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> 水力采煤是利用高速水流冲击煤层而进行的.假如煤层受到3.6×10 6N/m 2的压强冲击即可被破碎,若高速水流沿水平方向冲击煤层,不考虑水的反向溅射作用,则冲击煤层的水流速度至少应为 A．30m/s B．40m/s C．45m/s D．60m/s

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发布时间：2024-09-11

水力采煤是利用高速水流冲击煤层而进行的.假如煤层受到3.6×10 ⁶N/m ²的压强冲击即可被破碎,若高速水流沿水平方向冲击煤层,不考虑水的反向溅射作用,则冲击煤层的水流速度至少应为

A．30m/s B．40m/s C．45m/s D．60m/s

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