The main objective of this study was to determine the desiccation behavior of clay slurries. A clay slurry with high water adsorption capacity(W_L = 180%,W_P 60%,W_s = 20) was used to determine the soil water characte...The main objective of this study was to determine the desiccation behavior of clay slurries. A clay slurry with high water adsorption capacity(W_L = 180%,W_P 60%,W_s = 20) was used to determine the soil water characteristic curve(SWCC), shrinkage curve, and hydraulic conductivity. The last parameter was determined similar to the Instantaneous Profile Method using evaporation tests. Results indicated that the clay slurry had an air entry value(AEV) of 1000 kPa and a residual suction of 5000 kPa that occurred at the plastic limit and the shrinkage limit, respectively. The discrepancy between theoretical and measured shrinkage limit was due to the gradual increase in clay particle contact. Unlike soils, the saturated hydraulic conductivity varied by two orders of magnitude(4×10 ~10 m/s at 20 kPa to 3 x 10 ~12 m/s at AEV). The unsaturated k further decreased to 10 ~14 m/s at 6 x 10~4 kPa beyond which vapor flow took place.展开更多
The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and be...The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.展开更多
This paper investigates the geotechnical behavior of uranium mill tailings from Saskatchewan, Canada.The 4% tailings were well-graded with 29% fines whereas the 5% and 6% tailings were gap-graded with 49% fines. All s...This paper investigates the geotechnical behavior of uranium mill tailings from Saskatchewan, Canada.The 4% tailings were well-graded with 29% fines whereas the 5% and 6% tailings were gap-graded with 49% fines. All samples exhibited a negligible strength(0.4 k Pa) up to 60% solids, followed by a rapid increase. The 4% tailings exhibited a lower rate and amount of settlement than 5% and 6% tailings. The kidecreased from 10^(-2)to 10^(-4)m/s with a decrease in eifrom 16 to 4 and a decrease in ef from 8 to 4 such that 4% tailings showed one order of magnitude lower values than the 5% and 6%tailings. The settling potential decreased ten times(50%–5%) for 4% tailings and four times(60%–15%)for 5% and 6% tailings. The effective stress increased from 80 to 260 Pa in the settling tests. The 4%tailings were less prone to segregation when compared with 5% and 6% tailings. The average solids content after settling was 35% for 4% tailings, 40% for 5% tailings and 39% for 6% tailings with a solids content deviation of ±3%, ±8%, ±6%, respectively. All materials were essentially non-segregating at 40%initial solids.展开更多
基金the Natural Sciences and Engineering Research Council of Canada for providing financial assistance
文摘The main objective of this study was to determine the desiccation behavior of clay slurries. A clay slurry with high water adsorption capacity(W_L = 180%,W_P 60%,W_s = 20) was used to determine the soil water characteristic curve(SWCC), shrinkage curve, and hydraulic conductivity. The last parameter was determined similar to the Instantaneous Profile Method using evaporation tests. Results indicated that the clay slurry had an air entry value(AEV) of 1000 kPa and a residual suction of 5000 kPa that occurred at the plastic limit and the shrinkage limit, respectively. The discrepancy between theoretical and measured shrinkage limit was due to the gradual increase in clay particle contact. Unlike soils, the saturated hydraulic conductivity varied by two orders of magnitude(4×10 ~10 m/s at 20 kPa to 3 x 10 ~12 m/s at AEV). The unsaturated k further decreased to 10 ~14 m/s at 6 x 10~4 kPa beyond which vapor flow took place.
基金the University of Regina for providing laboratory space and the Natural Science and Engineering Research Council of Canada for financial assistance
文摘The main objective of this study was to determine the consolidation behaviour of clay slurries.A finegrained clay with high consistency limits(W_L = 180%,w_P= 120%) was investigated using conventional oedometer and bench-top centrifuge tests.Results indicated that the slurry had an apparent preconsolidation(due to initial conditions,electrochemical interactions,tortuous drainage,and thixotropic strength) from e = 5.7 to e = 5.5 followed by virgin compression.Likewise,the low hydraulic conductivity(10^(-10)-10^(-12) m/s) was due to low porosity(small pore throats) and high tortuosity(long flow paths).Unlike consolidation of soils,the c_v and m_v decreased with increasing σ' but increased with increasing e and k.The data from the two tests correlated well in the range of σ' = 10-65 kPa,e = 5.5-3.86,k= 1.7 × 10^(-10)-5×10^(-11) m/s,F_c = 1-40 MN.New equations were developed to correlate the consolidation parameters(e,σ',k) with F_c.The deviation of k beyond 40 MN(e = 4.65) was due to deviation from the initial straight line portion of the settlement curve in the centrifuge test.
基金the University of Regina for providing laboratory space and computing facilitiesCameco Corporation for material and financial support
文摘This paper investigates the geotechnical behavior of uranium mill tailings from Saskatchewan, Canada.The 4% tailings were well-graded with 29% fines whereas the 5% and 6% tailings were gap-graded with 49% fines. All samples exhibited a negligible strength(0.4 k Pa) up to 60% solids, followed by a rapid increase. The 4% tailings exhibited a lower rate and amount of settlement than 5% and 6% tailings. The kidecreased from 10^(-2)to 10^(-4)m/s with a decrease in eifrom 16 to 4 and a decrease in ef from 8 to 4 such that 4% tailings showed one order of magnitude lower values than the 5% and 6%tailings. The settling potential decreased ten times(50%–5%) for 4% tailings and four times(60%–15%)for 5% and 6% tailings. The effective stress increased from 80 to 260 Pa in the settling tests. The 4%tailings were less prone to segregation when compared with 5% and 6% tailings. The average solids content after settling was 35% for 4% tailings, 40% for 5% tailings and 39% for 6% tailings with a solids content deviation of ±3%, ±8%, ±6%, respectively. All materials were essentially non-segregating at 40%initial solids.
