All kinds of rotary drilling method of Rotary Pilling Rig are likely to cause the hole collapse occurred, the general features of the hole of water drops suddenly, hole cut fine blisters, slag increased without the footage, Rotary Piling Machine lifting load increase. Because the relative density of the mud does not reach the standard, the hole collapsing is caused by the mud density, which is suitable for the corresponding geological layer.
If there is pressure water in the hole, it is necessary to add a high cylinder or a mud pit at the hole to ensure the stability of the head in the barrel. Tube is too shallow due to the entire casing caused by bottom hole collapse, when drilling to press the protective cylinder. In the soft sand due to fast footage led to the collapse hole, the geological slow footage. If our local construction geology is easy to collapse, we can buy several protective canister at the same time, and use the lower casing to ensure the smooth construction of the borehole.