Water-filled boreholes in cold ice refreeze in hours to days, and prior attempts to keep them open with antifreeze resulted in a plug of slush effectively freezing the hole even faster. Thus, antifreeze as a method to stabilize hot-water boreholes has largely been abandoned. In the hot-point drilling case, no external water is added to the hole during drilling, so earlier antifreeze injection is possible while the drill continues melting downward. Here, we use a cylindrical Stefan model to explore slush formation within the parameter space representative of hot-point drilling. We find that earlier injection timing creates an opportunity to avoid slush entirely by injecting sufficient antifreeze to dissolve the hole past the drilled radius. As in the case of hot-water drilling, the alternative is to force mixing in the hole after antifreeze injection to ensure that ice refreezes onto the borehole wall instead of within the solution as slush.

中文翻译：

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冰川钻孔热点钻探避免融雪

冷冰中充满水的钻孔会在几小时到几天内重新冻结，之前尝试用防冻剂保持它们打开的尝试导致雪泥塞子有效地更快地冻结了钻孔。因此，防冻液作为一种稳定的方法热水钻孔已基本废弃。在里面热点钻孔情况下，钻孔过程中不会向孔中添加外部水，因此可以在钻头继续向下熔化的同时更早地注入防冻液。在这里，我们使用圆柱形 Stefan 模型来探索代表热点钻井的参数空间内的雪泥形成。我们发现，较早的注入时间可以通过注入足够的防冻剂来溶解超过钻孔半径的孔，从而完全避免雪泥。与热水钻井的情况一样，替代方法是在注入防冻剂后强制在孔中混合，以确保冰重新冻结在钻孔壁上，而不是在溶液中作为雪泥。