厂坝间巨型压力钢管在常规荷载作用下受力特性研究

水电站坝后式厂房，在厂坝间交界处的压力钢管不设伸缩节，而是采用在一段钢管外周设垫层结构，以适应荷载作用下钢管的变位，这是一种有效的途径。通过对某大型水电站的三维有元计算，得出了在常规荷载作用下厂坝间垫层压力钢管的变位及受力情况。从对计算结果的分析，为使这种垫层结构的受力能得到进一步的改善，建议：尽量提高河床坝段厂坝间接缝混凝土的高程，使厂坝能较好地联系受力；尽可能增加垫层管段的长度；尽量推迟厂坝间压力钢管的最后一条环缝的施焊时间，且在施焊前尽可能蓄高水库的上游水位，这时厂坝自重引起的不均匀沉陷已基本终了，且已蓄水位的荷载对垫层管不再增加应力。

Study on the stress characteristics of huge pressured steel pipe between dam and power plant under the action of routine load

For the hydropower station with the powerhouse at the dam toe, there is no expansion section of the pressure steel pipe at the juncture between the powerhouse and the dam but a cushion structure should be set up in some section of the pressure steel pipe to adapt to the deformation of the pipe under the action of loads, which is an effective way. On the basis of the three dimensional finite element calculations on a large sized hydropower station, we gained the deformations and stresses of the pressure steel pipe with cushion structure between powerhouse and dam under the action routine loads. According to the analysis on the calculation results and in order to improve the stresses of such cushion structure, the author suggests that the elevation of joint concrete between powerhouse and dam should be enhanced to make the powerhouse and dam jointly bear the stresses. The length of the steel pipe with cushion structure should be increased as possible. The welding of last ring joint of the pressure steel pipe between powerhouse and dam should be delayed as possible, and the upstream water level of reservoir also should be increased as possible before the welding. At this time, the non uniform settlement caused by the dead weight of powerhouse and dam has been basically finalized and the stresses on the cushioned steel pipe caused by the load of the stored water of reservoir could not be increased.