Study On The Treatment Of Collapsible Loess Foundation By Cement-Soil Compaction Pile

Cement-soil compaction pile composite foundation is widely used in various fields of engineering construction,especially in dealing with collapsible loess foundation,while significantly improving the reinforcement effect,the construction process is gradually simplified.In engineering practice,the final parameter for evaluating the reinforcement effect of collapsible loess foundation is the capacity of cement-soil compaction pile composite foundation.The bearing capacity is an important data guarantee for the safe and normal use of structures.This paper summarizes the application and development status of cement-soil compaction piles at home and abroad for the treatment of collapsible loess composite foundations,and explains the collapsible mechanism of foundations in collapsible loess areas and the formation mechanism,strengthening mechanism and construction method of cement-soil compaction piles,analyze and calculate the stress characteristics and eigenvalues of the composite foundation under the vertical load.Combined with the test results of the construction site of the engineering case,comprehensive theoretical calculation and finite element simulation results,the cement soil compacted piles are treated to strengthen the collapsible loess foundation.The effect is summarized as follows:(1)Through drilling and coring test,it is proved that the integrity and strength of the cement-soil compacted pile completed in the construction of this case project all meet the design requirements.(2)Field bearing capacity test results the load-settlement curve is deformed slowly,and neither the proportional limit nor the limit load are clearly reflected.The foundation does not show damage characteristics under the vertical maximum load,indicating that the bearing capacity of the composite foundation has not reached the limit state during the test.(3)The characteristic value of the bearing capacity of the single-pile composite foundation of the cement-soil compaction pile obtained by the staticload test is compared with the theoretical value.The theoretical calculated value is greater than the field test value.The theoretical value is the calculation result of the parameter taking the conservative value.(4)The result of finite element simulation calculation is slightly lower than the field static load test result,and the difference between the two is very small.In the absence of standard test conditions,design and construction may refer to numerical simulation calculations.(5)Combining theoretical calculation,on-site testing and finite element simulation results,the cemented soil compacted pile has significant pile forming quality and reinforcement effect,and the collapsibility of collapsible loess foundation is completely eliminated.