The Vacuum Preloading Method In The Project Of The Reclaimed Soil Soft Foundation Reinforcement Effect Research

In recent years, with the high-speed development of coastal cities, andaccelerating the pace of opening to the outside world, the coastal city of demand forland is becoming more and more urgent. And China’s long coastline and sea resourcesare very abundant. So land reclamation from the sea becomes the only way for urbandevelopment.The so-called reclaimed soil foundation, remediation and dredging inrivers and waterways when using dredgers and mud at the bottom of the harbor siltedrivers and silt deposited is formed by hydraulic fill. Engineering properties ofreclaimed soil foundation presentes three high and one low, that includes high naturalmoisture content, large void ratio, high compressibility, low shear strength andpermeability characteristics. In order to improve its engineering properties, increasethe bearing capacities of reclaimed soil, in engineering practice, it often can be treatedby vacuum preloading method in soft soil foundation. Vacuum preloading method isthe use of atmospheric pressure for preloading load of a drainage consolidationmethod, which is composed of extraction system, drainage (gas) system and sealingsystem. in the widening of old road. It can decrease the settlement of newembankment through improving the stiffness, then reduce the differential settlementbetween the new&old embankment ultimately. On the other hand, the high tensilestrength of geogrid improves the structural connection between the widened and oldembankment, as a result, ensuring sufficient integrity of them. It has short reinforcingcycle, good strengthening effect, obvious economic benefit, and is suitable forlarge-area soft foundation so in the treatment of the reclaimed soil engineering it hasbeen widely used in soft soil foundation. And therefore, for vacuum preloadingmethod in soft foundation engineering of reclaimed soil reinforcement effect, theconstruction technology of optimization design research, it has important practicalguiding significance.Firstly, the mechanism of vacuum preloading is discussed in detail, and for thecalculation based on the ABAQUS finite element constitutive model this articleismade a detailed introduction. Secondly, combined with the actual situation of fill soft foundation treatment project of Lianyungang Coastal Area, obtain measured data ofpore pressure, displacement and other related reinforcement effect settlement by fieldmeasurements. Through finite element software ABAQUS to simulate the process ofvacuum preloading, comparative analysis and study of reinforcement effect underdifferent construction conditions, draws the following conclusion:(1) In Lianyungang seaside soft foundation treatment engineering, theengineering design and technical construction method of vacuum preloading methodhas obtained the quite ideal reinforcement effect, meet the requirements of thespecification and design.(2) For vacuum preloading method, play set of plastic drainage plate spacingand the shape coefficient of the strengthening area, has great influence. With theplay set plastic drain spacing decreasing and foundation reinforcement area shapefactor increasing, there is obvious improvement in vacuum preloading reinforcementeffect. And according to the specific circumstances,and economic benefit, selectreasonable combination.(3) During the construction the seal of the reinforced area, the stability of thevacuum degree, vertical drainage channels for the vacuum preloading reinforcementeffect will have an impact. Work area sealed in place, vacuum stability, normal,smooth vertical drainage channels, these will greatly improve the efficiency ofmembrane vacuum degree of the transfer, reduce the loss of the vacuum degree, andenhance the reinforcement effect of ascension.