为提升盾构隧道专用反力架轻量化水平和降低制造及运输成本，对其结构进行优化。首先，依据设计的反力架结构建立其有限元模型，并结合工程数据类比确定载荷条件，验算反力架强度及刚度； 然后，以所有板材厚度为自变量、反力架总质量为因变量，利用方差分析的方法获得主效应图，确定5种对结构总质量贡献量大的板厚为优化变量； 最后，以5种板厚为设计变量，强度、刚度指标作为约束条件，反力架质量最小为优化目标，采用PSO算法进行求解。结果表明： 优化后结构的最大应力为252.2 MPa,最大变形为10.6 mm，反力架总质量从305.78 t降至274.85 t，减重比例为10.1%(30.90 t)，验证了结构优化的有效性。

The structure optimization design of counterforce frame used in shield tunnel is carried out to improve its lightweight level and reduce its manufacturing and transportation cost. Firstly, the finite element analysis model of counterforce frame is established based on design structure, the loading conditions are determined by analogy of similar engineering data，and the stress and stiffness of counterforce frame are checked. And then, the main effect diagram is obtained by using variance analysis with taking all plate thickness as independent variables and total weight of the counterforce frame as dependent variable, and 5 kinds of plate thickness effecting on structure total weight largely are set as optimization variables. Finally, the particle swarm optimization (PSO) algorithm is used to calculate by taking 5 kinds of plate thickness as design variables, strength and stiffness as constrains, and minimizing the counterforce frame mass as object. The calculations results show that the maximum stress of the optimized structure is 252.2 MPa, the maximum deformation is 10.6 mm, the total mass of the counterforce frame is reduced from 305.78 t to 274.85 t, and the mass reduction ratio is 10.1% (30.9 t), which proves the effectiveness of the structure optimization.