Investigation on the Effect of Curing Time on Uni-Axial Strength of Clayey Soils Strengthened by Saturated Lime Solution
This paper describes some of the main results of an investigation on the effect of passing saturated lime solution with different curing time on the clayey soil. Six series of laboratory tests had been set up, on lean clay samples, to investigate simultaneously the effect of volume of solution and curing time. The samples were classified based on average volume of passing. Three categories were considered, 19Vv, 28Vv and 40Vv. The volume of the saturated solution was fixed and all of the samples were held in a chamber with desired condition of temperature and humidity for different curing period, followed by a mechanical and chemical test. The findings released from the tests indicated that the length of curing period and volume of saturated lime solution at which curing took place had an important influence on the amount of strength developed. An exponential evolution was found for the uni-axial strength as a consequence of the curing time. Especially after 28 days. Calcium ion consumption after 28 days and also exponential evolution for uni-axial strength demonstrated the threshold value of curing period of 28 days for treatment of soil by saturated lime solution.
Increase in basin sediment yield from landslides in storms following major seismic disturbance
The landslide area along the Tachia River catchment of central Taiwan was investigated using the remote sensing images of various typhoon and earthquake events taken from 1996 to 2004 and the sediment discharge measured at hydrometric stations. Our findings indicate that 88% of the coseismic landslides triggered by the 1999 Chi-Chi earthquake were first-time occurrences. After the Chi-Chi earthquake, 59% of the landslide area was reactivated during typhoon Toraji and 66% during typhoon Mindulle. The landslides prone to reactivation were on the formations with closely spaced discontinuities. It is suggested that further rock-mass defects in the formations were added or opened by the earthquake, and that the landslide areas continued to extend until the end of 2004. Post-1999 rainstorms delivered large amounts of colluvial sediment into the main channel, leading to a 2-fold increase in post-seismic sediment discharge while the precipitation was only half that of the pre-earthquake rate.
Genetic Effects of Acute and Chronic Ionizing Irradiation on Pinus sylvestrisL. Inhabiting the Chernobyl Meltdown Area
The main results of the 12-year radiation-genetic monitoring of radiobiological, cytogenetic, and genetic parameters in Pinus sylvestrisforest plantation from the Chernobyl meltdown area are presented. The acute ionizing irradiation at doses > 1 Gy was shown to induce formation of morphoses and depressed growth; at doses >2 Gy, the reproductive ability of the trees declined. The radiobiological parameters showed a linear or close to linear dose-dependence relationship. The acute irradiation at a dose of 0.5 Gy induced cytogenetic and genetic effects that were significantly higher than the corresponding control values. The relationship between the cytogenetic effects and the absorbed dose was exponential. The dependence of the mutation frequency at specific loci on the absorbed dose was described by a nonlinear curve. The results of cytogenetic analysis of seedlings obtained from seeds annually collected in zones of slight, moderate, and strong damage of Pinus sylvestrisL. are presented.