What Precautions Should Be Taken When Using Steel Sheet Piles?

As a construction material for the medium foundation of a building, when installing sheet piles, relevant personnel at the construction site use the screen driving method to ensure the accuracy of steel sheet pile driving. First, use a crane to lift the steel sheet pile to the pile insertion point for insertion. When inserting the pile, the lock mouth should be aligned. After each piece is inserted, put on the pile cap and hammer gently. During the piling process, to ensure verticality, two theodolites were used to control the pile in two directions. To prevent the plane displacement of the center of the lock, a clamping plate is installed at the lock of the steel sheet pile in the direction of the piling to prevent the displacement of the sheet pile. At the same time, the position of each plate on the purlin is calculated in advance so that it can be checked and corrected at any time. The steel sheet piles are driven several times. When driving the piles, the driving position and direction of the first and second steel plates must be ensured with accuracy and measured every 1m driven.

(1) Requirements: There must be high standard requirements in construction construction, and safety requirements are the first step. ① Jiangxi steel sheet piles are suitable for supporting structures with shallow burial depths. ②Steel sheet pile driving is suitable for weak strata such as clay soil, sand, and silt. ③ Before constructing steel sheet piles, piles should be tested first, and the number of test piles should not be less than 10. ④ During the setting-out construction of steel sheet piles, the position of the pile head must be correct and vertical. During the pile sinking process, the pile head must be inspected at any time to detect problems and deal with them in time. The allowable deviation of pile sinking is 100mm vertically in the plane position, -50 mm~0 mm horizontally; the verticality is 5. ⑤ Before pile driving, underground, ground, and high-altitude obstacles must be cleared away, and underground pipelines that need to be retained should be dug out and protected. ⑥ After excavation of the foundation pit, the steel sheet piles are vertical and smooth, with no serious distortion, tilt, or splitting, and the lock joints are tightly connected. During the construction of the foundation pit earthwork and structure, dynamic observation of the surrounding rock and support system of the foundation pit shall be carried out. Discover problems and deal with them promptly.

(2) Impact pile sinking: What is the impact driving method? The classification here is more detailed. ① Impact pile sinking machinery is selected according to the number of piles driven and construction conditions, and the operation and construction are performed according to technical performance requirements. ② Inspect steel piles before use. If they do not meet the requirements, they should be repaired. Holes for hanging plates are drilled behind the reinforcing plate at the upper end of the steel pile. Apply oil to the lock mouth of the steel sheet pile, plug the lower end with a removable object, and conduct a passing test using the 2m standard. ③A single I-shaped steel pile is sunk, and the steel sheet piles are sunk using the purlin method to ensure that the wall surface is vertical and smooth. ④ The purlin piles of Jiangxi steel sheet pile purlin supports must be vertical, the purlins must be horizontal, and the setting position must be correct, strong, and reliable. The height of the purlin supports should be no less than 5m above the ground; the distance between the lower purlins and the ground should not be greater than 50cm; the clear distance between purlins should be 8-15mm larger than the combined width of two steel sheet piles. ⑤Steel sheet piles are divided into 10-20 pieces. After inserting the purlins one by one, first drive the positioning piles at both ends and then drive the piles in each group in a stepwise manner in groups of 2-4. ⑥ The steel sheet pile purlin is adjusted and closed within the axis of the 10 pile positions of the two pile walls at the corner. If it cannot be closed, the two piles at the corner can be overlapped, and the backside must be waterproofed. ⑦ Before sinking the pile, first stand the steel pile upright and fix it in the pile cap bayonet of the pile hammer, then pull up the pile hammer and hit the vertical j position of the I-shaped steel pile or insert the steel sheet pile lock into the adjacent pile lock, first drive 2-3 Use an empty hammer once, and then lightly hammer to stabilize the pile. Only after checking that the pile position and verticality are correct can the pile be sunk. ⑧ During the pile sinking process, the verticality of the pile should be detected and corrected at any time. The penetration of steel pile sinking shall not be less than 10mm every 20 times. Otherwise, stop the machine for inspection and take measures. ⑨ During the pile sinking process, if the center line of the pile driver guide frame is found to be deflected, it must be adjusted in time.

(3) Vibration pile sinking: To ensure that the steel sheet pile does not sink ① The vibration frequency of the vibrating hammer is greater than the natural vibration frequency of the steel pile. Before vibrating the pile, the pile clamp of the vibrating hammer should clamp the upper end of the steel pile and make the center of gravity of the vibrating hammer and the steel pile in the same straight line. ② The vibrating hammer clamps the steel pile and lifts it so that the I-beam pile or the steel sheet pile lock is inserted into the adjacent pile lock in the vertical position. After the pile is stable, in the correct position, and vertical, it vibrates and sinks again. Every time the Jiangxi steel sheet pile sinks about 1 to 2mm, the vibration is stopped to detect the verticality of the pile, and any deviation is found and corrected in time. ③ The number of vibration-sinkable steel sheet pile test piles shall not be less than 10. ④ If the sinking speed of the steel pile suddenly decreases during pile sinking, pile sinking should be stopped, the steel pile should be pulled up 0.6 to 1.0m, and then sink rapidly again. If it still cannot sink, other measures should be taken.

(4) Static pile pressing: The latter method emphasizes the need to ensure ultra-deep conditions during construction. ① When the pile driver presses the pile, the center line of the pile cap and pile body must coincide. ② Check the verticality of the pile body at any time during the pile pressing process. During the initial pressing process, if the pile body is found to be displaced or tilted, and the pile body suddenly tilts during the pressing process or the equipment reaches the rated pressure and continues for 20 minutes, but still cannot sink, take timely measures. measure. Static pressure pile planting machine: ① initial pressing ② steel sheet pile pressing ③ can be constructed under geological conditions within the standard penetration test N value of 500, including pebbles, boulders, rock formations, etc. Precautions for piling: 1) After the guide piles are driven, weld them firmly with channel steel to ensure that the guide piles do not shake, to improve the accuracy when driving the piles; 2) Line piles are inserted and driven. After the Jiangxi steel sheet piles are lifted, the piles are manually inserted into the locks. Move slowly to prevent damage to the lock. After insertion, loosen the sling slightly to allow the pile to slide in by its weight; 3) When the steel sheet pile is vibrated and driven to 20~40cm below the design elevation, be careful during construction to prevent over-depth from occurring.