Experimental Study On The Effect Of Vacuum Combined With Preloading Preloading Method On Dredger Fill Reinforcement And Surrounding Environment Influence

There are too many people and less land in Wenzhou city,which seriously restrict the development of urban economy.It reflects the growing important of the exploitation of perfectly tidal flat resources,to re-creating a “new maritime Wenzhou” is the best hope to expand space.A large amount of dredger fill exists in Wenzhou.This type of soil has a high water content and a very low shear strength.Reinforcement is required to improve the strength of the soil.The vacuum combined surcharge preloading method is often used for the reinforcement of dredger fill by virtue of its simple construction,obvious reinforcement effect and short construction period.As the landfill continues to expand deep into the ocean,the thickness of the dredger fills deepens,and the requirements for soil reinforcement and impact on the surrounding environment are increasing.In order to fully improve the utilization efficiency of vacuum combined preloading and improve the construction process,this paper puts forward the idea of equal pressure,starting from designing the degree of vacuum and the amount of pile load,conducting indoor tests through the model barrel to explore its reinforcement effect;The effects of vacuum combined surcharge preloading method on the horizontal displacement of surrounding soil under different over pressure ratios(ratio of stack load and vacuum load)are discussed.The main contents include:(1)Taking the advantage of the indoor test vacuum degree and the controllable load capacity,the vacuum preloading and vacuum combined with the preloading control group are prepared under the conditions of equal pressure,and the stacking is started after the vacuum is applied to the stable settlement of the soil.The reinforcement effect of the dredger fill is explored.The test results show that the surface sedimentation,soil displacement and pore water pressure dissipation of the soil after loading are obviously increased.Combined with the monitoring data of water content and crossplate shear strength,the results show that it is blown for Wenzhou.The reinforcement of the fill,the vacuum combined with the preloading method is superior to the vacuum preloading method,and should be popularized and applied in the project.(2)Set three different vacuum combined surcharge preloading schemes under equal pressure conditions,through real-time monitoring of vacuum degree,soil settlement,pore pressure change,and soil moisture content and cross plate after the test Determination of shear strength,analysis of soil reinforcement effect.The test results show that the larger the pile load,the better the soil reinforcement effect,but the increase of the pile load will cause the drainage plate to bend and affect the uniformity of the soil treatment effect.The optimal pre-compression combination of this test is the vacuum degree 50kpa+ The load capacity is 30 kpa.(3)Three sets of different overload-to-vacuum combined preloading preloading tests were carried out under certain conditions of vacuum,and the reinforcement effect was explored.The horizontal displacement of the surrounding soil was monitored by the modified horizontal displacement measuring device.The test results show that the larger the overload ratio,the better the soil reinforcement effect,and the increase of the overload ratio is beneficial to reduce the horizontal displacement of the soil inward and promote the upward shift of the horizontal displacement dynamic equilibrium point.The best overload in this test group The best ratio is 0.5.