基于修正的传递系数法的粉土质边坡冻融稳定性分析

Stability Analysis of Freeze-thaw Silty Soil Slope Based on Modified Transfer Coefficient Method

为了给冻融边坡的稳定系数计算方法提供更多的有效途径,以G580线和田至康西瓦公路段K81+100粉土边坡为研究对象,从冻融边坡的特征入手,考虑边坡融化后的渗透力,以及热流量对融化深度的影响。对传递系数法进行修正,推导出冻融边坡稳定系数的计算公式。通过具体条件分析不同温度变化下融化深度与稳定系数的关系,得出融深1.2 m时边坡稳定性最差。基于日气温变化正弦函数公式分析,得出上午7~10时稳定系数降低幅度最大,约7.2%;14时的时候达到每日最大融深,稳定系数降至最小值1.255。通过改变粉土含水率发现当含水率大于20%,边坡开始处于最不稳定状态。最后利用Flac3D建立温度场模拟土体冻结融化的情况,得出边坡稳定系数为1.281,在水的渗流和自重情况下,竖直方向在坡体上缘发生约53.5 mm的最大位移,水平方向在滑体中下部发生约82.6 mm的最大位移。模拟数据与现实情况吻合良好,为冻融区粉土边坡稳定性研究提供了理论依据。

In order to provide more effective ways to calculate the stability coefficient of freeze-thaw slope,take the G81 line and the K81+100 silt slope of the Hetian-Kangxiwa highway section as the research object,starting from the characteristics of the frozen-melt slope,consider the side After the slope is melted,and the influence of heat flow on the melting depth,the transfer coefficient method is modified t-o derive the formula for calculating the stability coefficient of the frozen-thaw slope.The relationship between the melting depth and the stability coefficient under different temperature changes is analyzed by specific conditions,and the stability of the slope is the worst when the depth is 1.2 m.Based on the analysis of the sinusoidal function of the daily temperature change,the stability coefficient of the 7:00 to 10:00 am is the largest,about 7.2%.At 14 o’clock,the maximum daily penetration is reached,and the stability coefficient is reduced to a minimum of 1.255.By changing the moisture content of the silt,it is found that when the water content is greater than 20%,the slope begins to be in the most unstable state.Finally,using Flac3 D to establish the temperature field to simulate the freezing and melting of the soil,the stability coefficient of the slope is 1.281.Under the condition of water seepage and self-weight,the vertical displacement of the upper edge of the slope is about 53.5 mm,and the horizontal direction is the maximum displacement of about 82.6 mm occurs in the middle and lower part of the sliding body.The simulation data is in good agreement with the actual situation,which provides a theoretical basis for the stability study of silt slope in the freezing and thawing research.