Engineering Characteristic And Post-construction Subsidence Prediction Of Soft Soil In Tianjin Binhai New Area

Because the engineering geology characteristics of soft soil in reclaimedepeirogenic Tianjin Binhai New Area is poor, which decides the region stability. Thereclamation projects aggravate land subsidence. Therefore solving the land subsidenceproblem in reclamation projects is very necessary for the prevention and control ofenvironmental geological problems. Taking the Centre Fishing Port and TextileIndustrial Zone of Tianjin Binhai New Area as the main study area, this researchcombines theoretical analysis and experimental results, the micro research and themacroscopic mechanical behavior characteristics, qualitative analysis and thequantitative statistical analysis, laboratory test and field exploration working method.In the case of lacking long-term monitoring data, revealing the rules of theconsolidation settlement foundation soil after reclamation projects provides the basisfor establishing theoretical models to predict the surface subsidence for a long time.1.Geological characters of dredger fill has been studied in recent years and theengineering geological properties of dredger fill is comprehensively affected by thematerial composition and microstructure. Because there’re many difficult factors suchas sampling and sample preparation, microstructure is indispensable but seldominvolved in the former research. Taking the dredger fill in Tianjin Binhai New Area asstudy object, the mineral composition is identified by X-ray diffraction approach, andthe microstructure is studied by scanning electronic microscope (SEM), along withquantificational analysis of the microstructure using WD-5picture processing system.And then the changing of evaluation indicators in two different reinforcementapproaches, such as the size of structure element and pore, abundance, and directionalfrequency are discussed. The conclusion can provide theory basis for evaluating theengineering geological properties of dredger fill. The conclusion indicates that afterwater drainage treatment, the porosity becomes smaller, the dispersed structuralelements of soil become agglomerated elements, displaying a variety of oblate.Simultaneously, the pores in the soil are diminished and lose balance, and directingproperty becomes indistinct. Consolidation degree of soil becomes higher. 2. Under the condition of lacking long-term monitoring data, using the numericalsimulation to simplify the calculation of soil consolidation, and realizing mass rapidcalculation of ground settlement in a large area. It can provide the basis forengineering geological zoning, making precise quantitative analysis to regionalsubsidence and settlement prediction. Through the partition of upper soil layer inCenter Fishing Port, according to the contrast of the muddy soil engineeringgeological properties in different regions and different depth,it can be concluded thatthe depth of foundation consolidation settlement deformation is limited, and thedifferent methods of consolidation scope is about8~10m. By calculating thesubsidence depth, the subsidence after vacuum preloading processing will be reducedin Center Fishing Port and mainly occur in the shallow soil layer.The pore pressure oflower layer soil is always higher for a long period, and is difficult to dissipate. That isto say, a certain super static pore pressure is usually accumulated in the foundation.