When pile drivers are used for drilling in the construction of corrugated guardrail piles, the collapse of hole walls is an inevitable issue. What causes this collapse? Today, let's discuss this topic, hoping to help everyone avoid such occurrences in future construction. Here are the main reasons for hole wall collapse and the corresponding solutions:

1. Insufficient maintenance of water head pressure.

2. The depth of the casing is inappropriate. If the casing is embedded in sand or coarse sand, the sand is prone to collapse due to water leakage under hydraulic pressure; additionally, vibration and impact can loosen the soil around and under the casing, causing collapse.

3. Directly installing the drill rod on the casing can cause vibration during drilling, loosening the soil around and under the casing, leading to water loss in the drill hole and subsequent wall collapse.

4. Excessive static water pressure: If the water head is too high and exceeds the required level, the water pressure at the bottom of the casing can be greater than the weight of the overlying soil at that depth, causing soil upheaval and sand rollover outside the drill hole, leading to damage.

5. Presence of coarse-grained sand and gravel layers or strong water-permeable layers: When the drill reaches such layers, water leakage causes a rapid drop in the water level inside the hole, leading to wall collapse.

6. Presence of strong artesian water with very high water head, especially when it exceeds the internal water pressure of the hole, can lead to sand rollover at the bottom of the hole and wall collapse.

7. The weight and vibration of heavy construction machinery on the ground, along with the self-weight stress of the soil layers, often cause wall collapse at about 80-150 cm below the ground.

8. Too rapid hole formation: If a mud film cannot form on the hole wall in time, it can easily lead to collapse.

9. Excessive deformation of the casing or improper shape can cause water loss in the drill hole, leading to wall collapse.

10. Improper operation causing pressure agitation.