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土体重度、强度和膨胀力是与含水率相关联、且直接影响膨胀土边坡稳定性的三类主要因素。为量化分析其作用效应,基于条分法建立稳定性计算力学模型并依托某膨胀土路堑边坡工程,研究与含水率相关联的三类因素对边坡稳定系数的影响机理,探讨了各影响因素对稳定系数的敏感度大小。分析表明:随含水率上升,重度、强度和膨胀力分别呈线性增加、急剧衰减和渐缓型减小变化规律,稳定系数相应呈先缓后陡的下降趋势,当含水率小于塑限时土坡稳定系数较高,超过塑限后稳定性急剧下降并迅速达到失稳临界状态;考虑膨胀力的稳定系数比忽略时小18%~40%,且侧向、竖向膨胀力之比越小,土条底部的膨胀应力分解产生的切向下滑分量越大,边坡稳定系数相对越小;三类因素的作用效应中,土体软化是导致失稳的最主要因素,随含水率上升,膨胀力效应和增重效应分别约为总效应的10%~20%和20%~30%。
Soil mass, strength and expansive force are the three main factors that are directly related to the water content and directly affect the stability of the expansive soil slope. In order to quantify and analyze its effect, a stability calculation mechanics model was established based on the bar method and the influence mechanism of three factors related to water cut on the slope stability was studied based on the engineering slope slope of expansive soil. The sensitivity of factors to the stability factor. The analysis shows that with the increase of water cut, the intensity, intensity and expansive force increase linearly, decay rapidly and decrease slowly, respectively. The stability coefficient decreases first and then steeply. When the moisture content is less than the plastic limit The stability coefficient is high, the stability falls sharply beyond the plastic limit and quickly reaches the critical state of instability; the stability coefficient considering the expansion force is 18% ~ 40% less than that when ignored, and the smaller the ratio of lateral expansion force and vertical expansion force, The greater the tangential sliding component caused by the expansive stress decomposition at the bottom of soil strip is, the smaller the slope stability coefficient is. The softening of the soil is the most important factor leading to instability in the effect of the three kinds of factors. With the increase of moisture content, The effect of force and weight gain are respectively about 10% ~ 20% and 20% ~ 30% of the total effect.