当今国内外既有建筑物的加固改造业发展非常迅速，其中混凝土结构的加固理论与技术的研究与应用是结构工程学科的重要研究课题之一。 本文从理论方面对外包钢法加固混凝土轴压柱的工作机理进行分析，并通过结构试验和数值模拟方法，研究和分析了外包钢加固轴压柱的工作性能，由此得出了几点研究结论：采用干式外包钢加固法加固混凝土轴压柱，加固后承载力的提高要远小于湿式外包钢加固法；在湿式外包钢加固轴压柱中，核芯混凝土处于三向受压应力状态，从而提高了混凝土的抗压强度；外包钢的缀板承受拉应力，有利于充分发挥缀板的材料性能，加强对混凝土的约束作用；采用二次应力下外包钢利用系数对湿式外包钢加固法承载力计算公式进行修正；并根据试验及以往工程实例，提出G型灌浆料作为结合剂的施工工艺。

As the development of reinforcement and reconstruction of buildings rapidly, the study and application on the reinforcement theory and technology of concrete structures become the one of most important research tasks of structure engineering. In this paper, the work mechanism of the wet-connected envelop iron columns under compression is studied by theory analysis, moreover the work characteristics of the columns is studied and analyzed by experiments and numerical simulation. So some conclusions are made. Firstly, the bearing capacity of wet-connected envelop column is more than the one of dry- connected envelop column; secondly the stress of concrete of wet-connected envelop iron column is three-dimensional compression which can increase the compression strength of concrete, so the material property of batten plate can be used enough. Furthermore the calculation formulas of wet-connected envelop iron columns are modified using coefficients under secondary stress, and basing on tests and engineering the construction technology which the G form grouting is regard as anchoring material is given.