FINDING SOLUTIONS IN CONSTRUCTION ON WEAK SOIL IN VIETNAM

     In general, in the construction of traffic works, the construction of new highways, bridge approach roads, upgrading and renovating old roads... requires ensuring the durability and long-term stability of the roadbed, which is decisive for the efficiency of the road. With the characteristics of our country, large urban areas and economic centers are located in the Red River Delta and the Mekong River Delta. These are areas with favorable natural conditions for trade, but in terms of construction, they are disadvantageous because the foundation layers are river and sea sediments with complex structures, including weak soil layers distributed over a large area and the thickness of the layer can be up to 40 - 50m. Therefore, the cost of construction can increase by 10 - 20%.

    For weak ground, many methods of ground reinforcement have been studied and applied such as: Solutions using wicks combined with preloading or vacuum, using counter-pressure platforms, sand piles, soil cement piles, reinforced piles, geotextiles... However, the application of these traditional solutions to treat weak ground in some cases still does not meet the requirements, leading to construction incidents such as the phenomenon of embankment sliding on the Hoang Long bridge - Thanh Hoa, subsidence of Nguyen Huu Canh road - Ho Chi Minh City... Figure 1 is an example of roadbed damage at the junction between the bridge and the bridge approach road due to differential subsidence.

Damage to the embankment of the approach road to the bridge due to differential settlement

    Therefore, choosing the appropriate construction solution for each project, ensuring factors related to the ground such as the subject of treatment, construction materials and equipment, treatment means, cost, impact on neighboring areas, environment... is an urgent and highly practical requirement in the current period.

Excerpt: Bridge and Road Magazine No. 4, 2020