2.1% under various efficient confined pressures from 98kPa to 294kPa. As we can observe from the stress-strain curve and pore water pressure-curve that are obtained by moist tamping method and undrained triaxial axial compression test, the deviator stress begins to decrease and reaches to a residual stress after the peak point. The test result also shows that the shear stress and volume of the specimens reach to the unchangeable value when the value of strain is about 12%. Therefore, in this study, the determination of stability point is obtained from the last value before test.
Second, the course of the excess pore water pressure increased in the treated sand specimens is similar with various curing period, and the excess pore water pressure increases to the direction of positive value when the specimens are compressed under cyclic deviator stress;on the other hand, the excess pore water pressure increases to the direction of negative value when the specimens are decompressed under cyclic deviator stress; Finally the specimens are destroyed in final stage. Meanwhile, the excess pore water pressures become larger negative value. Above mentioned, the untreated sand differs from the treated sand in which the excess pore water pressure increases gradually to the direction of negative value.
Last, with increasing curing period of the sand specimens, the liquefaction resistance of treated soil increase. The results are observed as followed: the liquefaction resistance in 28 days is 36% higher than that in 7 days; the liquefaction resistance in 14 days is 13% higher than in 7 days. On the whole, the liquefaction resistance of treated soil is 4.4~4.6 times higher than that of untreated soil increase when the curing period are classified into three broad categories-7, 14, and 28 days. | en_US |