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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。
As the stress and deformation of earth-rock dam have great changes in the completion, storage and operation periods, it is of great guiding significance to understand the stress-strain. Taking the existing dam widening project of Tianxian Lake in Chongqing as an example, the stress and strain of the three-dimensional finite element analysis are analyzed by Mohr-Coulomb strength criterion. The results show that the principal stress distribution of dam body is uniform in all working conditions, no stress concentration zone and no tensile stress zone appear. After the reservoir is impounded, the small principal stress of dam body decreases obviously and decreases with the increase of water level ; The minimum principal stress of the dam during the operation period of the reservoir has a slight increase compared with that of the reservoir, so it is less likely to judge the stress damage of the dam; the settlement of the dam mainly occurs in the broadening of the dam, The distribution of displacement has a greater impact, the horizontal displacement of the dam to the upstream of each condition mainly occurs in the original dam body, and the horizontal displacement to the lower reaches mainly occurs in the part of the dam body. In addition, the driving direction affects the dam settlement, horizontal displacement, Stress, the impact of small principal stress are small.