Cause Analysis And Treatment Of Lime Soil Solidified Salty Soil Foundation Expansion Under Rainfall Infiltration In Qinghai Physical Geological Database

Salty soils are widely distributed in China,and most of them,which accounting for 60%of the salty soil area in China are concentrated in the northwest.Among them,loess sulfate salty soils caused by drought are widely distributed in Qinghai.With the rapid development of the western region in recent years,various disadvantages of salty soil foundation appears incessantly,which seriously affect the normal operation of projects.Therefore,to study the engineering properties of sulfate salty soil and improve its treatment methods has a great significance.Based on the foundation expansion control project of Qinghai physical geological database,this paper firstly studies the permeability and expansion characteristics of lime-solidified sulfate salty soil through indoor permeability experiments and expansibility experiments,then simulates the influence of rainfall infiltration on the permeability and saturation of foundation soil by FLAC^2D,and finally puts forward a suitable foundation treatment method for this area through comparative analysis of the expansion mechanism.Also,some useful conclusions are acquired.1.The result of permeability experiments of solidified salty soil foundation in this area shows that the permeability coefficient of soil samples increases rapidly at first,then slowly and finally tends to be stable with the increa sing number of seepage experiments.The inflection point is the third and the sixth,the permeability coefficient and the number of experiments correspond to logarithmic function.2.With the increasing initial water content of soil sample,the permeabilit y coefficient increases slowly in the early stage,and then presents two kinds of changes.The first is that in the first three permeability experiments,the permeability coefficient decreases in the beginning,then increases and then decreases again;the second is that from the fourth experiment on,the permeability coefficient increases first and then decreases.Also,with the increase of soil sample density,soil permeability coefficient increases first,then decreases sharply,then rises again and then decreases slowly.3.The expansion rate decreases gradually as the overlying load of soil sample increases,and the change law conforms to the exponential function.The contribution of different levels of load to the inhibition of expansion rate is differe nt,and the inhibition rate is different.For different soil samples,there is an optimal inhibition load.4.Water is the external cause while calcium oxide and sodium sulfate are the internal causes in this foundation expansion,and the internal causes a ct through the external one.Calcium oxide plays a dominant role in the internal causes,while sodium sulfate plays an auxiliary role.The external cause is the direct cause,while the internal cause is the precondition,and both of them together cause the foundation expansion of the geological reservoir.For this reason,a comprehensive prevention and control thought of"three combinations,two strictness and three emphasis"was put forward,and different sub-bank applied different governance measures to control it.Finally,good governance effect was achieved.