The Vibration Liquefaction Of Silty Soil Subgrade Test Method Of High Water Saturation Of Low Embankment

This paper under the background of the roadbed project of Xi Niu Jiao area Bing Hai highway Guangxi.this paper make a research for the liquefaction and deformation of high-lever water position lower embankment salurated silty soil roadbed mainly.At present,judgmingthe silty soil liquefaction is mainly based on the silty soildistinguished criterion of the silty soil which is under the earthquake load effect.This kind of the distinguished criterion is limited obviously.This distinguished criterionis suitable for the earthquake load effect but not for the vehicle load effect perhaps.The engineering project practice,for by soil test(such as particle analysis test)was found to have the type of soil liquefaction potential(such as saturated silty soil)is available as roadbed?As if the roadbed would liquefy happen?How to determine the liquefaction criteria?How deformation characteristics?How to advance the test?The problem has been the relationship between engineering and theory,therefore,this paper based on the principle of effective stress as liquefaction criterion,construct experimental model,experimental design and test methods for different conditions,expand the trial on the issues.The following conclusions:(1)Under traffic cyclic load effect,the similar total of loadbed stable speed is fast than similar pore water pressure.Like the change of pore water pressure can be divided into two stages:the first stage is a linear growth phase,the second phase is the phase of slow growth,"with hardening curve".Along with the groundwater depth decreases and the increase of the load,as the total stress and pore water pressure are growing like that,the underground water level is higher,the greater the vehicle load,the greater impact on the stability of roadbed;(2)In single drainage conditions,the dynamic stress of adjacent(2kPa to 4kPa,4kPa to 8kPa,8kPa to 16kPa)on the pore water pressure is found:Pore water pressure increase of buried depth of groundwater caused by the change of pore water pressure increase is far greater than the stress caused by the change of underground water level change,indicating high compared to the change of dynamic stress of subgrade and greater harm;(3)Under undrained condition,with the increase of vibration frequency(frequency of 30Hz),the dynamic stress increases to a certain extent(dynamic stress for 18kPa and 36kPa),Shallow as the total stress amplitude increases abruptly,influence on the saturated soil subgrade top immediately increased,reflecting the drainage condition,the vehicle is bigger,more serious harm to the highway subgrade(4)In the dynamic load under cyclic loading,the effective stress increase with time showed a fluctuation change,the peak of each cycle fluctuations in the effectivestress decreased gradually with time increasing,Soil liquefaction is reflected in the trend of the development of the local deformation of soil,increase,causing the settlement;(5)The model test under different buried depths,the total stress in soil is larger than that of the pore water pressure,based on Terzaghi effective stress principle,the effective stress in soil is always greater than zero,the traffic cyclic loading under saturated silty sand roadbed vibration only deformed but not liquefy.In conclusion of above analyses,in order to build the experiment method,which is about checking whether the liquefied soil will become liquefaction under the shaking condition and make the inspection purpose before engineering project.It has very important guiding significance to the actual engineering project.