Preconsolidation stress （ σP） is the maximum effective stress that a soil has suffered throughout its life. From a geotech- nical point of view, pre-consolidation stress has great importance because it separates el...Preconsolidation stress （ σP） is the maximum effective stress that a soil has suffered throughout its life. From a geotech- nical point of view, pre-consolidation stress has great importance because it separates elastic and reversible deformations from inelastic and only partially irreversible deformations and marks the starting point of high compressibility. In this study we calculated the preconsolidation stress for 72 undisturbed soil samples from the Yellow River Delta, using the oedometer test and applying the method proposed by Casagrande. The results showed that the over-consolidation ratio （OCR-the ratio of pre-consolidation stress to current natural overburden stress） values of the soil from soil surface to 6m depth varied from 1.72 to 15.34 and the maximum pre- consolidation stress was above 200 kPa. In consequence, the soils of the Yellow River Delta are highly over-consolidated within the upper 6m, the OCR decreasing gradually with depth from 6 to 12m. For samples from deeper than 12m the soils were found to be under-consolidated, which was proved by standard penetration tests （SPTs）. The main causes of this type of consolidation are the mineral composition and the designability of the soil body.展开更多
Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of cloggin...Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of clogging process on permeability of loose dam foundation of plateau reservoir.Through laboratory test,the soil can cause clogging effect by itself,and the effect of clogging is relative to the water pressure.The clogging effect can be caused obviously by adding fine particles,and the clogging effect of the particles with 0.063-0.25 mm diameter is best,which verifies the rationality of the optimal diameter interval.It provides the realistic significance for the anti-seepage of the plateau reservoir dam foundation.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 40472137 and 40606020)
文摘Preconsolidation stress （ σP） is the maximum effective stress that a soil has suffered throughout its life. From a geotech- nical point of view, pre-consolidation stress has great importance because it separates elastic and reversible deformations from inelastic and only partially irreversible deformations and marks the starting point of high compressibility. In this study we calculated the preconsolidation stress for 72 undisturbed soil samples from the Yellow River Delta, using the oedometer test and applying the method proposed by Casagrande. The results showed that the over-consolidation ratio （OCR-the ratio of pre-consolidation stress to current natural overburden stress） values of the soil from soil surface to 6m depth varied from 1.72 to 15.34 and the maximum pre- consolidation stress was above 200 kPa. In consequence, the soils of the Yellow River Delta are highly over-consolidated within the upper 6m, the OCR decreasing gradually with depth from 6 to 12m. For samples from deeper than 12m the soils were found to be under-consolidated, which was proved by standard penetration tests （SPTs）. The main causes of this type of consolidation are the mineral composition and the designability of the soil body.
基金Supported by Project of the National Natural Science Foundation of China(No.41072197)
文摘Taking Zhuoyu reservoir in Shannan of Tibet as the test site,the authors collected soil samples for laboratory analysis,and devised infiltration-clogging equipment for laboratory test to research the effect of clogging process on permeability of loose dam foundation of plateau reservoir.Through laboratory test,the soil can cause clogging effect by itself,and the effect of clogging is relative to the water pressure.The clogging effect can be caused obviously by adding fine particles,and the clogging effect of the particles with 0.063-0.25 mm diameter is best,which verifies the rationality of the optimal diameter interval.It provides the realistic significance for the anti-seepage of the plateau reservoir dam foundation.
