不同降雨工况下的矿山修复工程边坡稳定性评价

Slope stability evaluation of mine rehabilitation project under different rainfall conditions

山体修复是目前环境工程的主要项目,回填形成的人工边坡填土较为松散,极易受到降雨强度的影响,导致边坡失稳。联合采用数值模拟技术以及现场监测技术对顶冠峰山体修复形成的人工边坡进行稳定性分析,通过建立准确的地质模型,定义材料参数、设定边界条件,得出边坡在设置的4种不同降雨工况条件下的稳定性系数,模拟边坡在不同条件下渗流场的变化特征,分析边坡在不同条件下的变形分布特征。在现场建立了实时监测云平台,对现场填土边坡的地表水平位移与深层水平位移进行监测,最后与数值模拟分析得到的结果进行对比,定量评价不同工况下的边坡稳定性。研究结果表明,填土边坡在不同降雨工况下的稳定性系数均大于临界面滑动的安全系数,在不同工况下,边坡坡角处部分与靠近坡面部分孔隙水压力上升较大,坡体前缘和坡面陡峭处多发育渗水通道,降雨对此处的稳定性影响也相对较大,随着降雨强度的加剧,边坡中下部的最大水平位移逐渐增加,相同时间内渗透到边坡的降水量增多,导致抗剪强度显著下降,从而使得产生较大水平位移的区域范围扩展,并逐渐向坡体前后缘延伸,通过将数值模拟结果与现场监测得到的数据进行对比,发现两者具有较好的一致性,边坡基本处于稳定状态。因此,今后对于数值模拟分析产生的数据,应与现场监测数据相结合,对工程稳定性进行更加全面的评价。

[Objective]Mountain restoration is currently one of the major projects in environmental engineering.The backfill formed in artificial slopes is relatively loose and highly susceptible to the impact of rainfall intensity,leading to slope instability.[Methods]In this study,a combination of numerical simulation method and onsite monitoring technology was used to analyze the stability of artificial slopes formed during the restoration of Dingguanfeng Mountain.By establishing precise geological models,defining material parameters,and setting boundary conditions,the stability coefficients of the slope under the four different rainfall working conditions set were obtained,and the distribution characteristics of the seepage field and deformation field of the slope under different conditions were simulated.A real-time monitoring cloud platform was established on the site to monitor the surface horizontal displacement and deep horizontal displacement of the fill slope on site.The monitoring results were compared with those obtained from numerical simulation to quantitatively assess the slope stability under different working conditions.[Results]The results indicate that the stability coefficients of the fill slope under different rainfall conditions are greater than the critical factor for interface sliding.Under various working conditions,the pore water pressure at the slope toe and the portion close to the slope surface increases considerably.Seepage channels are mostly developed at the front edge of the slope body and the steep areas of the slope surface,and the stability of these areas is relatively more affected by rainfall.With the increase in rainfall intensity,the maximum horizontal displacement in the middle and lower parts of the slope gradually enlarges.The greater the amount of rainfall infiltrating into the slope within the same time,the more significant the reduction in shear strength,the larger the area with large horizontal displacement,and it gradually extends towards the front and rear edges of the slope.By comparing the numerical simulation results with the data obtained from on-site monitoring,it is discovered that there is a good consistency between them,and the slope is basically in a stable state.[Conclusion]Henceforth,for the data generated from numerical simulation analyses,they should be combined with on-site monitoring data to conduct a more comprehensive assessment of the engineering stability.