基于 Mohr-Coulomb强度准则，利用极限分析上限定理，推导出浅埋小净距隧道围岩压力计算新公式。 采用 MATLAB数值模拟软件中的 fmincon函数进行最优化计算，求解该破坏模式下围岩压力的上限解，并将该计算值与规范法计算结果进行了对比。研究结果表明：该计算值与规范法计算结果比较接近，验证了该计算方法可行；随着系数 m的增大，浅埋小净距隧道两侧破坏土体的范围逐渐增大，围岩压力也逐渐增大且增长率呈递减的趋势。
Based on the nonlinear Mohr Coulomb strength criterion and the upper bound limit theory，a new formula for calculating the stress in the surrounding rock of shallow-buried small spacing tunnel was derived. The optimization calculation was conducted by using the fmincon function in MATLAB software. The upper solution of the stress in surrounding rock under the failure mode was obtained. The calculated values were compared with the results by the standard suggested method. The results show that the calculated value of the upper bound analysis is close to that of the standard suggested method， which verifies the proposed calculation method. With the increase of the coefficient m，the scope of soil failure on both sides of the shallow-buried small spacing tunnel increases gradually，the stress in surrounding rock also increases gradually，and the growth rate has a decreasing trend.