Dynamic compaction foundation is suitable for gravel soil, sandy soil, collapsible loess, low saturated silt and cohesive soil. Through (t ō ng The rammer (8t-30t) of crane (crane tripod or gantry) rises to the predetermined height (6m-20m) and falls freely. The ramming energy can produce a shock wave on the foundation. The ramming energy can produce a shock wave and tamping application on the foundation. The ground fissures and soil mass decompose, forcing the soil voids to compress and the soil to liquefy, forming a good drainage channel, and water and gas escaping between the pores In order to improve the bearing capacity of the foundation and reduce the settlement, a uniform hard layer is formed on the surface of the foundation to bear the upper load. What are the requirements and impacts of dynamic compaction construction equipment on foundation dynamic compaction treatment
1) Rammer: the weight of rammer is generally 8t-30t, and triangle and polygon are used at the bottom of rammer. The rammer is usually made of steel bar concrete and made into a cone (with steel plate at the bottom). The bottom of the rammer should have a number of through holes, which is conducive to the quick exhaust of air at the bottom of the rammer and reduce the suction at the bottom of the pit. The hammer weight is determined according to the thickness of soil layer, hammer bottom area and drop distance, and the bottom dimension of rammer is determined according to soil type: 2-4m2 for sandy soil and gravel soil; 3-4m2 for cohesive soil.
2) Crane: generally, crawler crane of more than 15t or other lifting equipment are used. Special tripod and wheel type dynamic compaction (H ā ng) machine are manufactured abroad, which can lift 400kN rammer and drop distance can reach 40m. When the hammer weight does not exceed the hoisting capacity of the crane, the single cable hammering method can be used.
3) Uncoupling device: when the hammer weight exceeds the lifting weight of the crane, the single cable hammering method cannot be used. In this case, pulley group and unhooking device can be used to lift and lower the hammer. Hang the rammer on the decoupling device, lift the ram to the specified height (Gu ī D ì ng) with a crane, and use the decoupler to make the hammer fall freely. The detaching device is flexible, which can keep the rammer falling down smoothly, and the hook is convenient and rapid.