Research On Settlement Characteristics Of Unsaturated Silt And Silty Clay Subsoil Between Qingdao And Jinan Special Passenger Train

According to the study on the settlement characteristic and foundation treatment technique of unsaturated silt and silty clay subsoil between Qingdao and Jinan special passenger train, a series of tests have been carried out, such as filed plane loading test, static cone penetration test, standard penetration test, lateral pressure meter test, standard indoor consolidation test, triaxial compression test and field settlement observation. Through a series of tests the settlement characteristic of unsaturated subsoil can be generalized and the settlement pattern can be obtained. From the settlement pattern the deformation of subgrade can be pre-estimated. According to comparison analysis of the results of between the calculation and the field observation, further the calculation method put forward is available. Some results can be generalized as followings:(1) Through a series of field test, the engineering geology and basic physical and mechanic characteristic of silt and silty clay subsoil can be surveyed particularly.(2) Through indoor consolidation test and triaxial compression test, the consolidation characteristic relationship of the silt and silty clay subsoil can be analysed. On the condition of lateral confinement, the relationship of between stress and strain of silt and silty clay fits the hyperbola pattern. The relationship of between strain and time of silt fits 'S' curve pattern. The relationship of between strain and time of silty clay fits hyperbola pattern.(3) According to the stress and strain relationship of indoor consolidation test, and analysis of the mechanism of subgrade settlement, the method of calculation of the ultimate settlement is put forward. Comparison analysis of results between the field test and modified calculation methods, the modified calculation method is confirmed to be available.(4) Through field settlement observation, the settlement law under embankment load was studied. According to the field settlement data in the course of fillings the ultimate settlement can be pre-estimated.(5) Through the analysis of lots of field settlement data, the settlement characteristic of the unsaturated silt and silty clay is obtained. The settlement theory should be further studied dependent on the settlement charchateristic.