(1) Pile driving causes displacement and vibration of surrounding buildings
When driving piles, steel pipe piles enter the soil layer and squeeze the soft soil, causing horizontal and mercury vertical displacements of underground pipelines in nearby buildings, which may lead to cracks or damage in serious cases; at the same time, the vibration caused by diesel hammer pile driving will cause the foundations of surrounding buildings will subside and collapse, which will also affect the performance of nearby equipment and various precision machinery.
During construction, in order to reduce soil squeezing, in addition to using open piles, you can also set up shallow anti-crush ditches, squeeze-reducing sand wells or other drainage piles on the side close to the building. If the anti-extrusion trench is shallow, an empty trench can be used. If it is deep, it can be filled with foam plastic, sand and other loose materials to absorb or reflect the vibration waves from the piling, which can reduce vibration by 1/3 to 1/10.
In addition, in order to reduce the impact of vibration, the steel pile itself can be used to sink the pile with a cushioning layer or buffer. Reasonably select pile hammers with low vibration intensity and high vibration frequency. Finally, before construction, the surrounding neighboring buildings should be inspected, necessary temporary reinforcement measures should be taken, and some dangerous components of dangerous buildings should be removed.
(2) Difficulty in pile sinking
There are two situations in which pile sinking is difficult. One is that during the entire pile sinking process, there is a hard soil layer in the middle that needs to be penetrated, making pile sinking difficult; the other is that when the pile tip is close to the bearing layer, the penetration is too small, and it is difficult to reach it. Actual elevation.
For some important buildings, in order to ensure high bearing capacity and reduce settlement, designers often design piles to be very long, so the pile tips have to pass through the hard soil layer that can originally be used as a bearing layer. During construction, construction personnel should judge the possibility of penetrating the hard soil layer based on the mechanical performance of the pile driver and the allowable stress that the steel pile can withstand. Otherwise, necessary measures should be taken. Generally speaking, when the middle hard soil layer is about 20 m below the surface, it is easy to penetrate; when the N value is above 50, the sand layer is 5 m thicker and difficult to penetrate; when the N value is less than 30, it is difficult to penetrate through the hard soil layer of about 5 m. It is possible.
(3) The pile sinks sharply
The reason for the rapid sinking of the pile may be that it encounters a soft upper layer, a soil hole, or the pile's body is bent. Then the pile should be pulled up, inspected, corrected, and driven again, or the pile should be repaired near the original pile position and the inspection before sinking the pile should be strengthened.
When driving piles, steel pipe piles enter the soil layer and squeeze the soft soil, causing horizontal and mercury vertical displacements of underground pipelines in nearby buildings, which may lead to cracks or damage in serious cases; at the same time, the vibration caused by diesel hammer pile driving will cause the foundations of surrounding buildings will subside and collapse, which will also affect the performance of nearby equipment and various precision machinery.
During construction, in order to reduce soil squeezing, in addition to using open piles, you can also set up shallow anti-crush ditches, squeeze-reducing sand wells or other drainage piles on the side close to the building. If the anti-extrusion trench is shallow, an empty trench can be used. If it is deep, it can be filled with foam plastic, sand and other loose materials to absorb or reflect the vibration waves from the piling, which can reduce vibration by 1/3 to 1/10.
In addition, in order to reduce the impact of vibration, the steel pile itself can be used to sink the pile with a cushioning layer or buffer. Reasonably select pile hammers with low vibration intensity and high vibration frequency. Finally, before construction, the surrounding neighboring buildings should be inspected, necessary temporary reinforcement measures should be taken, and some dangerous components of dangerous buildings should be removed.
(2) Difficulty in pile sinking
There are two situations in which pile sinking is difficult. One is that during the entire pile sinking process, there is a hard soil layer in the middle that needs to be penetrated, making pile sinking difficult; the other is that when the pile tip is close to the bearing layer, the penetration is too small, and it is difficult to reach it. Actual elevation.
For some important buildings, in order to ensure high bearing capacity and reduce settlement, designers often design piles to be very long, so the pile tips have to pass through the hard soil layer that can originally be used as a bearing layer. During construction, construction personnel should judge the possibility of penetrating the hard soil layer based on the mechanical performance of the pile driver and the allowable stress that the steel pile can withstand. Otherwise, necessary measures should be taken. Generally speaking, when the middle hard soil layer is about 20 m below the surface, it is easy to penetrate; when the N value is above 50, the sand layer is 5 m thicker and difficult to penetrate; when the N value is less than 30, it is difficult to penetrate through the hard soil layer of about 5 m. It is possible.
(3) The pile sinks sharply
The reason for the rapid sinking of the pile may be that it encounters a soft upper layer, a soil hole, or the pile's body is bent. Then the pile should be pulled up, inspected, corrected, and driven again, or the pile should be repaired near the original pile position and the inspection before sinking the pile should be strengthened.
