Study On PTC Pile Net Processing Deep Soft Foundation Project In Ningde Nuclear Electricity High Embankment Abutment

In China, road construction continues to extend to the coastal area, more and more need to build a foundation and abutments on soft deep silt layer. Due to poor geological conditions, soft foundation treatment is difficult, such as roadbed subsidence slip, rear abutment jumping and other issues frequently.In recent years, vacuum preloading of soft ground method is widely used, in recent years, vacuum preloading of soft ground method is widely used, but because of long construction period, a large settlement after construction is completed, the road is not suitable for abutment soft foundation treatment, often in place of pile net composite foundation treatment. Pile net composite foundation supported embankment is still in the research phase of the trial, immature theory, engineering design and construction require further study, research for practical problems encountered in engineering and solving methods is especially lacking.In this article, theory of soft foundation treatment method and pile net composite foundation were introduced and summarized firstly, lay the foundation for later study and solve problems, then, The problem of construction of PTC pipe net composite foundation supported embankments on soft ground has been studied in Ningde nuclear electricity road, and the soft ground conditions are subject to perennial water immersion, surface floating silt thick, deep mud, carrying capacity low. The main contents are as follows:first, analyzed the reasons of slip and sinker of pile net composite foundation supporting embankment in the above conditions, the main reason is the flow of soil between piles around and insufficient carrying capacity, as well as internal friction angle of subgrade filling is smaller.Second, researched the treatment over piled embankment subsidence instability, used the high pressure spraying pile reinforcement, and achieved good results. Third, optimized design for the construction of PTC pipe pile net composite foundation supporting embankment in the above conditions, studied the method of the stress reducing soil between piles, studied the pretreatment method when the foundation bearing capacity is insufficient, studied and applied the construction techniques for pile-net composite foundation supporting the embankment. Finally, studied the construction process embankment supported by pile-net structure in the abutment section, analyzed its reason of shortening the construction period.