为分析Ⅴ级围岩中圆形顶管工作井后背墙及土体的应力、位移空间分布特征，依托枝江尾矿库排水工程，对圆形顶管工作井的稳定性进行监测，并建立三维数值模型，研究井体结构尺寸参数和顶力值对后背墙土体水平位移的影响。实测和模拟结果表明： 1）后背墙土体水平位移和应力竖向分布最大值均出现在顶力范围内，距后靠背钢板左右边外侧2.5 m范围内的后背墙处出现拉应力集中区域，且沿井深集中在后靠背钢板高度范围内。2）井壁厚度对限制土体水平位移影响最大，后靠背中部厚度影响次之，底板厚度影响最小； 当以优化结构尺寸提高土体稳定性时，应优先考虑增大后靠背中部厚度。3）对于在中风化泥质粉砂岩层中的顶管施工，工作井井壁嵌岩深度的改变对后背墙土体水平位移影响不大，井壁可不进行嵌岩处理。4）后背墙土体水平位移与油缸顶力呈近似线性关系。

To analyze the spatial distribution characteristics of the stress and displacement of the back wall and soil of circular pipe jacking working shaft in Grade V surrounding rock, the stability monitoring of the circular pipe jacking working shaft of Zhijiang End reservoir drainage project is monitored, and a threedimensional numerical model is established to study the influence of size parameters of shaft structure and jacking force on the horizontal displacement of back wall soil. The results of actual measurement and simulation show the following: (1) The maximum value of horizontal displacement and vertical stress distribution of soil at the back wall appear in the range of jacking force. There is a tensile stress concentration area at the back wall within 2.5 m from the outer side of the left and right sides of the backrest steel plate, and the tensile stress concentrates on the height of the backrest steel plate along the shaft depth. (2) The shaft wall thickness has the greatest influence on the horizontal soil displacement, followed by the middle backrest thickness, and the bottom plate thickness is the smallest. When optimizing the structure size to improve soil stability, the rear backrest thickness should be prioritized. (3) For pipe jacking in a moderatelyweathered muddy siltstone layer, the change in the rock-socketed depth of the working shaft slightly affects the horizontal soil displacement on the back wall, showing that the rock-socketed treatment is unnecessary for the shaft wall. (4) The horizontal displacement of back wall soil is linearly related to the jacking force of a cylinder.