Laboratory Tests On Consolidation Behavior Of Soft Soils Under Vibration Drainage Conditions

With the rapid economy development and shortage of building land resources, many buildings have been set up in soft soil area. How to deal with the deep soft soil has been an important problem that should be solved. Basis on vibration oil recovery and combining with dynamic drainage consolidation method, vibration drainage consolidation were proposed for deal with soft soil foundation. In order to study the feasibility of vibration drainage consolidation reinforcing soft soil foundation and to improve the construction technology of vibration. There is necessary to carry out indoor test for the theory of technology is not fully mature. The main job of this paper is based on indoor test to analyze drainage consolidation properties of soft soil. The research contents are as follows:(1) Research on dynamic response of soft soil under vibration loading. A dynamic consolidation permeameter developed by ourselves can apply vibration loading on soft soil to simulate the reinforcement effect of vibration drainage consolidation method for soft soil foundation, it can apply static loading also.By the way compare the drainage consolidation drainage rate, axial strain rate in the process of two kind methods, and the physical properties change of soil before and after the test, to determine improve efficiency of vibration drainage consolidation compared to static pressure drainage consolidation. Test and analysis vibration parameters(including the vibration frequency, vibration amplitude, and the size of the confining pressure), vibration waveform, drainage and type the channel set mode and soft soil itself properties(stress history, moisture content and disturbance) to the drainage consolidation test the influence, and has a guiding significance on practical engineering applications.(2) Explain the consolidation mechanism of soft soil under vibration loading. Combined with the test result and predecessors’ studying results, we discuss the mechanism from four aspects,including Vibration wave produces potential energy differences; transformation of bound water to free water; vibration wave can improve permeability; vibration load can promote the accumulation of plastic deformation.This paper shows that the drainage consolidation method can effectively reduce themoisture content and void ratio of soft soil, and raise the shear strength of soft soil; Compared with static pressure drainage consolidation, vibration drainage consolidation method has higher drainage rate, axial strain rate and can improve drainage volume and axial strain, has obviously improved the soft soil consolidation; Vibration frequency, vibration amplitude and confining pressure have important effects on vibration drainage consolidation test. Vibration amplitude increases and the natural frequency applied close to the soft soil has better vibration drainage consolidation effect.