Experimental Study On Soft Soil Foundation Reinforced By Deep Vacuum Preloading

Vacuum preloading as a method of soft soil consolidation,because of its low cost,large effective area and other advantages are widely used in soft soil reinforcement process,but because of its limit of effectiveness and effective depth,its promotion has been limited.Therefore Vacuum preloading need to be optimized.This paper proposed Deep Vacuum preloading as a optimized method of Vacuum preloading.Through theoretical analysis,laboratory experiments,numerical simulations to explain the reason of the Deep Vacuum preloading is better then the traditional Vacuum preloading and the concrete manifestation of the vacuum transfer and the final reinforcement effect.The main conclusions and significance of this paper are as follows:(1)Draw Deep Vacuum preloading method to achieve maximum effective stress increment to P_a(10)?_mh by analyzing the principle which is the theoretical basis of that Deep Vacuum preloading is effect then the traditional Vacuum preloading.Preliminary instructions the method of the design calculation for the Deep Vacuum preloading,to provide references for the further implementation of the methods in design and calculation.(2)From the results of laboratory experiments,initial vacuum surface moves down can improve the effect of reinforcement,embodied in the reduce of moisture content,the increase of dry density,more final Settlement quantity and settlement development rate of increase,and negative pressure in soil mass transfer efficiency is improved.Meanwhile,experiments using sand as a media of horizontal drain pipes and vertical drain board is feasible,but there is a vacuum loss.(3)By ABAQUS analysis proved that Deep Vacuum preloading is effect than the traditional Vacuum preloading.Also proved that finite element method as a computer-aided design for Deep Vacuum preloading’s design and calculation method is feasible.Can effectively guide the engineering practice.