天仙湖拦沙坝坝顶加宽工程通车条件下的应力变形分析

Stress and Deformation Analysis of Tianxian Lake Sediment Storage Dam Widening Project under Traffic Conditions

由于土石坝的应力和变形在竣工期、蓄水期和运行期变化较大,因此了解其应力应变具有重要的指导意义。以重庆市天仙湖既有坝顶加宽工程为例,采用Mohr-Coulomb强度准则进行了静力三维有限元应力应变分析。结果表明,各工况坝体大主应力分布均匀,未出现应力集中区,亦无拉应力区;水库蓄水后,坝体小主应力有明显减小趋势,且随水位的增加而减小;水库通车运行期的坝体最小主应力较蓄水期有小幅度增加,以此判断坝体发生应力破坏的可能性较小;坝体沉降主要发生在拓宽坝体内,蓄水对坝体水平位移的分布有较大影响,各工况坝体向上游水平位移主要发生在原坝体内,向下游水平位移主要发生在培厚坝体部分;此外,行车方向对坝体沉降、水平位移、大主应力、小主应力影响均较小。

The stress and deformation of earth-rock dam changed greatly during the completion period,storage period and operation period.Therefore,it＇s significant to understand the stress and strain of earth-rock dam.Taking the dam crest widening of Tianxian Lake for an example,the stress and strain analysis of the static three-dimensional finite element method was carried out by using Mohr-Coulomb＇s strength criterion.The results show that in each working conditions,the main stress distribution of the dam body was uniform;there was no stress concentration area and tensile stress zone.After reservoir water storage,the minor principal stress of the dam was obviously decreased,and decreased with the increase of the water level.In open traffic operation period,the minimum principal stress of the dam was smaller than that of the water storage period,which was less likely to judge the failure occurrence of stress;the horizontal displacement of dam body was mainly occurred in the primary dam body,and the horizontal displacement of the dam body mainly occurred in the part of the dam body;the main dam settlement occurred in the widening of the dam body,the water storage had greater impact on the distribution of the horizontal displacement of the dam.In addition,the impacts of the direction of traffic on the dam settlement,the horizontal displacement,the main stress,the small main stress were small.