Effects Of Staturation On Sensitivity Of The Silt Based On Laboratory Test

The structure of soil is one of very important factors which determine soilmechanical properties.Through indoor unconfined compressive strength testand cone penetration test, the sensitivity of silt and the ratio of conepenetration was studied respectively, and from these two aspects to analyze thesoil structure changing rules when the soil was disturbance or saturationchanges. The experimental results showed that:(1) When the silt is affected by soaking are usually defined changing rulesof sensitivity with saturation,when soil saturation is at about70%,soil responseto external load is the most sensitive and sensitivity achieves maximum value,and soil strength changes obriously before and after the disturbance, and soildamage is easy under external load.(2) In the analysis of strain sensitivity of the experimental results,through test it shows the peak point of stress sensitivity to strain curverepresents cracking moment of the undisturbed soil.Before peak point,thedeformation to plastic deformation of soil is plastic and after the peak point soil gradually loses the original structure,and along with the development ofcracks, the gap of compressive capacity between undisturbed soil andremolded soil is more and more small, and the ratio of the corresponding stressdecreases and the curve declines.(3) In the analysis of stress sensitivity of the test experimental resultsgraph of the stress sensitivity to strain has no peaks, curve shows monotonousrising trend, and with the increase of pressure,the deformation rate ofundisturbed soil is greater than that of the remoulded. Therefore,the ratio of thestress sensitivity is becoming more and more large under the same stresscondition curve also objectively reflect the influence of load on soil structure.(4) From the comparison of three kinds of sensitivity analysis,it showsthat the strain sensitivity is focused on the structural strength of soil, the largerthe ratio is the greater between undisturbed soil and remolded soil intensitydifference, so the soil response is more sensitive when it is disturbed byexternal loads before and after.While stress sensitivity is focused on thedeformation ability of soil, the ratio is larger shows that under the same loads,small incremental force impacts on the deformation of undisturbed soil iscloser to the influence of the deformation of remolded soil. Usually define thesensitivity is just a single one that reflects the strength of the soil sensitivitythrough the ratio of strength between undisturbed soil and remolded soil afterdestructioned. (5) In the numerical analysis of ratio of the cone penetration, the ratio ofthe cone penetration changes from low to high as the change of saturation, theratio will be under the present trend, firstly the ratio reached minimum volve atabout70%of saturation then with the increasing of saturation,the curve showsa rising trend, and no matter how the change of saturation is,the ratio of onepenetration is less than1.(6) The ratio of cone penetration and the compared analysis of threekinds of sensitivity show that the ratio of cone penetration and usually definedsensitivity have a corresponding relationship, when the two parties are in theperformance of soil structure the graph is approximate to the axis of symmetry,and the greater sensitivity of the structural is the more obvious strength of soilis the smaller the ratio of cone penetration is, the more obvious soil structuralstrength is instead; Overall the ratio of cone penetration and the graph of themaximum strain sensitivity have a certain relation.While from every point onthe curve,when soil strain sensitivity gets maximum value,the soil is notcompletely destroyed,and the structural strength of soil has not been fullyreleased, each value of the ration of cone penetration reflects the undisturbedsoil and remolded soil resist shear failure; In the ratio of cone penetration andthe law of stress sensitivity changing with saturation, the change of eachmaximum value of stress sensitivity is not large, therefore influence fromchange of saturation is limited, while the ration of cone peneration with the increasing of saturation shows decreased first and then increased,so theinfluence of the ratio of cone penetration affected by saturation is obvious.