基于Geo-studio的尾矿坝渗流及地震动力响应研究

利用Geo-studio软件, 对尾矿坝的稳态渗流和地震动力响应进行了计算。结果表明, 2个计算断面在正常水位和洪水位运行时的浸润线埋深均较浅, 坝体自由面较高, 水力坡降值在初期坝下游靠近坝基部位最大, 超过规范值, 水从初期坝坝面溢出, 可能发生流土或管涌; 动力加速度在2个断面均未呈现明显放大, 动应力只在局部区域出现较大值, 坝体整体动力稳定性较高; 地震响应下, 最终坝高不发生液化, 二级子坝库区局部发生液化, 坝体整体不会出现液化造成的动力破坏。鉴于初期坝下游坝基水力坡降较大, 建议采取坝体深部排水措施(如水平排水管、辐射井等), 降低坝体的自由面, 提高坝体稳定性, 有效杜绝渗透破坏乃至溃坝事件。

Seepage Calculation and Seismic Dynamic Response Analysis for A Tailings Dam Based on Geo-studio

The steady state seepage and seismic dynamic response of tailings dam were calculated by using Geo-studio software. Results illustrate that the cover depth of the phreatic line is relatively shallow for two calculated sections in case of normal water level and flood level, and the dam has a higher free face. Hydraulic gradient is maximum at downstream of the starter dam close to the foundation,exceeding the normative values. The water overflows from the surface of the starter dam, which possibly results in soil flow or piping. Dynamic acceleration of two sections shows no significant amplification, and a larger dynamic stress only occurs in local area, leading to overall dam with relatively high dynamic stability. Under the circumstances of seismic dynamic response, liquefaction won't occur at the final height of the dam, but occur in the part areas of sub-dam reservoir (second level), without any dynamic failure occurred to the overall dam due to liquefaction. In view of the larger hydraulic gradient at downstream of the starter dam, it is suggested that the measures of draining at the deep part of dam body (such as horizontal drainage pipes, radial well, etc) shall be taken to bring down the free face of the dam, resulting in the dam with an improved stability. Thus those safety event including seepage and failure of the dam, even more serious dam breaks can be effectively prevented.