为了解决冻融循环下排土场软岩边坡稳定性问题，基于内蒙古地区的露天矿散体软岩在排土场堆载之后受冻融循环的影响，其排土场边坡局部台阶上出现坡顶岩体崩落及单台阶滑坡现象为研究背景，对散体软岩物料进行颗粒级配及试样制备试验，进行了散体软岩物料的冻融循环和剪切破坏试验，定量分析了散体软岩物料的抗剪强度、黏聚力及内摩擦角与冻融循环次数、含水率间变化关系，提出了抗剪强度与冻融循环次数、含水率的关系的指数表达式和冻融循环边坡的时效稳定性计算公式，揭示了冻融循环下的排土场散体软岩边坡的时效性变化规律。试验结果表明：不同正应力下，散体软岩物料破坏时的抗剪强度随冻融循环次数的变化表现出相似的规律且呈指数型破坏模式，黏聚力及内摩擦角都随冻融循环次数的增加呈指数型衰减；含水率越高，其黏聚力与内摩擦角的弱化幅度都越大，且黏聚力的弱化幅度比内摩擦角的大，两者在冻融循环6次后趋于稳定值；排土场散体软岩边坡受冻融影响具有时效性，散体软岩堆积后的新边坡在初次受冻后岩土黏聚力、内摩擦角等会迅速受到弱化，造成堆积形成之后稳定性系数急剧下降，随着冻融循环周期年数的延长，稳定系数的下降速率逐渐降低，且在6～7 a之后边坡趋于稳定。

In order to solve problem of stability of waste dump under the freeze-thaw cycle,based on the influence of freeze-thaw cycle on the waste dump of open-pit mine in Inner Mongolia,the phenomenon of rock collapse at the top of the slope and single step landslide on the local steps of dump slope was studied.Grain grading and sample preparation tests were carried out for the materials. Freeze-thaw cycle and shear failure tests were carried out for the materials. The relationship between shear strength,cohesion and internal friction angle of the materials and freeze-thaw cycle times and moisture content was quantified. The exponential expression of the relationship between shear strength and freeze-thaw cycle times and moisture content and the aging stability of the frozen thaw cycle slope were put forward.The calculation formula reveals the regularity of time effect change of loose soft rock slope in dump under freeze-thaw cycle. The results show that under different normal stress,the shear strength of bulk soft rock material changes with the number of freeze-thaw cycles in a similar pattern,and the cohesion and internal friction angle decrease exponentially with the increase of the number of freeze-thaw cycles; the higher the moisture content,the greater the weakening range of cohesion and internal friction angle,and the weakening range ratio of cohesion When the internal friction angle is large,they tend to be stable after six freeze-thaw cycles; when the loose soft rock slope in the waste dump is affected by freeze-thaw,it is time-dependent; when the loose soft rock is accumulated,the new slope will be weakened rapidly after the initial freeze-thaw,resulting in a sharp decline in the stability coefficient after the accumulation. With the extension of the freeze-thaw cycles,the stability will be stable The decline rate of coefficient decreases gradually,and the slope tends to be stable after 6-7 years.

0 引言

1 试验概述

   1.1 试样的选取与制备

   1.2 试验方案

2 抗剪特性劣化结果分析

   2.1 抗剪强度与冻融循环次数的关系

   2.2 黏聚力和内摩擦角与冻融循环次数的关系

3 冻融循环边坡时效性分析

   3.1 冻融循环边坡时效性计算公式

   3.2 冻融循环边坡的时效稳定性变化规律

4 结论