库水位骤降后面板缺陷坝体渗漏量和坝坡稳定性分析

为研究库水位变动情况下面板不同缺陷的面板堆石坝渗透稳定特性,利用著名岩土分析软件Geo-studio的Seep/w与Slope/w模块,以浙江省临海市西部括苍镇境内某面板堆石坝为例,对不同土工膜缺陷及库水位变动工况的组合进行了渗流特性及稳定性的数值模拟分析,得到了浸润线,渗漏量及稳定性系数的变化曲线,计算结果表明:(1)面板一旦发生缺陷,静库水位下坝体的浸润线有一个明显的抬升,缺陷尺寸越大,浸润线高程越高,但是差异不大。库水位高程越高,静库水位下坝体内部的浸润线高程也就越高;(2)库水位水平越高,缺陷尺寸越大,坝体渗漏量也就越大;(3)库水位骤降下面板坝内部浸润线呈现先疏后密的规律,库水位下降速率越大,上游坝体浸润线疏的部分则越疏。在库水位骤降经过面板坝缺陷高程时,有一个浸润线突降的过程;(4)从整体上看,上游坝坡的稳定性系数要大于下游坝坡的稳定性系数;静库水位下,库水位水平越高,上游坝坡稳定性系数越大,而下游坝坡稳定性系数则越小,缺陷位置越高,稳定性系数越低;库水位骤降情况下上游坝坡稳定性系数随库水位下降呈现先下降后上升的趋势,下游坝坡则呈现一直上升的规律,一旦面板发生缺陷,稳定性系数较完整面板来说有一个较大幅度的下降,面板缺陷尺寸越大,稳定性系数整体上越小。

Numerical simulation of seepage stability of slab dam with sudden drop of reservoir water level based on face plate defect

In order to study the seepage stability characteristics of face rockfill dam with different face slab defects under the condition of reservoir water level change,the Seep/w and Slope/w modules of the famous geotechnical analysis software Geo-studio are used.Taking a face rockfill dam in Jiecang Town,west of Linhai City,Zhejiang Province as an example,the seepage characteristics and stability of different geomembrane defects and reservoir water level are analyzed by numerical silulation,and the infiltration line is obtained.The results show that:(1)once the defect occurs in the face slab,there is an obvious uplift of the seepage line of the dam body under the static reservoir water level.And the size of the defect is larger.The higher the height of the infiltrating line,the smaller the difference.The higher the water level,the higher the height of the infiltration line inside the dam body under the static reservoir water level;(2)the higher the water level,the larger the defect size,the greater the leakage of the dam body;(3)under the sudden drop of reservoir water level,the inner soakage line of concrete face rockfill dam shows the law of thinning first and then dense.The larger the falling rate of reservoir water level is,the less the sparse part of the infiltration line of upstream dam body is.When the reservoir water level suddenly drops through the defective elevation of the face slab dam,there is a process of sudden decline of the infiltrating line;(4)the safety factor of the upstream dam slope is larger than that of the downstream dam slope as a whole;under the static reservoir water level,the higher the reservoir water level is,the higher the upstream water level is.The higher the safety factor of dam slope,the smaller the safety factor of downstream dam slope,the higher the defect location and the lower the safety factor.In the case of sudden drop of reservoir water level,the safety factor of upstream dam slope decreases first and then increases with the decrease of reservoir water level,and the downstream dam slope shows the law of rising all the time,once the face slab is defective,the safety factor is lower than that of the whole panel,and the larger the defect size,the smaller the safety factor as a whole.