开展地下水管破损射流冲蚀土层的室内模型试验,研究了覆土类型、进水压力和供水管径3种影响因素下,土层的冲蚀破坏形态、冲蚀高度和冲蚀速度的发展变化.结果发现:覆土类型会从本质上影响冲蚀破坏形态,砂土层中的塌陷空洞会堆积在冲蚀区顶部,含砾砂层中出现\上细下粗"的土颗粒重排现象,黏土层中的冲蚀空坑能暂时维持稳定;增大进水压力和减小供水管径,本质上都提高了破损口的冲蚀压力,覆层表面由向下塌陷破坏转为上凸小丘破坏.通过试验相似比尺和冲蚀高度曲线,可估算相似工程环境下水管破损射流的冲蚀时间,为城市地下市政供水管网的建设和维护提供参考.
An indoor model test was conducted to study the erosion failure pattern, erosion height, and erosion velocity of the soil layer, considering three influencing factors: soil type, water inflow pressure, and water supply pipe diameter. The results showed that the soil type affected the form of erosion failure. Collapse cavities accumulated on top of the erosion zone in a sand layer, while the erosion zone in a clay layer maintained a temporary stability. Moreover, the gravelly sand layer exhibited a rearrangement of the soil particles into a "fine upper and coarse lower" layer. Increasing the water inflow pressure, and reducing the water supply pipe diameter substantially increased the erosion pressure on the damaged mouth. The overburdened surface transformed from a downward collapse failure to an upward hill failure. Based on the test similarity scale and erosion height curve, the erosion time for a damaged jet in a similar engineering environment could be estimated, providing a reference for the construction and maintenance of urban underground water-supply networks.
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