Experimental Research And Numerical Simulation Analysis Of Coastal Soft Foundation Strengthened By Deep Cement Mixing Pile

The deep cement mixing pile reinforcement technology has the advantages of wide application range,short construction time,low cost,no pollution,rapid and efficient improvement of foundation bearing capacity and control of foundation settlement.However,experimental research and theoretical analysis are far behind engineering practice,which seriously restricts the application and development of deep cement mixing pile reinforcement technology in coastal engineering.Based on the existing theory of deep cement mixing pile composite foundation,combined with reinforcement engineering on soft foundation,through indoor model test,in-situ test and numerical simulation research on engineering characteristics and engineering application.On the one hand,it provides engineering actual data and accumulated experience for similar engineering,on the other hand,it is of great significance to understand its reinforcement mechanism and to promote and apply its technology.First of all,this paper analyzed and revealed the change law of the influence of main influencing factors(cement type and label,cement incorporation,water-cement ratio,age,admixture and cement soil mixing degree)on the compressive strength and water content of cemented soil,and compare the performance of deep solidification and shallow solidification engineering.According to the experimental results,established the relational formula between compressive strength of cement-soil solids at different ages,which can be predicted;Secondly,on the basis of laboratory tests,in order to in-depth explore the influence of cement incorporation on the reinforcement effect of deep cement mixing pile composite foundation,in-situ pile test was carried out on site,by analyzing indoor test pieces and in-situ pile strength test data,the author proposed the optimal cement incorporation and puts it into construction;Thirdly,in order to verify the reinforcement effect of composite foundation consolidation under the optimal cement incorporation,the author carried out 12 groups of tests on site.according to the test results,It was found that the applicability of cement-soil solidification parameters can be further analyzed by orthogonal method.the test gave the optimal combination of parameters based on 16 orthogonal groups;Finally,the paper established a finite element calculation model based on laboratory tests and in-situ tests,which verified that it could replace the actual pile,and then The author used this model to further analyze the bearing deformation characteristics of the deep cement mixing pile composite foundation,for example,analysis of the stress field and displacement field of cement mixing piles under different pile modulus.