Pine wood piles have some unique properties when used for foundation treatment, as detailed below: 1) High strength and low density, with the advantages of light weight and high strength; 2) Good elasticity and toughness, able to withstand impact and vibration; 3) Under proper maintenance Under certain conditions, it has good durability; 4) The joint structure is simple, easy to process, and can be made into products of various shapes; 5) Pine wood piles have strong hygroscopicity and swelling and shrinkage properties. When dry pine wood absorbs moisture, As the adsorbed water increases, pine wood will expand in volume; 6) Due to the structural characteristics of pine wood, it has four strengths: tensile strength, compression resistance, bending resistance and shear resistance. Pine wood pile foundations are mostly used at this stage. Temporary projects for emergency repair or modification of existing bridges should be repaired and reinforced in a quick and safe manner.

1. Due to freezing damage, the bottom of the pile will bulge. When the height difference does not exceed 30cm, the plywood can be disassembled, the cap wood can be lifted up, the pile head can be sawed flat according to the original height of the pile top, and then the cap wood can be installed.

2. If one of the pile rows is damaged and cracked, saw off the broken part and use a new log of equal length to connect the remaining pile wood. In order to buy time, you can temporarily fix the long pile wood with razor nails first. After opening to traffic, use plywood and bolts to connect the piles to reinforce them. The method is the same as the above-mentioned boundary pile method. If the pile row is damaged and cracks more than 2 piles, saw off the broken parts of each pile to make the tops of the piles left by sawing the same height, and install small caps on them. wood, and replace it with small racks.

3. When some of the underwater pile rows are damaged and cracked and cannot be connected and used, the piles can be interrupted before and after the piles are broken (in each interval). 2 This chapter briefly introduces the pine piles used in the structure, including materials, equipment, construction and inspection and other relevant regulations. .