降雨工况下露天矿排土场边坡稳定性与治理措施

Stability and control measures of open-pit mine dump slope under rainfall conditions

为了研究河曲旧县露天煤矿内排土场边坡在降雨饱水工况下的稳定性状态以保证边坡体西侧选煤厂等建筑物的安全,首先,利用FLAC3D软件采用强度折减法确定了其潜在滑移面,并通过FISH语言建立了潜在滑移面的拟合模型,利用极限平衡计算软件Geo-slope分析计算了现状边坡与终了排弃边坡在自然工况和暴雨工况下的整体稳定性,其次,对边坡体采用不同压脚参数的各个工况条件进行模拟计算,得到不同条件下的安全系数与滑体剪出口位置。研究结果表明:在自然工况下,现状边坡与终了排弃边坡都能达到稳定或基本稳定状态;而在暴雨工况下,边坡体基底出现弱层,同时坡体力学参数严重弱化,安全系数骤降,滑面与滑体范围扩大,滑体由从坡脚剪出扩大为从基底弱层剪出,各个典型剖面的安全系数与自然工况下相比降低20%~30%,失稳概率极大,根据排土场的具体情况确定采用压坡脚工艺提高排土场稳定性并优化了压脚高度与宽度工艺参数,采取宽度40 m、高度20 m的压脚方式确保边坡的稳定性。

In order to study the stability of the dump slope in the open-pit coal mine of Hequ Jiuxian under rainfall conditions to ensure the safety of buildings such as the coal preparation plant on the west side of the slope body,the FLAC3D software was used to determine the potential slip surface by the strength reduction method,and the fitting model of the potential slip surface is established by the FISH language.The ultimate stability calculation software geo-slope was used to analyze the overall stability of the current slope and the final abandoned slope under natural conditions and heavy rain conditions.Secondly,the simulation calculation is carried out for each working condition of the slope body using different presser foot parameters,and the safety factor under different conditions and the position of the sliding body shear outlet were obtained.The results show that under natural conditions,the current slope and the final abandoned slope can reach a stable or basically stable state.However,under heavy rain conditions,the base of the slope body has a weak layer,and the mechanical parameters of the slope are seriously weakened.The safety factor drops sharply,the range of the sliding surface and the sliding body expands,and the sliding body is cut from the foot of the slope to be cut out from the weak layer of the base.The safety factor of each typical section is reduced by 20%~30%compared with the natural working condition.The probability of stability is extremely large.According to the specific conditions of the dumping site,the slope foot process is used to improve the stability of the dumping field and optimize the process parameters of the height and width of the presser foot.Adopting a presser foot with a width of 40 m and a height of 20 m to ensure the stability of the slope.