Study On The Technology Of Subgrade Treatment For Environmental Protection Highway In Wetland

As the development of traffic construction,some highway routes must pass through the wetland.Due to the low strength and large compressibility of wetland soil,the soft foundations should be reinforced to meet the driving requirements for design.Cement mixing piles are usually used to strengthen deep soft foundations in wetland.However,this method can easily lead to non-uniform stirring of pile which will cause the difference in strength of pile body and will produce too much carbon dioxide to pollute the environment caused by the extensive use of cement.In order to reduce environment pollution and improve treatment efficiency for soft foundation,a technology of subgrade treatment for environmental protection highway in wetland is proposed in this study supported by the extension project of Hetong Road.This technology uses the geotextile active material pile,which consists of boiler slag from industrial waste and a small amount of quicklime,to strengthen the deep soft foundation in wetland.To study the reinforcing principle and practicability of geotextile active material pile for strengthening the deep soft foundation in wetland,bearing mechanism of hard crust is analyzed based on the numerical simulation and laboratory test and the applicability of the bearing mechanism of hard crust for soft foundation in wetland is verified.Then the strength and deformation law of light mixed material,which consists of lime and slag,is studied by using laboratory test.In the test,the rational mix proportion between lime and slag in soft soil with different moisture content is analyzed.Also the pile sinking technology and the strengthening mechanism of geotextile active material pile to improve deep soft foundation in wetland is analyzed,and a specific construction scheme are worked out.Based on these research results,the field test of geotextile active material pile is carried out to verify the feasibility of the construction technology.By comparing with the technology of cement mixing piles,the rationality and economic efficiency of this technology is verified.This technology can produce two-thirds less carbon dioxide than the technology of cement mixing piles.It realizes the shallow ground treatment for deep soft foundations and will not damage the neighboring environment of wetland.Adopting this method in wetland will reduce project cost,accelerate project schedule and ensure traffic safety.This project provides a reference and guidance to soft foundation treatment for similar projects in wetland.