低含水率砂质边坡稳定特性机理分析

Study on Stability Analysis of Sandy Slope with Low Moisture Content

含水率对边坡的稳定性有重要影响。文中通过对砂质边坡模型进行含水率测量和直剪试验,分别对砂质边坡含水率的变化规律、含水率对砂土的抗剪强度指标及边坡安全系数的影响进行研究。结果发现,砂质边坡表层充满水分后,在30 min之前,水分迅速向内层渗流,30 min之后,砂质边坡中的水分大致以坡顶为中心向外扩散的弧状分布,含水率由坡顶至内层和坡脚逐次增大。含水率在12%以下时,砂土的内摩擦角φ随含水率增大而减小,粘聚力c随含水率增大而增大,当砂质边坡的含水率由0增大至9%、10%、11%和12%时,用瑞典条分法计算求得的安全系数变化了-5.9%、-3.6%、0和10.3%,Bishop法计算的安全系数变化了-2.8%、-0.4%、2.4%和12.6%,Bishop法求得的安全系数均比瑞典条分法分别高3.4%、3.3%、2.4%和2.2%,两种计算方法求得的安全系数变化趋势一致,研究成果可为砂质边坡的稳定分析提供理论依据。

Moisture content is an important factor affecting slope stability.Based on the measurement of moisture content of sandy slope model and direct shear test,the variation law of moisture content of sandy slope and the influence of moisture content on shear strength index and safety factor of slope were studied respectively.Test results indicated that after the surface layer of sandy slope was full of water,the water quickly seept into the inner layer before 30 min.after 30 min,the moisture content in the sandy slope was distributed in an arc shape with the top of the slope as the center,and the moisture content increased gradually from the top to the inner layer and the foot of the slope.When the moisture content was below 12%,theφof sand decreased with the increase of moisture content,but the c increased.When the moisture content of sandy slope increased from 0 to 9%,10%,11%and 12%,the safety factors calculated by Felenius method changed by-5.9%,-3.6%,0 and 10.3%,and those calculated by Bishop method changed by-2.8%,-0.4%,2.4%and 12.6%.The safety factor calculated by Bishop method was 3.4%,3.3%,2.4%and 2.2%higher than that of Felenius method respectively.The change trend of safety factor obtained by two calculation methods was consistent.The research results can provide theoretical basis for stability analysis of sandy slope.