边坡稳定性温度效应数值模拟研究

摘要

As the climate change,the property of rock and soil changes accordingly with environmental temperature changes.In this paper,the influence of temperature field on the stability of the slope by some manifestation mechanism.The direct shear test of cohesive soil under different temperature conditions is carried out to explore the change law of cohesion and internal friction angle.Furthermore, combine ANSYS(finite element software)with the measured geothermal data to simulate the evolution temperature field of slope. According to the field of temperature, cohesion field is calculated which can find distribution of the safety factor by using optimized swedish method. Through a series of laboratory tests, it is found that the cohesive force of Xiashu is affected by temperature. Soil moisture content and density affect the soil showing thermal consolidation or thermal softening phenomenon. The evolution in temperature field of slope is simulated by ANSYS during the high temperature in summer of Nanjing suburb.The variation law of slope stability index is deduced.The results show that the slope stability is lower in summer hot temperature environment,and the safety factor of urban slope is lower.The heat island environment has a negative effect on the stability of slope.%气候变化引起环境温度改变,岩土体的性质随之产生相应变化.文章分析了温度对边坡稳定性产生的影响,于不同温度状况下开展粘性土直剪试验,探究粘聚力及内摩擦角随温度变化的特征.进一步利用有限元软件ANSYS结合实测地温数据模拟边坡温度场演变过程,基于试验结果将温度场推导出粘聚力场,利用瑞典条分法结合粘聚力分布特征求得边坡安全系数.通过一系列室内试验发现,下蜀土粘聚力受温度影响变化规律较为明显;土体含水量和密度不同使土体随温度升高相应的产生热软化或热固结现象.通过ANSYS模拟南京城郊边坡夏季高温期间温度场的演变,推算出了边坡安全系数的变化规律.结果表明,对于高含水量的土体,在夏季高温环境下边坡稳定性降低,而城区温度更高相应边坡的安全系数通常更低,高温对边坡稳定性具有负面作用.