极端降雨条件下灰渣坝渗流与变形特性分析

Analysis of Seepage and Deformation Characteristics of Ash Dam Under Extreme Rainfall

灰渣坝为贮灰场的控制性工程,若灰渣坝发生溃坝将造成极大的工程事故,而极端降雨对贮灰场的安全有严重影响。对此,以许家沟贮灰场为例,采用有限元瞬态流固耦合计算方法,分析灰渣坝在极端降雨条件下的渗流和变形规律。结果表明,当降雨强度较大时,随着降雨量的逐渐增加,坝坡下部孔压显著升高、有效应力降低,坝体产生显著的卸载回弹现象。其中,二级子坝由于处于一级、三级子坝的中间,排水条件最差,强降雨过程中,孔压最大,回弹量最大。当降雨强度降至一定程度时,子坝孔压逐渐降低,坝坡回弹量降低。结合该灰场现场情况,二级子坝坝坡出现显著隆起,验证了有限元分析结果。

Ash dam is a control project of ash storage yard.If ash dam breaks,it will lead to serious engineering accidents.Extreme rainfall has a significant impact on the safety of ash yard.The Xujiagou ash storage yard is taken as the example.The seepage and deformation characteristics of ash dam under extreme rainfall conditions are analyzed by using the transient fluid solid coupling calculation method of finite element.The results show that when the rainfall intensity is large,with the gradual increase of rainfall,the pore pressure at the lower part of the dam slope increases significantly,the effective stress decreases,and the significant unloading rebound phenomenon occurs.Among them,the secondary sub dam is located in the middle of the first and third sub dams,so the drainage condition is the worst.In the process of heavy rainfall,both of the pore pressure and the rebound are the largest.When the rainfall intensity decreases to a certain extent,the pore pressure of the sub dam gradually decreases and the rebound amount of the dam slope decreases.Combined with the site conditions of the ash yard,the slope of the second sub dam is significantly uplifted,which verifies the results of the finite element analysis.