On Research Of The Stability Technology Of Coarse-Grained Salty Soil Subgrade

As a kind of special soil, salty soil could perform some distinctive project characteristics because of the transference and gathering, crystallization and dissolution and the frequent interchange and repetition process of salification and desalination of the ingredient of salinity and alkali during the change of environmental condition, which could have different effects to project construction, for instance it would cause extremely harm to the construction if it was untreated or treated improperly. There are plently of salty soil and saline soft soil along the first-class highways of Jia Yu-guan to An Xi, so it's the key technical problem to be solved that how to effectively design the subgrade of saline soil road according to the special project characteristcs of salty soil so that ensure the construction quality and long-time steady during later operation.The paper work on the study of salty soil's project characteristics and stability technology of subgrade which rely on the first-class highways of Jia Yu-guan to An Xi as the experimental project. Through the basic geotechnical test, saline soil project characteristic and the related subgrade construction technologies were studied and the influencing factor and the change rule of saline soft soil foundation's special nature and the physical mechanics nature were analyzed; According to the laboratory test and the scene home position test result, the saline soft soil project characteristics were summarized, and found that the selections of vibrosinking sand-gravel compaction pile and dynamic consolidation method were the economical reasonable ground processes measures which has obtained a good result; Through the uniform design method and the thaw-freeze cycle experiment, the coarse-grained saline soil's salty bulge characteristic were deep researched from five aspects which were the soil, the water, the salt, temperature, the strength, and given the applicability index of coarse-grained salty soil embankment filling according to the fact that coarse-grained salty soil still had reduce phenomenon in the process of temperature drop; Main techniques for construction were offered through the improved experiments of filling materials for subgrade which used lime, lime and coal ash, and lime, coal ash and cement as the modifier and the study to improved the mechanical properties and long term performance; Optimal design of insulating layer and building control methods were offered according to traits of different insulating layer and construction adjustability in the saline soil subgrade. The proper type of cross section of saline soil road subgrade was put forward through further experiments and the caculation of numerical simulation in thaw-freeze cycle condition.