The construction of vibroflotation stone columns for the Cao Dian Rubber Dam in the Xianghe section of the North Canal is undertaken by Beijing Vibroflotation Engineering Machinery Co., Ltd. The North Canal section starts from the Beijing-Hebei boundary in the north and ends at the Cao Dian Rubber Dam in the south, with design chainage from Z0+000 to Z8+200, about 8.2 km long. The second phase includes river dredging, widening, and bank protection from chainage Z2+500 to Z8+200. This area belongs to an alluvial plain with a single geomorphological type, the North Canal section. The elevation of exploration points ranges from 4.19 m to 14.84 m. The groundwater type in this section is mainly Quaternary pore water. The measured stable groundwater depth in the project area is 2.00–5.90 m, corresponding to elevations of 8.55–9.20 m. The environmental water has weak sulfate corrosion to concrete and weak corrosion to steel reinforcement in reinforced concrete structures. The environmental water has weak corrosion to steel reinforcement in reinforced concrete structures.


　　The surface of the project area is covered by Quaternary strata. The strata exposed at the surface and revealed by drilling are mainly composed of Holocene alluvial-proluvial deposits. This section is generally a sandy soil section, with lithology mainly sandy loam and sandy soil.


　　Before foundation treatment, the vibroflotation engineering conducted trial piles and pile testing in accordance with the "Technical Specification for Vibroflotation Foundation Treatment of Hydropower and Water Resources Projects," and determined the compaction current, retention time, and compaction segment length through field tests.


　　The project has a pile diameter of 0.8 m, with a pile spacing of 2.5 m for the rubber dam base slab and 2.0 m for the retaining walls on both banks. The pile depth is 15 m, arranged in an equilateral triangle pattern. Based on the geological data, the liquefiable layer is the 4th layer of medium-fine sand, and the treatment depth extends to 1 m below the bottom of the 4th medium-fine sand layer. The pile bottom elevation is -7.0 m. The filling amount per linear meter of the pile body is not less than 0.7 m³. The total length of vibroflotation stone column construction is 38,500 meters. The total construction period is 30 days.

　　To cooperate with the client in completing the construction schedule as planned, the vibroflotation engineering team has currently deployed six rigs operating simultaneously.