Observation And Variation Research Of Stress And Strain In The Subgrade Of The High Fill

Along with the reform and opening-up, China’s economic construction is booming andthriving. Highway career has also ushered in its golden time of rapidly development, and manyhigh fill subgrade different from the traditional ones has emerged. The subgrade stability is adecisive factor in road safety, and the settlement of subgrade is the most common disease inhighway engineering. Therefore, deeply research and analyze the reason of subgrade settlementis needed, so that to prevent subgrade settlement, the early pavement damage, the bridgeheadbump and other disease phenomenon. In order to guarantee subgrade stability, it is necessary todeeply analysis the reason of subgrade settlement, and propose the corresponding solutions.Using FLAC3D to stimulate the four factors including filling height, subgrade slope Poe rate,filling materials and foundation treatment methods which are influence the settlement of high fillsubgrade. Find out subgrade settlement law to prevent and avoid accident caused by settlement.In addition, provide technical basis for the future high fill subgrade constrction.This article takes cross-section1and2of Xinfen highway in Xingtai Hebei province asobject for observing stress and strain. The main research content is as follows:(1) Widely collect the information at home and abroad. Take the main settlement mode andreason of high fill subgrade as research object. Take around the subgrade settlement calculationtheory and stability theory to analysis high fill subgrade stress-strain condition. Put forward thepresent main treatment method towards subgrade settlement as well.(2) Sample and analysis on-site soil by the consolidation test. Compare with Tianjin localundisturbed soil and determine their density, liquid limit, plastic limit and plasticity index. Basedon the specification requirement, determine the highway subgrade packing degree of compaction.And conduct indoor shear test combining on-site soil with geogrid.(3) Conduct numerical simulation by using FLAC3D-finite difference software. This paperanalyzes four infactors including filling height, subgrade slope Poe rate, filling materials andfoundation treatment methods which affect settlement condition of high fill subgrade. It isobtained the researched section subgrade settlement changes. And put forwards the feasibletechnical operation measures to reduce subgrade settlement.(4) Take Xingfen highway as object to conduct on-site test. Monitoring early stress strainchanges to get compressed deformation and stress distribution of soil-rock layer after compactedby loads at all levels, as well as elastic-plastic state of subgrade. Monitor the settlement ofsubgrade through arranging settlement plane on the base of two selected culvert cross section. Inaddition, arrange whole section sedimentation tube to monitor uneven settlement variation of thefoundation surface. Lay earth pressure cells in the base of both sides of the culvert. Research and discuss stress changes with the filled height.