Abstract: This paper,based on the analysis of site construction and cracks in the experimental concrete box culvert under ShaBin road,draws a deduction that when the side earth fill has some settlement,there will be two failure surfaces in the earth fill which are above the box culvert and exist side friction pointing to earth.Moreover,calculation for the box culvert under the load which based on the deduction is given in the paper

Key words: analysis of cracks, settlement, failure surfaces, side friction, calculation of stmeture

摘要： 通过对现场施工和箱涵内部裂缝的分析，提出沟埋式箱涵两侧填土发生一定量沉降时，会在箱涵顶板上的 填土中产生破裂面且对箱涵侧壁有负摩阻力的推断，并将此作为箱涵实际受载条件进行结构计算，计算结果与实 际情况非常吻合。

关键词: 裂缝分析, 沉降, 破裂面, 负摩阻力, 结构计算