Influence Facters Analysis On The Lime-miscellaneous Fill Pile Composite Foundation Engineering Characteristics

Lime-soil compaction piles with its simple construction, short construction period, quality guaranteed easily, and low cost are widely used in foundation treatment, and more widely used in loess, miscellaneous fill foundation,etc.. In the north of Shandong province,limestone mineral resources are relatively abundant and provides a good condition for the foundation treatment, So this thesis has introduced various factors influencing the composite foundation, as a reliable basis for the solution to the problem of the foundation treatment in the urban and rural construction in the north of Shandong province, will bring a certain economic profits and social benefits.This thesis has introduced the method of the lime-soil and foundation treatment, analyzed the problems of foundation in north of Shan Dong province; the design and calculation method of lime-soil compaction piles foundation, provides theoretical basis for parameter determination; the geotechnical constitutive model,the theory of finite element outline,the feasibility of lime-soil compaction piles in treating miscellaneous fill in the north of the Shandong province,etc.. Considering the contact between pile and soil, this thesis has used finite element analysis software ANSYS to develop Lime-Miscellaneous fill pile composite foundation dimensional model under the linear elastic-plastic Drucker-Prager yield criterion. studies have shown that: First, When the load of the primary miscellaneous filling foundation reaches 100 k Pa, the foundation will appear excessive large settlement, the maximum value of settlement is 112 mm and the maximum differential settlement is 4.4 percent,so the treatment of the former miscellaneous filling foundation is needed to meet the requirements of the project. Second, the pile diameter is suitable for 0.3m, the pile of soil compaction effect is good, sedimentation value meet the requirements and more economic. Third, the design of pile lengh of 6m is appropriate, from the aspects of bearing capacity and settlement are illustrates. Fourth, With the increase of pile spacing, pile and soil settlement increases, when the pile spacing of 0.8m, it is advisable to take the value theory of pile spacing. Fifth, the engineering characteristics of composite foundation is related to the thickness and modulus of cushion. Increase of the thickness of mattress layer can effectively relieve stress concentration phenomenon of pile head, but the mattress thickness more than 0.3m, the pile of load change decreases; Mattress layer modulus increases, the axial stress of pile increase decreases, and the appropriate size of the modulus, help to adjust the size of the stress ratio of pile-soil, but modulus is too large, lead to stress concentration phenomenon of pile head. According to the actual situation in the north of Shandong province,modulus is suitable take 45MPa~60MPa. Sixth, comparing the calculated results with the original foundation calculation result analysis, and verify the reliability of the scheme, proved that treatment effect is obvious.