Soil slope stability in seasonally frozen regions is a challenging problem for geotechnical engineers.The freezethaw process of soil slope caused by the temperature fluctuation increases the difficulty in predicting t...Soil slope stability in seasonally frozen regions is a challenging problem for geotechnical engineers.The freezethaw process of soil slope caused by the temperature fluctuation increases the difficulty in predicting the slope stability because the soil property is influenced by the freeze-thaw cycle.In addition,the frozen soil,which has ice crystal,ice lens and experienced freeze-thaw process,could present stronger heterogeneity.Previous research has not investigated the combined effect of soil heterogeneity and freeze-thaw cycle.This paper studies the influence of soil heterogeneity on the stability of frozen soil slope under freeze-thaw cycles.The local average subdivision(LAS)is utilized to model the soil heterogeneity.A typical slope geometry has been chosen and analysed as an illustrative example and the strength reduction method is used to calculate the factor of safety(FOS)of slope.It has been found that when the temperature is steady,the FOS of the frozen soil slope is influenced by the spatial variability of the thermal conductivity,but the influence is not significant.When the standard deviation and the SOF of the thermal conductivity increase,the mean of the FOS is equal to the FOS of the homogeneous case and the standard deviation of the FOS also increases.After the frozen soil goes through freeze-thaw process,the FOS of the frozen soil slope decreases due to the reduction in the cohesion and the internal friction angle caused by the freeze-thaw cycles.Furthermore,the decreasing ratio of the FOS becomes more scattered after the 5th freeze-thaw cycle compared to that of the FOS after the 1st freeze-thaw cycle.The larger variability of the FOS could induce inaccuracy in the prediction of the frozen soil slope stability.展开更多
To simplify the stability analysis of frozen soil slope, a pseudo-coupled numerical approach is developed. In this approach, the coupled heat transfer and water flow in frozen soils are simulated first, and based on t...To simplify the stability analysis of frozen soil slope, a pseudo-coupled numerical approach is developed. In this approach, the coupled heat transfer and water flow in frozen soils are simulated first, and based on the computed thermal-hydro field, the stability of frozen soil slope is evaluated. Although the shear strength for frozen soil is very complicated and is usually represented by a nonlinear MC failure criterion, a simple linear MC yield criterion is utilized. In this method, the internal friction angle is expressed as a function of volumetric ice content and the cohesion is fitted as a simple bilinear expression of Tand volumetric water content. To assess slope stability, the limit analysis is employed in conjunction with the recently developed a-section search algorithm. A frozen soil slope example is used to examine the proposed pseudo-coupled numerical approach, and numerical studies validate its effectiveness. Based on numerical results, it is seen that slope stability may be remarkably influenced by warming air （or grotmd surface） temperature. With increasing ground surface temperature, slope stability indicated by FOS may reduce to 1.0, implying that wanning air temperature could be a trigger of frozen soil slope failure.展开更多
基金The research is supported by the Natural Science Foundation of Anhui Province(Grant No.1908085QE242)the Fundamental Research Funds for the Central Universities(Grant No.JZ2021HGTB0097)the Natural Science Foundation of China(NSFC)(Grant No.51908175).The financial support is gratefully acknowledged.
文摘Soil slope stability in seasonally frozen regions is a challenging problem for geotechnical engineers.The freezethaw process of soil slope caused by the temperature fluctuation increases the difficulty in predicting the slope stability because the soil property is influenced by the freeze-thaw cycle.In addition,the frozen soil,which has ice crystal,ice lens and experienced freeze-thaw process,could present stronger heterogeneity.Previous research has not investigated the combined effect of soil heterogeneity and freeze-thaw cycle.This paper studies the influence of soil heterogeneity on the stability of frozen soil slope under freeze-thaw cycles.The local average subdivision(LAS)is utilized to model the soil heterogeneity.A typical slope geometry has been chosen and analysed as an illustrative example and the strength reduction method is used to calculate the factor of safety(FOS)of slope.It has been found that when the temperature is steady,the FOS of the frozen soil slope is influenced by the spatial variability of the thermal conductivity,but the influence is not significant.When the standard deviation and the SOF of the thermal conductivity increase,the mean of the FOS is equal to the FOS of the homogeneous case and the standard deviation of the FOS also increases.After the frozen soil goes through freeze-thaw process,the FOS of the frozen soil slope decreases due to the reduction in the cohesion and the internal friction angle caused by the freeze-thaw cycles.Furthermore,the decreasing ratio of the FOS becomes more scattered after the 5th freeze-thaw cycle compared to that of the FOS after the 1st freeze-thaw cycle.The larger variability of the FOS could induce inaccuracy in the prediction of the frozen soil slope stability.
基金supported in part by the Scientific Research Foundation for the 973 Program of China (No. 2012CB026104)Research Fund of Young Teachers for the Doctoral Program of Higher Education of China (No. 20110009120020)the Fundamental Research Funds of the Central Universities (No. 2013JBM059)
文摘To simplify the stability analysis of frozen soil slope, a pseudo-coupled numerical approach is developed. In this approach, the coupled heat transfer and water flow in frozen soils are simulated first, and based on the computed thermal-hydro field, the stability of frozen soil slope is evaluated. Although the shear strength for frozen soil is very complicated and is usually represented by a nonlinear MC failure criterion, a simple linear MC yield criterion is utilized. In this method, the internal friction angle is expressed as a function of volumetric ice content and the cohesion is fitted as a simple bilinear expression of Tand volumetric water content. To assess slope stability, the limit analysis is employed in conjunction with the recently developed a-section search algorithm. A frozen soil slope example is used to examine the proposed pseudo-coupled numerical approach, and numerical studies validate its effectiveness. Based on numerical results, it is seen that slope stability may be remarkably influenced by warming air （or grotmd surface） temperature. With increasing ground surface temperature, slope stability indicated by FOS may reduce to 1.0, implying that wanning air temperature could be a trigger of frozen soil slope failure.
