排土场工后沉降及蠕变规律

采用Burgers模型对排土场散粒体蠕变的减速蠕变和等速蠕变两阶段进行描述,利用分层总和法的思想,将垂直填筑的排土场进行分层处理,底层在上覆“自重”变荷载作用下发生沉降变形,分别采用定常和非定常Burgers蠕变模型从理论解析角度推导排土场填筑动态过程中沉降、工后沉降及累计沉降计算公式.以齐大山铁矿排土场监测数据进行实例验算,应用结果表明：非定常Burgers模型和定常Burgers模型拟合的相关系数均较高,非定常Burgers模型沉降最终收敛于5.07 m,定常Burgers模型沉降曲线具有发散性,可见非定常Burgers模型能更好地表述排土场沉降真实工况；将排土场分为十个分层,结合FLAC3D软件的蠕变数值分析计算,得出各单层沉降率的变化规律,即各单层工后沉降量上层沉降值小于下层和中间层,且上层沉降量呈现单调递减变化,越接近排土场顶部单层沉降量越小；中间层沉降量相对下层沉降量要大,其中第5单层的沉降量最大.

Post-construction settlement and creep law of waste dumps

The grain body creep of waste dumps including deceleration creep and constant creep was described by the Burgers model. Using the layered summation method, the vertical filling waste dump was sliced and the bottom part settled under the variable weight load of the overlaid part. The computational formulas of settlement in the waste dump filling dynamic process, post-construction settlement and cumulative settlement were derived from theoretical analysis though the steady and unsteady Burgers creep models. The monitoring data of Qidashan Iron Mine were used as a case of proofing. The results show that the correlation coefficients of fitting with both the unsteady and steady Burgers models are high, and the final settlement value of the former is 5. 07 m, while the settlement curve of the latter is divergent, thus the unsteady Burgers model performs better in simulating the real working condition of mine sub-sidence. The waste dump was divided into ten layers and the settle rate of each layer was calculated by the creep simulation model in Flac3D. The post-construction settlement of the top layers is smaller than that of the middle layers and bottom layers, the settlement of the top layers decreases when getting closed to the upper surface of the waste dump. The settlement of the middle layers is larger than that of the bottom layers, and the fifth layer performs a largest settlement.