LD河床式水电站厂房坝段变形研究

Deformation of powerhouse dam section of LD Riverbed Hydropower Station

LD水电站蓄水后厂房坝段坝顶变形持续增大,且最大变形超过原计算值。为分析其原因,利用有限元软件对LD水电站厂房坝段进行仿真计算。从外荷载分量、温度分量、时效分量3个方面开展厂房坝段变形计算。将变形叠加后与实测变形相比较,分析坝顶变形持续增大的原因。结果表明:坝顶变形中外荷载分量占比最大,为总变形的50%,其次为时效分量和温度分量,分别占总变形的27%和23%。坝前水位稳定之后坝顶变形增量主要由时效和温度引起,其中时效变形占后期变形增量的86%,温度变形占14%。随着时间的推移,混凝土徐变逐渐收敛,温度场逐渐稳定,时效变形和温度变形趋于稳定,因此坝顶变形不会持续增大。原变形计算对温度及时效影响的考虑不足,导致监测值大于原计算值。建议类似工程变形计算应充分考虑温度与时效对结构变形的影响。研究成果可为河床式电站厂房坝段变形复核及预测提供参考,为解决类似工程问题提供了一种思路。

After the impoundment of the LD Hydropower Station,the dam crest deformation of its powerhouse dam section continued to increase,and the maximum deformation exceeded the original calculated value.In view of this situation,a finite element software is used for the simulation calculation of the section from three aspects,namely,external load component,temperature component and aging component.The reason for the continuous increase of dam crest deformation is analyzed by comparing the superimposed deformation with the measured deformation.The calculation results show that the external load component accounted for the largest proportion of the dam crest deformation,which was 50%of the total deformation,followed by the aging component and temperature component,accounting for 27%and 23%of the total deformation respectively.After the water level in front of the dam reached the stable state,the deformation increment of the dam crest was mainly caused by aging and temperature,of which aging deformation accounted for 86%and temperature deformation accounted for 14%.With the passage of time,the concrete creep gradually converged,the temperature field gradually stabilized,and the aging deformation and temperature deformation tended to stabilize as well.Therefore,the dam crest deformation did not continue to increase.The original deformation calculation method did not consider the influence of temperature and aging,resulting in the monitoring value being greater than the original calculated value.It is suggested that the influence of temperature and aging on structural deformation should be fully considered in the deformation calculation of similar projects.The research results can provide a reference for the deformation review and prediction of the powerhouse dam section of riverbed hydropower stations,and provide a new idea for solving similar engineering problems.