A region once covered in deserts has now become a city competing for the hosting rights of the World Expo, which itself proves the speed of Dubai's development. But development does not stop here. With the expansion of cities and population growth, Dubai's construction must not stop there.
The impact roller can be divided into two types for land reclamation: one is connected to the mainland coast, and the other is the formation of artificial islands in the suspended shallow sea. There are two ways of reclamation in the land reclamation connected to the mainland Embankment shall be built directly on the mudflat beyond the shoreline; ② For the mudflat inside the harbor, sometimes the harbor gate is first blocked by embankment, and then the mudflat is surrounded by embankment. The method adopted mainly depends on the local technological and economic conditions.
The process of land reclamation project mainly includes the artificial siltation promotion project of mudflat before reclamation, the tidal barrier dam, the tide retaining and waterlogging drainage sluice project and the supporting project of water diversion, light storage, drainage and irrigation in the reclamation area.
Artificial siltation can generally be divided into two types: biological siltation and engineering siltation: biological siltation refers to planting plants such as rice grass and mangroves to promote sediment deposition; Engineering siltation promotion refers to the use of light siltation promotion projects such as artificial water plants and mesh dams, as well as heavy siltation promotion projects such as riprap and groin construction.
The main project of reclaiming land from the sea is the tidal barrier dam. The elevation, structure, and cross-sectional form of the embankment are determined by factors such as terrain and geological conditions, highest tide level, wave height, and climbing height. Tidal gates are built at the embankment of the seawall to prevent the tide from flowing back, and to drain and store fresh water.
The impact roller is used to excavate waterways and build internal embankments in the mudflat reclamation area, so as to separate salt water and fresh water. Alternatively, terrain conditions can be utilized to enclose bays and deep harbors, construct coastal plain reservoirs and drainage and irrigation projects, in order to solve irrigation water sources and freshwater aquaculture water surfaces. Excavate infiltration ditches on the inner side of the embankment to prevent seawater from replenishing salt in the reclamation area, accelerate soil desalination and groundwater desalination. When the ground elevation is low or cannot flow and drain due to the influence of tides, a pumping station should also be established at the tide gate to lift and discharge saline water into the sea. The land formation time of newly cultivated land is short, and soil improvement measures should be taken to promote soil maturation
The application scope of impact roller compaction technology is roughly as follows:
1. Shallow compaction and high filling compaction of collapsible loess foundation. Collapsible loess is mainly due to the large gap between loess particles, which causes the soil to sink under its own weight and load after a large amount of water seepage. Impact compaction by impact rollers can effectively reduce or eliminate the compressibility and collapsibility of the soil by applying high-strength impact force to the loess.
2. Treatment of shallow soft foundation (within 3m). Soft foundation refers to a foundation mainly composed of silt, muddy soil, alluvial fill, miscellaneous fill, or other highly compressible soil layers. This type of foundation has a natural moisture content that is too high, low bearing capacity, and is prone to sliding or consolidation settlement under load. In recent years, the impact roller crushed stone stamping method has emerged as a new construction technology with high economic benefits.
3. Rolling of the original foundation. This is the foundation compaction method commonly used by impact rollers. In many cases where the nature of the foundation is difficult to distinguish, the impact compaction method directly used by impact rollers is fast and convenient.
4. Layered compaction of high fill subgrade with a design height of 1.5m or above for island reclamation.
5. Layered compaction of semi filled and semi excavated subgrade. This is basically a working condition where an impact roller must be used, with half filling and half excavation. The settlement coefficients of the foundation on both sides are different and have a significant difference. The impact compaction method is an effective construction process to eliminate foundation settlement.
6. Layered compaction of high fill stone embankment.
7. Roadbed construction for high-speed railways. The settlement requirements for high-speed railway subgrade are extremely high, and impact compaction by impact rollers is one of the more effective methods to prevent post construction settlement of the subgrade and foundation.
8. Compaction of airport runways, fragmentation and reinforcement of old runways. Impact rollers were more commonly used in the impact compaction of airport runways with higher construction requirements or some high-grade highway foundations.
9. Landfill and compaction of garbage sites, compaction of building and factory foundations, and compaction of waste such as fly ash.
10. Reinfrcement and compaction of reclamation projects. It can prevent post construction settlement, enhance the uniformity and overall strength of fill and stone.
11. Impact compaction of old road reconstruction and roadbed widening.
12. The compaction and reinforcement of hydraulic engineering embankments, the compaction and anti-seepage of farmland, and the compaction and anti-seepage of salt fields.
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