水电站地下埋藏式钢岔管承载能力是工程设计中非常重要的一个内容，但目前对于钢岔管与围岩联合承载的机理还缺乏系统深入的研究。本文结合某抽水蓄能电站的工程实际，按照钢衬与围岩联合承载的原理，用三维非线性有限元对埋藏式钢岔管进行了计算分析。计算结果表明：在钢衬与围岩共同承受内水压力时，围岩发挥了重要作用，围岩的性能越好，所分担的内水压力就越大，因此在埋深足够的情况下，应充分利用围岩进行分载，以减小钢衬厚度，从而节约工程投资。

本文在综合分析坝内埋管现行设计理论和方法的基础上，提出了坝内埋管极限状态设计方法。该方法以钢筋混凝土非线性分析为主要手段，可以同时考虑坝体荷载、内水压力、温度荷载的作用，全面分析坝内埋管中钢管、钢筋和混凝土的应力状态和承载情况，并决定钢管壁厚和外围坝体混凝土的配筋，它对于改进坝内埋管的强度设计，具有重要实际意义。

Structural research into the performance of a composite steel-reinforced concrete penstock designed for use at the Three Gorges power station in China is described. The stress state, load capacity and mechanism of deformation of the penstock under internal water pressure were obtained from theoretical analyses based on a non-linear finite element simulation of the original design. Using the results from the numerical research, a large-scale prototype model has been developed and tested to verify the modified penstock. The conclusions obtained have potential value with respect to other similar projects both in China and elsewhere.

A composite stucture for penstock bifurcations, comprising a steel lining and outer reinforced concrete shell, is proposed as a method to increase structural integrity and reliability as a result of the interaction of the two materials. This method represents an economical solution for developing countries. Model studies for the concept are described.

钢衬钢筋混凝土无梁岔管与无梁钢岔管与其它梁式岔管相比，具有受力条件好、钢管较薄、施工方便等优点，是一种新的岔管结构型式，特别适合于中高水头的中小型水电站。通过一个大比尺物理模型试验，对钢衬钢筋混凝土无梁岔管的承载机理和结构特性进行了深入的研究，取得了令人满意的结果。