(2) Spanning Method: Used for treatment where collapse pits or soil cavities are relatively deep and large, making excavation and backfilling difficult. Generally, beams and slabs are used to span across, with both ends supported on reliable rock or soil masses. According to experience in Guangxi, the support length on each side should be no less than 1.0–1.5 m.

　　(3) Dynamic Compaction Method: A tamper weighing 10–20 t is lifted to a certain height (10–40 m) and allowed to fall freely, creating a strong impact to heavily compact the soil. On one hand, it compacts the loose soil layer after collapse and the backfill soil in collapse pits or soil cavities to improve soil strength; on the other hand, it can eliminate hidden soil cavities and weak zones, making it a measure combining treatment with prevention. According to tests by Christain (1984): with a tamper weight of 15 t and a drop distance of 20 m, the influence can reach a depth of 8–9 m below the ground surface. Using this method, when no other conditions impose restrictions, the location of soil cavities above 4.5 m can be determined.

　　(4) Grouting Method: Grouting materials are injected through boreholes or karst openings, with the purpose of strengthening the soil layer or cavity fillings, filling karst cavities and fissures, cutting off groundwater flow channels, and reinforcing building foundations. The grouting materials are mainly cement, aggregates (sand, slag, etc.) and accelerators (water glass, calcium oxide). The cement grade should be higher than 450. Grouting can be carried out by low-pressure intermittent quantitative grouting or circulating grouting, with the purpose of reducing grout loss; the intermittent time can be controlled at about 7–8 hours.

　　(5) Deep Foundation Method: For soil cavities and collapses that are relatively deep and beyond the capacity of spanning structures, pile foundations are usually adopted to transfer loads to the bedrock.

　　(6) Jet Grouting Reinforcement Method: In shallow areas, jet grouting piles are used to form a "hard shell layer", on which a raft foundation is then set. The thickness of the "hard shell layer" depends on specific geological conditions and the design requirements of the structure, and can generally reach 10–20 m.

　　(7) Dredging, Drainage, Enclosure and Diversion of Surface Water: During the treatment stage of soil cavities and collapse foundations, the treatment of surface water cannot be ignored or relaxed and should be further improved on the basis of preventive measures.

　　(8) Water and Air Pressure Balancing Method: As the water level rises and falls, the water and air pressure in karst cavities changes, often causing gas explosions or burst collapses in karst reservoir areas, resulting in massive leakage or even failure of the reservoir water. Therefore, after identifying the underground karst channels, various ventilation devices for karst conduits should be installed to balance the water and air pressure and eliminate their effects.