The Skikda Refinery is situated in the Skikda Industrial Zone in eastern Algeria, processing condensate oil into products such as naphtha, aviation kerosene, butane, light diesel, and heavy diesel. The refinery has an annual capacity of 5 million tons of condensate, yielding 3.7–4 million tons of naphtha, 0.45–0.68 million tons of aviation kerosene, 0.11 million tons of butane, and additional diesel products.
This project, commissioned by the Algerian National Oil and Gas Company, involves the construction and ground treatment of the refinery and associated facilities. The foundation of the main refinery building utilizes concrete pouring pile technology, with a pile diameter of 0.8 meters, a pile length of 50 meters, and a single-pile bearing capacity of 6,000 kN.
For the 50,000-ton oil storage tank, vibro-compaction gravel pile technology was applied. The treatment increased the composite foundation’s bearing capacity from 120 kPa to 240 kPa, meeting all design specifications. Our company is responsible for the construction of this project, ensuring high-quality ground treatment to support the refinery’s extensive operations and infrastructure.
The second stage cofferdam is a vital water-retaining structure for ensuring the safe and efficient construction of the Three Gorges Dam on the Yangtze River. The upstream cofferdam is 1,137.54 meters long, and the downstream cofferdam spans 985.94 meters, both reaching a maximum height of 90 meters. The cofferdam consists of rock and slag piles on either side, with wind-blown sandstone filling the middle section. To enhance stability and prevent slot collapse during the construction of the cut-off wall, the vibroflotation method was adopted after extensive testing and demonstrations. Construction began in May 1996 and was completed in July 1998.
The process involved using BJ-75 kW electric vibroflots, as well as 130 kW and 150 kW hydraulic vibroflots, with piles arranged in positive triangular formations at 1.5-meter and 2.0-meter intervals, extending four to nine rows outward from the cut-off wall. Gravel packing of 0.5–2.0 cm and 2–8 cm was applied for the inner and outer layers, respectively, achieving a depth of 34 meters and a total footage of 93,570 meters. Following vibro compaction, the dry density of the cofferdam’s blast sand exceeded 1.8 g/cm³, typically reaching 2.0 g/cm³, with standard penetration tests showing results above 15 strokes. This treatment ensured no slot collapses occurred during the construction of the cut-off wall, significantly contributing to the cofferdam’s stability and the overall success of the Three Gorges Project.
The Dalian Xinghai Exhibition Center Phase II Project is located east of Xinghai Square and west of the Malan River, covering an area of 53,000 square meters with a building area of 11,000 square meters. The project utilized a composite ground base with vibro-stone columns for an independent foundation. Each pile had a diameter of 1,100 millimeters, and the project included a total of 7,202 piles. Construction commenced on September 3, 2002, and was completed on November 2, 2002. During the construction process, the project team received unanimous recognition from the owner and supervisor for the high-quality execution. The total footage of vibro-stone columns reached 78,782.3 meters, ensuring a stable and reliable foundation for the exhibition center.
This project, which included the main workshop, chimneys, and cooling towers, was the first in China to employ vibro-stone column technology for ground improvement in a 600MW unit. Construction began in June 2001 and was completed in October 2001. The site’s main strata consisted of fine sand and medium-coarse sand. Using 75kW vibroflot equipment, the project constructed 7,688 vibro-stone columns with a diameter of 1,100 millimeters, arranged in an equilateral triangular layout with a spacing of 2,300 millimeters.
Post-treatment, the composite foundation’s bearing capacity was improved to 400 kPa for the main workshop, 350 kPa for the chimney, and 300 kPa for the cooling tower, with a deformation modulus exceeding 20 MPa. After two years of operation, the foundation remained stable with settlement recorded at less than 21 millimeters, demonstrating the success of the ground improvement works in ensuring long-term reliability.
