As the groundwater environment changes in a goaf, the creep deformation of the backfill underwater pressure is worthy of attention. This paper takes the undercut goaf filling in the Yuzhou section of the middle route of the South-to-North Water Transfer Project as an example. Grading loading creep testing of the backfill under different water pressures was carried out using equipment developed by our research team. Based on the experimental results, the following key points were observed: (1) under the same axial stress, the creep strain and steady creep rate increase with increasing water pressure. Under the same water pressure, the creep strain and steady creep rate also increase with increasing axial stress. (2) The long-term strength of a backfill sample decreases with increasing water pressure and has a nonlinear relationship with water pressure. (3) The increase in water pressure exacerbates the damage of a backfill sample, which is manifested by the secondary crack propagation at the time of failure. Therefore, the increase in water pressure degrades the mechanical properties of the backfill to some extent. The results of this paper provide a reliable theoretical basis for the long-term stability analysis of goaf filling underwater pressure.

中文翻译：

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采空区水下压力下水泥回填蠕变特性的试验研究。

随着采空区地下水环境的变化，回填水下压力的蠕变变形值得关注。本文以南水北调中线禹州段暗挖采空区为例。使用我们的研究小组开发的设备对不同水压下的回填进行分级荷载蠕变测试。根据实验结果，观察到以下要点：（1）在相同的轴向应力下，蠕变应变和稳定蠕变率随水压的增加而增加。在相同的水压下，蠕变应变和稳定蠕变率也会随着轴向应力的增加而增加。（2）回填样品的长期强度随着水压的增加而降低，并且与水压呈非线性关系。（3）水压的升高加剧了回填样品的破坏，这在破坏时二次裂纹扩展中得到了体现。因此，水压的增加在一定程度上降低了回填的机械性能。本文结果为采空区水下压力长期稳定性分析提供了可靠的理论依据。