The Experiment And Numerical Research On The Reinforced With Cement Mortar Soil Mixing Pile In Flood Area

Kaifeng is located in the middle and lower reaches of the Yellow River, because of historical reasons,the thousand years old city kaifeng was several times subjected to the floods and formed the wonders ofstack city, the HuangFanOu soil representative of kaifeng is consisted of miscellaneous soil and the YellowRiver alluvial soil With the development of urban construction, this soil is more and more not suitable forthe needs of the construction of large-scale modern high-rise buildings.Pile foundation is the treatment ofeffective means for natural foundation. The strength of cement-soil piles is a good choice for foundationprocessing, but the strength of cement-soil pile exists its deficiencies.For the strength of cement-soil piles, the main factors of affecting the ultimate bearing capacity ofsingle pile include: concrete core pile body material compressive strength; The sum of side friction andinterface limit resistance between concrete piles and core of mixing pile; Cement-soil material strength;The sum of side friction and interface limit resistance of the strength of cement-soil pile.There are four kinds for the failure mode of the strength of cement-soil pile: First, concrete core pilehead was crushed. The reason for causing concrete core pile head is that the sum of side friction andinterface limit resistance between concrete piles and soil formation of the mixing pile is greater than thevertical load of concrete core pile head bear; Second, concrete core pile bottom Pierce cement-soil pile. Thereason for concrete core pile Piercing is that side friction between soil-cement mixing piles and piles ofconcrete core is less than the vertical load of concrete core pile head bear, internal and external pile thesurface contact interface is destruction; Third, The no core section of mixing pile are crushed. The reasonfor mixing pile no core section was crushed is that the cement-soil piles is too long and cement-soilstrength reducing;Finally, cement-soil pile overall pierced in the pile endpoint soil. The reason for thedamage is that cement-soil pile no core period extremely short relative, when side friction and bottomresistance of soil cement milling pile is less than the pile load, and the sum of frictional resistance andbottom resistance of no core segment is the less than the section the axial compression bearing capacity, thewhole pile body piercing the below the earth can appear.In the four failure modes, the second and third kind of damage all is due to the strength of cement-soillow. Water soil own strength low causes the strength of the soil cement milling pile P-the S curve difference is bigger. Because of the Concrete core and water soil is not strong, finally affects the strength ofcement-soil pile bearing capacity and the scope of application, so the high strength concrete core materialscan't full play. Therefore, this paper through the change of the material composition of soil water, and putsforward the strength of cement mortar cement soil stir to make up for the shortage of the strength ofcement-soil pile.This paper first researches the bearing capacity of the pile foundation characteristics, and discusses thevertical bearing capacity of the single pile certain common method. Second through the indoor cementmortar soil test, this paper analyzes the dosage of cement, chemical curing agent, sand-total dosage, quicklime dosage of cement mortar compressive strength of influence, and also through the cement mortar addedin the gravel, forming the modified cement mortar soil, the gravel mixed with the increased modifiedcement mortar compressive strength of the change rule.Through the large finite element software ABAQUS analyzing the concrete piles and core of mixingpile length to the influence of the bearing capacity of strength of mixing pile, determining the critcal ratioof the pile length of inside and outside and the optimal pile type; analyzing the cement-soil modulus effecton the bearing capacity of the strength of cement-soil piles,which is the bearing character of the strengthof the cement mortar cement soil stir;analyzing the soil stick together force effect on the bearing capacityof the strength of cement-soil piles; analyzing the distribution of stress of the strength of cement-soil pilesin the whole process of stress.With reference to the optimal pile of the finite element analysis model, the tests pile experiment forthree pillars of the pile in Kaifeng has been done. Experiment shows that the result for field test is slightlymore than the results of finite element analysis, so as to prove the validity of the finite element analysis andthe feasibility of application for the strength of mixing piles in kaifeng.