Analysis On Shoulder Of Road Pushing Of Nankun Railway And Lab Research Of Improved Soil

Expansive soil, is formed in nature geology process and special clay distributed all over the world, while swell when possess water and shrink when loses water. It can harm to building that construct in low-surface groundsill. It's clay agglomeration is composed of montmorillonite that can strong hydrophilic and other clay minerals. It have characteristics, such as overtake concretion, many fissures, marked intenerated when drinking water and shrink when loses water. Therefore, railway bed happen shoulder of road pushing frequently. The distances Nankun railway expansive soil bed is 146 kilometer, it affected the traveling of rail strongly.The paper firstly analysis the geology environment condition of the form of expansive soil, and analysis the principle shoulder of road pushing. The cause of shoulder of road pushing of expansive soil is divde from outside factor and inside factor.The inside factors are the expansion,fissures and over-consolidation referred as 'THREE PROPERTIES". The expansion factor is composed of montmorillonite that can strong hydrophilic and other clay minerals.The outside causes is composed of sub-tropic climate of Guang-xi area and train loading, especially vibration loading of trains.The intension of soil is decreasing and expansion periodicity because of dry-wet variety.the cause is bed circle and bring shoulder of road pushing of expansive soil.Therefore, only improvement of chemical component and expansion retrained, can prevents shoulder of road pushing of expansive soil.The feasibility and advantages and disadvantages that prevent shoulder of road pushing by cement pouring is put forwards. The test expansive soil is taken from the Tiandong of Nankun railway. Firstly, the soil's physics and mechanics properties are measured .Secondly ,different mixed cement ,mixed ratio is 4%, 6%, 8%, 10%,12%,14%,16%,18 %. The sample is maintained seven days and twenty-eight days, two kinds of maintaining condition is immersion and non-immersion. Afterwards, pressure quality in no-side limited, are measured. Other physics and mechanics properties includes free expansive ratio, plastic index and liquid index. By the tests, the laws of improvement of expansive soil is known. Optimum mixing ratio is 8% from economics, technology and constructing angles analysis. The intensions of expansive soil is linearity increasing with cement mixed ratio increasing. At same time, improved expansive soil has strong waterproof effect, and restrains swelling and shrinking to-and-fro.Improved expansive soil and expansive soil are FLAC numeric simulated under the stationary pressure and dynamic loading condition. By the FLAC numeric simulation, expansive soil bed plastic area is decreasing owing to cement pouring. Especially, breakage effect of expansive soil structure is evidence by dynamic loading.